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신뢰성부문 2015 년도춘계학술대회논문집 일자 : 2015 년 2 월 25 일 ( 수 )~27 일 ( 금 ) 장 주 소 : 제주대학교국제교류회관 관 : 대한기계학회신뢰성부문 공동주관 : 제주대메카트로닉스공학과, 연세대무한내마모연구단, 동아대해상풍력고출력발전기핵심기술, 에너지인력양성센터, 순천대기계공학과 사단법인대한기계학회

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14:30~16:00 < 워크숍 > 소재부품명품화를위한신뢰성향상방안 ( 제 1 발표장 ) [ 좌장 : 박종원 ( 기계연 )] 시간 발표장 제 1 발표장제 2 발표장제 3 발표장홀 세션명신뢰성예측및설계 (I) 신뢰성공학및이론신뢰성시험및평가포스터 좌장백동천 ( 기계연 ) 이정률 (KAIST) 한창운 ( 전자부품연 ) 1 09:00~ 민형철 이성현 이주화 2 09:20~ 이충안 양조예 김홍윤 3 09:40~ 황정호 박성훈 정동수 4 10:00~ 정해동 김정주 정수식 10:20~10:40 포스터필수대기시간 Ⅰ 세션명신뢰성예측및설계 (II) 보건및건전성관리피로 좌장 이승표 ( 일진글로벌 ) 김종운 ( 철기연 ) 허용학 ( 표준연 ) 1 10:40~ 김희성 정준하 곽시영 2 11:00~ 유한민 이정률 조인식 3 11:20~ 성기우 박정호 Rando Tungga Dewa 4 11:40~ 백동천 하종문 김종일 점심 12:00~ 장소 : 글로벌하우스 총회 13:00~ 장소 : 대회의실 / 진행 : 김대은 ( 연세대 ) 세션명 특별강연 ( 장소 : 대회의실 ) 좌장 김대은 ( 연세대 ) 특별강연Ⅰ 13:20~ 기초사진강의 ( 초보자가사진잘찍는법 ) 최연돈상무 (SK 브로드밴드 ) 특별강연Ⅱ 13:50~ 다학제적관점의신뢰성기술동향김용수교수 ( 경기대 ) 특별강연 III 14:20~ 신기술신뢰성확보체계화정원욱부회장 (( 전 ) 현대자동차 ) 14:50~15:00 Coffee break 세션명 신뢰성예측및설계 (III) [ 특별세션 ] 기계류부품의가속수명및내환경시험 (I) - v - [ 특별세션 ] 신재생에너지기술신뢰성 (I) 좌장 변찬 ( 영남대 ) 강보식 ( 기계연 ) 한승호 ( 동아대 ) 1 15:00~ 김완구 양희선 김성안 2 15:20~ 이승표 이용범 전효근 3 15:40~ 이승표 이기천 김양균 4 16:00~ 이제성 장무성 김태영 16:20~16:40 포스터필수대기시간 Ⅱ 세션명 전자부품 [ 특별세션 ] 기계류부품의가속수명및내환경시험 (II) [ 특별세션 ] 신재생에너지기술신뢰성 (II) 좌장김경준 ( 부경대 ) 박종원 ( 기계연 ) 한승호 ( 동아대 ) 1 16:40~ 박승일강보식박성호 2 17:00~ 한창운이용범김현구 3 17:20~ 변찬이충성윤정환 4 17:40~ 황경정이주홍김학민 만찬 18:30~ 장소 : 제주퍼시픽호텔 2 층대연회장 ( 우수논문시상식거행 ) 허남수 ( 서울과기대 ) 김종성 ( 순천대 ) 김선진 ( 부경대 ) 오전 [9:00-13:00] 서응수, 서응수 구병춘, 류경하 김준원, 김태순 조정민, 김성옥 이만재, 이관섭 박태국, 김재훈 신유림, 신유림 박치용, 이성호 정한영, 이재호 이지환, 김종철 김대종, 강동훈 (22 명 ) 오후 [14:00-18:00] 최종식, 최종식 우창수, 박원희 신인선, 윤형석 주지훈, 이기천 최인영, 방유마 조인식, 윤정환 김경준, 홍경민 이우근, 김희성 김선진, 김선진 유한주, 유한주 한석윤, 나재성 (22 명 )

시간 발표장 제 1 발표장제 2 발표장제 3 발표장홀 세션명 [ 특별세션 ] 금속소재분야의신뢰성기술 재료물성 (I) 수송기계포스터 좌장박신화 (RIST) 김진원 ( 조선대 ) 최우성 ( 한전전력연 ) 심재술 ( 영남대 ) 전인수 ( 전남대 ) 신동길 ( 영남대 ) 1 09:00~ 박중철김성수김대성 2 09:20~ 김성남염영진김종운 3 09:40~ 박신화김우곤성대운 4 10:00~ 윤병준김산위장진우 10:20~10:40 포스터필수대기시간 Ⅲ 세션명 에너지플랜트및항공우주 재료물성 (II) 좌장성대운 ( 현대차 ) 김우곤 ( 원자연 ) 1 10:40~ 이상민김진원 2 11:00~ 최우성 I MADE WICAKSANA E 오전 [9:00-12:00] 신동길, 이재학 김형규, 심재술 곽재섭, 김재강 서국진, 김정석 이상봉, 전병욱 이경동, 진지원 강보식, 임현택 한태송, 장윤영 정재욱, 장성호 이관섭, 이상훈 (20 명 ) 3 11:20~ 조만식박재영 - vi -

구두발표 ( 제 1 발표장 ) 2015 년 2 월 26 일목요일 장소 : 제 1 발표장 [2 월 26 일 09:00-10:20] 신뢰성예측및설계 (I) 좌장 : 백동천 ( 기계연 ) 15RE-Th01A001 궤도고유치의기계학습을통한회전기기의 Anomaly Detection / 민형철 *, 정해동, 이승철 (UNIST), 이상 진 ( 두산중공업 ) / 1 15RE-Th01A002 오비탈성형공정의유한요소해석신뢰성검증및평가 / 이충안 *, 김헌영 ( 강원대 ), 이승표, 이왕열, 15RE-Th01A003 15RE-Th01A004 안현규 ( 일진글로벌 ) / 2 Alloy617 과 12Cr강의이종용접부의잔류응력을포함한기계적특성평가 / 황정호 *, 이주화, 김태 민 ( 성균관대 ), 박정현, 조상명 ( 부경대 ), 배동호 ( 성균관대 ) / 3 궤도이미지패턴인식을이용한회전기기의이상진단 / 정해동 *, 민형철, 이승철 (UNIST), 구재량, 배용 채 ( 한전전력연 ) / 4 [2 월 26 일 10:40-12:00] 신뢰성예측및설계 (II) 좌장 : 이승표 ( 일진글로벌 ) 15RE-Th01B001 탄소성압착기구의통계기반성능해석교정및검증에관한연구 / 김희성 *, 김동성, 최주호 ( 항공대 ) / 5 15RE-Th01B002 텍스트마이닝을이용한보증데이터분석및사례연구 / 유한민 ( 현대차 )* / 6 15RE-Th01B003 다중판별분석을이용한자동차에어컨냄새종류구분모형개발 / 성기우 *, 이태희, 유한민, 김지완, 박소윤 ( 현대차 ) / 7 15RE-Th01B004 물리적복제물을이용한기계구조물의파손예측 / 백동천 *, 배근호, 이재호, 박종원 ( 기계연 ) / 8 [2 월 26 일 12:00-13:00] 오찬장소 : 글로벌하우스 [2월 26일 13:20-14:50] 특별강연 좌장 : 김대은 ( 연세대 ) 특별강연 Ⅰ 기초사진강의 ( 초보자가사진잘찍는법 ) / 최연돈상무 (SK 브로드밴드 ) 특별강연 Ⅱ 다학제적관점의신뢰성기술동향 / 김용수교수 ( 경기대 ) 특별강연 III 신기술신뢰성확보체계화 / 정원욱부회장 (( 전 ) 현대자동차 ) [2 월 26 일 15:00-16:20] 신뢰성예측및설계 (III) 좌장 : 변찬 ( 영남대 ) 15RE-Th01C001 동특성을고려한베어링내구해석을위한접촉알고리즘의개발 / 김완구 ( 버추얼모션 )*, 배대성 ( 한양대 ), 15RE-Th01C002 이승표 ( 일진글로벌 ) / 9 통계적방법을이용한자동차용휠베어링의수명예측 / 이승표 ( 일진글로벌 ) / 10 15RE-Th01C003 회전을고려한자동차용휠베어링의피로수명예측 / 이승표 *, 안정호 ( 일진글로벌 ) / 11 15RE-Th01C004 열사이클에대한폴리머정 동특성예측모델개발 / 이제성 *, 최주호, 이성엽, 박성호 ( 항공대 ) / 12 [2 월 26 일 16:40-18:00] 전자부품좌장 : 김경준 ( 부경대 ) 15RE-Th01D001 실런트경화시간에따른염료감응형태양전지모듈의내구성최적화연구 / 박승일 *, 한창운 ( 전자부 품연 ) / 13 15RE-Th01D002 FPCB 모듈에발생하는간헐고장발생원인분석및결함측정방법설계 / 한창운 *, 이현석 ( 전자부품연 ) / 14 15RE-Th01D003 핀치오프구역을갖는롱채널모스펫의열적신뢰성평가연구 / 손창희, 변찬 * / 15-17 15RE-Th01D004 초고장력강판점용접부내구신뢰성확보위한피로강도특성연구 / 황경정 ( 현대차 ) / 18 - vii -

구두발표 ( 제 1 발표장 ) 2015 년 2 월 27 일금요일 장소 : 제 1 발표장 [2 월 27 일 09:00-10:20] 금속소재분야의신뢰성기술좌장 : 박신화 (RIST) 15RE-Fr01A001 박판소재피로시험법 / 박중철 *, 김재우, 박신화, 김종한 (RIST) / 19 15RE-Fr01A002 동적광산란기술을이용한철강소재부식가속시험방법 / 김성남 *, 이동길, 박재현 (RIST) / 20 15RE-Fr01A003 재료파손기국와분석평가방법 / 박신화 (RIST)* / 21 15RE-Fr01A004 린듀플렉스스테인리스강의기계적변형거동에대한연구 / 윤병준 (RIST)*, 최점용 (POSCO), 박경 태 ( 한밭대 ), 이호성 ( 경북대 ) / 22-23 [2 월 27 일 10:40-11:40] 에너지플랜트및항공우주좌장 : 성대운 ( 현대차 ) 15RE-Fr01B001 5MW 초임계 CO2 발전시스템개념설계 / 이상민 *, 최우성, 박명수, 송기욱, 장성호 ( 한전전력연 ) / 24 15RE-Fr01B002 화력발전소증기터빈의모델기반고장예지기법개발 / 최우성 ( 한전전력연 )*, 윤병동 ( 서울대 ) / 25 15RE-Fr01B003 장기운영항공기전기배선시스템 (EWIS) 의 QCRM에기반한신뢰성분석 / 조만식 ( 공군항공기술연 )*, 이호용, 강우현, 강성구, 서찬교 ( 공군 10 전투비행단 ), 김순길 ( 공군항공기술연 ) / 26 - viii -

구두발표 ( 제 2 발표장 ) 2015 년 2 월 26 일목요일 장소 : 제 2 발표장 [2 월 26 일 09:00-10:20] 신뢰성공학및이론좌장 : 이정률 (KAIST) 15RE-Th02A001 XFEM을이용한 3차원균열성장예측 / 이성현 *, 전인수 ( 전남대 ) / 27 15RE-Th02A002 유한요소법을이용한온간쇼트피닝잔류응력예측 / 양조예 *, 이영석 ( 중앙대 ) / 28 15RE-Th02A003 불확실성을고려한차량부품의래틀해석 / 박성훈 *, 최주호 ( 항공대 ) / 29 15RE-Th02A004 자동차용휠베어링시일의유한요소해석을위한고무물성시험법연구 / 김정주 *, 김헌영 ( 강원대 ), 김학진 ( 컨버트 ), 박중양, 박민철, 박종직 ( 일진글로벌 ) / 30 [2 월 26 일 10:40-12:00] 보건및건전성관리좌장 : 김종운 ( 철기연 ) 15RE-Th02B001 저널베어링시스템의강건한상태진단과이상상태수준예측 / 정준하 *, 전병철, 윤병동 ( 서울대 ), 15RE-Th02B002 15RE-Th02B003 김연환, 배용채 ( 한전전력연 ) / 31 Development of Laser-powered Wireless Sensing System for Structural Heath Monitoring / 최미 진 ( 전북대 ), 이정률 (KAIST)* / 32 운행중인기어의치강성추정에관한연구 / 박정호 *, 하종문, 윤병동 ( 윤병동 ), 박성호, 최주호 ( 항공 대 ) / 33 15RE-Th02B004 풍력발전기정상운행조건의정량적정의를통한선택적진동기반상태감시전략수립 / 하종문 *, 박정호, 오현석, 윤병동 ( 서울대 ) / 34 [2 월 26 일 12:00-13:00] 오찬장소 : 글로벌하우스 [2월 26일 13:20-14:50] 특별강연 좌장 : 김대은 ( 연세대 ) 특별강연 Ⅰ 기초사진강의 ( 초보자가사진잘찍는법 ) / 최연돈상무 (SK 브로드밴드 ) 특별강연 Ⅱ 다학제적관점의신뢰성기술동향 / 김용수교수 ( 경기대 ) 특별강연 III 신기술신뢰성확보체계화 / 정원욱부회장 (( 전 ) 현대자동차 ) [2 월 26 일 15:00-16:20] [ 특별세션 ] 기계류부품의가속수명및내환경시험 (I) 좌장 : 강보식 ( 기계연 ) 15RE-Th02C001 위치결정용볼스크류의가속시험에따른수명연구 / 양희선 *, 성백주 ( 기계연 ), 이병철 ( 한산리니어시스 템 ) / 35 15RE-Th02C002 발전소의유압서보액추에이터용공기배출밸브의모델링 & 시뮬레이션 / 이용범 ( 기계연 )* / 36 15RE-Th02C003 소형굴삭기용주행구동유니트의신뢰성평가에관한연구 / 이기천 *, 이용범, 최병오 ( 기계연 ) / 37 15RE-Th02C004 승강문시스템의정비데이터를이용한신뢰성분석사례 / 장무성 *, 최병오 ( 기계연 ) / 38 [2 월 26 일 16:40-18:00] [ 특별세션 ] 기계류부품의가속수명및내환경시험 (II) 좌장 : 박종원 ( 기계연 ) 15RE-Th02D001 폴리머재질의리테이너베어링수명특성분석 / 강보식 *, 이충성 ( 기계연 ), 서동수, 김성곤 ( 국방기술 품질원 ) / 39-40 15RE-Th02D002 굴삭기용기어박스의수명평가결과분석 / 이용범 *( 기계연 ), 김태석 ( 우림기계 ) / 41 15RE-Th02D003 팬터그래프용유압댐퍼의고장및수명특성분석 / 이충성 *, 백동천, 강보식 ( 기계연 ) / 42 15RE-Th02D004 플라스틱및금속사이클로이드기어드모터의신뢰성비교평가 / 이주홍 *, 김도식, 박종원 ( 기계연 ) / 43 - ix -

구두발표 ( 제 2 발표장 ) 2015 년 2 월 27 일금요일 장소 : 제 2 발표장 [2월 27일 09:00-10:20] 재료물성 (I) 좌장 : 김진원 ( 조선대 ) 15RE-Fr02A001 304스테인리스강에서단범위규칙화에따른격자변화가치수변화에미치는영향 / 김성수 *, 김영석 ( 원자연 ) / 44 15RE-Fr02A002 폴리에스터수지의기계적성질에대한탄소나노튜브와그래핀산화물의영향 / 염영진 *, 황반토 ( 울산대 ) / 45 15RE-Fr02A003 초고온가스로용 Alloy 617의크리프균열성장속도확률적평가 / 김우곤 ( 원자연 )*, 박재영, I.M.W. Ekaputra. 김선진 ( 부경대 ), 김민환 ( 원자연 ) / 46 15RE-Fr02A004 고분자전해질연료전지용가스확산층의소수성제함량이계면접합력에미치는영향 / 김산위 (KAIST)*, 정병헌, 홍보기 ( 현대차 ), 김택수 (KAIST) / 47 [2 월 27 일 10:40-11:40] 재료물성 (II) 좌장 : 김우곤 ( 원자연 ) 15RE-Fr02B001 모사시편시험을통해탄소강곡관의기계적물성치에미치는굽힘공정의영향평가 / 김진원 *, 김성훈, 최명락 ( 조선대 ) / 48 15RE-Fr02B002 Alloy 617 합금의톱니모양소성변형현상과가공경화거동 / I.M.W. Ekaputra( 부경대 )*, 김우곤 ( 원 자연 ), 박재영, 김선진 ( 부경대 ), 김민환 ( 원자연 ) / 49 15RE-Fr02B003 Modified 9Cr-1Mo 강의크리프균열성장속도의신뢰성분석 / 박재영 ( 부경대 )*, 김우곤 ( 원자연 ), I.M.W. EKAPUTRA, 김선진 ( 부경대 ), 김민환 ( 원자연 ) / 50 - x -

구두발표 ( 제 3 발표장 ) 2015 년 2 월 26 일목요일 장소 : 제 3 발표장 [2 월 26 일 09:00-10:20] 신뢰성시험및평가좌장 : 한창운 ( 전자부품연 ) 15RE-Th03A001 Ni-Base Alloy 617 과 P92 강이종용접부의미세조직및기계적특성평가 / 이주화 *, 황정호, 김태민 ( 성 균관대 ), 박정현, 조상명 ( 부경대 ), 배동호 ( 성균관대 ) / 51 15RE-Th03A002 샤프트리니어모터의신뢰성시험및평가방법 / 김홍윤 *, 윤영민, 심호근, 권영목 ( 고려대 ), 강보식, 이충성 ( 기계연 ) / 52 15RE-Th03A003 유압식변속기시험기술 / 정동수 ( 기계연 )* / 53 15RE-Th03A004 외부충격에의한타이어손상시험법개발및판정기준수립연구 / 정수식 ( 현대차 )*, 김동오 ( 금오 타이어 ), 우종선 ( 한국타이어 ) / 54 [2 월 26 일 10:40-12:00] 피로좌장 : 허용학 ( 표준연 ) 15RE-Th03B001 웹기반구조응력적용아크용접구조물피로설계툴의개발 / 곽시영 *, 박준경 ( 생기원 ) / 55 15RE-Th03B002 베어링강에대한동탄성계수측정및초음파피로신뢰성평가 / 권오철 *, 이선호, 신철수 ( 일진글로벌 ), 15RE-Th03B003 노희청, 박태현, 조인식, 박인규 ( 선문대 ) / 56 상온에서 Alloy 617 모재와용접부재의저사이클피로거동과수명예측 / Rando Tungga Dewa*, 황 정준, 김태수 ( 부경대 ), 김우곤, 김민환 ( 원자연 ), 김병탁, 김선진 ( 부경대 ) / 57 15RE-Th03B004 DIC 기법을이용한 GFRP 복합재의피로손상특성화 / 김종일 *, 허용학 ( 표준연 ), 김용환 ( 충남대 ) / 58 [2 월 26 일 12:00-13:00] 오찬장소 : 글로벌하우스 [2월 26일 13:20-14:50] 특별강연 좌장 : 김대은 ( 연세대 ) 특별강연 Ⅰ 기초사진강의 ( 초보자가사진잘찍는법 ) / 최연돈상무 (SK 브로드밴드 ) 특별강연 Ⅱ 다학제적관점의신뢰성기술동향 / 김용수교수 ( 경기대 ) 특별강연 III 신기술신뢰성확보체계화 / 정원욱부회장 (( 전 ) 현대자동차 ) [2 월 26 일 15:00-16:20] [ 특별세션 ] 신재생에너지기술신뢰성 (I) 좌장 : 한승호 ( 동아대 ) 15RE-Th03C001 소형풍력발전기용 AFPMG 의스톨영역을고려한최대출력제어에관한연구 / 김성안 *, 변상인, 조윤현 ( 동아대 ) / 59 15RE-Th03C002 직접구동형축방향자속형영구자석풍력발전기에관한연구 / 변상인, 전효근 *, 조윤현 ( 동아대 ) / 60 15RE-Th03C003 대용량풍력발전기용하이브리드다단직접구동형발전기 / 김양균 *, 김태영, 박정민, 조윤현, 한승 15RE-Th03C004 호 ( 동아대 ) / 61 대용량풍력발전기용직접구동형발전기의냉각장치 / 김태영 *, 김양균, 이명곤, 조윤현, 한승호 ( 동 아대 ) / 62 [2 월 26 일 16:40-18:00] [ 특별세션 ] 신재생에너지기술신뢰성 (II) 좌장 : 한승호 ( 동아대 ) 15RE-Th03D001 풍력발전기기어박스를위한전달오차기반스퍼기어의결함진단연구 / 박성호 *, 유자원 ( 항공대 ), 박정호, 윤병동 ( 서울대 ), 최주호 ( 항공대 ) / 63 15RE-Th03D002 라이다 (LiDAR) 측정을이용한나셀전달함수의유도 / 김현구 *, 강용혁, 윤창열 ( 에기연 ) / 64 15RE-Th03D003 바이오디젤혼합연료의정량적배기특성평가 / 윤정환 *, 염정국 ( 동아대 ) / 65 15RE-Th03D004 에멀젼연료충돌분무의거동특성에관한연구 / 김학민 *, 염정국 ( 동아대 ) / 66 - xi -

구두발표 ( 제 3 발표장 ) 2015 년 2 월 27 일금요일 장소 : 제 3 발표장 [2 월 27 일 09:00-10:20] 수송기계좌장 : 최우성 ( 한전전력연 ) 15RE-Fr03A001 3 세대휠베어링내구시험방법차이에따른내구손상도분석 / 김대성 ( 자동차부품연 )*, 이승표 ( 일 진글로벌 ), 여준철 ( 일진베어링 ) / 67 15RE-Fr03A002 철도차량필드데이터에의한고장빈도영향요인분석사례연구 / 김종운 ( 철기연 )* / 68 15RE-Fr03A003 승용차용하이드로엔진마운트열화메커니즘분석 / 성대운 *, 류용현 ( 현대차 ) / 69 15RE-Fr03A004 Inside Blowout Preventer 고압밸브의자재특성에관한연구 / 장진우 *, 배재일 ( 은광산업 ), 최정주 ( 동 아대 ) / 70 - xii -

포스터발표 ( 홀 ) 2015 년 2 월 26 일목요일 장소 : 홀 [2 월 26 일 9:00-13:00] 포스터발표 ( 오전 ) 좌장 : 허남수 ( 서울과기대 ), 김종성 ( 순천대 ), 김선진 ( 부경대 ) 15RE-Th01P001 해석을통한슬롯다이코팅의최적화된조건에관한연구 / 서응수 *, 예정우 ( 영남대 ), 황중국 ( 동아대 ), 채영석 ( 동아대 ) / 71 15RE-Th01P002 열풍건조로성능향상을위한전산유체해석 / 서응수 *, 김용식 ( 영남대 ), 황중국 ( 동아대 ), 심재술 / 72 15RE-Th01P003 국부변형률과공칭응력을사용한용접부피로수명평가 / 구병춘 ( 철기연 )* / 73 15RE-Th01P004 노화된공기구동밸브작동의신뢰성측면접근을위한프레임워크 / 류경하 *, 이태현, 이상혁, 김대환 ( 기계 연 ) / 74 15RE-Th01P005 석도원판의표면색상차이원인규명을위한특성분석 / 김준원 *, 신광수, 홍기정, 권혁대 (RISST) / 75 15RE-Th01P006 APR+ 원전가압기밀림관시료채취노즐의피로수명평가 / 김태순 *, 김성환 ( 한국수력원자력 ) / 76 15RE-Th01P007 선진사제품과비교평가를통한국산연속가변밸브리프트제어용액추에이터의내구 기능적특성고찰 15RE-Th01P008 15RE-Th01P009 / 조정민 *, 박정임, 이상훈, 김형민, 위신환 ( 자동차부품연 ) / 77 HALT장비의국산화개발을위한신뢰성평가및분석에관한연구 / 김성옥 *, 박상욱 ( 자동차부품연 ), 김 철한 (KNR 시스템 ) / 78 고Si 오스테나이트계스테인리스강의결정입도측정을위한에칭방법 / 이만재 *, 오규찬, 진현호, 김학 현 (RIST) / 79 15RE-Th01P010 도시철도차량상태기반스마트유지보수체계의단계별활동요건분석 / 이관섭 *, 김종운 ( 철기연 ) / 80 15RE-Th01P011 프로세스밸브의수명특성평가 / 박태국 *, 성백주, 장무성, 장영규, 양청광 ( 기계연 ) / 81 15RE-Th01P012 철도차량 Metal Spring 자가발전모듈적용을위한피로수명연구 / 김재훈 ( 철기연 )*, 강기원 ( 군산대 ) / 82 15RE-Th01P013 Rope type Screen Door 건전성평가 / 신유림 *, 김종성 ( 순천대 ), 김선광, 김형렬 (SKD HI-TEC) / 83 15RE-Th01P014 풍력발전기보수를위한작업대건전성평가 / 신유림 *, 김종성 ( 순천대 ), 전현익, 유태우 (KLES) / 84 15RE-Th01P015 원전장기신뢰성향상을위한원자로용기보관재확보현황 / 박치용 *, 정선미, 박상규 ( 한수원중앙 연 ) / 85 15RE-Th01P016 원전감육배관건전성평가적용기술기준고찰 / 이성호 *, 이요섭 ( 한수원중앙연 ) / 86 15RE-Th01P017 탈황슬러리이송용펌프의신뢰성평가를위한시험법연구 / 정한영 *, 김종철, 정동수 ( 기계연 ), 김인수 ( 정신기계 ) / 87 15RE-Th01P018 피스톤형수도용감압밸브신뢰성평가기법개발 / 이재호 *, 백동천, 양청광 ( 기계연 ) / 88 15RE-Th01P019 사판식피스톤펌프의밸브플레이트노치유무에따른수치해석연구 / 이지환 *, 윤종혁, 강명철, 김경 15RE-Th01P020 15RE-Th01P021 15RE-Th01P022 수 ( 건설기계부품연 ), 진정만, 전광옥 ( 에스에프하이월드 ) / 89 Two zone type의온도충격시험장비의온도안정화구간에관한연구 / 김종철 *, 정동수, 최병오, 정한 영 ( 기계연 ), 전태현 ( 한국가스공사 ) / 90 화학기상증착된탄화물의기계적특성및열충격거동 / 김대종 *, 이동희, 박지연, 이현근, 김원주 ( 원자 연 ) / 91 철도시스템의구조건전성모니터링을위한광섬유센서의장기온도특성평가 / 강동훈 ( 철기연 )*, 김헌 영, 김대현 ( 서울과기대 ) / 92 [2 월 26 일 14:00-18:00] 포스터발표 ( 오후 ) 좌장 : 심재술 ( 영남대 ), 김종성 ( 순천대 ), 김동민 ( 표준연 ) 15RE-Th01P023 단일입력-다출력기어박스의시험조건해석 / 최종식 *, 이용범, 이기천 ( 기계연 ) / 93 15RE-Th01P024 중심형그루브버터플라이밸브의수명예측 / 최종식 *, 김도식, 장무성, 전준완, 최병오 ( 기계연 ) / 94 15RE-Th01P025 고무부품피로수명예측및통합설계시스템개발 / 우창수 *, 김완두 ( 기계연 ) / 95 15RE-Th01P026 화재상황에서의신뢰성평가시화재현상을예측하기위한물성예측방법소개 / 박원희 ( 철기연 )* / 96 15RE-Th01P027 향상된신뢰성예측을위한최적중도절단시험계획 / 신인선 *, 박주영, 권대일 (UNIST) / 97 15RE-Th01P028 Fan-Out Wafer Level Package의불량매커니즘규명 / 윤형석 *, 전인수 ( 전남대 ) / 98 15RE-Th01P029 표면텍스쳐링에따른금속의마찰특성에관한연구 / 주지훈 *, 김대은 ( 연세대 ) / 99 15RE-Th01P030 인장압축시험기를이용한기계류부품의피로시험사례 / 이기천 *, 이용범, 이종직, 최병오 ( 기계연 ) / 100 - xiii -

15RE-Th01P031 15RE-Th01P032 15RE-Th01P033 이미지상관법을이용한원공결함주변부변위측정에관한연구 / 최인영 *, 강영준, 고광수, 김성종 ( 전북대 ), 유원재 ( 탄소융합기술원 ) / 101 강제대류내히트싱크형상변화를통한방열성능개선 / 방유마 ( 동아대 )*, 서재형 ( 엔티에프텍 ), 김형 진 ( 동아대 ), 이우영 ( 영창시스템 ), 강석주, 이무연 ( 동아대 ) / 102 초음파피로시험법을이용한티타늄합금의브레이징접합강도평가 / 안종기, 이동엽 ( 삼성테크윈 ), 노희 청, 박태현 ( 선문대 ), 조인식 ( 엠브로지아 )*, 이창순, 박인규 ( 선문대 ) / 103 15RE-Th01P034 에멀젼연료증발특성에관한기초연구 / 윤정환 *, 염정국 ( 동아대 ) / 104 15RE-Th01P035 해수에냉각되는폴리머히트싱크의열성능에대한수치적연구 / 니코스띠아완에벤디 *, 원문충, 김 15RE-Th01P036 경준 ( 부경대 ) / 105 비접촉식이미지상관법을이용한이종재료마찰교반용접부의파단위치측정 / 홍경민 *, 강영준, 고광 수, 최인영, 김성종 ( 전북대 ) / 106 15RE-Th01P037 마그네슘합금 AZ61 압출판재의마찰교반용접특성평가 / 이우근 *, 김정석, 임재용 ( 철기연 ) / 107 15RE-Th01P038 GENOA와 ANSYS 시뮬레이션을이용한 CFRP판의인장과굽힘특성예측및평가 / 김희성 ( 조선대 )*, 최병희, 김정호 ( 조선이공대 ), 김지훈 ( 조선대 ) / 108 15RE-Th01P039 TiO 2 첨가한 ZrO 2 /SiC 복합세라믹스의비커스경도에대한와이블통계해석 / 남기우, 김선진 ( 부경대 )*, 15RE-Th01P040 김대식 ( 하이에어코리아 ) / 109 SiC첨가한 ZrO 2 의기계적특성에대한와이블통계해석 / 남기우, 김선진 ( 부경대 )*, 김대식 ( 하이에어코 리아 ) / 110 15RE-Th01P041 퀵커넥터와퀵커플러의압력, 유량특성에관한수치해석 / 이용범, 이규석, 이기천, 유한주 ( 기계연 )* / 111 15RE-Th01P042 풍력발전기피치기어박스의시험법개발에관한연구 / 이용범, 이기천, 유한주 ( 기계연 )*, 김태석 ( 우림기계 ) / 112 15RE-Th01P043 경량전철자료를이용한시스템엔지니어링전산모델검증방안 / 한석윤 *, 김주욱 ( 철기연 ), 최요철 (LS 산 전 ) / 113 15RE-Th01P044 매트릭스의균열로인한복합재로터블레이드의강성감소예측모델링 / 나재성 *, 이창용 ( 부경대 ) / 114 - xiv -

포스터발표 ( 홀 ) 2015 년 2 월 27 일금요일 장소 : 홀 [2 월 27 일 9:00-12:00] 포스터발표좌장 : 심재술 ( 영남대 ), 전인수 ( 전남대 ), 신동길 ( 영남대 ) 15RE-Fr01P001 섬유강화복합재료의정적및동적파괴거동모사 / 손인서, 신동길 ( 영남대 )* / 115 15RE-Fr01P002 하중및온도범위에따른스핀들의수명해석 / 이재학 ( 산업기술대 )* / 116 15RE-Fr01P003 완전접촉문제의점근해석시고유치거동에관한연구 / 김형규 *, 이영호, 윤경호 ( 원자연 ) / 117 15RE-Fr01P004 온도변화에따른고온가스덕트의자연대류해석 / 이인준 ( 영남대 ), 김찬수, 홍성덕 ( 원자연 ), 홍승열, 심재 술 ( 영남대 )* / 118 15RE-Fr01P005 실험계획법에의한초음파가부가된자기연마가공의특성평가 / 진동현, 곽재섭 ( 부경대 )* / 119 15RE-Fr01P006 마이크로볼베어링의표면파손현상에관한연구 / 김재강 *, 김대은 ( 연세대 ) / 120 15RE-Fr01P007 AFM 팁마모와표면형상측정에관한연구 / 서국진 *, 김대은 ( 연세대 ) / 121 15RE-Fr01P008 복합소재대차와기존대차의곡선부성능비교 / 김정석 *, 이우근, 윤혁진 ( 철기연 ) / 122 15RE-Fr01P009 주조스테인리스강의열화평가에소형펀치시험의적용성확인 / 이상봉 *, 김진원 ( 조선대 ) / 123 15RE-Fr01P010 유한요소해석을이용한리프트의캐빈및브라켓의구조안전성평가 / 전병욱 *, 장윤정 ( 군산대 ), 최찬 15RE-Fr01P011 15RE-Fr01P012 웅 ( 자동차부품연 ), 강기원 ( 군산대 ) / 124 자연대류및유입전류에따른 FFC의열전달특성에관한연구 / 이경동 ( 경북하이브리드부품연 )*, 심재 술 ( 영남대 ), 김대현 ( 에이씨티코리아 ), 정희진 ( 경북하이브리드부품연 ) / 125 철도차량모니터링을위한진동기반형자가발전기의내구성평가 / 진지원 ( 군산대 )*, 권용규 ( 국민체육 진흥공단 ), 김재훈 ( 철기연 ), 강기원 ( 군산대 ) / 126 15RE-Fr01P013 고온강판이송용하쓰롤러의고장특성분석 / 강보식 *, 이충성, 남태연 ( 기계연 ) / 127 15RE-Fr01P014 차량용앞유리열선의잠재고장에대한고찰 / 임현택 *, 위신환 ( 자동차부품연 ), 김규로 ( 경기과학기술대 ) 15RE-Fr01P015 15RE-Fr01P016 15RE-Fr01P017 / 128 노즐용접부물성이원자력배관의파단전누설평가에미치는영향 / 한태송 *, 허남수 ( 서울과기대 ), 강 선예, 박홍선 ( 한국전력 ) / 129 내압이작용하는직관과엘보우경계면에존재하는원주방향관통균열의새로운소성영향함수 / 장윤 영 *, 한태송 ( 서울과기대 ), 정재욱 ( 성균관대 ), 허남수 ( 서울과기대 ) / 130 복합균열배관에대한응력확대계수및탄성균열열림변위예측 / 정재욱 *, 최재붕 ( 성균관대 ), 허남수 ( 서울과기대 ) / 131 15RE-Fr01P018 발전설비최적투자를위한경제성평가 / 장성호 *, 이상민 ( 전력연 ) / 132 15RE-Fr01P019 도시철도차량상태기반스마트유지보수체계의단계별활동요건분석 / 이관섭 *, 김종운 ( 철기연 ) / 133 15RE-Fr01P020 자동차용카메라모듈의잠재적고장모드분석및신뢰성검증 / 이상훈 *, 신민경, 이진식, 위신환 ( 자동 차부품연 ) / 134 - xv -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 1 KSME15RE-Th 궤도고유치의기계학습을통한회전기기의 Anomaly Detection 민형철 * 정해동 * 이승철 * 이상진 ** * UNIST, ** 두산중공업 - 1 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 2 KSME15RE-Th 오비탈성형공정의유한요소해석신뢰성검증및평가 이충안 김헌영 * 이승표 ** 이왕열 ** 안현규 **,* 강원대학교, ** 일진글로벌 Verification and Evaluation for Reliability of Finite Element Analysis of Orbital Forming Process Chung An Lee, Heon Young Kim*, Seung Pyo Lee**, Wang Weol Lee** and Hyun Gyu An**,* Department of Mechanical and Biomedical Engineering, Kangwon National University ** R&D Center, ILJIN GLOBAL Key Words: Orbital forming( 오비탈성형 ), Finite element analysis( 유한요소해석 ), Hub bearing( 허브베어링 ) Abstract: The orbital forming process involves large deformation contact with continuously changing forming load, because a peen inclined at about 5~10 is used that spins at high speed for forming. This makes it very difficult to perform FEA modeling that exactly reflects the conditions of actual process. In order to resolve the problems of orbital forming process, it is necessary to establish a 2D/3D FEA(finite element analysis) technique for predicting the occurrence of crack in inner ring. In this paper proposes an FEA modeling method for improving the reliability of orbital forming process. The orbital forming analysis was studied to predict forming performances using the explicit code finite element method. To find that an efficient analysis method for the orbital forming process, axisymmetric finite element models and 3D solid element models were solved and numerically compared. In addition, the credibility of FEA was verified by comparing the result of actual test. 초록 : 오비탈성형공정은 3 세대휠베어링의결합에사용되는점진성형기법이다. 이공정은 5~30 도정도기울어진성형핀이회전운동과직선운동을통해허브를성형하는방식으로과도한성형하중의발생을줄이고안정적인성형을유도하는기술이다. 오비탈성형공정의성형핀은고속으로회전하기때문에표면과의접촉과전달하중이지속적으로변하는대변형접촉문제이고, 또한성형시고속회전으로인한소재의떨림현상등의문제로인해성형공정에서다양한문제가발생할수있다. 오비탈성형공정의최적의조건을정립하기위해서는유한요소해석을통해공정조건과성형시발생되는다양한문제점을예측하고해결하는기술이반드시필요하다. 하지만불연속적인경계조건으로인해유한요소해석시과도한해석시간과낮은신뢰성의문제점가발생한다. 이러한문제를해결하기위해서는오비탈성형공정의유한요소해석기법을제시하고신뢰성검증을통해해석기술을보완할필요가있다. 따라서본연구에서는오비탈성형공정의유한요소해석기술향상을위해실제성형조건을반영할수있는경계조건을도출하고해석결과의신뢰성을검증하였다. 성형해석은 ABAQUS explicit code 를사용하였으며, 3 차원및축대칭해석을통해해석경계조건을분석하고신뢰성을보장할수있는새로운경계조건을제안하였다. 또한제안된해석방법의신뢰성검증및평가를위해시험결과와비교하여해석의신뢰성을검증하였다. (1) Moon, H.K., Joun, M.S., Chung, J.H. and Park, C.N., 2004, "Prediction of defect formation ring rolling by the threedimensional rigid-plastic finite element method" Trans. of the KSME(A), Vol. 28, No. 10, pp. 1492~1499. (2) Cho, H., Koo, J., Bae, W., Lim, J.,2008, "A study on orbital forming analysis of automotive hub bearing using the explicit finite element method" Trans. of the KSAE, Vol. 16, No. 1, pp. 29~36. (3) Nowak, J., Madej, L., Ziolkiewicz, S., Plewinski, A., Grosman, F., and Pietrzyk, M.,2008, "Recent development in orbital forging technology" Int Mater Form, Suppl 1, pp.387-390. (4) Jung, Y.J., Lee, C.A., Lee, W.Y., An, H.G., Lee, S.P. and Kim, H.Y, 2014, "A study on the axisymmetric Orbital forming analysis of automotive hub bearing" KSAE 2014 Annual Conference, KSAE14-A0352. (5) Lee, W.Y., Lee, C.A., An, H.G.., Lee, S.P. and Kim, H.Y., 2014, "Orbital forming analysis of automotive hub bearing using axisymmetric model" KSAE 2014 Annual Conference, KSAE-A0000. (6) Lee, C.A., Lee, S.P., An, H.G.., Lee, W.Y. and Kim, H.Y., 2014, "A Study on For Axisymmetric Analysis of Orbital Forming Process" KSME 2014 Fall Annual Meeting, 2014.11, pp. 789-790. * Corresponding author : khy@kangwon.ac.kr - 2 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 3 KSME15RE-Th Alloy617 과 12Cr 강의이종용접부의잔류응력을포함한기계적특성평가 황정호 이주화 * 김태민 * 박정현 ** 조상명 ** 배동호 *** 성균관대학교기계공학과, * 성균관대학교기계공학과, ** 부경대학교신소재시스템공학과, *** 성균관대학교기계공학부 Assessment of Mechanical Characteristics Including Welding Residual Stress of Dissimilar Weld of Alloy617 and 12Cr Steel Jeong Ho Hwang, Ju Hwa Lee*, Tae Min Kim*, Jung Hyun Park**, Sang Myung Cho** and Dong Ho Bae*** Graduate school of Mechanical Engineering, Sungkyunkwan University * Graduate School of Mechanical Engineering, Sungkyunkwan Universiy ** Graduate School of Materials System Engineering, Pukyong University *** School of Mechanical Engineering, Sungkyunkwan University Key Words: Dissimilar weld( 이종용접 ), Welding residual stress( 용접잔류응력 ), Finite Element Method( 유한요소법 ), Micro structure( 미세조직 ) Abstract: Nowadays, researches for increasing efficiency of thermal power generation have been actively conducted to solve the problems, which are derived by carbon dioxide emission, global warming, and so on. Generally it is known that the higher main steam temperature brings out the more effective power efficiency. Developed countries have been actively carried out research on the A-USC(advanced-ultra super critical) thermal power plant in raising in the main steam temperature to 700. However, to develop the A-USC thermal power generation technology raising the main steam temperature to 700, it must be secured in advance that to develop suitable materials in such extreme environments. Therefore in this paper, dissimilar welding using major candidate materials for the A-USC thermal power generation, Alloy617 and 12Cr steel was conducted and welding residual stress analysis, metallurgical microstructure analysis, mechanical properties were assessed. Based on this, it is laid emphasis on that ensuring remaining life expectation and basic datum securing for A-USC thermal power plant. 초록 : 전세계전력사용량의 60% 이상을차지하고있는화력발전으로인한이산화탄소배출, 지구온난화등의수많은문제들을해결하기위해화력발전의효율성증가를위한연구가활발히진행되고있다. 주증기의온도가 10 상승하면발전효율은 0.5% 씩증가한다고알려져있어, 유럽, 미국등일부선진국에서는주증기온도를 700 이상으로올린차세대초초임계 (advanced-ultra super critical;a-usc) 급화력발전에대한연구를활발히수행하고있다. 하지만주증기온도를 700 이상으로올린차세대초초임계화력발전기술을개발하기위해서는이러한극한환경에적합한재료를개발하고기초데이터확보를선행해야한다. 따라서, 본연구에서는차세대초초임계급소재의주요후보인 Alloy617 과 12Cr 강을대상으로이종용접을실시하였고, 용접부에대한용접잔류응력 (welding residual stress) 해석, 야금학적조직 (metallurgical microstructure) 분석, 기계적성질 (mechanical properties) 등을평가하였다. 이를바탕으로초초임계급화력발전설비설계 (generating unit design) 와잔존수명예측 (remaining life expectation) 을위한기초데이터확보에주안점을두었다. (1) Brian Vitalis., 2007, Overview of Oxy-Combustion Technology or Utility Coal-Fired Boilers, Advances in Materials Technology for Fossil Power Plants Proceedings, pp. 968~981. (2) Hong, K. D., Brydon, A., Leweke, T. and Thompson, M. C., 2004, "Interactions of the Wakes of Two Spheres Placed Side by Side," Trans. of the KSME(B), Vol. 23, No. 5, pp. 137~145. (2) Hong, K. D., Brydon, A., Leweke, T. and Thompson, M. C., 2004, "Interactions of the Wakes of Two Spheres Placed Side by Side," Trans. of the KSME(B), Vol. 23, No. 5, pp. 137~145. (3) Hoiser J. G., Tillack D. J., 1972, "Inconel alloy 617-a new high temperature alloy," Metals Eng Quart12, Vol. 15, No. 3, pp. 51~55. (4) Hosseini, H. S., Shamanian, M. and Kermanpur, A., 2011, "Characterization of microstructures and mechanical properties of Inconel 617/310 stainless steel dissimilar welds," Materials Characterization, Vol. 62, No. 4, pp. 425~431. (5) Naffakh, H., Shamanian, M. and Ashrafizadeh, F., 2008, "Dissimilar welding of AISI 310 austenitic stainless steel to nickel-based alloy Inconel 657," Journal of Materials Processing Technology, Vol. 209, No. 7, pp. 3628~3639. Jeong Ho Hwang, reflika@skku.edu - 3 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 4 KSME15RE-Th 궤도이미지패턴인식을이용한회전기기의이상진단 정해동 * 민형철 * 이승철 * 구재량 ** 배용채 ** * UNIST, ** 한전전력연 - 4 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 5 KSME15RE-Th 탄소성압착기구의통계기반성능해석교정및검증에관한연구 김희성 김동성 * 최주호 ** 한국항공대학교항공우주및기계공학과, * 한국항공대학교항공우주및기계공학과. ** 한국항공대학교항공우주및 기계공학부 A Study on the Statistical Calibration and Validation of Elasto-Plastic Computational Model Hee seong Kim, Dong seong, Kim*, Joo Ho Choi ** * Korea Aerospace University, Department of Aerospace and Mechanical Engineering ** Korea Aerospace University, Faculty of Mechanical Engineering Key Words: Uncertainty Parameter( 불확실변수 ), Statistical Calibration( 통계적교정 ), Validation( 검증 ), Abstract: Computer model is a useful tool that provides solution via physical modeling instead of expensive testing. In reality, however, it often does not agree with the experimental data owing to simplifying assumption and unknown or uncertain input parameters. In this case, calibration method is widely used to improve the accuracy of the unknown parameters of predictive model by using the actual test data. However, if the parameters are calibrated without considering uncertainties due to a limited test data, errors of test and modeling, the result can mislead to wrong conclusions. To solve this problem, a lot of studies have been published that utilized statistical method to quantify uncertainty for calibration of computer model. In this study, a Bayesian approach is proposed to calibrate the computer model in a probabilistic manner using the measured data. The computer model is focus on the process of elasto-plastic piston insertion into the housing due to the generated pressure. Finite element model is constructed to determine the resistance force in terms of displacement using the commercial code ANSYS. Experimental data are made by making quasi-static movement of piston using the UTM machine. The difference of the finite element analysis against the experiment is minimized by calibrating some unclear input parameters such as the supporting boundary condition and friction coefficient between the piston and housing. Markov Chain Monte Carlo technique is employed to estimate the parameters in the probabilistic way. Once the calibration is carried out for a baseline model, the calibrated model is applied to the analysis of new models, and the result is validated by the corresponding experiments in a probabilistic way. 초록 : 컴퓨터해석모델은물리현상을바탕으로단순화된모델을구축하여실험에들어가는시간적, 경제적비용을절감하는데쓰이는유용한도구이다. 그러나많은경우지나친단순화가정또는입력변수정보의미비나파라미터의불확실성으로인해실제데이터를완벽히반영하기가매우어렵다. 이경우예측모델의정확도를높이기위해실제시험데이터를이용하여미지의파라미터를교정하는방법이많이이용되고있다. 그러나이과정에서해석모델이나시험의오차, 제한된시험횟수등에의해발생하는불확실성을제대로반영하지않은채파라미터를단일값으로교정하여해석에활용한다면이는잘못된결론으로이어질위험이있다. 이러한문제를해결하기위해통계적기법을이용하여불확실성을정량화하고이를해석의교정에활용하는연구들이많이발표되고있다. 본연구에서는교정방법으로베이지안확률이론을이용하였으며, 그결과미지의파라미터는실제로시험한측정데이터를통해해석모델을교정하는방법을발생된압력에의해하우징에억지끼워맞춤되는피스톤을통해제시한다. 본연구에서는상용해석코드를이용하여억지끼워맞춤에대한통계기반성능해석과정을개발하였다. 그러나이해석은형상, 유한요소모델및소성거동모델의단순화로인해실제거동과차이가존재하며, 또한여러입력변수중에서마찰계수와해석을위해추가한등가영역물성에대해서사전에정확한값을알기어려운문제가있다. 이를해결하기위해피스톤의압착거동을시험하여실제모델에대한변위대저항력을측정하고이로부터얻은실제측정데이터로부터이들미지파라미터들을통계적으로추정한다. 추정된파라미터를이용하여유사모델의다른케이스에대해해석을수행하고해당케이스에대해시험수행및비교를통해해석결과를검증한다. 이렇게검증된해석은새로운모델의해석에서신뢰구간으로결과가제시되며시험으로검증되었기때문에믿고사용할수있다. 김희성, 한국항공대학교항공우주및기계공학과 E-mail : heesung1206@naver.com - 5 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 6 KSME15RE-Th 텍스트마이닝을이용한보증데이터분석및사례연구 유한민 현대자동차 The study of an analysis method for warranty data using text mining Han Min You HYUNDAI Motor Research Center Key Words: Text mining( 텍스트마이닝 ), Bigdata( 빅데이터 ), Warranty preion( 보증기간 ), Smell( 냄새 ), Fuel door( 연료도어 ), emotion topic( 감성항목 ) Abstract: Text mining, also referred to as text data mining, roughly equivalent to text analytics, refers to the process of deriving high-quality information from text. High-quality information is typically derived through the devising of patterns and trends through means such as statistical pattern learning. Text mining usually involves the process of structuring the input text (usually parsing, along with the addition of some derived linguistic features and the removal of others, and subsequent insertion into a database), deriving patterns within the structured data, and finally evaluation and interpretation of the output. Customers free repair in the A/S center if the vehicle problem within the warranty period and customer complaints and work information is stored in the Database by auto mechanic in the form of the RO (Repair Order). In this study two kinds of cases are analyzed using textmining, smell and fuel door. The first reason for using textminig, emotional topic is impossible based on part-munber like battery, lamp. The second reason for using textminig, RO data is big data so it takes a long time to read and all of data and grasp the point. Through the textmining is able to derive a meaningful results like keyword analysis and visualization, association analysis between words, failure phenomenon/cause automatic classification model, mean time to failure. In this study, it suggests that there may be a new direction fot the emotion topic. 초록 : 텍스트마이닝은빅데이터분석기법중의하나로써자연어와같이구조화되지않은비정형텍스트로부터관계데이터를추출한후텍스트에나타나는단어를형태소단위로분해하고, 통계적기법을통해추론하는방법이다. 이를통해지식매체또는언어매체를구성하는텍스트에나타나는단어를분석하여새로운지식을발견할수있다. 자동차고객은보증기간내에차량문제가발생하는경우 A/S 센터에서무상수리를하고, 정비사는고객불만및작업내용을 RO(Repair Order) 의형태로 GQMS(Global Quality Management System) 라는 DB 에저장이된다. 본연구에서는냄새및연료도어두가지사례의보증데이터특이사항내용에대해텍스트분석을수행하였다. 이를위해자동차분야고유의한글사전을구축하였고신조어, 오탈자, 복합명사, 동의어, 불용어등의작업을거쳐정교한형태소추출을실시하였다. 텍스트분석을실시한이유는첫째냄새, 소음과같은감성항목의경우램프, 배터리등과같은일반부품과달리파트넘버기준의분석이불가능했기때문이다. IQS, VDS 와같은자동차대외지수는감성항목에대한고객불만이증가하고있지만, 다양한부품과연관된문제이기때문에발생현상및원인을파악하기가어렵다. 이를해결하기위해키워드기반의분석을수행하였다. 두번째는 RO 의텍스트데이터는대용량데이터로써기존에는문제부품의특이사항을육안으로읽어서일일이확인하는작업을했기때문에많은시간이소요됐지만, 텍스트마이닝을통해정보파악을위한소요시간을감소할수있었기때문이다. 이를통해주요키워드분석및시각화, 단어사이의연관관계분석, 시점별키워드변화비교, 고장현상 / 원인자동분류모델, 고장부품수명파악등의정량적인결과를도출할수있었다. 본연구를통해서기존에분석이불가능했었던감성항목에대해새로운분석방향을제시했다는점에서의의가있다고할수있다. 후기본논문은테라데이터와공동연구로진행된내용임을알려드립니다. (1) Sholom, M, W, 2012, "Predictive Methods For Analyzing Unstructured Information", Springer-Verlag New York Inc (2) Michael, W, 2010, Text Mining Application and Theory, Willey Presenting Author, victoryyhm@hyundai.com - 6 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 7 KSME15RE-Th 다중판별분석을이용한자동차에어컨냄새종류구분모형개발성기우 이태희 유한민 김지완 박소윤 현대자동차 The Development of Classification Model for Car air conditioning smells Using Multiple Discriminant Analysis Sung, Ki Woo Lee, Tae Hee* You, Han Min* Kim, Ji Wan* Park, So Woon* HYUNDAI Motor Research Center * HYUNDAI Motor Research Center Key Words: Multiple Discriminant Analysis( 판별분석 ), Air conditioning odor( 에어컨냄새 ), Volatile organic compound( 휘발성유기합물 ), Evaporator core ( 에바코아 ) Abstract: Lately, customers think highly of the emotional satisfaction and as a result, issues on odor are matters of concern. The cases are odor of interior material and air-conditioner of vehicles. In particualar, with respect to the odor of air-conditioner, customers strongly claimed defects with provocative comments : "It smells like something rotten", "It smells like a foot odor", "It stinks like a rag." Generally, it is known that mold of evaporator core in the air-conditioning system decays and this produce VOCs which causes the odor to occur. In this paper, a predictive model to determine the kind of smell is developed. Especially the multiple discriminant analysis model was used. 초록 : 최근고객감성품질증대에따라냄새와같은항목에대한관심이크게고조되고있다. 차량용에어컨은일반가정용에어컨과는달리, 외부환경에노출되어있다. 사용조건이매우가혹하다고할수있는데, 자동차배기가스, 담배연기, 흙먼지, 황사등과사용자의사용환경인향수, 차량실내내장재냄새, 카매트냄새등이모두에어컨의 HVAC(Heating, Ventilation, and Air Conditioning) 안으로순환되어냄새의원인이된다. 주목할사항은어떠한외부환경에노출되어도, 실내에서나는냄새에대한불만고객들의표현은몇가지로한정된다는사실이다. 즉, 신냄새, 달콤한냄새, 타는냄새, 먼지냄새, 화장품냄새, 매운냄새, 배기가스냄새, 음식냄새, 땀냄새, 곰팡이냄새, 담배냄새, 쓰레기냄새, 젖은걸레냄새, 비린내, 양말냄새, 신차내부냄새, 부패한냄새등이다. 일반적으로에어컨냄새는증발기코어표면및내장재에서발생하는휘발성유기화합물 (VOCs; volatile organic compound) 의농축에의한것으로만알려져있을뿐, 그원인및유발인자가명확하게밝혀져있지않았다. 이는냄새에대한표현이매우다양하고, 차량한대의에어컨에서도십여가지의다른냄새가나기도하며, 냄새발생조건의재현이어렵다는한계때문이다. 본연구에서는에어컨냄새가발생하는차량에서포집된냄새종류를판별하는예측모델을개발하여전자코개발시활용하고자한다. 특히냄새의종류가다양함으로모형식은다중판별분석을이용하여냄새종류를분류하는모형을개발하였다. 전자코란생물학적코의냄새확인메커니즘을이용하여냄새분자를나노소자센서로감지하여냄새를측정하여객관화된데이터를제공할수있는인공적인코를말한다. (1) Robert B. Simmons, Laura J. Rose, Sidney A. Crow, Donald G. Ahearn, "The Occurrence and Persistence of Mixed Biofilms in Automobile Air Conditioning Systems", Current Microbiology, Vol. 39, pp. 141~145, 1999. (2) Tae-ung Yee, Man-Gu Kim, "Comparison and investigation on car air conditioning evaporator with and without coating", The Korean Society of Analytical Sciences, Vol. 186, pp. 1. 2008. Presenting Author, mynamu42@hyundai.com - 7 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 8 KSME15RE-Th 물리적복제물을이용한기계구조물의파손예측 백동천 * 배근호 * 이재호 * 박종원 * * 한국기계연구원 Study on Physical-Clone-Based Prognostics for Mechanical Structures Dong-Cheon Baek *, Keun-Ho Bae*, Jae-Ho Lee* and Jong-Won Park* *Korea Institute of Machinery & Materials Key Words: Physical Clone( 물리적복제물 ), Failure Prognostics( 고장예지 ), Mechanical Structure( 기계적구조물 ). Prognostic Distance( 고장예지거리 ) Abstract: Due to the inherent uncertainties caused by the manufacturing process variation, future loading conditions and damage modeling, the lifetime of the part or system used in field condition substantially different from the result in laboratories. The physical clone, newly proposed term in this paper, is a slightly weak physical structure installed in-situ and designed to produce failure earlier than target structures. So it reflects all kinds of physical loadings that target structures undergo including non-measurable physical quantities or unconcerned factors in models. The time to failure of the physical clone can be tuned by devised method to secure proper prognostic distance for maintenance or golden time to evacuation. In this paper, the physical-clone was studied and designed for failure prognostics of mechanical structure with a case study of 316L stainless steel structure under high cycle uniaxial fatigue loading. 초록 : 제조공정편차, 사용조건그리고손상모델의근본적인불확실성으로인하여실제사용환경에서작동하는제품이나시스템의수명은실험실의결과와상당한차이를보일수밖에없다. 이로인하여안전계수를도입하여과잉설계를하거나, 그렇게하였더라도설계된수명보다일찍파손이발생하여막대한인명과재산의손실이발생하는경우가있다. 최근에는설계수명이도래한대형플랜트나산업기반시설물의운용수익극대화를위해수명연장을하고자하는데, 이러한불확실성이큰위험요인중하나이다. 본논문에서새롭게제안된물리적복제물이란실제구조물보다아주약간약하게설계되는반면동일한환경에설치됨으로써대상물보다사전에고장을일으키도록고안된물리적장치이다. 따라서물리적복제물은측정불가능한물리량은물론모델에서고려하지못한요인까지포함하여대상구조물이겪는환경을그대로겪고이를반영함으로써제조공정의편자, 사용조건그리고손상모델의근본적인불확실성을상당량제거하고, 물리적복제물자체가파손이되어대상물의교체주기나참사징후를명확히사전에알려준다. 손상을직접적으로물리적복제물에누적하여사전에예지한다는측면에서. 퓨즈와같은일회성이벤트에대한안전장치와는다르며, 기존의모델기반이나데이터기반의고장예지기법을보완하거나대체할수있는새로운접근방법이다. 사례연구로써고온, 부식및피로환경에많이사용되는 316L 스테인리스강을선택하여단축피로하중을받는구조물의고장예지를위해물리적복제물을고안, 내재설계하였다. 그과정에서물리적복제물의설계시고려해야하는제약사항들과및각각에대한해결방안을도출할수있었는데, 1) 물리적구조물의파손이대상구조물의신뢰성및성능에영향을주지말아야하므로, 대상구조물과하중경로가병렬로연결됨과동시에하중영향성이 1% 미만이되도록설계를하였다. 또한 2) 부식환경등의물리적외부환경요인을반영하기위해표면이대상구조물과같은환경에노출되도록설계하였고, 3) 소재나공정편자로발생하는불확실성을제거하기위해동일 batch 소재로동시가동이될수있도록내재설계를하였다. 4) 마지막으로대상구조물보다물리적복제물이사전에파손이발생하는시점을조절하기위해기계적응력수준을조절하는해야하는데, 이를위해물리적복제물의단면적변화및구간변화를이용하였고, 표준피로시험을통하여획득한재료물성의근본적산포도고려하여이른바고장예지거리가적절히확보되도록하는기법을제시하였다. 후기본연구는국가과학기술연구회가지원하고있는 신뢰성평가기술고도화를통한중소기업기술지원 사업의일환으로진행되었습니다. Baek, Dong-Cheon, dcbaek@kimm.re.kr - 8 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 9 KSME15RE-Th 동특성을고려한베어링내구해석을위한접촉알고리즘의개발 김완구 배대성 * 이승표 ** 버추얼모션, * 한양대학교기계공학과, ** 일진글로벌기술연구소 Development of Contact Algorithm for Bearing Durability Analysis considering Dynamic Characteristics Wan Goo Kim, Dae Sung Bae* and Seung Pyo Lee** VirtualMotion *Department of Mechanical Engineering, Hanyang University **R&D Center, ILJIN Global Key Words: Bearing( 베어링 ), Durability analysis( 내구해석 ), Contact algorithm( 접촉알고리즘 ) Abstract: Rotating bearing is required excellent durability. To predict performance and durability of bearing, various studies have been conducted long time. In general, bearing durability was calculated by ISO international standards based on the empirical data under static load. It is, therefore, necessary to consider the dynamic characteristics to predict bearing life more precisely. Contact between ball and raceway is one of the important factors to take into account dynamic characteristics. This paper developed simplified contact algorithm in order to analyze the bearing with rotation to consider dynamic effects. General contact algorithm is not appropriate because it takes too much time to converge the solution. Thus, simplified contact algorithm which is based on Hertz contact theory is developed to converge quickly. It was performed in DAFUL. To verify the developed algorithm, two examples was solved. The results by developed algorithm showed the same results by general contact algorithm. 초록 : 회전하는베어링은내구성이매우중요하다. 오랜기간동안베어링을내구성능을예측하기위하여수많은노력을해오고있다. 일반적으로베어링의내구성능은 ISO 에서제시한국제표준으로부터계산할수있다. 그러나, 이는정적해석의결과이며따라서, 베어링의수명을보다정확히예측하기위하여동적특성을고려한해석이필요하다. 이때중요한것이볼과레이스웨이로이루어진궤도부의접촉해석이다. 본연구에서는베어링의동적해석을고려한해석을수행하기위하여접촉알고리즘을개발하였다. 전형적인접촉알고리즘은수렴시간이너무오래걸리기때문에베어링과같은구조물의해석에사용할수없다. 따라서, 본연구에서제안한접촉해석은 Hertz 접촉이론에근거하여수렴이빨리되도록개발하였다. 개발된접촉알고리즘은상용소프트웨어 DAFUL 에서구동할수있도록개발하였다. 개발된알고리즘의검증을위하여두개의예제에대하여적용하였다. 본연구에서제안한알고리즘의결과는기존접촉알고리즘의결과와동일한결과를보임을확인하였다. (1) Harris, T. A., and Kotzalas, M. N., 2006, Rolling Bearing Analysis: Essential Concepts of Bearing Technology, Taylor & Francis Group, LLC. (2) Seong, S. K., Kim, W. G., Bae, D. S., and Lee, S. P., 2014, Life prediction method of wheel bearings considering the dynamic characteristics, Proceedings of KSME Autumn conference, pp. 777~779. (3) Lee, J. H., Bae, D. S., Lee, S. P., Cho, Y. G., Park, J. Y., and Seong, S. K., 2014, Prediction of flange fatigue by using Structural Dynamics model of Automotive Wheel Bearing, Proceedings of KSAE Spring conference, pp. 1108 (4) Yoon, K. C., Choi, D. H., 2000, A Design of an Automotive Wheel Bearing Unit for Long Life, Trans. of the KSME(A), Vol. 24, pp. 319~328. (5) Ricci, M. C., 2009, Internal loading distribution in statically loaded ball bearings subjected to a combined radial thrust and moment load, 60 th international Astronautical Congress, ISSN 1995-6258. 김완구, wgkim@virtualmotion.co.kr - 9 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 10 KSME15RE-T 통계적방법을이용한자동차용휠베어링의수명예측 이승표 일진글로벌기술연구소 Bearing Life Prediction of Automotive Wheel Bearing using Statistical Method Seungpyo Lee R&D Center, ILJIN Global Key Words: Automotive wheel bearing( 자동차용휠베어링 ), Bearing life( 베어링수명 ), 통계적방법 (Statistical method) Abstract: Automotive wheel bearing is one of the important components in vehicle to translate rotation motion and support vehicle weight. Bearing life is affected by many parameters such as bearing geometry, bearing specification, vehicle specification, loading conditions, lubrication conditions, and material properties. Lundberg and Palmgren was proposed to basic rating life of rolling bearing in order to calculate bearing life in 1947. Recently, according to manufacturing technique has been advanced, bearing life was expected to increased. Therefore, it is necessary to predict accurate bearing life. For this purpose, ISO revised the international standard to calculate the rating life of bearing. Revised international standard was proposed to methodologies to calculate modified rating life as well as basic rating life of the bearing. In this paper, bearing life was predicted by using the statistical method. The variation of the bearing life which is based on the revised international standard in accordance with design tolerance was calculated and the results was investigated. Sampling technique is used Hammersley method that is a kind of Monte-Carlo simulation in HyperStudy. Repetition was 10,000 times. The dispersion of bearing life in accordance with design tolerance showed that relatively uniform normal distribution. Between the conventional bearing life and the average value of statistical bearing life exists a slight difference. In the future, bearing life test will be performed and will compare with the theoretical bearing life. 초록 : 자동차용휠베어링은회전을전달하고차량의무게를지탱해주는자동차의중요한부품이다. 베어링의수명은베어링형상, 베어링제원, 차량제원, 하중조건, 윤활조건, 베어링재료의물성치등고려해야할인자들이매우다양하며이들이서로복잡하게연관되어있다. 베어링의수명을계산하기위하여 1947 년 Lundberg 와 Palmgren 은구름베어링의정격수명계산을제안하였다. 최근들어생산기술이발전함에따라베어링수명이증가하게되었고이를정확히예측할수있는베어링수명계산이필요하게되었다. 이에따라서 ISO 에서는베어링의수명을계산할수있는국제표준을개정하였다. 개정된국제표준은정격수명뿐만아니라보정수명을계산할수있는방법을제안하였다. 본연구에서는통계적방법을이용하여베어링의수명을예측하였다. 즉, 국제표준에서제안하는베어링수명계산시설계공차에따른베어링수명산포를계산하고, 그결과를분석하였다. 이를위하여상용소프트웨어인 HyperStudy 를사용하였다. Sampling 방법은 Monte-Carlo Simulation 의일종인 Hammersley method 를이용하였고, 10,000 회반복수행하였다. 설계공차에따른베어링수명산포를분석한결과, 비교적고른정규분포형태를보였다. 기존의베어링수명과통계적방법에의하여구한수명의평균값간에는약간의차이가존재하였다. 향후에는베어링수명시험을수행하여그결과를이론적방법에의해구해진수명과비교할예정이다. (1) International organization for Standardization, 2007, Rolling Bearings-Dynamic Load Ratings and Rating Life, ISO281, Geneva. (2) Lundberg, G. and Palmgren, A., 1947, Dynamic Capacity of Rolling Bearings, Acta Polytechnica Mechanical Engineering Series, Vol. 1, No. 10, Stockholm, Sweden. (3) Lee, S. P., Lee, N. Y. and Lee, I. H., 2012, Bearing life calculation by using the ISO281:2007, Proceedings of KSPE Spring conference, pp. 903~904. (4) Lee, S. P., Lee, N. Y., Cha, C. Y., Lee, I. H., Lee, S. R., Kim, W. I. and Kim, T. W., 2012, Bearing Life Optimization for Automotive Wheel Bearing using Design of Experiments, Proceedings of KSME Autumn conference, pp. 281~284. Presenting author name; 이승표, e-mail address; leeseungpyo@iljin.com - 10 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 11 KSME15RE-T 회전을고려한자동차용휠베어링의피로수명예측 이승표 안정호 * 일진글로벌기술연구소, * 일진글로벌기술연구소 Fatigue Life Prediction of Automotive Wheel Bearing Considering Rotation Seungpyo Lee, Jungho An* R&D Center, ILJIN Global *R&D Center, ILJIN Global Key Words: Automotive wheel bearing( 자동차용휠베어링 ), Fatigue analysis( 피로해석 ), 베어링수명 (Bearing life), 회전체 (Rotating part) Abstract: The automotive wheel bearing is one of important components in vehicle to translate the rotating motion and support the weight. Because performance should be maintained until the end use of the vehicle, if wheel bearing are mounted on the vehicle once, fatigue property is important. It is common to perform a fatigue test to investigate the fatigue property. But, actual products and test device are required for this purpose. To save time and cost, it is necessary to numerical method to evaluate the fatigue life for automotive wheel bearing. In this paper, fatigue analysis was carried out for automotive wheel bearing. Because wheel bearing consists of several rotating parts, rotation effect was considered. Rotary bending fatigue tests which are necessary to evaluate fatigue analysis were also performed. In general, fatigue analysis can be divided into two steps, that is, stress analysis and fatigue analysis. The commercial software MSC.MARC which is based on the finite element method was used to analyze the stress and the commercial software FEMFAT was used to analyze the fatigue. From the results of this study, it was found that fatigue analysis including rotating parts should be performed fatigue analysis considering the rotation. 초록 : 자동차용휠베어링은회전을전달하고차량의무게를지지해주는자동차의중요한부품이다. 휠베어링은차량에한번장착하면차량의사용이종료될때까지그성능이유지되어야하므로특히피로특성이중요하다. 피로특성을검토하기위하여는피로시험을수행하는것이일반적이나, 이를위하여는실제제품과시험장치등이필요하다. 따라서, 시간과비용을절약하기위하여해석적으로구현하는방법이요구된다. 본연구에서는자동차용휠베어링의피로해석을수행하였다. 특히, 휠베어링은회전체로구성되어있으므로회전을고려한해석을수행하였다. 피로해석을위하여는피로물성치가필요하며, 이를위하여베어링소재에대한회전굽힘피로시험을수행하였다. 일반적으로피로해석은응력해석과피로해석의두단계로나눌수있다. 본연구에서는유한요소법에기반한상용소프트웨어인 MSC.MARC 를이용하여응력해석을수행하였고, 피로해석상용소프트웨어인 FEMFAT 을이용하여피로해석을수행하였다. 본연구의결과로부터회전체를포함한구조물의피로해석은반드시회전을고려한피로해석을수행해야함을알수있었다. (1) Lee, S. P., An, J. H., Cho, Y. G., Lee, I. H. and Kim, T. W., 2013, Fatigue Analysis for Automotive Wheel Bearing, Proceedings of the KSAE, KSAE13-B0203. (2) Lee, S. H., Lee, S. P. and Kang, K. W., 2013, Probabilistic Analysis of Fatigue Behavior of Induction Hardened Steel, Trans. of the KSME(A), Vol. 37, No. 3, pp. 429~436. (3) MSC.MARC 2012 User s Manual (4) FEMFAT 5.0e User s Manual Presenting author name; 이승표, e-mail address; leeseungpyo@iljin.com - 11 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 12 KSME15RE-T 열사이클에대한폴리머정 동특성예측모델개발 이제성 최주호 * 이성엽 ** 박성호 ** Static Dynamic mechanical properties of polymer prediction model development for thermal cycle Je Seong Lee, Joo Ho Choi*, Seong Yeop Lee**, Sung Ho Park** Department of Aerospace and Mechanical Engineering, Korea Aerospace University, 412-791, Goyang, Korea * School of Aerospace and Mechanical Engineering, Korea Aerospace University, 412-791, Goyang, Korea ** Department of Aerospace and Mechanical Engineering, Korea Aerospace University, 412-791, Goyang, Korea Key Words: Polymer( 고분자 ), Thermal Cycle( 열사이클 ), Storage Modulus( 저장탄성률 ) Abstract: Polymer materials are used in the automotive interior component such as instrument panels, body panels, handle, housing due to the merits of light weight. However, a noise so called squeak and rattle (S&R) often occur at the small gaps and preloaded interfaces of the instrument panel, when they are subjected to excessive vibration, which takes major part of field complaints. Recently, there have been many efforts to predict S&R at the design stage by constructing the FEA model consisting of the plastics and conducting FRF analysis. In the analysis, the dynamic materials property of polymers such as storage and loss moduli are necessary. What one has to look at is that the S&R are more generated in the aged vehicle than the new ones. Therefore, it is important to consider the degradation property of the polymer that undergoes thermal cycle. In the polymer degradation study, there have been many researches for dynamic properties change, but has been little to no those of for dynamic properties change for thermal cycle. In this study, develop the static, dynamic property especially elastic modulus and storage modulus prediction model for isothermal degradation. Furthermore, develop the prediction model for thermal cycle. In order to account for the scatter of the data, statistical method is used, which includes the maximum likelihood estimation and the bootstrap sampling. Then the predicted value is validated in the probabilistic sense by real data that is measured after it undergoes the corresponding cycles. 초록 : 폴리머재료는경량화의이점으로인스트러먼트판넬, 바디판넬, 핸들, 하우징같은자동차내장재부품으로많이사용되고있다. 그러나진동현상을겪고있을때스퀵래틀이라불리는소음이인스트러먼트판넬의작은갭, 또는예하중의인터페이스에서종종발생하곤한다. 그리고이것은고객컴플레인의상당수를차지하고있다. 최근에설계단계에서플라스틱유한요소모델을구성하고주파수응답해석을함으로써이러한스퀵과래틀소음발생을예측하려는노력을하고있다. 이러한분석에서는저장탄성률손실탄성률같은폴리머의동적물성이필요하다. 주목해야할것은스퀵과래틀소음이새로운차량보다노후된차량에서발생된다는것이다. 그러므로열사이클을겪는폴리머의열화물성을고려하는것이중요하다. 기존에폴리머의동적물성에대한연구는많이있지만열화를겪었을때의동적물성에대한연구는미비한실정이다. 이번연구에서는등온열화를겪었을때의폴리머의정적, 동적물성 ( 탄성계수, 저장탄성률 ) 의예측모델을개발하고나아가열사이클에대한예측모델을개발하였다. 이때데이터의산포를설명하기최대우도법, 부트스트랩샘플링방법을포함한통계적기법이사용되었다. 그리고예측된값은같은열사이클조건의실제시험데이터와비교하여검증하였다. 후기 본연구는산업통상자원부의산업원천기술개발사업 ( 과제번호 :10037360) 에의해수행되었고이에감사를표합니다 (1) Rodríguez, Olga. "Dynamic mechanical study on the thermal aging of a hydroxyl terminated polybutadiene based energetic composite." Journal of applied polymer science 87.14 (2003): 2397-2405. (2) Review of accelerated ageing methods and lifetime prediction techniques for polymeric materials. National Physical Laboratory, 2005 Je Seong Lee, ljs7@kau.ac.kr - 12 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 13 KSME15RE-T 실런트경화시간에따른염료감응형태양전지모듈의내구성최적화연구 박승일 * 한창운 ** * 전자부품연구원 Study on Dye-sensitized Solar Cell Module Durability Optimization with Sealant Curing Time Seungil Park * and Changwoon Han* * Korea Electronics Technology Institute Key Words: Dye-sensitized Solar Cell( 염료감응태양전지 ), Electrolyte( 전해질 ), Sealant( 실런트 ), Shadow moiré( 그림자모아레법 ) Abstract: Dye sensitized solar cell (DSC) modules are vulnerable in high temperature conditions. The expansion of liquid electrolyte in the module is one of the most determinant factors of the degradation; the expansion of electrolyte induces the breakage of sealant material of DSC module in high temperature. This study optimizes the durability of the DSC module with the curing time of sealants used in dye-sensitized solar cell. Sealant samples are prepared with several curing times. Shadow moiré technique is used to measure the coefficient of thermal expansion of the samples. The durability of the sealant with DSC module is optimized by stress analysis with a commercial FEA package. The test results show that samples with a longer curing time improve the durability of the DSC module. 초록 : 염료감응형태양전지 (Dye-sensitized solar cell) 는고온조건에서모듈의내구성이취약하다. 고온조건에서모듈내액체전해질의팽창으로모듈유리를봉합시켜주는실런트 (sealant) 파괴로인한전해질누출이내구성취약의큰원인으로알려져있다. 본연구에서는염료감응형태양전지에사용되는실런트의경화시간에따라모듈의내구성을최적화한다. 경화시간에따라샘플을제작하고, 그림자모아레 (shadow moiré) 법장비를이용하여실런트의열팽창계수를측정한다. 유한요소법을이용하여염료감응형태양전지모듈의내구성을최적화한다. 실험결과는실런트를오랜시간경화하였을때, 염료감응형태양전지모듈의내구성이향상됨을보인다. 후기 본연구는지식경제부에너지기술평가원의지원으로수행되었습니다. Park Seungil, heasa03@keti.re.kr - 13 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 14 KSME15RE-T FPCB 모듈에발생하는간헐고장발생원인분석및결함측정방법설계 한창운 * 이현석 * * 전자부품연구원 Mechanism Analysis and Detection Method Design for Intermittent Failure in Flexible Printed Circuit Board Assembly Changwoon Han * and Hyeonseok Lee * * Korea Electronics Technology Institute Key Words: Intermittent Failure( 간헐고장 ), FPCB( 유연전자회뢰기판 ), No-Fault-Found( 노폴트파운드 ) Abstract: If a failure of a function is reported for a limited period of time and subsequent recovery of the function in a product, it s called intermittent failure. The intermittent failure is one of the causes of so called no-fault-found (NFF). It was reported that connecting areas are one of the most detrimental source for the intermittent failure of electronic devices in vibration environment. In this study, intermittent failure is investigated at flexible printed circuit board (FPCB) assembly. First, it is shown that thermal cycling loading could induce intermittent failure in FPCB assembly. Next, to understand how intermittent failures are generated, stress and failure analysis are conducted and reveals a mechanism for the intermittent failure in FPCB assembly. After testing in several random vibration and thermal loading conditions in real-time monitoring, intermittent failure detecting method is finally designed and optimized for the FPCB assembly. 초록 : 간헐고장이란고장이일시적으로발생하였다가일정시간후나환경이바뀐후에는다시사라져정상상태로복원하는형태의고장을의미한다. 간헐고장은일반적으로원인불명으로처리되는 NFF(No- Fault-Found) 현상의원인중하나이다. 기존연구에서전자부품의경우전자부품의연결부위에서주로간헐고장이발생한다고알려져있다. 본연구에서는 FPCB(Flexible Printed Circuit Board) 모듈에발생하는간헐고장에대해서연구한다. 먼저, 반복적온도사이클하중이 FPCB 모듈에가해질때 FPCB 모듈에간헐고장이발생할수있음을실험으로보인다. 다음으로, 간헐고장의발생원인을밝혀내기위하여간헐고장이발생한 FPCB 모듈에대해고장분석을수행하여결함위치를밝히고응력해석을통해간헐고장의발생메커니즘을추정한다. 마지막으로진동환경과온도환경하에서간헐결함측정장치를이용하여실시간으로간헐결함이측정가능함을보이고시험결과를바탕으로간헐결함측정조건을최적화한다. 후기 본연구는대한민국공군항공기술연구소의지원으로수행되었습니다. (1) Qi, H. et al., "No-fault-found and intermittent failures in electronic products," Microelectronics Reliability, vol. 48, pp. 663-674, 2008. (2) Sorensen, B. A. et al., "An analyzer for detecting intermittent faults in electronic devices," IEEE AUTOTESTCON Systems Readiness Technology Conference, pp. 417-421, 1994. Changwoon Han, cw_han@keti.re.kr C 2014 The Korean Society of Mechanical Engineers - 14 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 15-17 KSME15R 핀치오프구역을갖는롱채널모스펫의열적신뢰성평가연구 손창희 * 변찬 * Thermal reliability of long channel MOSFET devices with pinch-off region Chang Hee Son * Chan Byon * Key Words: MOSFET ( 모스펫 ), Thermal reliability ( 열적신뢰성 ) Abstract A compact electro-thermal model is proposed to predict the temperature profile of MOSFET devices. For simplicity, the heat generation region is divided into the channel region and the pinch-off region, and each region is under a uniform heat generation assumption. A series solution for temperature profile of MOSFET devices is obtained by solving a heat conduction equation with the heat generation model and boundary conditions with effective heat transfer coefficient. Based on the model, the location of the highest temperature point is about center of the pinch-off region near drain side. 1. Introduction Lots of research works have been conducted to increase the performance, to reduce the size, and to investigate the electrical characteristics of MOSFET devices. However, research for thermal characteristics of MOSFET devices is relatively small comparing with other kinds of researches. As Moore (1) mentioned, the number of transistors in a chip is exponentially increasing continuously. As a result, the heat generation density of the chip is also increasing, even though the space for cooling is decreasing. It necessarily causes the temperature increase of a chip and components in the chip including MOSFET devices. The high temperature reduces the performance of MOSFET devices by changing operating characteristics of the MOSFET devices. Furthermore, the lifespan of MOSFET devices also decreases under the high temperature condition. Therefore, it is important to investigate the thermal characteristics of MOSFET devices, particularly, the temperature of MOSFET devices. A hot spot is the most severe location that can cause thermal failure because the temperature peaks at the point. Even though, the average temperature in a device is acceptable, the peak temperature at the hot spot can be higher than a limit of a component. Then, thermal 교신저자 (corresponding author) E-mail : cbyon@ynu.ac.kr TEL : (053)810-2452 FAX : (053)810-4627 * 영남대학교기계공학부 failure occurs at the point. Because of that, cooling devices are generally over-designed with lack of the information of the peak temperature. Therefore, to predict the temperature distribution is very important for thermal design of various devices. Many researchers proposed models to describe the temperature distribution in MOSFET devices and some of them are compared with experimental data (2-6). These works employ full set of transport equations either continuum or Boltzmann transport eq. to obtain rigorous solutions, and require a large computational efforts. There are continuous researches to reduce the calculation time (7-8). In this paper, a compact, analytical electrothermal model for a long-channel MOSFET device is introduced for the first time to consider the nonuniformity of heat generation as a first step of compact modeling to predict the hot spot on the MOSFET device. 2. Analytic model 2.1. Model for heat generation: Consider an n-channel MOSFET with gate length L which is for long-channel devices, gate width W, and SiO 2 gate oxide thickness t ox with steady-state and saturation region operation. In the saturation region, the electric current I sat can be written as I sat (W 2L c )( 0 ox t ox )(V G V T ) 2 (1) where L c is the channel length, μ is the electron mobility, ε 0 is the vacuum permittivity, ε ox is the dielectric constant of the gate oxide, V G is the gate voltage, and V T is the - 15 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 15-17 KSME15R threshold voltage. In Eq. (1), μ and L c have to be estimated to describe I sat. For the electron mobility, many expressions were proposed before. In this study, the expression of Arora et al. (9) when the electric field E is smaller than 10 6 V/m, and of Caughey and Thomas (10) for the higher than 10 6 V/m electric field case is used as in the research of Lai and Majumdar (4) and of Fushinobu et al. (8). The channel length, L c, is generally considered same as the gate length L in the long channel MOSFETs. It is based on an approximation that the channel length modulation by pinch-off is so small to be negligible. However, the heat generation characteristics in the channel region and in the pinch-off region are very different. Therefore, the channel length L c and the length of pinch-off region, ΔL c, have to be evaluated, even though the model in this study is for long channel MOSFETs. The length of pinch-off region is conceptually same as the thickness of the horizontal depletion-layer on the surface of the substrate near the drain side. Therefore, ΔL c is expressed as follows (11) L c (2 Si 0 qn A )(V bi s V D ) (2) where ε Si is dielectric constant of bulk silicon, q is electron charge, N A is the number density of acceptor in p-type substrate, V bi is the built-in voltage of the junction near the drain side, and ψ s is the surface potential. Then, the channel length is expressed as follows L c L L c (3) As introduced before, the heat generation characteristics in channel and in pinch-off region are very different. Therefore, in this study, the channel and the pinch-off region are considered as two different thin electric resistance heaters. The length of channel becomes shorter by increasing the drain voltage, and the electric potential at the drain side channel edge is the saturation voltage V D,sat. Then, the heat generation rate of each resistance can be evaluated. With an assumption that the heat generation rate of each resistance is uniform, the heat generation of each region is evaluated as follows. In this study, the source voltage is zero for simplicity. q c I sat V D,sat (L c W ) X 1 x X 2 (channel) (4a) q p I sat (V D V D,sat ) ( L c W )X 2 x X 3 (pinch-off region) (4b) Figure 1 shows the heat generation model for a long channel MOSFET. MOSFET, consider a simple 2-dimensional heat conduction problem by considering W as a unit length. Then, a heat conduction equation has to be solved with several boundary conditions. With the assumption of constant thermal conductivity of silicon substrate and steady state operation of the MOSFET, the equation that has to be solved is as follows. 2 T x 2 2 T y 2 0 (5) where the boundary conditions are: constant heat transfer coefficients h x,eff at x=0, x=x and h y,eff at y=0; constant heat flux q (x) at y=y where q (x) is given in Eq. (4) at the channel and zero at rest of the boundary (0 x < X 1, X 3 < x X.) The value of h eff is evaluated by using the thermal resistance concept as follows (12). R th 1(h eff A) (6) The R th is the thermal resistance between a boundary of calculation region and the ambient air. The R th should include all thermal resistances outside of the calculation region including conduction resistance, spreading resistance, contact resistance, thermal resistance of cooling devices and so on. The solution of the Eq. (5) can be obtained by separation of variables. T T T 0 y k C n k n cos h n x sin n x n cosh n 1 eff,x h n y sinh n y eff,y (7) In Eq. (7) T 0 is the zero-order term of the Fourier series which represents for the average temperature which is a function of y and C n s are Fourier coefficients. y q c (X 2 X 1 ) q p (X 3 X 2 )} X ](1 h eff,y y k) (8) T 0 [{ (9) C n (A 1 A 2 ) k n (k h eff,y )sinh n Y cosh n Y where q c k n (sin n h n X 2 sin n X 1 ) (cos n X 2 cos n X 1 ) eff,x A 1 ( X 2){(k n h eff,x ) 2 1} (10) q p k n sin n h n X 3 sin n X 2 cos n X 3 cos n X 2 eff,x A 2 (X 2)[(k n h eff,x ) 2 1] (11) The eigenvalue λ n is the n-th positive root of the following transcendental equation. (k 2 2 2 n h eff,x 1)sin n X 2(k n h eff,x )cos n X (12) The Eq. (12) is not easy to solve. However, in the Fig.1 Heat generation model 2.2. Model for temperature distribution: In order to find the temperature distribution in a case of that k/h eff,x 0.1 and k/h eff,x 10, the value of λ n approaches to nπ/x. When k/h eff,x = 0.1 and k/h eff,x = 10, the difference between the exact solution of the Eq. (12) and nπ/x is about 5%. However, in the most cases, h eff,x is smaller than k by several orders because there is thick isolation oxides near the side boundaries generally. - 16 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 15-17 KSME15R 3 Because of that, the adiabatic side boundary condition is widely used in most researches. Therefore, it is acceptable to consider λ n as nπ/x. 3. Validation Figure 2 shows results of comparison between results from the proposed model and existing data of other researches (4-5). Ostermeir et al. (5) experimentally measured temperatures of several points on the surface of Si-MOSFETs by micro Raman spectroscopy. The experimental conditions used in Ref (5) are used in the proposed model in this research as the input data for the comparison. The parameters not given in Ref (5) are temporarily given in this research in acceptable values as X = 8 μm, h eff,x = 0.1 W/m 2 K, and h eff,y = 2.8 10 7 W/m 2 K. Lai and Majumdar (4) conducted numerical simulations to investigate the temperature profile of MOSFET devices based on a hydrodynamic model. The research (4) is for sub-micrometer devices, however, the researchers showed the temperature profile in a non-dimensional form for comparison with the experimental data in Ref (5). Therefore, the non-dimensional result is converted into a dimensional form for the comparison. Fig. 2 Comparison between proposed model and existing results 4. Conclusion In this study, a compact electro-thermal model for MOSFET devices is proposed to reduce the calculation time for prediction of temperature profile in the MOSFET devices. To propose the model, several assumptions were used. One of them is an assumption that the heat generation region can be separated to the channel region and the pinch-off region, and the regions are very thin. Based on those assumptions, the heat generation characteristics is very simplified and it made the expression of the temperature profile very compact. Even though, the model is very simple, the characteristics of the temperature profile are described well. The asymmetric profile and the existence of a hot spot are well-shown in the model which well-matched with the existing experimental results. However, this model is limited for long channel MOSFET devices because of the assumptions. The limit has to be tackled by further research. Reference: (1) Moore, Electronics 38-8(1965) 114 (2) Pop et al, Proc IEEE, 94-8(2006) 1587 (3) Narumanchi et al, Heat Mass Transfer 42(2006) 478 (4) Lai and Majumdar, J. Appl. Phys. 79-9(1996) 7353. (5) Ostermeir et al, IEEE Trans Electron Devices 39-4(1992) 858 (6) Lai et al, IEEE Trans Electron Device Letter 312(1995) 312 (7) Hatakeyama et al, J. Thermal Sci & Technol 1-2(2006) 101 (8) Fushinobu et al, Proc ITherm 2010, (2010) No. 008 (9) Arora et al, IEEE Trans Electron Devices, 29-2(1982) 292 (10) Caughey and Thomas, Proc IEEE 55(1967) 2192 (11) Sze, Physics of semiconductor devices 2 nd ed, Wiley, (1981) (12) Incropera and DeWitt, Fundamentals of Heat and Mass Transfer, 6 th ed., Wiley, (2005) As shown in Figure 2, the proposed model is wellmatched with experimental and numerical results of other researches. Because the experimental data are scattered too much, it cannot be known where is the location of the highest temperature point based on the experimental results. However, the general trend and the asymmetric behavior of the temperature profile are very similar between the experimental data and proposed model. The location of the peak temperature point is about the center of the pinch-off region near the drain side. The location and the value of peak temperature based on the proposed model are very close to the numerical results, even though the proposed model is very compact. - 17 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 18 KSME15RE-T 초고장력강판점용접부내구신뢰성확보위한피로강도특성연구 황경정 * * 현대자동차 - 18 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 19 KSME15RE-F 박판소재피로시험법 박중철 * 김재우 * 박신화 * 김종한 * * 포항산업과학연구원 Fatigue Testing Method for the Sheet Material Joong-Cheul Park *, 2 nd Jae-Woo Kim *, 3 rd Shin-Wha Park *, 4 th Jong-Han Kim * * Research Institute of Industrial Science and Technology(RIST) Key Words: Fatigue( 피로 ), Sheet material( 박판소재 ), Low cycle fatigue( 저주기피로 ), Buckling( 좌굴 ) Abstract: This study was performed to establish Reliability Standard(RS) for the method of axial strain-controlled fatigue testing(low cycle fatigue testing) on the sheet metallic materials great than thickness of 0.3 mm. Generally strain-controlled fatigue testing for the sheet material is impossible because of its buckling. Therefore, the ISO and ASTM standards, etc. present the fatigue testing method using the anti-buckling jig. But the limit of thickness that can be tested is about 1.0 mm according to our experience. In this study, we introduced the method of strain-controlled fatigue testing using a special designed anti-buckling jig to prevent buckling for the sheet materials having a thickness of 0.3 mm. 초록 : 본연구는두께 0.3t 이상의금속박판소재에대한축방향변형제어피로시험 ( 저주기피로시험 ) 방법에대한신뢰성평가기준제정사업으로수행한연구이다. 일반적으로박판소재에대한변형제어피로시험은좌굴현상때문에판재상태그대로는시험이불가능하여 ISO 와 ASTM 기준에서는좌굴방지용지그 (Anti-buckling jig) 를이용한피로시험방법이제안되고있으나, 두께 0.3t 정도의박판은기준에서제안된지그로는실험이불가능하다. 본연구에서는두께 0.3t 의박판에대한변형제어피로시험이가능하도록하는특별한좌굴방지용지그를포함하는피로시험방법에대해소개하였다. 본연구는하이브리드및전기자동차의구동모터에적용되는전기강판소재의저주기피로시험을위해시작하였다. 현재생산되는전기강판소재는두께는약 0.3t ~ 0.5t 정도이다. 최근자동차구동모터의내구수명해석을위해이러한박판소재에대한저주기피로시험요구가증가되고있는실정이다. 해석에필요한저주기피로물성으로는반복항복강도 (cyclic yield strength), 단일 / 반복변형경화지수 (monotonic/ cyclic strain hardening exponent), 단일 / 반복강도계수 (monotonic/cyclic strength coefficient), 피로강도계수 / 지수 (fatigue strength coefficient/exponent), 피로연성계수 / 지수 (fatigue ductility coefficient/exponent) 등이다. 저주기피로시험은응력비 (R)=-1 조건이어야함으로압축시좌굴을방지할수있어야한다. 일반적인벌크소재는 ASTM, KS 및 ISO 규격에서제안된표준시험편으로가공하면원하는저주기피로시험을할수있다. 그러나판재일경우에는좌굴방지용지그를사용하더라도시험가능한두께는시험장비의얼라인먼트 ( 정렬 ) 가최상인상태임에도경험적으로 1.0t~1.5t 정도의두께이다. 본연구에서는두께 0.3t 인박판소재에대해저주기피로시험이가능한방법과그결과에대해소개하고자한다. 본연구로자동차등에적용되는박판소재에대한피로시험이가능하고, 설계시수명예측을위한피로과련소재물성 DB 확보가가능하다. 그리고본연구결과는 2013 년소재부품신뢰성평가기반구축사업 ( 기초금속소재분야 ) 신뢰성심의위원회의심의를거쳐신뢰성평가기준인 "R-RIST-2013-001 : 박판소재축방향변형제어피로시험방법 " 이제정되었다. 후기 본연구는소재 부품신뢰성평가기반구축사업 ( 기초금속소재분야 ) 의일환인신뢰성평가기준제정사업으로수행된것입니다. 관계자여러분께감사드립니다. (1) ASTM D 695, 2010, "Standard Practice for Compressive Properties of Rigid Plastics" (2) ASTM D 3846, 2008, "Standard Practice for In-Plane Shear Strength of Reinforced Plastics" (3) ASTM E 606, 2004, "Standard Practice for Strain-Controlled Fatigue Testing" (4) ASTM E 1012, 2014, "Standard Practice for Verification of Test Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application" Joong-Cheul Park, ltpark@rist.re.kr - 19 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 20 KSME15RE-F 동적광산란기술을이용한철강소재부식가속시험방법 김성남 * 이동길 * 박재현 * * RIST - 20 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 21 KSME15RE-F 재료파손기국와분석평가방법 박신화 * * RIST - 21 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 22-23 KSME15R 린듀플렉스스테인리스강의기계적변형거동에대한연구 윤병준 1 최점용 2 박경태 3 이호성 4* 1 포항산업과학연구원분석평가센터 2 POSCO 기술연구원 STS 연구그룹 3 한밭대학교신소재공학부 4 경북대학교신소재공학부 Investigation for Mechanical Deformation Behavior of lean duplex stainless Steel. Byung-Jun Yoon 1, Jeom-Yong Choi 2, Kyung-Tae Park 3, and Ho-Seong Lee 4 1 Analysis and Assessment Dept., Research Institute of Industrial Science and Technology, Korea 2 Stainless Steel Research Group, POSCO Technical Research Lab., Pohang 790-785, Korea 3 Division of Advanced Materials Science and Engineering, Hanvat National University, Daejon 305-719, Korea 4 School of Materials Science and Engineering, Kyungpook National University, Daegu 702-701, Korea Key Words: Duplex Stainless Steel( 듀플렉스스테인리스강 ), Strain rate( 변형율속도 ), Phase Transformation( 상변태 ), Deformation Behavior( 변형거동 ). Abstract: In this study, the tensile response of Lean Duplex stainless steel has been investigated over various strain rate at the initial deformation temperature of 298K, by using a Zwick/Roel testing machine and an EBSD, equipped with a semi in-situ tensile stage. the tensile response of Lean Duplex stainless steel has been investigated over various strain rates. It was observed that the mechanical response, especially, the total elongation of a tested alloy, was strongly affected by the strain rate. As the strain rate decreased from 10-1 s -1 to 10-4 s -1, the elongation increased. As the strain rate increased, the deformation mode in an austenite phase was dominated by the dislocation glide, resulting in the deterioration of the elongation. The substructure of the only ferritic phase showed the dislocation cell structure that was independent of the applied strain rate. Therefore, the optimum mechanical properties of duplex stainless steel can be obtained by the control of the deformation mode in the austenitic phase. 초록 Cr 을주성분으로하는페라이트계스테인리스강의고강도와우수한응력부식저항성과 Cr-Ni 을주성분으로하는오스테나이트계스테인리스강의우수한연성을동시에나타내는듀플렉스스테인리스강 (Duplex Stainless Steel, DSS) 은 70 년대이후부터활발하게연구해오고있다. 듀플렉스스테인리스강은기지조직인페라이트 (α) 와제 2 상인오스테나이트 (γ) 두상으로이루어진미세조직을가지며, 기계적특성은각구성상의변형특성에의해결정된다 [1]. 일반적으로, 페라이트상은상온소성변형시완전전위의활주에의해지배되며, 변형이진행됨에따라전위 Cell 구조를형성하며, 가공경화율 (Work hardening rate) 속도는변형이진행됨에따라점차감소한다 [2]. 이에반해, 오스테나이트상의경우는페라이트상과다르게, 적층결함에너지 (Stacking Fault Energy, SFE) 에따라변태유기소성 (TRIP), 쌍정유기소성 (TWIP), 전위활주등의변형기구가작동하여가공경화와동시에연신율을향상시키는것으로보고되었다 [3-5]. 그러나기존듀플렉스스테인리스강의연구사례에서볼때, 각각의변형율속도에대해서인장변형중페라이트와오스테나이트상의변화거동을연구한결과는아직보고되지않았다. 따라서본연구에서는유사강종인린듀플렉스스테인리스강의변형율속도를구분하여각각의변형율속도에대한페라이트상및오스테나이트상의변화거동을규명하고자하였으며, 이에따른미세조직변화와기계적특성의상관관계에대해연구하였다. 린듀플렉스스테인리스강의인장거동은 10-1 s -1, 10-2 s -1, 10-3 s -1, 10-4 s -1 의다양한변형율속도를통해연구되었다. 이렇게해서얻어진인장실험결과, 변형율속도가느릴수록연신율은증가하는형태를확인하였다. 가장느린변형속도 10-4 s -1 의경우대략 60% 를상회하는수치를나타내었다. 네조건의상온인장실험으로부터얻은데이터를바탕으로가공경화거동을확인하였으며, 가장느린변형율속도 10-4 s -1 에서유일하게가공경화율속도가상승하는현상을나타내었다. 가장느린변형율속도 10-4 s -1 의경우변형량증가에따라전위평면활주, single variant twin, multi variant twin, twin이교차되며미세해지는발달단계를나타내었으며, 페라이트상에서는변형량증가에따라 BCC결정구조의전형적인변형조직인엉킨전위조직과전위 Cell이형성된반면오스테나이트상의경우 FCC결정구조의기계적으로변형된쌍정이주로분포되어있음을확인하였다. 오스테나이트상의변형거동은쌍정유기소성 (Twinning induced plasticity) 에의해지배됨을확인하였다. 이러한강화거동에있어발달단계가진행될수록강재가고연성을나타내었다. Presenting author name: Ho-Seong Lee e-mail address: [hs.lee@knu.ac.kr] - 22 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 22-23 KSME15R 2 [1] E. C. Bain and W. E. Griffiths., 1927, "An introduction to the iron-chromium-nickel alloys." Trans. AIME, Vol 75, No. 166, pp 166~211 [2] K. T. Park, G. Kim, S. K. Kim, S. W. Lee, S. W. Hwang, and C. S. Lee., 2010, "On the transitions of deformation modes of fully austenitic steels at room temperature." Met. Mater. Int. Vol. 16, No. 1, pp. 1~6 [3] M. Humbert, B. Petit, B. Bolle, and N. Gey., 2007, "Analysis of the γ ɛ α variant selection induced by 10% plastic deformation in 304 stainless steel at 60 C." Mater. Sci. Eng. A, Vol. 454-455, No.25, pp. 508~517. [4] C. H. Seo, K. H. Kwon, K. Choi, K. H. Kim, J. H. Kwak, S. Lee, and N. J. Kim., 2012, "Deformation behavior of ferrite austenite duplex lightweight Fe Mn Al C steel." Scripta. Mater. Vol. 66, No. 8, pp. 519~522. [5] K.T. Park., 2013, "Tensile deformation of low-density Fe Mn Al C austenitic steels at ambient temperature." Scripta. Mater. Vol. 68, No.6, pp. 375~379. - 23 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 24 KSME15RE-F 5MW 초임계 CO2 발전시스템개념설계 이상민 * 최우성 * 박명수 * 송기욱 * 장성호 * * 한전전력연 - 24 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 25 KSME15RE-F 화력발전소증기터빈의모델기반고장예지기법개발 최우성 * 윤병동 ** * 한전전력연구원, 발전연구소 * 서울대학교, 기계항공공학부 A model based approach to prognostics and health management for steam turbine Woosung Choi and Byengdong Youn * Power generation Laboratory, KEPCO Research Institute, Daejeon305-760, Republic of Korea. * School of mechanical and aerospace engineering, Seoul National University, Seoul 151-742, Republic of Korea Key Words: model ( 모델 ), prognostics ( 고장예지 ), RUL ( 잔존유효수명 ) Abstract: To make a plan for the cost-effective operation and maintenance, condition-based maintenance (CBM) has been widely used in the process industry for many years. A CBM program consists of three main steps: data acquisition, data processing and maintenance decision- making. Data processing step includes not only diagnostics for fault detection, fault isolation and identification but also prognostics for RUL(remaining useful life) prediction before failure. Especially, prognostics can be classified as model-based and data driven approaches is able to predict RUL so that can help in maintenance and investment planning. In case of complicated and large-scaled system such as power plant, there is limitation to use data-driven prognostics because measurement related with life consumption is not easy and there is little failure data. This paper presents a stochastic prognostics methodology based on the physical model to reflect dominant damage mechanisms to predict RUL for steam turbine which is a key equipment to determine maintenance planning. 초록 : 다년간장치산업에서효율적인운전및정비계획수립을위해상태기반정비방법이사용되고있다. 상태기반정비는데이터취득, 데이터처리및정비의사결정의단계로구성되어있으며데이터처리단계에서데이터분석을통해이상상태를진단하는상태진단과고장이전잔여수명을예측하는고장예지분야를포함하고있다. 특히모델기반및데이터기반기법으로분류되는고장예지는설비의잔존수명을예측할수있기때문에유지보수나설비투자계획을수립하는데무엇보다중요한정보를제공한다. 발전소와같은복잡하고큰시스템의경우수명저하관련데이터측정이쉽지않고파손데이터가거의없기때문에데이터기반고장예지기법을사용하는데한계가있다. 본논문에서는화력발전소정비계획수립을결정하는핵심설비인증기터빈을대상으로주요손상기구에따른물리모델에기반하여잔존수명을예측할수있는통계적고장예지기법을소개하고자한다. (1) Jardine, A.K.S., Lin, D. and Banjevic, D., 2006, A review on machinery diagnostics and prognostics implementing condition-based maintenance, Mechanical Systems and Signal Processing, Vol.20, pp.1483-1510 (2) Son, K.L., Fouladirad, M., Barros, A., Levrat, E. And Iung, B.,2013, Remaining useful life estimation based on stochastic deterioration models : A comparative study, Reliability Engineering and System Safety, Vol. 112, pp. 165-175 (3) An, D., Kim, N. H. And Choi, J.H., 2015 Practical options for selecting data-driven or physics-based prognostics algorithms with reviews, Reliability Engineering and System Safety, Vol. 133, pp. 223-236( ) (4) Andrzej M. Rusin, 2007, Technical risk involved in long-term operation of steam turbines, Reliability Engineering and System Safety, Vol. 92, pp. 1242-1249 (5) Choi, W.S., Fleury E., Kim, B. S., Hyun, J. S.,2008, Life assessment of steam turbine components based on viscoplastic analysis, JSME Journal of Solid Mechanics and Materials Engineering, Vol. 2, pp.478-486 (6) Mao, H., Mahadevan, S., 2000, Reliability analysis of creep-fatigue failure, International journal of fatigue, Vol.22, pp.789-797 (7) Choi, W.S., Song, G. W.,Kim, B. S., Hyun, J. S. and Heo, J. S., 2010, Development and application of life assessment guidelines for fossil fuel power plant facilities in Korea, Trans. Korean Soc. Mech. Eng. A, Vol. 34, No.9, pp.1265-1272 (8) Choi, W.S., Fleury E., Song, G. W., Kim, B. S. and Chang, S.H., 2011, Study on creep damage model of 1Cr1Mo1/4V steel for turbine rotor, Trans. Korean Soc. Mech. Eng. A, Vol. 35, No.4, pp.447-452 (9) Viswanathan R. 1989, Damage mechanisms and life assessment of high-temperature components, ASM International, pp.265-328 Byengdong Youn, bdyoun@snu.ac.kr C 2014 The Korean Society of Mechanical Engineers - 25 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 26 KSME15RE-F 장기운영항공기전기배선시스템 (EWIS) 의 QCRM 에기반한신뢰성분석조만식 * 이호용 * 강우현 * 강성구 * 서찬교 ** 김순길 * * 공군항공기술연구소, ** 공군 10 전투비행단 EWIS Reliability Analysis of EWIS in Aging Aircraft Based on QCRM 1 st M.S. Jo*, 2 nd H.Y. Lee*, 3 rd W.H. Kang*, 4 th S.K. Kang*, 5 th CH.K. Seo**, 6 th S.K. Kim* *Aero Technology Research Institute, ** 10th Tactical Fighter Group Key Words: Aging Aircraft( 장기운영항공기 ), Wiring inspection( 전선점검 ), EWIS( 전기배선시스템 ), QCRM( 결함상태분류기법 ), Connector( 커넥터 ), Elongation( 연신률 ), Abstract: This study presents that ROK Airforce carried out investigation and analysis to find out how EWIS (Electrical wiring interconnect system) in aging aircrafts were worn out and how they effected on military aircraft. The objects of study were aircraft which were just retired after operating for more than 40 years. Airforce tried to judge the type and tendency of frequent defects through detailed visual inspection in order to make action plans for aging aircraft. The defects found were divided into four groups depending on status of defects (QCRM), and then action plans based on the degree of damage were established. And Airforce also implemented an elongation test to compare the degree of aging according to the regions of aircraft. Additionally, it was checked for the existence of defects in connectors through decomposition. 초록 : 공군에서는항공기장기사용에따라항공기전기배선시스템 (EWIS) 의노후와정도및결함영향성을판단하기위한정밀분해점검을수행하였다. 대상항공기는 40 년이상운영후도태된항공기들로서, 정밀점검을통해발췌된결함유형및경향성분석을통해연장운영시필요한조치계획을수립하고타항공기노후화에대비한기초자료로활용하고자한다. 발췌된결함들은유형별상태를기반으로, 4 단계구분평가하여, 가중치에따른조치계획을수립하였다. 추가적으로 Wire 노후화정도를판단하기위해연신율 (Elongation) 시험을수행하였으며, 간헐적결함의주원인이되는커넥터를완전분해하여장기사용에의한부식, 마모, 이물질흔적등내부손상여부를확인하였다. (1) FED-STD-228, Federal Test Method Standard, Revision A (DEFENSE LOGISTICS AGENCY, 17 December 2009). (2) Walter Shawlee II, How Parts and Systems Age, Avionics System Design, Avionics Magazine, November 2000. (3) V.L Press, A.M Bruning, D.C Wood and R.L. Steinman, Advanced Risk Assessment Methods for aircraft Electrical Wiring Interconnection Systems(EWIS), presented at 6 th Joint FAA/DoD/NASA Conference on aging aircraft, 2002 (4) E. White, M.. Manders, Randall J. Decker, Improvement of Wire System Integrity for Legacy Aircraft, presented at 7 th Joint FAA/DOD/NASA Conference on Aging Aircraft, 2003. (5) Alex Paterson, "aircraft electrical wire types associated with aircraft electrical fires", an aviation safety article, http://www.vision.net.au/~apaterson/aviation/wire_types.htm, last updated: 11 February 2007. Mansik Jo, nopy09@gmail.com - 26 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 27 KSME15RE-T XFEM 을이용한 3 차원균열성장예측 이성현 전인수 *, * 전남대학교기계공학부 Prediction of 3D Crack Growth Using XFEM Sunghyun Lee, and Insu Jeon*, *School of Mechanical Engineering, Chonnam National University Key Words: 3D crack growth(3 차원균열성장 ), Microfoucs X-ray( 마이크로포커스 X- 선 ), XFEM( 확장유한요소법 ) Abstract: To predict the 3D crack growth in the metal structures, in this study, a Crack-growth test and two simulations namely, Real-model simulation and Ideal-model simulation were performed using extended Finite Element Method (XFEM) to predict crack behavior three-dimensionally. In the crack growth test, crack behavior was observed for a notched metal specimen. In the Real-model simulation, the FE model was constructed using a 3D reconstruction model of the specimen, and crack growth was simulated. In the Ideal-model simulation, the simulation was performed using the FE model that involved ideal notch. The obtained crack growth simulation results were compared with tension test result. It was shown that modeling with the real crack shape of structure may be essential to predict 3D crack growth. 초록 : 균열은제조하는과정에서생긴결함이나사용중에국부적인손상의원인으로나타나며, 이러한균열의성장을예측하는것은재산상의손실을줄이는데매우중요하다. 본논문에서는균열의성장을예측하기위해재료에내포된균열의정확한검출 (detect) 기술과 XFEM 해석기술을바탕으로 3 가지실험을실시하였다. Real-model simulation 에서는노치가있는시편을마이크로포커스 X- 선단층촬영장비로영상을얻어 3 차원모델로다시재구축하였고, XFEM 해석으로균열성장을시뮬레이션하였다. Crack-growth test 에서는노치가있는시편을 Mode-I 방법으로균열성장의형상을 X- 선영상으로관찰하였다. 마지막으로 Ideal-model simulation 에서는이상적인모양의노치를만든모델로 XFEM 해석을하였다. 실제균열의성장을실험한 Crack-growth test 의결과를기준으로시뮬레이션결과들을비교하였다. 비교결과 Real-model simulation 이더유사한균열성장의경로를보이는것으로판단되었다. (1) Chu, S. J. and Liu, C., 2012, Finite Element Simulation of Fatigue Crack Growth: Determination of Exponent m in Paris Law, Trans. Korean Soc. Mech. Eng. A, Vol. 36, No. 7, pp. 713~721. (2) Sander, M. and Richard, H. A., 2005, Finite element analysis of fatigue crack growth with interspersed mode I and mixed mode overloads, International Journal of Fatigue, Vol. 27, No. 8, pp. 905~913. (3) Moes, N., Dolbow, J. and Belytschko, T., 1999, A finite element method for crack growth without remeshing, International Journal for Numerical Methods in Engineering, Vol. 46, No. 1, pp. 131~150. (4) AlloysKeswani, K., Singh, K. L. and Arokkiaswamy, A., 2012, Computation of SIF and Crack Growth Simulation using XFEM Techniques, International Conference on Advanced Research in Mechanical Engineering. (5) Das, P., Singh, I. V. and Jayaganthan, R., 2012, Crack growth simulation of bulk and ultrafine grained 7075 Al alloy by XFEM, International Journal of Materials & Product Technology, Vol. 44, No. 3~4, pp. 252~276. (6) Gigliotti, L., 2012, Assessment of the applicability of XFEM in Abaqus for modeling crack growth in rubber, Master thesis, KTH School of Engineering Sciences. (7) Jiang, Y., Tay, T. E., Chen, L. and Sun, X. S., 2013, An edge-based smoothed XFEM for fracture in composite materials, International Journal of Fracture, Vol. 179, No. 1~2, pp. 179~199. (8) LEVEN, M., 2012, Stationary 3D crack analysis with Abaqus XFEM for integrity assessment of subsea equipment, Master thesis, Chalmers University of Technology. (9) Seabra, M. R., Sustaric, P., Cesar de Sa, J. A. and Rodič, T., 2012, Damage driven crack initiation and propagation in ductile metals using XFEM, Computational Mechanics, pp. 1~19. (10) Ye, C., Shi, J. and Cheng, G. J., 2012, An extended Finite Element Method (XFEM) study on the effect of reinforcing particles on the crack propagation behavior in a metal matrix composite, International Journal of Fatigue, Vol. 44, pp. 151~156. Sunghyun Lee, a3hyun@naver.com - 27 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 28 KSME15RE-T 유한요소법을이용한온간쇼트피닝잔류응력예측 양조예 이영석 * 중앙대학교기계공학부, * 중앙대학교기계공학부 Predict of Residual Stress Distribution using Finite Element Analysis of Warm Peening Zhaorui Yang, Youngseog Lee*,* Department of mechanical Engineering, Chung-Ang University Key Words: Warm Peening ( 온간피닝 ), Residual Stress ( 잔류응력 ), FEM( 유한요소법 ) Abstract: The compressive residual stress due to shot peening process can increase the intrinsic fatigue strength. Therefore, to be widely used in surface processing. The present study through experiment and FEA investigate the effects of temperature on the residual stress in the warm shot peening process of hard spring steel. Developed a new warm peening system using an air blast machine at elevated temperatures. In addition, finite element model of warm peening was used to calculation of residual stress. The results indicated that accompanied the surface residual stress increases with the peening temperature. 초록 : 쇼트피닝가공된소재표면의압축잔류응력이부품의피로수명연장시키는중요한영향을주고있다. 그러나기계부품사용된강종강도증가에따라기존쇼트피닝가공효율의한계가있다. 본연구에서는유한요소해석을통하여온간피닝잔류응력분포를계산하였고개발된온간피닝장비를실험해서유한요소해석모델을검증하였다. 검증된해석모델을이용하여소재표면온도를변화시켜서온간피닝해석을수행했다. 소재표면잔류응력크기는온도증가에따른증가하지만잔류응력최대값이분포된깊이가온도와상관없는것을확인하였다. (1) Farrahi, G. H., Lebrijn, J. L., & Couratin, D., 1995, Effect of shot peening on residual stress and fatigue life of a spring steel, Fatigue & Fracture of Engineering Materials & Structures, Vol.18, No.2, pp.211~220. (2) Higounenc, O., 2005, Correlation of shot peening parameters to surface characteristic, ICSP-9, Paris, France, pp.28~35. (3) Al-Obaid, Y. F., 1995, Shot peening mechanics: experimental and theoretical analysis, Mechanics of Materials, Vol.19, No.2, pp.251-260. (4) Harada, Y., & Mori, K., 2005, Effect of processing temperature on warm shot peening of spring steel, Journal of Materials Processing Technology, Vol.162, pp.498-503. (5) Menig, R., Schulze, V., & Vöhringer, O., 2002, Optimized warm peening of the quenched and tempered steel AISI 4140, Materials Science and Engineering: A, Vol.335, No.1, pp.198-206. Zhaorui Yang, snrquk@nate.com - 28 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 29 KSME15RE-T 불확실성을고려한차량부품의래틀해석 박성훈 최주호 * 한국항공대학교항공우주및기계공학과, * 한국항공대학교항공우주및기계공학부 Rattle Analysis of Automotive Components under Various Uncertainties Sung-Hoon Park, Joo-Ho choi* Department of Aerospace and Mechanical Engineering, Korea Aerospace University. *School of Aerospace and Mechanical Engineering, Korea Aerospace University Key Words: BSR(Buzz, Squeak and Rattle), Frequency response analysis ( 주파수응답해석 ), Response surface method( 반응표면법 ) Abstract: The BSR is the critical issue in automobile industry as the customer highly concern about perceived quality which is related to annoying noise. Typically, BSR occur at contact interface or in the gap of two parts under forced vibration. To eliminate the BSR efficiently, developer s efforts have been changed from find-fix approach to predicting the noise at design stage using FEM(Finite element method). In this study, the method to predict rattle based on the frequency response analysis is introduced. Two types of physical quantities at two nodes in potential contact are computed to use them as principal response to determine rattle. Also, variation of rattle occurrence due to various uncertainties is considered in terms of probability. The probabilistic analysis is employed by the combined response surface method and Monte-Carlo simulation. Response surface method is applied to obtain regression model of modal parameters and Monte-Carlo simulation is to generate random samples of modal parameters, which make possible to calculate distribution of frequency response via modal superposition. All the developed rattle analysis and probabilistic approach are applied to numerical examples such as seat rail and air bent to examine their validity by comparing with results from experiments and simulation respectively. 초록 : 최근 BSR(Buzz, Squeak and Rattle) 은고객들의소음과같은감성품질에대한관심이높아지면서자동차산업에서주요이슈가되었다. 일반적으로 BSR 은과도한진동에의해두부품의간극이나접촉부위에서발생한다. 이러한 BSR 을효율적으로제거하기위해서기존의제품생산후후처리하는방법에서설계단계에서유한요소해석을이용하여소음의발생을예측하고자하는기술개발에초점이바뀌어왔다. 본연구에서는주파수응답해석을이용한래틀예측방법을소개한다. 또한, 다양한불확실성에의한래틀발생의변동성을확률로나타내고자하였다. 확률적해석은반응표면방법과몬테 - 칼로시뮬레이션방법을이용하여수행하였다. 반응표면법은모드파라미터 ( 고유값, 고유벡터 ) 의근사모델을구하고몬테 - 칼로시뮬레이션을이용하여모드파라미터들의샘플을생성하고모드중첩법을이용하여주파수응답의확률분포를계산한다. 개발된래틀해석과확률적접근방법은시트레일과에어벤트모델에적용후실험과시뮬레이션결과와비교하여유효성을검토하였다. 후기 본연구는지식경제부 (MKE, Korea) 가지원하는산업원천기술개발사업 ( 과제번호 : 10037360) 에의해수행되었고, 이에감사를표합니다. (1) Kavarana, F. and Rediers, B., 2001, "Squeak and Rattle-State of the Art and Beyond," Sound and Vibration, 35.4, pp. 56~65. (2) Trapp, M. and Chen, F., 2011, Automotive Buzz, Squeak and Rattle: Mechanisms, Analysis, Evaluation and Prevention First Ed, Oxford, Butterworth-Heinemann. (3) Park, S. H., Choi, J. H., 2014 Probabilistic analysis of rattle occurrence in the gap of automotive interior parts, Journal of Mechanical Science and Technology, Vol. 28, No. 10, pp.3991~3996. (4) Choi, J. M., Lyu, S. J., Seol, Y. S., and Jun, I. K., 2013, A BSR Analytical Evaluation Method Considering the Sound Quality Perception, SAE International, 2013-01-1913. (5) Nieuwenhof, B. V. and Coyette, J. P., 2003, Modal approaches for the stochastic finite element analysis of structures with material and geometric uncertainties, Computer Methods in Applied Mechanics and Engineering, Vol. 192, pp. 3705~3729. (6) Petyt, M., 2010, Introduction to Finite Element Vibration Analysis, Cambridge, NewYork, pp. 362~363.Put reference information here. Sung-Hoon Park, hoon217@kau.ac.kr - 29 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 30 KSME15RE-T 자동차용휠베어링시일의유한요소해석을위한고무물성시험법연구 김정주 * 김헌영 * 김학진 ** 박중양 *** 박민철 *** 박종직 *** 강원대학교기계의용공학과, * 강원대학교기계의용공학과, ** 컨버트, *** 일진글로벌기술연구소 Study of Rubber Properties Test Method for Finite Element Analysis of Automotive Wheel Bearing Seal Jeong-ju Kim, Heonyoung Kim*, Hakjin Kim**, Jungyang Park***, Minchul Park*** and Jongzik Park*** Dept. of Mechanical & Biomedical Engineering, Kangwon National University *Dept. of Mechanical & Biomedical Engineering, Kangwon National University **Convert ***R&D Center, ILJIN Global Key Words: Wheel bearing( 휠베어링 ), Universal testing machine( 만능재료시험기 ), Uniaxial tension test( 단축인장시험 ), Planar tension test( 평면변형시험 ), Strain energy potential( 변형률에너지포텐샬 ), Finite element method( 유한요소법 ) Abstract: A part which plays an important role in the driving of the wheel bearing is for automotive vehicle. The life of a wheel bearing problem is caused by the polarity of the bearing seal. The part that a lot of influence on seals bearing seals. A significant impact factor of sealability is bearing seal. Sealability of seal is depend on contact force of seal lip. However, the high contact force of the seal lip is to increase the drag torque. In this study, to measure the physical properties for use in the analysis using a Universal Testing Machine(UTM). The Finite Element Method(FEM) was applied to the measured physical properties was performed to calculate the drag torque. 초록 : 베어링시일이란베어링외부로부터내부로의이물질의침입및윤활제의누유를방지하기위한역할을하는부품으로베어링시일의밀봉성능은시일립의형상에의하여결정된다. 따라서시일의형상설계에따른기술이더욱중요해지고, 립의형상에따른밀착력예측기술이중요하게되었다. 그러나현재의시장추세는연비기준의향상과공해물질배출저감규제의강화로인하여저토크베어링에대한시장의요구가높아지고있다. 이에보다시일성능이좋은베어링이요구되고있다. 본연구에서는시일의비선형해석시의기계적특성을결정하기위하여고무재료의물성을측정하였다. 이를위해만능재료시험기 (UTM) 을사용하여고무재료의단축인장시험과평면변형시험을실시하였다. 단축인장시험을통하여고무의인장특성을확인하였고, 평면변형시험을통하여고무의전단효과를고려한물성을확인하였다. 시험결과기존의평면변형시험에서는밀림현상이발생하였고, 이로인하여해석결과와시험결과의차이가발생하였다. 본연구에서는이를개선하여보다정확한고무의기계적물성을얻었다. 그리고시험에의해얻어진물성값을상용프로그램인 ABAQUS 를이용하여 Monny-Revlen, Ogden, Mallow 등의변형률에너지포텐샬방정식을사용하여확인하여보았다. 이렇게하여계산된물성을바탕으로유한요소해석을실시하였다. 연구결과를토대로휠베어링시일의해석에사용하는고무물성에대한시험프로세스를정립하였고, 이에따라베어링시일의해석을수행할때의정확성을높일수있을것으로예상할수있다. (1) L. A. Horve, 1975, "Achieving dimensional control with molded lips", ASLE Transactions, Vol. 19, pp. 181-186. (2) J. H. Bihn, M. C. Park, M. H. Lee and K. H. Kim, 2014, "Development of Low Torque Seal Material for Hub Bearing", KSAE Spring Conference Proceedings, pp. 1094. (3) Rivlin. R. S, 1948, Large elastic deformation of isotropic IV, Futher developments of the general theory, Phill. Trans., Vol. 241, A, pp 379-397 (4) Ogden. R. W, 1972, Large deformation isotropic elasticity on the correlation of theory and experiments for incompressible rubber-like solid, Proc.R.Soc.Lond., 326, A, pp. 565-584 김헌영, khy@kangwon.ac.kr - 30 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 31 KSME15RE-T 저널베어링시스템의강건한상태진단과이상상태수준예측 정준하 전병철 * 윤병동 * 김연환 ** 배용채 ** 서울대학교기계항공공학부, * 서울대학교기계항공공학부, ** 한국전력전력연구원 Robust Diagnosis Method and Anomaly Index Prediction for Journal Bearing Systems Joonha Jung, Byungchul Jeon*, Byeng D. Youn*, Yeonwhan Kim**, and Yong-Chae Bae** Department of Mechanical and Aerospace Engineering, Seoul National University *Department of Mechanical and Aerospace Engineering, Seoul National University **Power Generation Laboratory, KEPCO Research Institute Key Words: Journal Bearing( 저널베어링 ), Diagnostics ( 진단 ), Anomaly Index( 이상상태수준 ), Vibration( 진동 ) Abstract: Current diagnosis of a journal bearing system exclusively relies on the vibration magnitude. But for a stable operation and efficient maintenance of the system, the current diagnosis method must be revised to incorporate the systems various characteristics. This research suggests an algorithm that robustly diagnoses the anomalies and predicts the severity of the anomaly. First, the vibration data were acquired for a normal case and three different anomaly cases, each anomaly case being tested by three severity degrees for the development of the anomaly index. Then, an appropriate signal processing is conducted on the acquired vibration data, and 19 time and frequency features representing the physical characteristics of the system are extracted. Next, all the data are divided into the training and the testing data. The training data are used to train the classifier (supervised learning), while the testing data are used to evaluate the performance of the trained classifier by actually predicting the classes of the testing data. Upon the predicted results of the testing data, the anomaly index is developed by quantifying the severity of the anomaly and scaling the range between 0 and 1. A journal bearing system can guarantee safe operation and efficient maintenance by the developed real-time robust algorithm and by the developed anomaly index that shows the severity of the anomaly. 초록 : 현재저널베어링시스템의상태진단은단순히진동크기에만의존하고있으나, 시스템의안정적인운영과효율적인유지보수를위해서는다양한특징을고려하여시스템의상태를정확히진단할수있어야한다. 본연구에서는진동신호를기반으로저널베어링시스템의동특성을고려한강건한상태진단과이상상태의수준을예측할수있는진단알고리즘을개발하였다. 먼저저널베어링모사시험기에서정상상태와 3 가지이상상태 ( 오정렬, 접촉, 오일훨 ) 에대한진동신호를측정하였으며, 각이상상태의수준예측연구가가능하도록각이상상태는 3 가지수준으로인가하였다. 획득한진동신호는저널베어링시스템에적합한신호처리방법을적용하고, 각이상상태의물리적특징을표현해주는 20 개의특성인자들을추출하였다. 각이상상태수준별데이터의 50% 를기계학습 ( 감독학습 ) 의훈련데이터로사용하여이상상태분류기를설계하였고, 나머지 50% 의데이터는학습된분류기의정확도를평가및검증하는데사용하였다. 상태분류가진행된결과를바탕으로이상상태의수준을예측하기위해각상태를대표할수있는특성인자를선정하였다. 또한각이상상태를대표하는특성인자를통해이상상태의수준은 0 과 1 사이의비정상지수를개발하여정량화를수행하였다. 본연구에서개발된알고리즘을통해강건한이상상태진단이실시간으로이루어지고, 해당이상상태의심각성을나타낼수있는이상상태수준을정량화함으로써저널베어링시스템의안정적인운영과효율적인유지보수가가능하다. 후기 본논문은 2012 년도지식경제부한국에너지기술평가원의전력산업원천기술개발사업의지원에의하여연구되었음 (2012101010001C). (1) Jeon, B. C., Jung, J. H., Youn, B. D., Kim, Y. H. and Bae, Y. C., 2014, Statistical Approach to Diagnostic Rules for Various Malfunctions of Journal Bearing System Using Fisher Discriminant Analysis, European Conference of the Prognostics and Health Management Society. (2) Chu, F. and Lu, W., 2005, Experimental Observation of Nonlinear Vibrations in a Rub-impact Rotor System, Journal of Sound and Vibration, Vol. 283, pp. 621~643. (3) Lees, A. W., 2007, Misalignment in Rigidly Coupled Rotors, Journal of Sound and Vibration, Vol. 305, pp. 261~271. Joonha Jung, reallibero@gmail.com - 31 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 32 KSME15RE-T Development of Laser-powered Wireless Sensing System for Structural Heath Monitoring Mijin Choi 1 and * Jung-Ryul Lee 2 1 LANL-CBNU Engineering Institute Korea, Chonbuk National University 2 Department of Aerospace Engineering, KAIST *Corresponding author: email: leejrr@kaist.ac.kr Key Words: Laser Power Transmission( 레이저전력전송 ), Wireless Strain Gauge Device( 무선변형률센싱장치 ), Wireless Ultrasonic Device( 무선초음파장치 ), Damage Evaluation( 손상평가 ), Structural Health Monitoring( 구조건전성모니터링 ) Abstract: In recent years, wireless sensor and sensing networks have emerged as a reliable method for structural health monitoring (SHM). Consequently, powering methods to these wireless sensors is one of important factors to consider for their practical applications. Most of the wireless sensors are powered using the conventional AA batteries which could supply power for a typical wireless sensor working for 1~2 years. In many applications, wireless sensors must be operated in locations that are difficult or even impossible to access, and often these systems have desired operational lifespan that exceeds that of conventional batteries. Replacing the batteries is labor intensive and time consuming. Especially, replacing batteries of embedded sensors in concrete or composite structures are very difficult or even impossible. Therefore, novel wireless powering methods is necessary in order to guarantee the long life-span for wireless sensors. In this study, we explored potential solutions to this challenge by collecting energy from a laser beam to power devices called wireless strain gauge device (WSGD) and wireless ultrasonic device (WUD). The proposed laser wireless power transmission system (WPT) features the capabilities of transmitting laser beam to and rapid switching direction to sensor nodes using a laser mirror positioner (LMP). Furthermore, one more smart component called fiber optic bolt is also developed to solve the line-of-sight issue. The delivered light is captured by a photovoltaic cell and collected a storage medium to supply the power to the sensor. The WSGD was developed based on the Mote platform. This device features wireless and battery-free operation, and utilized conventional strain gauges as a measurement sensor. The WUD was developed using the MSP430FG4618 evaluation board and CC2500 and designed to include actuator and sensor interface to evaluate structural damages. The applicability of the proposed system to monitoring strain and detection of various damage types such as a crack and artificial corrosion is experimentally investigated. The results show that the proposed wireless sensing system gives good agreement with those of wired system and feasibility for implementation of the proposed system for SHM. ACKNOWLEDGMENT This research was supported by Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning (2011-0030065) and by a grant (20140312-B1-002) from Jeonbuk Research & Development Program funded by Jeonbuk Province. Jung-Ryul Lee, leejrr@kaist.ac.kr - 32 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 33 KSME15RE-T 운행중인기어의치강성추정에관한연구 박정호 * 하종문 * 윤병동 * 박성호 ** 최주호 ** * 서울대학교기계항공공학부, ** 한국항공대학교항공우주및기계공학과 Study on Estimating the Mesh Stiffness of Rotating Gear Jungho Park *, Jong Moon Ha *, Byeng D. Youn *, Sungho Park **, Joo-Ho Choi ** * Department of Mechanical and Aerospace Engineering, Seoul National University ** Department of Aerospace & Mechanical Engineering, Korea Aerospace University Key Words: spur gear( 스퍼기어 ), Transmission error( 전달오차 ), mesh stiffness( 치강성 ), Abstract: Gear mesh stiffness is a key parameter for understanding a dynamic behavior and estimating a health state of the gear system. Lots of works have been performed to estimate gear mesh stiffness only in an analytical way. Limited works have been performed in an experimental methods. Moreover, previous studies have limitations that they were only performed either in a static or a normal state. In this study, we develop algorithm for estimating gear mesh stiffness in a rotating state. In this procedure, we exploit transmission error which is defined as the difference between rotation of input and output gear. Especially, this study proposes the concept of relative mesh stiffness to consider the effect of low frequency component from shaft motion. Also, we propose an algorithm for differentiating faults between root crack and surface failure using the characteristics in transmitting the load. Then we develop corrected mesh stiffness to exactly estimated stiffness of cracked gear. The developed algorithm is validated measuring the transmission error from a test bed of a spur gear. Consequently, the algorithm has classified the gear in root crack and surface failure, and calculated the corrected stiffness of the cracked gear. 초록 : 기어치강성은기어의동적거동을이해하고기어의건전성을추정하는데에있어필수적인변수이다. 기어의치강성을추정하기위해많은해석적방법들이연구되어왔다. 하지만기어의치강성을실험적으로추정하는연구는많이진행되지않았다. 특히지난연구들은정적상태혹은정상상태에서만기어의치강성을추정할수있었다. 이연구에서는동적거동상태에서기어의치강성을추정하는알고리즘을개발하고자한다. 이를위해기어의회전변위의차인전달오차를이용한다. 특히, 이번연구에서는축의저주파성분으로인한효과를고려하기위해상대적강성이란개념을도입하여기어의정상상태에서의치강성을정량화한다. 또한기어의부하전달특성을고려하여뿌리균열및표면손상을구분하는알고리즘을제안하고, 뿌리균열상태에서의정확한치강성추정을위해보정치강성의개념을도입한다. 개발된알고리즘은스퍼기어테스트베드의전달오차측정을통해검증하였다. 검증결과해당알고리즘이뿌리균열에의한고장과표면손상에의한고장을구분할수있음을확인하였고, 뿌리균열의치강성을보정치강성을통해계산할수있었다. 후기 이논문은 2015 년도 BK21 플러스사업에의하여지원되었음. (1) Curà, Francesca, and Andrea Mura., 2013, "Experimental procedure for the evaluation of tooth stiffness in spline coupling including angular misalignment." Mechanical Systems and Signal Processing, Vol. 40, No. 2, pp. 545~555.Put reference information here. (2) Endo, H., R. B. Randall, and C. Gosselin., 2009, Differential diagnosis of spall vs. cracks in the gear tooth fillet region: Experimental validation, Mechanical Systems and Signal Processing, Vol. 40, No. 3, pp. 636~651 Jungho Park, hihijung@snu.ac.kr - 33 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 34 KSME15RE-T 풍력발전기정상운행조건의정량적정의를통한선택적진동기반상태감시전략수립 하종문 박정호 * 오현석 * 윤병동 *i 서울대학교기계항공공학부, * 서울대학교기계항공공학부 Development of an adaptive condition monitoring strategy of wind turbine by quantitative definition of stationary operating condition 1 st author name, 2 nd author name* and 3 rd author name** 1 st author affiliation *2 nd author affiliation **3 rd author affiliation Key Words: Wind turbine ( 풍력발전기 ), Condition monitoring ( 상태감시 ), Fault diagnostics ( 고장진단 ), Classification of operating condition ( 운행환경분류 ), Stationary condition ( 정상상태 ) Abstract: Condition monitoring system (CMS) has been widely developed to reduce the economic loss occurs from an unexpected failure of wind turbines. Frequency or order analysis of vibration signal are the conventional signal processing techniques which are typically used for most of CMSs. These conventional signal processing techniques, however, can produce lots of uncertainties when they are used for condition monitoring of wind turbines which are exposed to significant time-variant operating condition. Some of advanced CMSs proposed to classify the operating condition into multiple regions in which respective condition monitoring is performed. This classification procedure would reduce the effect of varying operating condition on the signal processing results by limiting the range of variation of operating condition. However, it is still challenging for operators of wind farm to use it in practice because of 1) lack of a physical evidence for the classification method, and 2) absence of quantitative classification criteria. In this paper, classification rule based on physical phenomenon is proposed. Furthermore, a method to define quantitative classification criteria for stationary operating condition of wind turbine is presented to effectively use the conventional signal processing techniques for the condition monitoring of wind turbines. For this purpose, empirical probability density function for the operating condition of wind turbines was developed, and a cluster formed around the rated rotor speed and power were effectively separated using quantitative criteria. The proposed classification method and condition monitoring strategy were demonstrated by testbed which simulates a planetary gearbox of a wind turbine. 초록 : 풍력발전기의상태감시시스템은갑작스러운고장에의한경제적손실을줄이기위하여활발하게개발되어왔다. 진동신호에기반을둔주파수분석및오더분석기법은이러한풍력발전기의상태감시시스템에가장대표적으로활용되는고전적신호분석기법이다. 하지만가변적인운행속도및토크운행환경에항시노출되어있는풍력발전기의경우이러한고전적신호분석기법을적용할경우결과에많은불확실성이내포될수있다는문제를갖고있다. 이를해결하기위해소수의선진상태감시시스템은운행데이터를여러구간으로나누어구간별로개별적상태감시를수행함으로써운행데이터의변화에의한영향을줄이고자하는방법을제시하고있다. 하지만, 이들은운행구간을나누는데에물리적근거가부족하며각구간에대한정량적기준이제공되지않아실제로사용하기가힘들다는문제가있다. 이논문에서는고전적인회전체상태감시기법을풍력발전기상태감시에효과적으로적용하기위해물리적현상에기반한풍력발전기의운행데이터분류기법을제안하였으며, 나아가정상 (stationary) 운행조건을정량적으로정의하였다. 이를위해경험적확률밀도함수가구축되었으며물리적현상에기반하여정상운행조건의밀집군을효과적으로분리하는절차를마련하였다. 정의된정상운행조건의기준을활용하여풍력발전기의선택적진동기반상태감시전략을수립하였으며, 풍력발전기유성기어박스의모사시험을통해그타당성을검증하였다. 후기 본연구는지식경제부의재원으로한국에너지기술평가원 (KETEP) 의지원을받아에너지국제공동연구사업 (20118520020010) 으로수행되었습니다. (1) Crabtree, C. J., Zappalá, D., & Tavner, P. J., 2014, Survey of commercially available condition monitoring systems for wind turbines, Supergen Wind Energy Technologies Consortium and Durham University School of Engineering and Computing Sciences. Presenting author, Jong M. Ha, billyhjm@snu.ac.kr - 34 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 35 KSME15RE-T 위치결정용볼스크류의가속시험에따른수명연구 양희선 * 성백주 * 이병철 ** * 한국기계연구원, ** 한산리니어시스템 A Study of Life Based on the Accelerated Test of Ball Screw for Positioning Hui Sun Yang *, Beak Ju Sung* and Byeong chul Lee** *Korea Institute of Machinery & Materials, **Hansan Linear System co., Ltd. Key Words: Ball Screw( 볼스크류 ), Accelerated test( 가속시험 ), Reliability( 신뢰성 ), Weibull distribution( 와이블분포 ) Abstract: A ball screw is used in the system to determine the precise position for the linear motion in the automation equipment. A nut with the screw shaft rotates and the reciprocating linear motion. Since the ball screw directly to the failure of automated equipment ensuring the reliability of the ball screw is urgently required in the event of a failure during operation. In this study, we propose a method for the failure analysis, and the reliability evaluation test of the ball screw. Also check the field mode and sending the ball screw through a failure analysis, and the evaluation items were determined for reliability evaluation. Calculating a no-failure life test for evaluating the durability life characteristics of a ball screw and, by selecting the load to the acceleration condition to reduce the test time, the accelerated life test time was determined. In consideration of the field operating conditions developed ball screw dedicated test equipment. To apply a load in the axial direction of the ball screw, in a manner to take advantage of the hydraulic cylinder for setting the pressure relief valve in accordance with the test equipment was constructed. The axial load can be applied to reproduce the actual conditions of usage in the state of the ball screw with rotation of the servo motor. As a results of the accelerated life test for the four samples, the confidence level of 80 % were obtained the results to ensure the warranty life 1.0 10 6 cycle. 초록 : 볼스크류는자동화장비에서직선운동에대해정확한위치를결정하는시스템에사용된다. 나사축의회전으로너트가왕복직선운동을한다. 볼스크류는작동중에고장이발생할경우자동화장비의고장으로직결되기때문에볼스크류의신뢰성확보가절실히요구된다. 따라서본연구에서는볼스크류의신뢰성평가를위한고장분석및시험방법을제안하였다. 또한고장분석을통해볼스크류의주고장모드를확인하고, 신뢰성평가를위한평가항목을결정하였다. 볼스크류의내구수명특성을평가하기위한무고장수명시험시간을산출하고, 시험시간을줄이기위해가속조건으로하중을선택하여, 가속수명시험시간을결정하였다. 현장작동조건을고려하여볼스크류전용시험장비를개발하였다. 볼스크류의축방향으로하중을가할수있도록, 유압실린더를활용하여릴리프밸브에따라압력을설정하는방식으로시험장비를구성하였다. 축방향하중이가해진상태에서서보모터의회전으로볼스크류의실사용조건을재현할수있다. 시료 4 개에대해무고장시험시간동안수명시험을실시한결과, 신뢰수준 80 % 에서보증수명 1.0 10 6 cycle 을보장하는결과를도출하였다. 후기 본연구는한국산업기술진흥원신뢰성산업체확산사업지원으로수행되었습니다. (1) D. K. Park, H. K. Kim, C. M. Lee, 2008, "A Study of Endcap Type on Ball Screw," Journal of the Korea Society for Precision Vol. 25, No. 12, pp. 13~19. < 예시 > (2) Hong, K. D., Brydon, A., Leweke, T. and Thompson, M. C., 2004, "Interactions of the Wakes of Two Spheres Placed Side by Side," Trans. of the KSME(B), Vol. 23, No. 5, pp. 137~145. Hui Sun Yang, hsyang@kimm.re.kr - 35 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 36 KSME15RE-T 발전소의유압서보액추에이터용공기배출밸브의모델링 & 시뮬레이션 이용범 한국기계연구원 Modeling and simulation of the air vent valve for the hydraulic servo actuators of the power plants Yong-Bum LEE * Korea Institute of Machinery and Meterilas Key Words: Power plants( 발전소 ), Hydraulic servo actuator ( 유압서보액추에이터 ), Air & gas( 기체 ), Hydraulic fluid ( 유압작동유 ), Modeling and Simulation( 모델링 & 시뮬레이션 ) Abstract: In nuclear power plants and thermal power plants are to be supplied to the optimum amount of steam in the high-pressure and low-pressure steam turbine connected to a generator in order to produce a good quality of electricity. Also, if you cause damage to the steam turbine and power generation system that rotates at high speed to the speed of the turbine protection, blocking the steam supplied to the turbine immediately and shall protect the turbine. In the power plant using the steam supply to the steam turbine, or a special valve control device for interrupting the output of turbine, and, and the turbine output control device is driven by a hydraulic servo actuator. Therefore, the hydraulic servo actuator must be guaranteed as a key instrument of power plant performance and ensure fault-free for a long time. In this study, as to make up for the problem, the development is stopped and the performance degradation caused by failure of a hydraulic actuator due to the gas generated in the hydraulic system of a power plant, the conventional fixed orifice type problem analysis and load sensing relates to the interpretation of the analysis of the valves and air vent valve. 초록 : 원자력발전소와화력발전소에서는양질의전기를생산하기위해서는발전기에연결된고압및저압스팀터빈에최적량의스팀을공급하여야한다. 또한고속으로회전하는스팀터빈이나발전계통에이상이발생할경우터빈의과속방지를위하여, 터빈으로공급되는스팀을즉시차단하여터빈을보호하여야한다. 발전소에서는터빈에스팀을공급하거나차단하는특수한스팀밸브인터빈출력제어장치를사용하고있으며, 이터빈출력제어장치는유압서보액추에이터로구동된다. 따라서유압서보액추에이터는발전소의핵심기기로서고성능과장수명에대한신뢰성이보장되어야한다. 본연구에서는발전소의유압시스템에서생성되는기체 (air & gas) 로인하여유압액추에이터의성능을저하시키고고장유발하여발전이정지되는신뢰성문제를보완하기위한것으로서, 기존의고정형오리피스의문제점분석과부하감지형밸브의분석및에어배출밸브에대한해석을하였다. 후기 본연구는발전소의스팀터빈제어액추에이터용공기배출밸브기술지원 (NM810B) 과안전 / 신뢰성기반 Smarter 모바일작업기계시스템기술개발 (NK190C) 연구과제의일환으로수행되었습니다. (1) Pang-Chia Chen and Jeff S. Shamma, 2004, Gain scheduled l1control for boiler turbine dynamics with actuator saturation, Journal of Process Control, pp. 263-277. (2) Y. H. Yoon and Y. B. Lee, 2013, Modeling & Simulation of a Hydraulic Servo Actuator Cushion for Power Plants, The Korean Society of Tribologists & Lubrication Engineers, Vol. 29, No. 1, pp. 7~12. (3) Y. B. Lee, G. C. Lee and M. S. Chang, 2013, Study of wear characteristics of hydraulic equipment used in power plants, Trans. Korean Soc. Mech. Eng. A, Vol. 37, No. 9, pp. 1183~1188. (4) Y. B. Lee, 2013, "Performance characteristics analysis of the hydraulic system when hydraulic fluid contains a gas," Proceedings of the KSME Annual Meeting (fall), pp. 770~772. (5) Y. B. Lee, 2014, "A New Approach to the high efficiency of hydraulic excavator," Journal of The Korean Society for Fluid Power & Construction Equipments, Vol. 11, No. 4, pp. 39~45. (6) A. B. Goldwin, 1976, Fluid Power Systems Theory, worked examples and problems, The Macmillan Press Ltd., pp. 3~211. (7) A. Dukler, M. Wicks, R. Cleveland, 1964, Frictional pressure drop in two-phase flow. A.I.Ch.E. Journal 10 (1), pp. 38~51. (8) SimulationX 3.6 user manual and library manual, 2014, ITI GmbH, pp. 2~83. Yong-Bum Lee, lyb662@kimm.re.kr - 36 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 37 KSME15RE-T 소형굴삭기용주행구동유니트의신뢰성평가에관한연구이기천 * 이용범 * 최병오 * 한국기계연구원신뢰성평가센터 A study of the reliability assessment of the small track drive unit for excavator Gi-Chun LEE*, Yong-Bum LEE*, Byoung-Oh Choi* * Korea Institute of Machinery and Materials Key Words: Excavator ( 굴삭기 ), Track Drive Unit ( 주행구동유니트 ), Accelerated Life Test( 가속수명시험 ), Failure Mode( 고장모드 ), Reliability Assessement( 신뢰성평가 ) Abstract: Small size excavators have been generally used in the construction machinery less than 10 tons as the device forward and reverse driving. This power transmission unit used 2 step control valve to increase the efficiency of driving and quietness of the excavator. For the life test that is applied the variety driving modes of the small size excavator, it is required that the accelerated life test tested by overloads, which are over torque and speed, and it is required that the performance and life test equipments have been developed. This study analyzed failure modes about parts of the track drive unit in the small excavator, and calculated equivalent loads used in real used conditions at sites, and produced the acceleration factor adopted inverse formulation. Also, this study considered that the change of the acceleration factor and life test time for the cases of the rotary group and bearings through analyzing the failure modes. It was calculated the accelerated test time, 720 hours, which is calculated from the no failure test time considered the 2 samples with confidence level 90 %. Comprehensive performance tests to check the performance of the samples during the life test performed the efficiency and starting torque test, and environmental testing had performed the vibration test and low temperature test and high temperature test. Also the safety test had performed the maximum pressure test and maximum speed test. In this study, the track drive units performed the reliability assessment had completed the accelerated life for 720 hours and confirmed the reliability of the products in normal operation with no failures. 초록 : 소형굴삭기용주행구동유니트는소형굴삭기의전진및후진주행을하는장치로서일반적으로 10 톤미만의건설기계에사용된다. 이동력전달장치는주행및주차시운행의정숙성과주행효율을높이기위한 2-step control valve 를사용한다. 소형굴삭기의다양한주행모드를반영한내구수명시험을위해서는과부하 ( 과토크 & 과속도 ) 에의한가속수명시험연구가요구되며, 다양한성능시험을실시하기위해서는종합성능및수명시험장비구축이요구된다. 본연구에서는소형굴삭기의각부품별고장모드를분석하였고, 현장실사용조건에서사용되는부하를조사하여등가부하를계산하였고, 역승모형에적용하여가속계수를도출하였다. 또한본연구는주고장모드의분석을통해로터리그룹인경우와베어링인경우에대해서가속계수와수명시험시간의변화를고찰하였다. 신뢰수준 90 %, 시료수 2 개인경우에대해서무고장시험시간을계산하였으며, 이를통하여가속시험시간 720 시간을도출하였다. 수명시험중에시험품의성능을확인하기위한종합성능시험으로는효율시험, 기동토크시험을수행하였고, 내환경성시험으로는진동시험, 저온시험, 고온시험을수행하였다. 또한안전성시험으로최대압력시험과최대속도시험을수행하였다. 본연구에서신뢰성평가를수행한주행구동유니트는 720 시간의가속수명시험을완료하여시료 2 개에서고장이발생하지않고정상적으로동작하여제품의신뢰성확보를확인하였다. 후기 본연구는부품소재신뢰성평가기반구축사업 (MO5000) 과신뢰성평가기술고동화를통한중소기업기술지원 (NK193E) 연구과제의일환으로수행되었습니다. (1) Y. B. Lee, J. H. Park, 2005, "Accelerated Life Test and Analysis of Track Drive Unit for an Excavator", Journal of fluid power system, Vol.2, No.2, pp. 1-7. (2) Y. B. Lee, K. M. Kim, 2012, "Analysis of the Friction Characteristics of Parking Brake for Large Size Excavator", Journal of the Korean Society for Power System Engineering, Vol.16, No.2, pp. 5-10. (3) Yaguo Lei, Jing Lin, Ming J. Zuo, Zhengjia He, 2014, "Condition Monitoring and Fault Diagnosis of Planetary Gearboxes", Measurement, Vol.48, pp. 292-305. Yong-Bum Lee, lyb662@kimm.re.kr - 37 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 38 KSME15RE-T 승강문시스템의정비데이터를이용한신뢰성분석사례 장무성 최병오 * 한국기계연구원신뢰성평가센터, * 한국기계연구원신뢰성평가센터 Reliability Analysis using Maintenance Data of Door Systems Mu-Seong Chang, Byung-Oh Choi * Reliability Assessment Center, Korea Institute of Machinery and Materials * Reliability Assessment Center, Korea Institute of Machinery and Materials Key Words: Maintenance data( 정비데이터 ), Door system( 승강문시스템 ), Reliability prediction( 신뢰도예측 ), Reliability analysis( 신뢰성분석 ), Monte carlo simulation( 몬테카를로시뮬레이션 ) Abstract: This paper presents life prediction method for KTX door systems using maintenance data. The point estimates and lower confidence limits of Weibull parameters (shape and scale parameter) for the four modules are obtained. The reliability characteristics of KTX door systems are predicted by using reliability block diagram and the parameter estimates. It is also estimated Weibull parameters of the door system using system failure data generated from Monte carlo simulation. This simulation method has an advantage of obtaining a shape parameter of the system besides its life. 초록 : 일반적으로신뢰도예측은시스템목표신뢰도의실현가능성여부확인또는개발단계에서다양한설계대안들의비교등의목적으로부품의신뢰성정보를활용하여시스템의신뢰도를계산한다. 신뢰도예측결과의정확도는시스템의실사용조건에서획득한필드데이터를활용하는것이가장바람직하지만데이터확보에따른비용이나다양한유형의데이터수집체계와분석방법에익숙하지않은어려움이존재한다. 필드데이터로부터신뢰도를정확히산출하기위해서는수리시고장까지의가동시간정보를기록해야하며, 고장으로의심되는모든부품을일괄교체해서는안되며, 교체부품은반드시신품을사용해야한다 (1). 본연구에서는 KTX 승강문시스템을 4 개모듈로구분하고, 각모듈의정비데이터를이용하여신뢰성분석을실시한후승강문시스템의신뢰도를예측하고자한다. 각모듈정비데이터의신뢰성분석을위한가정으로분석기간은 2010 년 1 월 1 일부터 2012 년 12 월 31 일까지이며, 수리시간정보는고려되지않았고, 10 일이내의고장은정비오류또는불량으로판단하여분석에서제외하였고, 동일한승강문에서연속으로고장난경우는최초고장까지는고장데이터로해석하고최종고장시점에수리가완료된것으로해석하였다. 수리시간이나수리건수의누락으로인한수명의과대추정을고려하여신뢰성분석시척도모수와척도모수의신뢰하한을모두추정하였다. 단수명은보안문제로인하여수리적방법으로예측된시스템의척도모수값을 1 로하여변환하였다. 각모듈은와이블분포로추정하였으며, 각모듈의추정된모수 ( 형상모수, 척도모수, 척도모수의 60% 신뢰하한의순서 ) 는다음과같다. - 도어판넬 : 1.31, 6.85, 6.02 / 구동부 : 1.23, 1.58, 1.54 / 잠금장치 : 1.36, 8.37, 7.06 / 스텝 : 1.79, 1.99, 1.89 승강문시스템의신뢰도는모든모듈이직렬로구성되어있기때문에각모듈들의신뢰도곱으로얻 0 어진다. 평균수명 MTBF 는 R s ( t) dt = 0. 9026 가되며, 척도모수는 R S (t)=0.36788 를만족하는 t 가되며, 본연구에서는 1 이된다. 몬테카를로시뮬레이션을이용하여승강문시스템의랜덤고장시간생성절차는다음과같다. 정비데이터를이용하여구한각모듈들의형상모수와척도모수를이용하여고장시간을생성한다. 이중최소고장시간이시스템의고장시간이되며, 이러한과정을 10 만회 (2) 반복하여얻은고장시간데이터를이용하여시스템의분포모수, 평균수명및 B 10 수명을계산한다. 시뮬레이션데이터를이용하여얻은승강문시스템의수명은수리적방법의결과와유사하며, 형상모수는 1.39 가된다. 후기 본연구는국토교통부철도기술연구사업의 고속열차승강문시스템국산화개발 과산업통산자원부한국산업기술진흥원의 부품소재신뢰성평가기반구축사업 연구비지원에의해수행되었습니다. (1) Kwon, Y. I., 2008, "Collection and Analysis of Automotive Field Reliability Data," Journal of Applied Reliability, Vol. 8, No. 1, pp. 1~13. (2) Kang, B. S. and Chang, M. S., 2012, "Software Development for System Virtual Accelerated Life Testing," Journal of Applied Reliability, Vol. 12, No. 3, pp. 187~199. Mu Seong Chang, mirucms@kimm.re.kr - 38 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 39-40 KSME15R 폴리머재질의리테이너베어링수명특성분석 강보식 이충성 * 서동수 ** 김성곤 ** 한국기계연구원, * 한국기계연구원, ** 국방기술품질원 Analysis of lifetime characteristics of polymer retainer bearing Bo-Sik Kang, Choong-Sung Lee* and Dong-Su Seo**, Sung-Gon Kim** Korea Institute of Machinery & Matrerials *Korea Institute of Machinery & Matrerials **Defence Agency for Technology and Quality Key Words: Bearing( 베어링 ), retainer ( 리테이너 ), Life Characteristics ( 수명특성 ), polymer retainer ( 폴리머리테이너 ), retainer Bearing ( 리테이너베어링 ) Abstract: The bearing consists of the outer race, inner race, balls, and the retainer which disperses the load on the bearing and keeps the distance between the balls. The static and dynamic loads which are the main determinants of the lifetime are decided based on the loading conditions and rotation speed in the real field. However, the manufacturers calculate the static and dynamic load based on the formula in the ISO standard and they don't consider the effects of the material of each part. In this research, polymer was chosen to be the retainer material to analyze the effects of the material of the retainer. The failure and life characteristics were proposed based on the results of the experiment to represent the real conditions. The retainer bearing has the contact angle 90 and 22 balls whose diameter was 7.9 mm. The static load was calculated to be roughly 75kN and the dynamic load was 28kN following the load calculation of ISO 76 and ISO 281-1. The bearing life test to represent the real field was performed by fixating the outer race and rotating the inner race, applying the 200kg load to the axial direction. The bearing was mounted on the test equipment which can obtain 2,000 rpm rotation speed and the lifetime data were acquired. The failure causes of the polymer retainer bearing was the fracture of the ball-supporting groove in the inner retainer, not the surface flaking, crack, or wear (3) which are commonly observed in the normal ball bearing. The failure mechanism was analyzed to be the excessive friction of the balls between the retainers. The vibration was above 40 m/s 2 and it was set to be the failure criteria. 5 specimens were tested and the life characteristics were analyzed based on the 5 life data. The method of least square was used. The Weibull distribution was the most suitable based on the goodness of fit. The shape parameter was 2.52, the scale parameter was 164 hours, B10 life was 67 hours, MTTF was 142 hours, and the dynamic load was around 4kN. By analyzing the effects of the retainer material on the lifetime, the major failure cause was the fracture because of the lack of the friction resistance of the balls. The dynamic load was estimated to be 28kN by the calculation of ISO 281-1, but the experiment showed it to be 4kN, 7% of the estimation. Therefore, the effects of the material on the lifetime should be considered in the design of the bearing. 초록 : 베어링은기본적으로외륜및내륜, 볼, 볼사이의간격유지및베어링에가해지는하중을분산시켜주는리테이너등으로구성되어있고, 필드에서는적용되는하중조건및회전속도등의차이를고려하여베어링수명의주요인자인정정격및동정격하중등의특성에따라선정되고있다. 그러나, 베어링제조사에서는 ISO 규격에서제시하는계산식에의해정정격및동정격하중을계산할뿐, 베어링의각부의재질에따른수명이고려되지않고있다. 따라서, 본연구에서는베어링구성요소인리테이너재질이수명에미치는영향을알아보기위해폴리머재질의리테이너베어링을선정하였으며, 실사용조건을구현한수명시험을통해도출된데이터를바탕으로고장특성및수명결과를제시하고자한다. 연구대상품인리테이너베어링상세구조는접촉각은 90, 단열및 7.9 mm 의볼 22 개로이루어져있어, 이를 ISO 76 (1) 및 ISO 281-1 (2) 에서제안하는정정격하중계산식에대입한결과정정격하중은약 75 kn, 동정격하중은 28 kn 으로산출되어졌다. 베어링수명시험은실사용환경을구현하여베어링외륜을고정시킨상태에서내륜을회전한후, 200kg 의하중을축방향으로가하고 2,000rpm 의회전속도로구동가능한, 베어링전용시험장비에장착하여진동특성을측정하여수명특성데이터를확보하였다. 시험중발생한폴리머리테이너베어링의고장특성은일반볼베어링의고장현상인볼의표면플레이킹및크랙, 마모 (3) 에의한고장과달리내부리테이너에형성되어있는볼지지홈의파손에의한것임을확인하였고, 이에대한고장메커니즘은리테이너사이에장착된볼의과도한마찰에의한것으로분석되었으며, 이때발생되는진동량은 40 m/s 2 이상임을확인하여, 고장판정기준으로하였다. 리테이너베어링의수명시험을 5 개시료로수명시험을진행하여고장데이터를확보하였으며, 수명분석방법은최소제곱법을활용하였고분포적합도를검토하여와이블분포로선정 (4) 하였다. 분석결과폴리머재질의리테이너베어링의형상모수는 2.52, 척도모수는 164 시간, B 10 수명은 67 시간, MTTF 는 142 시간, 동정격하중은약 4kN 으로확인되었다. Bo-Sik Kang, kbs668@kimm.re.kr - 39 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 39-40 KSME15R 2 본논문에서리테이너재질이수명에미치는영향을분석한결과, 주요고장원인은일반강판용스틸을사용한베어링의주요고장원인인볼의크랙및마모와달리리테이너의볼의마찰에대한내성부족으로인한파손임을확인하였고, 동정격하중을확인한결과 ISO 281-1 의계산식을통해계산된동정격하중은 28 kn 이어야하지만, 실제시험결과를바탕으로계산한동정격하중은계산결과의 7% 수준인 4 kn 임을확인하였다. 따라서, 베어링설계시구성품의재질을선정할때에재질특성이지닌이점만을고려하는것도중요하지만, 재질이수명에영향을미칠수있으며, 이에대한고려가필요함을확인할수있다. (1) ISO 76., 2006, Rolling bearings - Static load ratings (2) ISO 281-1., 1977, Rolling bearings - Dynamic load ratings and rating life - Part 1: Calculation methods (3) Lee, Y. S., 2010, Bearing Technology (4) Seo, S. K., 2009, MINITAB Reliability Analysis - 40 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 41 KSME15RE-T 굴삭기용기어박스의수명평가결과분석 이용범 김태석 * 한국기계연구원, * 우림기계 Lifetime assessment result analysis of gearbox for excavator Yong-Bum LEE, Tae-Seok KIM* * Korea Institute of Machinery and Meterilas * Woorim Machinery Technical Research Center Key Words: Excavator ( 굴삭기 ), Pump drive gear box ( 펌프구동기어박스 ), Transfer case ( 동력분배장치 ), Life test ( 수명시험 ), Energy saving ( 에너지절감 ) Abstract: Extra-large hydraulic excavator is in increasing demand to improve fuel efficiency and to reduce manpower driving in a mine or a large plant construction. Since a large hydraulic pump that is suitable for the large engine of the large excavator doesn't exist, using single input multiple spindle output type gearbox, it is used after separating multiple spindle from the gearbox and installing many pumps. This gearbox has to be guaranteed long life since it works sustainably as long as the engine of the excavator works. About 2 gearboxes for operating a pump of 700 HP excavator, reliable life has been calculated, electricity revitalization type accelerated test equipment for energy saving has been designed, accelerated test time has been calculated, an increase in metal particle(fe, Cr) that is main element of the material of the gear(scm440) in lubrication oil has been analyzed regularly to check wear condition during life test and other test, frequency measurement and frequency spectrum analysis using a acceleration sensor has been conducted. In this study, approximately 85% of testing power for test equipment of the gearbox that consumes high power (600kW) has been reduced by regenerating electric load using 2 sets of 1700HP electric dynamometers, test time has been shortened by accelerating 45 times to increase torque and velocity, monitoring technique of wear and damage of the gearbox especially during long time test (1300 hrs.) has been established and oil change cycle of the gearbox has been verified. 초록 : 광산이나대형플랜트공사에서연비개선및운전인력감축을위하여초대형유압굴삭기의수요가증가하고있다. 대형굴삭기의대형엔진에적합한대형유압펌프가존재하지않음으로단일입력다축출력형기어박스를이용하여다축으로분리를한후다수의펌프를장착하여사용된다. 이기어박스는굴삭기의엔진이가동중에는지속적으로작동을함으로장수명을보장해야한다. 700 HP 급굴삭기의펌프구동용기어박스의 2 대에대하여신뢰수명산출과에너지절감형전기회생식가속시험장비를설계하고, 가속시험시간산출하였으며, 수명시험과시험중기어박스의마모상태를확인하는방법으로윤활유에기어 (SCM440) 소재의주성분인금속입자 (Fe, Cr) 가증가량을정기적으로분석하였으며, 기어의손상유무는가속도센서를이용한진동수측정과주파수스펙트럼분석하였다. 본연구에서는큰시험동력 (600kW) 이소요되는기어박스의시험장비를 2 대의 1700HP 전기 dynamometer 를이용하여기계적부하를전기발전으로회생시킴으로써시험동력의약 85% 를절감할수있었으며, 토크및속도크게함으로서약 45 배의가속으로시험시간단축과특히장시간 (1300 시간 ) 시험중기어박스의마모및손상을모니터링기법을확립하였으며, 기어박스의윤활유교체주기를확인하였다.. 후기 본연구는 7MW 급 Yaw & Pitch Drive 기술개발 (NE5110) 과안전 / 신뢰성기반 Smarter 모바일작업기계시스템기술개발 (NK190C) 연구과제의일환으로수행되었습니다. (1) H. G. Kim, J. W. Choi, S. J. Yoo and K. S, Yi, 2011, "Development of Power Management Strategies for a Compound Hybrid Excavator", Transactions of the Korean Society of Mechanical Engineers A, Vol. 35, No. 12, pp. 1537-1542. (2) W. S. Choi, J. Y. Sung, W. S. Lim, Y. B. Lee and S. W. Kang, 2014, Development of Durability Test Equipment for Heavy Machinery s Transfer Gearbox, Proceedings of the KSAE Annual Meeting (fall), pp 176 Yong-Bum Lee, lyb662@kimm.re.kr - 41 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 42 KSME15RE-T 팬터그래프용유압댐퍼의고장및수명특성분석 이충성 백동천 * 강보식 * 한국기계연구원, * 한국기계연구원, ** 한국기계연구원 Analysis of failure and lifetime characteristics of pantograph hydraulic damper Choong-Sung Lee, Dong-Cheon Baek* and Bo-Sik Kang** Korea Institute of Machinery & Matrerials *Korea Institute of Machinery & Matrerials Key Words: pantograph hydraulic damper ( 팬터그래프유압댐퍼 ), hydraulic damper ( 유압댐퍼 ), failure Analysis ( 고장분석 ), life characteristic ( 수명특성 ), failure characteristic ( 고장특성 ) Abstract: The hydraulic damper for the pantograph is installed on the top of the train and prevents the breakaway of the wire and the pantograph. Its failure can cause the sudden stop or the fire of the train, and the high level of reliability is required. However, since the hydraulic damper for the pantograph operates in the high speed and the force increases non-linearly as a function of the speed, the high reliability is difficult to guarantee. In this research, the failure and life characteristics were proposed based on the experiments to represent the real operating conditions of the hydraulic damper of the pantograph. The hydraulic damper for the pantograph consists of the piston module, rod, and body. The piston module is made up of the orifice assembly and the piston seal. The life test conditions were determined to be 0.2m/s based on the KS standards, EN standards, and the real field conditions. 5 specimens were tested until 3.50 x 10 6 cycles. The leakage of the inner hydraulic oil occurred in all the 5 specimens, the two fell into inoperable states. Specimen decomposition and oil analysis were performed. The cause of the leakage was found to be the misalignment of the axis and the faulty surface roughness and the cause of the inoperability was the blockage of the piston module because of the wear of the piston seal. The life characteristics were analyzed based on the 5 life data, the method of least square was used. The Weibull distribution was the most suitable based on the goodness of fit. The shape parameter was 4.57, the scale parameter was 2,098,916 cycles, MTTF was 1,917,335 cycles. In this research, the life test was performed to represent the real operating conditions of the hydraulic damper for the pantograph and as a result the failure and life characteristics were analyzed. 초록 : 팬터그래프용유압댐퍼는철도차량상단에장착된팬터그래프에설치되어가선과팬터그래프가이탈되는것을방지하는역할을수행하며, 고장발생시철도차량비상정차및화재발생의위험이있어높은수준의신뢰성이요구되는제품이다. 그러나, 팬터그래프용유압댐퍼의작동환경은일반유압댐퍼와달리고속작동환경에서사용되며, 팬터그래프용유압댐퍼의특성상인장되는속도에따라발생되는힘이비선형적으로증가하여신뢰성확보에어려움을겪고있다. 따라서, 본논문에서는팬터그래프용유압댐퍼의실제구동환경을재현한수명시험을진행한결과를바탕으로팬터그래프용유압댐퍼의고장및수명특성에대해제시하고자한다. 팬터그래프용유압댐퍼는크게피스톤모듈, 로드, 바디부로구성되어지며, 그중피스톤모듈부에는오리피스집합체와피스톤씰등으로구성되어있다. 수명시험조건은 KS (1) 및 BS EN (2) 규격, 실사용조건, 참조하여 0.2m/s 로결정되어졌으며, 이에대해 5 개의시료를 350 만사이클까지인장하는것으로하였다. 수명시험결과 5 개의시료중 5 개모두내부유압유누유현상이발생되었고, 그중 2 개의시료에서는작동불능상태가발견되기도하였다. 이에대해시료분해및유압유성분분석을수행하였고, 그결과누유의원인에대해서는축정렬불량및로드의표면조도불량으로확인되었으며, 작동불능의원인을파악한결과피스톤씰마멸에의해피스톤모듈막힘이발생하여작동불능이발생한것으로확인되었다. 5 개의수명데이터를바탕으로수명특성분석을수행하였으며, 분석방법은최소제곱법을활용하였고, 분포적합도를확인하였을때, 와이블분포가최적의분포으로확인되어이를활용하였다. 수명특성을분석한결과, 형상모수는 4.57, 척도모수는 2,098,916 사이클, MTTF 는 1,917,335 사이클로확인되었다. 본논문에서는철도차량팬터그래프에사용되는유압댐퍼에대하여실제작동조건을재현한수명시험을수행하였고, 그결과를바탕으로고장및수명특성을확인하였다. (1) KS R 9234., 2014, Oil damper for railway rolling stock (2) BS EN 13802., 2013, Railway applications. Suspension components. Hydraulic dampers Choong-Sung Lee, tsaar@kimm.re.kr - 42 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 43 KSME15RE-T 플라스틱및금속사이클로이드기어드모터의신뢰성비교평가 이주홍 김도식 * 박종원 * 한국기계연구원신뢰성평가센터 Reliability Comparative Assessment of Plastic & Metal Cycloid Geared Motor Joo Hong Lee, Do Sik Kim * and Jong Won Park * Reliability Assessment Center, Korea Institute of Machinery & Materials Key Words: Plastic gear( 플라스틱기어 ) Cycloid ruducer( 사이클로이드감속기 ), Geared Motor( 기어드모터 ), B 10 life(b 10 수명 ) Abstract: Plastic gears are commonly used for small toys and office equipment, but they are inappropriate for use in industrial applications because of low life & low load carrying capacity compared with metal. But, the advantage of lower production cost of the injection molding production is much attractive to the manufacturers, and so many studies on the plastic gears are recently carried out. Also cycloidal gear reducer which has the advantage of being able to create high ratio in a small space is required to be cautious in design for high load. Through these comparative assessment of the plastic gear and metal gear, the plastic cycloidal geared motors were evaluated whether or not the possibility of the application in general industry. 초록 : 플라스틱기어는금속기어에비해수명이낮고, 부하전달능력이떨어지며, 열에취약한성질때문에일반적으로소형완구류나동력이크게필요치않는사무용기기등에서많이사용하고있지만일반산업용으로는사용하지않고있다. 하지만사출성형제작시제작단가를낮출수있다는장점은생산자에게있어떨칠수없는매력이기때문에이에대한많은연구가계속되고있다. 또한사이클로이드감속기는작은공간에서도높은감속비를만들수있다는장점이있지만, 치형이받는부하가커서설계에주의가요구된다. 본연구에서는산업용으로사용되는사이클로이드기어드모터를이용하여소형금속기어드모터와플라스틱기어드모터를비교평가함으로써플라스틱사이클로이드기어의일 후기 본과제는 ( 복합환경 )Hybrid Dynamometer 시험장비개발 " 의지원으로수행되었으며, 이에감사드립 니다. (1) Heinz P. Bloch, Fred K. Geitner, "Machinery Failure Analysis and Troubleshooting" 3rd edition, Vol. 2. (2) D. S. Kim, B. J. Sung, 2013, Accelerated Life Evaluation of Propeller Shaft for Forklift Truck, Trans. Korean Soc. Mech. Eng. A (or) B, pp. 1286~1291. (3) D. J. Kim, Y. H. You, T. T. Linh, H. J. Ahn, 2013, Efficiency analysis of a 2-stage cycloid reducer, Trans. Korean Soc. Mech. Eng. A (or) B, pp. 2060~2062. (4) I. H. Hong, K. R. Kim, 2010, Effects of Manufacturing and Assembly Errors on Angular Transmission Error for Reducer with Cycloid Tooth Profile, Trans. Korean Soc. Mech. Eng. A (or) B, pp. 56~62. Joo Hong Lee, joohlee@kimm.re.kr - 43 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 44 KSME15RE-F 304 스테인리스강에서단범위규칙화에따른격자변화가치수변화에미치는영향 김성수 * 김영석 * * 원자연 - 44 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 45 KSME15RE-F 폴리에스터수지의기계적성질에대한탄소나노튜브와그래핀산화물의영향 염영진 * 황반토 * * 울산대학교기계공학부 The Effect of Carbon Nanotubes and Graphene Oxide on Mechanical Properties of Polyester Resin Young Jin Yum *, Hoang Van Tho * * School of Mechanical Engineering, University of Ulsan Key Words: Mechanical properties( 기계적성질 ), Multiwalled Carbon Nanotubes( 다중벽탄소나노튜브 ), Graphene Oxide( 그래핀산화물 ), Unsaturated Polyester Resin( 불포화폴리에스터 ) Abstract: Unsaturated Polyester Resin (UPR) is popularly used as the matrix of composite materials. In addition, carbon fillers such as Multiwalled Carbon Nanotubes (MWCNT), Graphene Oxide (GO) etc. are added to enhance the mechanical properties of UPR because of their superlative mechanical and physical properties. Many researchers have been studying the effect of additives on both matrix and reinforcement of composite materials. UPR was mixed with MWCNT, GO separately and both MWCNT and GO simultaneously by stirring machine at the same making condition of UPR. As the result, at 70 0 C stirring temperatue, UPR shows the highest compressive strength and Young s modulus. Moreover, the mixture of MWCNT and GO specimen shows the best distribution between additives and UPR and its compressive strength is significantly higher than that of pure UPR specimen. 초록 : 불포화폴리에스터는복합재료의기지로서널리사용되고있다. 여기에기계적, 물리적성질이뛰어난다중벽탄소나노튜브와그래핀탄소산화물을첨가하여폴리에스터의기계적성질을향상시키는연구가많이수행되고있다. 폴리에스터와탄소나노튜브, 그래핀산화물을각각첨가하거나둘을함께첨가하여동일한제작조건으로교반기에서균일하게혼합하였다. 그결과 70 0 C 의교반온도일때폴리에스터와탄소첨가물시편의압축강도와탄성계수가가장높은것을알수있었다. 또한이때탄소나노튜브와그래핀산화물의분포가가장균일하였으며압축강도가순수폴리에스터에비해월등하게향상된것을확인할수있었다. (1) Seyhan, A. T., Gojny, F. H., Tanoglu, M. and Schulte, K., 2007, "Critical aspects related to processing of carbon nanotube/unsaturated thermoset polyester nanocomposites," European Polymer Journal, Vol. 43, pp. 374-379. (2) Urena-Benavides, E. E., Kayatin, M. J. and Davis, V. A., 2013, " Dispersion and Rheological of Multiwalled Carbon Nanotubes in Unsaturated Polyester Resin," Macromolecules, No. 46, pp. 1642-1650. (3) Shokrieh, M. M., Saeedi, A. and Chtsazzadeh, M., 2013, "Mechanical properties of multi-walled carbon nanotube/polyester nanocomposites," Journal of Nanostructure in Chemistry, 2193-8865-3-20. (4) Petrova, I., Ivanov, E. R., Tsekov, K. Y. and Anglov, V., 2013, "Applied study on mechanics of nanocomposites with carbon nanofillers," Journal of Theoretical and Applied mechanics,vol. 43, No. 3, pp. 67-76. (5) Battisti, A., Skordos, A. A. and Partridge, I. K., 2008, "Monitoring dispersion of carbon nanotubes in a thermosetting polyester resin, " Journal of Composite Science and Technology, 0266-3538. (6) Seyhan, A. T., Tanoglu, M. and Schulte, K., 2009, "Tensile mechanical behavior and fracture toughness of MWCNT and DWCNT modified vinyl-ester/polyester hybrid nanocomposites produced by 3-roll milling, " Journal of Materials Science and Engineering A, 523 85-92, 0921-5093. (7) Bora, C., Gogoi, P., Baglari, S. and Dolui, S. K., 2013, "Preparation of Polyester resin/ Graphene Oxide Nanocomposite with Improved Mechanical Strength," Journal of Applied Polymer, 39068. Young Jin Yum, yjyum@ulsan.ac.kr - 45 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 46 KSME15RE-F 초고온가스로용 Alloy 617 의크리프균열성장속도확률적평가 김우곤 박재영 * I.M.W. Ekaputra * 김선진 김민환 ** 한국원자력연구원, * 부경대학교, ** 한국원자력연구원 Probabilistic Evaluation of Creep Crack Growth Rate of Alloy 617 for Use in VHTR Woo-Gon Kim, Jae-Young Park *, I.M.W. Ekaputra, Seon-Jin Kim * and Min-Hwan Kim ** Korea Atomic Energy Research Institute *Pukyong National University ** Korea Atomic Energy Research Institute Key Words: Creep crack growth ( 크리프균열성장 ), Alloy 617 ( 합금 617), Probability ( 확률 ), Monte Carlo simulation ( 몬테칼로시뮬레이션 ) Abstract: Alloy 617 is a major candidate material for the intermediate heat exchanger (IHX) component in a very high temperature reactor (VHTR) system. The experimental creep crack growth (CCG) data should be prepared for a design use of Alloy 617 because the CCG data for Alloy 617 are not available in the ASME design code. Experimental CCG data were obtained from a series of the CCG tests performed under different applied loads at 800 o C. The creep crack growth rate (CCGR) was characterized in terms of the C* fracture parameter. To logically obtain the B and q values in * q the CCGR equation, a B( C ), three methods in terms of the least square fitting method (LSFM), a mean value method (MVM) and a probabilistic distribution method (PDM) were adopted. The PDM was most useful because the CCGR line can be evaluated with a probabilistic reliability. Both the B and q coefficients followed a lognormal distribution. Using a lognormal distribution in the PDM, a number of random variables were generated by Monte Carlo simulation, and the CCGR lines could be predicted probabilistically. In addition, a fracture mode was found to be an intergranular fracture mode, which was generally observed in the creep rupture of Alloy 617. Summary A VHTR system is one of the most promising Gen-IV reactors for the economic production of electricity and hydrogen. Its major components are the reactor internals, reactor pressure vessel, hot gas ducts, and intermediate heat exchangers. Since the VHTR components are designed to be used for a 60 year lifetime at a high temperature, the creep crack growth behavior as well as creep behavior is very important for the design application due to creep damage during the long service life at elevated temperatures. Alloy 617 is a major candidate material for the IHX component. The design of the component, which will operate well into the creep range, will require a good understanding of creep crack growth deformation. Efforts are now being undertaken in the Gen-IV program to provide data needed for the design and licensing of the nuclear plants, and with this goal in mind, to meet the needs of the conceptual designers of the VHTR system, Gen-IV Materials Handbook DB is being established through an international collaboration program of GIF (Gen-IV Forum) countries. The CCG experimental data should be prepared to the Gen-IV Materials Handbook DB, because the CCG data for Alloy 617 are not available in the ASME design code. In this paper, experimental creep crack growth data for Alloy 617 were obtained through a series of CCG tests performed under different applied loads at 800 o C. The CCGR was characterized in terms of the C* fracture parameter, and the CCGR equation was constructed. A number of random variables were generated by Monte Carlo simulation, and the CCGR lines were estimated in the viewpoint of probability. Acknowledgment This study was supported by Nuclear Research & Development Program of the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP). (Grant code: NRF-2012M2A8A2 025682). References (1) Kim, W.G., Park, J.Y., Hong, S.D., and Kim, S.J., 2011, "Probabilistic Assessment of Creep Crack Growth Rate for Gr.91 Steel," J. of Nuclear Engineering and Design, Vol. 241, pp. 3580~3586. (2) Kim, W.G., Park, J.Y., Kim, S.J., Hong, S.D., and Kim, Y.W., 2012, "Reliability Evaluation on Creep Life Prediction of Alloy 617 for a Very High Temperature Reactor," Kor. J. Met. Mater, Vol. 50, No. 10, pp. 721~728. (3) Nikbin, K.M., Smith, D.J., and Webster G.A., 1986, "An Engineering Approach to Prediction of Creep Crack Growth, Transactions of the ASME," Vol. 108, pp.186-191. (4) Chang, J.H., et al., 2007, "A Study of a Nuclear Hydrogen Production Demonstration Plant," Nuclear Eng. and Tech., Vol. 39, No.2, pp. 111~122. (5) Saxena, A., 1997, "Nonlinear Fracture Mechanics for Engineers," CRC Press, New York, pp. 363-377. Woo-Gon Kim, wgkim@kaeri.re.kr C 2014 The Korean Society of Mechanical Engineers - - - 46 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 47 KSME15RE-F 고분자전해질연료전지용가스확산층의소수성제함량이계면접합력에미치는영향 김산위 정병헌 * 홍보기 * 김택수 KAIST 기계공학과 * 현대자동차연료전지개발 1 팀 Effects of hydrophobic agent content in macro-porous substrates on the fracture behavior of the gas diffusion layer for proton exchange membrane fuel cells. Sanwi Kim, Byeong-Heon Jeong*, Bo Ki Hong* and Taek-Soo Kim Department of Mechanical Engineering, KAIST *Fuel Cell Vehicle Team 1, Eco-Technology Center, Research & Development Division, Hyundai-Kia Motors Company Key Words: Gas diffusion layer ( 가스확산층 ), Interfacial fracture energy ( 계면접합력 ), Double cantilever beam fracture mechanics test ( 이중외팔보실험 ), Proton exchange membrane fuel cell ( 고분자전해질연료전지 ) Abstract: Although the adhesion between the macro-porous substrate (MPS) and micro-porous layer (MPL) of a gas diffusion layer (GDL) is a critical factor that affects the reliability and durability of proton exchange membrane fuel cells, systematic studies quantifying the interfacial fracture energy of GDL have not yet been reported. Therefore, in this study, the interfacial fracture energy of GDLs with different contents of hydrophobic agents in the MPS is quantitatively measured. GDL samples with 0, 5, 10, and 20 wt% of hydrophobic agent content are tested using double cantilever beam fracture mechanics tests. It is observed that the interfacial fracture energy of the GDLs increases as the content of hydrophobic agent increases, due to more favorable interactions between the hydrophobic agents of the MPL and MPS. Optical microscope, scanning electron microscope, and energy-dispersive X-ray spectroscope analyses are performed on the bare and delaminated surfaces in order to investigate the mechanism of the interfacial fracture energy increase of the GDLs. 초록 : 고분자전해질연료전지의중요부품중하나인가스확산층은기재층 (MPS) 과미세기공층 (MPL) 으로구성되어있고각각의내구성과신뢰성은높은효율을달성하기위하여매우중요한요소이다. 많은변수중 MPS 와 MPL 의접합력은내구성과신뢰성을결정짓는아주큰인자이지만계면접합력을측정하는정성적이고효과적인방법은아직연구되지않았다. 본연구는위와같은문제를해결하기위하여정확하고정성적인계면접합력을측정하는방법을소개하며이방법을통하여기재층의소수성제함량이계면접합력에어떤영향을미치는지연구하였다. 본실험에사용된가스확산층은기재층에소수성제가 0, 5, 10, 20 wt% 가함량되어있으며정성적인계면접합력을측정하는파괴역학실험중하나인이중외팔보실험을적용하였다. 실험결과, 가스확산층의기재층소수성제가 0, 5, 10, 20 wt% 로증가할때, 계면접합력또한 17.0, 39.6, 37.9, 53.3 J/m 2 으로증가하는경향을확인하였으며, OM, SEM, EDX 분석을통하여계면접합력증가의원인을밝혀내었다. 기재층의소수성제함량이증가할수록, 기재층과소수성제가포함된미세기공층이반응을더활발히하여박리를할때기재층의탄소섬유에미세기공층의잔여물이더욱더많이남아있는것을확인하였다. 본연구에서소개된실험방법과연구내용을바탕으로고분자전해질연료전지의가스확산층의내구성과신뢰성을효과적이고정성적으로측정하고연구할수있으며연료전지기술의상용화에많은도움이되리라예상된다. Sanwi Kim, sanca77@kaist.ac.kr - 47 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 48 KSME15RE-F 모사시편시험을통해탄소강곡관의기계적물성치에미치는굽힘공정의영향평가 김진원 * 김성훈 * 최명락 * * 조선대학교원자력공학과 Evaluating the Bending-Process Effect on the Mechanical Properties of Carbon Steel Pipe Bends using a Simulated Specimen Test Jin Weon Kim*, Seong Hun Kim* and Myung Rak Choi* *Department of Nuclear Engineering, Chosun University Key Words: Mechanical properties( 기계적물성치 ), Bending process( 굽힘공정 ), Simulated specimen test( 모사시편시험 ), Carbon steel pipe bend( 탄소강곡관 ) Abstract: This study performed tensile tests at RT~350 o C using the simulated specimens, which were prepared by 10% cold-working and heat-treatment at 620 for 30min., to understand the mechanical properties of pipe bends manufactured by cold-bending followed by heat-treatment for relieving residual stress at operating temperature of nuclear power plants. The results showed that at RT the strength and ductility of cold-worked and heat-treated material were respectively higher and lower than those of the parent material. However, this trend was changed at higher temperatures: At 100~350 o C, the ultimate tensile strength of cold-worked and heat-treated material was much lower than that of the parent material, while the yield strength was still higher than that of the parent material. The elongation of cold-worked and heat-treated material was also nearly recovered to the original level of elongation at 100~177 o C. Such different tendency in the mechanical properties between RT and higher temperatures is associated with the change in dynamic strain aging (DSA) characteristics of material through the cold-working and heat-treatment. 초록 : CANDU 형원전의피더관과같은소구경배관의곡관부는별도의곡관을사용하지않고직관의일부를상온에서굽힌후잔류응력제거열처리를통해제작한다. (1) 이와같은곡관부제작방법은현장에서임의의굽힘각을갖는곡관부를가공할수있으며곡관부부근에서용접부를제거할수있는장점이있다. 반면, 냉간굽힘에따른곡관부의기계적물성치변화와곡관부내에서위치에따른기계적물성치의큰편차가예상된다. 선행연구에서는굽힘에따른곡관부의냉간가공을모사한모사시편을가공하여냉간굽힘과굽힘후잔류응력열처리에따른기계적물성치의변화를평가한바있다. (2) 본논문에서는이들연구의연장선으로냉간굽힘과굽힘후잔류응력열처리에따른기계적물성치의변화를원전운전온도를포함하는고온조건에서평가하였다. 냉간가공과잔류응력제거열처리에따른기계적물성치변화는선행연구와같이모사시편을이용한인장시험을통해평가하였다. 모사시편은 ASTM A106 Gr.B 탄소강배관재로제작하였으며, 모사시편제작시굽힘에따른냉각가공률은 10% 로가정하였으며잔류응력을제거를위해 620 o C 에서 30 분간유지하는열처리조건을적용하였다. 인장시험은상온, 100, 177, 250, 350 o C 온도조건에서수행되었다. 시험결과, 상온에서는냉간가공후잔류응력제거열처리를수행하면냉간가공의의해증가된강도와감소된연성이회복되지만, 냉간가공이전에비해여전히높은강도와낮은연성을보였다. 그러나, 100~350 o C 의고온에서는냉간가공후잔류응력제거열처리된조건에서항복강도는냉간가공이전보다여전히높은값을보이지만인장강도는냉간가공전에비해휠씬낮은값을보였다. 또한, 100~177 o C 에서는연성이회복되어냉간가공전과비슷한수준의연신률을보였다. 이와같이고온에서냉간가공과잔류응력제거열처리에따른기계적물성치의변화경향이상온과다른것은냉간가공후잔류응력열처리에의해재료의동적변형시효특성이변화되기때문으로판단된다. 후기 본연구는 2013 년도산업통상자원부의재원으로한국에너지기술평가원 (KETEP) 의지원을받아수행한연구과제입니다. (1) KHNP, 2002, "Development of Technologies to Monitor for Feeder Thinning of CANDU Nuclear Power Plants," Final Report (99NS10) (2) Lee, M. Y., Kim, J.W. and Lee, S. Y., 2012, "Estimation of Tensile Properties of Pipe Bends Manufactured by Cold- Bending," Trans. of the KSME(A), Vol. 36, No. 9, pp. 1059~1063. jwkim@chosun.ac.kr - 48 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 49 KSME15RE-F Alloy 617 합금의톱니모양소성변형현상과가공경화거동 I.M.W. Ekaputra 김우곤 ** 박재영 * 김선진 * 김민환 ** 부경대학교기계자동차공학과, * 부경대학교기계자동차공학과, ** 한국원자력연구원 Serrated Plastic Flow Phenomenon and Work-Hardening Behavior in Alloy 617 I.M.W. Ekaputra Woo-Gon Kim ** Jae-Young Park * Seon-Jin Kim * Min-Hwan Kim ** Graduate School, Department of Mechanical Design Engineering, Pukyong National University, * Graduate School, Department of Mechanical Design Engineering, Pukyong National University, ** Korea Atomic Energy Research Institute Key Words: Alloy 617; Dynamic strain aging; Serrated plastic flow; Voce equation Abstract: A serrated plastic flow phenomenon on tensile true stress-true platic strain in Alloy 617 was investigated at the strain rate of 5.55 10-4 s -1 under various temperature conditions. A Voce-equation was proposed to be evaluated on true stress-true platic strain curves in Alloy 617. The discussion of the serrations was restricted based only on a physical process of dynamic strain aging (DSA). In addition, analysis of work-hardening behavior in Alloy 617 was performed by applying a Voce-relationship. Two stages of work-hardening behavior were observed in Alloy 617, as a rapid decrease at low stresses and a marginal decrease at high stresses, respectively. Each of Voce parameters exhibited three variants of temperature regions as low, intermediate, and high temperature regions. It was shown that anomalous variations in work-hardening behavior of the Voce parameters appeared at the intermediate temperatures as a plateaus. It is considered as DSA regions where the interaction between solute atoms and mobile dislocation occurs. Discussion Type C or D serration form appeared at low or room temperature (24 o C) and at high temperatures, above 600 o C (700 o C~ 950 o C). Whereas at intermediate temperature regions (200 o C~ 600 o C), various types of serrations were observed. The applicability of fitting line in the Voce-equation was presented on true stress-true platic strain curves for Alloy 617 at the strain rate of 5.55 10-4 s -1 under various temperature conditions. At low temperature and intermediate temperatures, a large deviation in fitting line appeared at the low strain. While at high temperatures, a deviation in fitting line was not exhibited significantly. In addition, in accordance with the Kocks-Mecking phenomenological, the Voce-relationship was derived for investigating the work-hardening behavior. Two stages of work hardening behavior were shown in θ-σ plots as a rapid decrease at low stresses and a marginal decrease at high stresses, respectively. The Voce-relationship can exhibit a good applicability in performing the fitting line at the last stage of θ-σ plots. Each of Voce parameters showed a marginal decrease or increase at intermediate temperatures. A small decrese in σ S (saturation stress) and σ I (initial stress) and a marginal increase in n v from room temperature to intemediate temperature regimes were considered as long range stress field due to dislocation multiplication and its interaction. Furthermore, rapid decrese in σ S and σ I and rapid increase in n v with increasing temperature indicated the acceleration of recovery processes at high temperatures. The dominance of dynamic recovery at high temperatures has been reported as a decrease in dislocation density, formation of well-defined subgrains rather than dislocation cells, and rapid increase in the size of dislocation substructure with increasing temperature. The anomalous variations in work-hardening at intermediate temperatures with a plateaus are considered as DSA phenomenon where the interaction between solute atoms and mobile dislocation occurs. Acknowledgment This study was supported by Nuclear Research & Development Program of the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP). (Grant code: NRF-2012M2A8A2 025682). References (1) Kim, W.G., Park, J.Y., I.M.W. Ekaputra., Hong, S.D., Kim, S.J., and Kim, Y.W.,2013, "Comparative Study on The High Temperature Tensile And Creep Properties of Alloy 617 Base And Weld Metals," J. of Mechanical Science and Technology, Vol. 27, pp. 2331~2340. (2) B.K.Choudhary., D.P. Rao Palaparti., and E. Issac Samuel,.2012, "Influence of Strain Rate And Temperature on Tensile Stress-Strain And Work Hardening Behavior of 9Cr-1Mo Ferritic Steel," J. of Materials Science and Engineering A, Vol.538, pp.110~117. (3) P. Rodriguez,.1984, "Serrated Plastic Flow, " J. of Materials Science, Vol.4, pp.653~663. (4) E. Issac Samuel,. B.K.Choudhary., and K. Bhanu Sankara Rao,.2002, "Influence of Temperature And Strain Rate on Tensile Work Hardening Behavior of Type 316LN Austenitic Satinless Steel, " Scripta Materialia, Vol.46, pp.507~512. Presenting author name, madewicaksana@yahoo.com - 49 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 50 KSME15RE-F Modified 9Cr-1Mo 강의크리프균열성장속도의신뢰성분석 박재영 * 김우곤 ** I.M.W.EKAPUTRA * 김선진 *** 김민환 ** * 부경대학교대학원, ** 한국원자력연구원, *** 부경대학교 Reliability Analysis of Creep Crack Growth Rate for Modified 9Cr-1Mo steel Jae-Young Park, Woo-Gon Kim*, I.M.W.EKAPUTRA*, Seon-Jin Kim*, and Min-Hwan Kim** * Graduate School, Department of Mechanical Design Engineering, Pukyong National Univ. *Korea Atomic Energy Research Institute ** Department of Mechanical & Automotive Engineering, Pukyong National Univ. Key Words: Creep( 크리프 ), Creep Crack Growth Rate( 크리프균열성장속도 ), Log-normal Distribution( 대수정규분포 ), Reliability Analysis( 신뢰성분석 ) Abstract: This paper deals with creep crack growth rate(ccgr) of modified 9Cr-1Mo steel at 500. Modified 9Cr- 1Mo steel is used as the structural components for Gen-IV reactor systems, such as a very high temperature reactor (VHTR) and sodium-cooled fast reactor (SFR). The CCG data were obtained by the CCG tests performed on 1/2" compact tension (CT) specimens under various applied loads at 500. The CCGR data were analyzed using the CCGR law of da/dt=b(c*) q. The constants B and q were determined by a least square fitting method. And they were also analyzed in terms of mean value method(mvm) and probability distribution method(pdm). Using the PDM, a number of random variables were generated by Monte-Carlo simulation technique. For an example the CCGR lines for 10% to 90% in the viewpoints of reliability were predicted for modified 9Cr-1Mo steel. 초록 : Modified 9Cr-1Mo 강은높은크리프강도와내식성을지니고낮은열팽창, 열응력과높은열전도성피로강도를갖기때문에미래형원자로인소듐냉각고속로 (sodium-cooled fast reactor, SFR) 나초고온가스로 (very high temperature reactor, VHTR) 의압력용기, 증기발생기, 핵연료피복관등의주요부품의후보재료이다 (1-2). 이러한원자로에사용되는구조물들은고온에서 60 년이상사용되도록설계되기때문에사용기간동안재료내부에발생되는결함이나미소균열들의성장에의해서발생되는크리프균열성장이수명에가장큰영향을미치므로이를정확히평가하는것이필요하다. 본연구에서는 Modified 9Cr-1Mo 강을 500 o C 에서의크리프균열성장실험을수행하여고온파괴역학매개변수 C * 에의한크리프균열성장속도식을계산하여얻었으며, 재료상수인 B 와 q 의대수정규분포로부터몬테카를로시뮬레이션으로보다정확한신뢰구간을제시하였다. 본연구에서사용한 Modified 9Cr-1Mo 강은열간압연후노말라이징및템퍼링처리된것으로, C* 파라메터의계산에필요한고온물성자료는 500 o C 에서의인장시험과크리프시험을실시하여얻었다. 크리프균열성장시험은 ASTM E1457 에준하여수행하였고, 시편은 1/2 CT(compact tension) 시편을사용하였으며, 초기균열비 (a/w) 는대략 0.45~0.55 가되도록하였다. 균열의터널링현상을막기위해시편두께의 20% 로측면홈을가공하였다. 예비균열은방전가공 (electro discharge machining, EDM) 으로형성시켰다. 시험중의균열길이는 8A 의일정한전류를시편에입력하고균열성장에따른저항변화를이용하는직류전위차법 (direct current potential drop, DCPD) 을사용하였다. 시험조건은 500 o C 에서다양한하중으로총 6 개의시편에대하여각각시험을수행하여시간변화에따른크리프균열성장데이터를얻었다. 크리프균열성장속도식의재료상수인상수 B 와 q 는각시험에서얻어진데이터를바탕으로최소제곱법에의해서얻었다. 그리고재료상수 B 와 q 의값을각각하나의확률변수로가정하여대수정규분포에대하여몬테카를로시뮬레이션을수행하여균열성장속도를 10~90% 에해당하는확률적인신뢰성구간을예측하였다. 후기 본연구는 2015 년도정부 ( 미래창조과학부 ) 의재원으로한국연구재단의재원으로한국연구재단의지원을받아수행된원자력연구개발사업임 (2012M2A8A2025682). (1) Kim, W. G., Kim, S. H. and Ryu, W. S., 2001, "Creep Characterization of Type 316LN and HT-9 Stainless Steels by the K-R Creep Damage Model", KSME International Journal, Vol. 15, No. 11, pp. 1463~1471. 박재영, jypark701@gmail.com - 50 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 51 KSME15RE-T Ni-Base Alloy 617 과 P92 강이종용접부의미세조직및기계적특성평가 이주화 황정호 * 김태민 * 박정현 ** 조상명 ** 배동호 *** 성균관대학교기계공학과, * 성균관대학교기계공학과, ** 부경대학교신소재시스템공학과, *** 성균관대학교기계공학부 Assessment of Microstructures and Mechanical Characteristics for Dissimilar Welds of Ni-Base Alloy 617 and P92 steel Ju Hwa Lee, Joeng Ho Hwang*, Tae Min Kim*, Jung Hyun Park**, Sang Myung Cho**, Dong Ho Bae*** Graduate school of Mechanical Engineering, Sungkyunkwan University * Graduate School of Mechanical Engineering, Sungkyunkwan Universiy ** Graduate School of Materials System Engineering, Pukyong University *** School of Mechanical Engineering, Sungkyunkwan University Key Words: Dissimilar welding( 이종용접 ), Welding residual stress( 용접잔류응력 ), X-Ray Diffraction Method(X- 선회절법 ), Micro-structure analysis( 미세조직분석 ), HAZ( 열영향부 ) Abstract:. In the world, greenhouse gas by burning fossil fuel causes extremely serious problems. To solve the problems, various studies are being progressed and tested domestically and internationally. The best realistic method is developing generating efficiency of the power plant. For this, the temperature and pressure condition of a steam turbine should be increased and systematic and practical studies on the welding quality of similar and dissimilar materials, the metallurgical material change, and the welding residual stress analysis should be progressed. This study evaluates micro-structure analysis and mechanical characteristic about dissimilar weld between the heat resisting materials, Ni- Base Alloy 617 and P92(9Cr2W). To analyze the effect on fracture behaviors of heat-affected zone which is weakness of dissimilar weld, micro-structure observation and hardness test were held and the relation between the micro-structure and hardness of the weld zone was considered. Thus, the residual stress of the weld zone analyzed by using ABAQUS the program for analysis on numerical value and it was compared and considered with the result of the diffraction method of X-ray to secure reliability for the analysis result of this study. 초록 : 전세계적으로화석연료의연소로인해발생되는온실가스는지구온난화에매우심각한문제가되고있다. 이러한문제를해결하기위해국내외적으로다양한연구가진행중에있으며, 가장현실성이높은방안은발전소의발전효율을향상시키는것이다. 이를위해서는발전소증기터빈의작동온도와압력조건을높여야하며, 고온의극한환경에서신뢰성을보장할수있는동종, 이종재료용접부의용접품질, 야금학적재질변화, 용접잔류응력해석등에관하여체계적이고실용적인연구가선행되어야한다. 본연구에서는고온내열소재인 Ni-Base Alloy 617 과 P92(9Cr2W) 강의이종용접부에대해미세조직분석및기계적특성을평가하고자하였다. 이종용접부취약부분인열영향부의파괴거동에미치는영향을분석하기위하여미세조직관찰과경도실험을수행하였고, 용접부의미세조직과경도의관련성을고찰하였다. 또한수치해석프로그램인 ABAQUS 를이용하여용접부의잔류응력을해석하였으며, 해석결과에대한신뢰성을확보하기위하여 X- 선회절법실험결과와비교검토하였다. (1) C.Wiednig., C.Lochbichler., N.Enzinger. and C.Sommitsch., 2014, "Dissimilar Electron Beam Welding of Nickel base Alloy 625 and 9% Cr Steel," Procedia Engnieeing 86, pp. 184~194. (2) Beom Soo Kim., Tae Ha Son., and Taek Ki Min., 2012, "A Study on the Mechanical Property and Microstructure of SA213 P992 Boiler Pipe Steel, "Korean Journal of Air-Conditioning and Refrigeration Engineeing, Vol. 24, No. 11, pp. 777~783. (3) Megumi Kimura., Koji Yamaguchi., Masao Hayakawa., Kazuo Kobayashi. and Kenji Kanazawa., 2006, Microstructures of creep-fatigued 9-12% Cr ferritic heat-resisting steels," International Journal of Fatigue 28, pp. 300~308. (4) Seung Yeb Baek., Dong Ho Bae., 2011, "Fracture Mechanics Approach to X-Ray Diffraction Method for Spot Welded Lap Joint Structure of Rolled Steel Considered Residual Stress," Trans. of the KSME(A), Vol. 35, No. 10, pp. 1179~1185. (5) Young Su Park., Tae Kyun Kim. And Dong Ho Bae, 2011, "Assessment of Fracture Mechanical Characteristics Including Welding Residual Stress of Alloy 617," Trans. of the KSME, pp. 961~966. Ju Hwa Lee, juhwa0207@skku.edu - 51 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 52 KSME15RE-T - 52 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 53 KSME15RE-T 유압식변속기시험기술 정동수 한국기계연구원 Testing Technique for a Hydraulic Type Transmission Dong Soo Jung Korea Institute of Machinery & Materials Key Words: Transmission( 변속기 ), Pump( 펌프 ), Motor( 모터 ), Reliability( 신뢰성 ), Gear Train( 기어트레인 ) Abstract: Hydraulic type transmission controls variable volume of the hydraulic pump and the hydraulic motor sequentially, so that it has continuous speed ratio. Since the hydraulic type transmission has no shifting shock, high power density and excellent mobility, it is widely used for heavy equipment machines. The hydraulic type transmission is applied in variable technique field depending on application fields or operation conditions, but appropriate testing technique is not supplied yet. In this study, a testing technique that improves reliability of the product is proposed. 1. 서론유압식변속기는유압펌프와유압모터의가변용적을연속적으로제어함으로써무단의변속비를가질수있다. 유압식변속기는변속충격이없고출력밀도가높으며또한기동력이우수하기때문에중장비기계장비에널리활용되고있다. 동력전달효율이낮은치명적인단점은있으나이를보완하기위하여기계식변속기와병합되는응용기술로널리확대되고있다. 또한, 엔진의최적운전조건과연동함으로써연비향상및배기가스를감소시킬수있다. 유압식변속기는적용분야또는운전조건에따라다양하게응용되는기술분야이기때문에아직적합한시험기술이보급되고있지않다. 본연구에서는현장에서발생될수있는고장을재현하고고장분석을통하여제품의신뢰성을개선시킬수있는시험기술을제안한다. 2. 연구내용가변용적인유압펌프와유압모터, 가변용적을제어하는스텝핑모터, 동력을분배및합성하는두개의유성기어, 그리고유압동력을차단하는클러치로구성된유압식변속기는유압펌프의용적을정방향과역방향을전환함으로써변속기가탑재된차량의전진과후진을가능하게하고유압모터의용적을추가적으로제어함으로써변속범위의확장을가능하게함으로써단위중량당출력비가높은고출력급차량에적용이가능하도록개발된차세대변속기이다. 본변속기는기어트레인에서내부적으로부품들간의동력흐름이원활하도록유압펌프와유압모터의가변용적이제어되어야하기때문에동력흐름의해석과병행하여시험기술이개발되어야한다. 본변속기는동력흐름의해석에서입력속도가낮고동력이높아질수록가변용적이전환되는변곡지점이높은속도비에서형성되고운전조건이반대가되면낮은속도비에서변곡지점이형성된다. 시험항목들은현장의작동조건을반영한 9 개의성능시험, 4 개의환경시험, 그리고 1 개의수명시험으로구성된다. 성능시험항목들중에서효율시험은순수하게기계동력만이전달되는영역과유압동력이최대로전달되는영역을구분하여진행되고있다. 그리고수명시험은신뢰수준 80% 에서 B 10 보증수명 5,000 시간을보증하기위하여가속모델을적용하여 ZFAT 로 250 시간으로정의하였다. 3. 결론본연구에서는유압식변속기에대한내부구조를분석하고동력흐름을해석하고이와병행하여시험평가기술을개발하고신뢰성을평가하였다. 시료 2 대에대하여 250 시간무고장가속시험 (ZFAT) 을수행하여신뢰수준 80 % 에서작동시간 5,000 시간 (B 10 수명 ) 을확보하였다. 이러한시험기술은제품의신뢰성을평가하기위한목적이될수도있지만고장분석을통하여제품의신뢰성을개선하는데도효과적으로활용된다. 향후, 인용된시험시간산출모델및가속시험모델에대한유효성을검증하기위하여고장데이터를확보하는추가시험이필요하다고사료된다. (1) Jhon, W. E. and Jillian, Y. E., 2001, "Product Integrity and Reliability in Design," Springer. (2) Wayne, N., 1985, "Weibull Analysis of Reliability Data with Few or No Failures, Journal of Quality Technology," Journal of Quality Technology, Vol. 17, No. 3, pp. 140~146. Dong Soo Jung, jds667@kimm.re.kr C 2014 The Korean Society of Mechanical Engineers - 53 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 54 KSME15RE-T 외부충격에의한타이어손상시험법개발및판정기준수립연구 정수식 김동오 * 우종선 ** 현대자동차, * 금호타이어, ** 한국타이어 The Study for Evaluation of Tire Impact Performance by Developing Indoor Pinch Cut Test Soo-Sik Chung, Dong-Oh Kim*, Jong-Sun Woo** Hyundai Motor Company *Kumho Tire Co. Ltd **Hankook Tire Co. Ltd Key Words: Tire Damage( 타이어손상 ), Bulge( 벌지 ), Tire Strength Index( 타이어강도지수 ),Repeatability( 반복성 ) Tire Impact Performance( 타이어충격성능 ), Reproducing method ( 재현시험 ) Abstract: Low series tires with inch up are increasing to enhance vehicle maneuverability and brand value. Though tire is one of the most important safety components, low series tire are often damaged, like bulging or cutting by careless driving on bad road conditions. Especially unpaved off-road, broken road surface, pot hole and curb stone cause major tire damage in developing countries. In this paper new indoor reproducing method (Pinch Cut Test) for tire damage is suggested instead of outdoor vehicle test on special pot hole. The outdoor test is not efficient in repeatability because the position of each impact on tire is not the same. The test driver may hurt and the vehicle can be damaged, too. Indoor test reproduces tire damage mechanism by manufacturing jig. Main results are as follows. Firstly the cause of tire damage is established and indoor test method is developed the same as driving vehicle condition. Secondly a tire strength index that indicates tire s robustness is suggested. It will be a standard to make a guideline to determine a moderate original equipment tire at global market. Finally vehicles with better tire impact performance enhance customer s safety and increase product reliability. 초록 : 차량주행성능및상품성향상을위해대구경 (17 인치이상 ) 및저편평비 (45 시리즈이하 ) 타이어적용비율이증가하고있으나주행중외부충격손상 ( 벌지등 ) 이자주발생하여고객의안전에위협이되고있다. 현재이러한타이어손상조건을반영한실차평가법이있으나시험운전자의안정성과평가결과의반복성, 재현성이부족하여실내평가법개발이필요한실정이다. 따라서본연구에서는실차평가보다안정성, 반복성및재현성이우수한실내단품시험법을개발하였고, 타이어충격강성을나타내는강도지수산출방법을만들었으며문제발생지역에적합한타이어강도지수기준을수립하였다. 또한본연구에서개발한실내시험법및강도지수로향후차량판매지역의환경조건에적합한타이어규격이선정및양산될수있도록글로벌지역별타이어규격선정가이드작성기준을제시하였다. 본연구에서의주요결과는다음과같다. 첫째, 차량메이커로서필드타이어손상의원인을규명하고, 단품재현시험법을개발하여독자적인필드문제재현기술을확립하였다. 둘째, 대구경, 저편평비타이어개발시사전에타이어강도수준을평가하여해외판매지역별적합성을정량적으로평가 판단할수있는양산기준을제시하였다. 셋째, 열악한도로환경조건에보다강건한타이어를개발, 판매하여타이어외부충격손상으로인한문제를미연방지함으로써고객의안전성및당사차량신뢰성을더크게향상시킬수있는기반을만들었다. 후기 본연구내용으로글로벌차량판매지역별타이어규격선정가이드를수립하였으며본연구에적극적으로협조해주신금호타이어, 한국타이어관계자분께감사드립니다. (1) Yokohama Rubber Inc., 1995, Pneumatic Tire Technology, pp. 75~89. (2) Thomas R. Giapponi, 2008, Tire Forensic Investigation Analyzing Tire Failure. (3) Mohammed Billal, Vinothkumar, Sabarinath, 2011, Simulation and Test Correlation of Wheel Impact Test, SAE2011-28-0129. (4) Trevor J. Brown, Rick S. Wallace, 1994, Development of the SAE J1981 Road Hazard Impact Test for Wheel and Tire Assemblies, SAE940534. Soo-Sik Chung bigchung@hyundai.com - 54 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 55 KSME15RE-T 웹기반구조응력적용아크용접구조물피로설계툴의개발 곽시영 박준경 * 한국생산기술연구원 & 과학기술연합대학원대학교, * 한국생산기술연구원 Development of Fatigue Design Web Tool of Arc Welded Structures Using Structural Stress Si-Young Kwak, Joon-Kyeong Park* Korea Institute of Industrial Technology & University of Science and Technology * e-design Group, Korea Institute of Industrial Technology Key Words: Arc Weld ( 아크용접 ), Fatigue( 피로 ), Structural Stress( 구조응력 ), Web Based( 웹기반 ) Abstract: Welding is an extensive process applied to only manufacture of automobiles but also architecture, civil, and plant fields. The role of weld process is bonding two or more parts to one piece, so the fatigue design of welded zone is very import step to achieve of reliability. However, the welded zone show stress singularity induced by geometry discontinuity and unexpected defects during welding. Most of Mechanical Design depends on CAE(Computer Aided Engineering) in these days. Fatigue analysis based on CAE shows weakness in element type and mesh size(mesh sensibility) in a welded structures especially. To overcome these challenges, Battelle has developed a novel, mesh insensitive structural stress method. The stresses are calculated using the balanced nodal forces and moments obtained at the weld toe location from the finite element solutions. Battelle s structural stress procedure has been adopted as design weld fatigue codes by ASME Sec. VIII Div. 2, API 579/ASME FFS-1 and BV(Bureau Veritas). In this country, Famous heavy industry companies have tried out the approach in ship building design. In the others domestic fields, even though global car makers dose not try the method due to high cost and insufficient information and knowledge. In this study, we developed the fatigue design tool of welded structures based on Web. Many related engineers can encounter the method proposed Battelle and as a results, the study will contributes to increase of the fatigue reliabilities. 초록 : 용접은제품의제조공정뿐만아니라, 건설, 토목, 플랜트등다양한분야에서구조물의조립에적용되는공정이다. 또한작게는고속으로움직이는자동차에서크게는빌딩, 대형선박에이르기까지고위험구조물에적용되기때문에용접구조물의신뢰성척도인피로예측은설계단계에서매우중요한문제이다. 하지만용접부위는기하학적불연속과용접공정에서수반되는결함의발생으로용접끝단부위에서응력집중현상이발생하고정확한피로예측을어렵게만드는요인이되고있다. CAE 기술의발전과더불어구조해석을통한피로평가가이루어지고있으나해석요소의크기에따라응력값이변하는등여전히많은연구를필요로하고있다. 용접부의피로해석을위해 Battelle 에서개발한요소의크기및종류에둔감한구조응력법은용접부응력집중을평형조건을이용하여효과적이고일관성있게평가하는방법으로근래조선, 자동차등의피로설계에서시도및적용되고있는방법이다. 하지만일부전문가나대형조선소의전문적인조직이외에는구조응력법에접근하기어려운것이현실이다. 본연구에서는그동안오프라인에서구축된기술을웹상에서구현하여누구나구조응력기법을적용하여피로예측을할수있도록웹용설계툴을개발하였다. 이를사용함으로써국내에서첨단피로해석기술의접근용이성확보와피로설계기술발전에기여할수있을것으로기대된다 (1) S. Y. Kwak, C. H. Lim and J. W. Beak, 2009, Contribution Analysis Using Shape Simplification Method for Casting Structure Shrinkage, Trans. of the KSME(A), Vol. 33, No. 8, pp. 807~812. (2) Dong, P., Hong, J. K., and De Jesus, A. M. P., 2007, Analysis of Recent Fatigue Data Using the Structural Stress Procedure in ASME Div 2 Rewrite, Transactions of ASME, Journal of Pressure Vessel Technology, Vol. 139, pp. 355-362. (3) Hong, J. K. and Forte, T. P.,2012, Development of Fatigue Evaluation Procedure for Weld-Bonded Joints using the Battelle Structural Stress Method, SAE Paper No. 2012-01-0477. (4) Fatigue Analysis of Offshore Steel Structures-Battelle Structural Stress Methodology, Bureau Veritas, Under Final Review, 2012 Presenting author name, e-mail address - 55 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 56 KSME15RE-T 베어링강에대한동탄성계수측정및초음파피로신뢰성평가 권오철 * 이선호 * 신철수 * 노희청 ** 박태현 ** 조인식 ** 박인규 ** * 일진글로벌, ** 선문대학교 Dynamic Elastic Modulus Measurement and Ultrasonic Fatigue Reliability Assessment of Bearing Steel 1 st OhChul Gwon*, 2 nd SeonHo Lee*, and 3 rd ChulSoo Shin*, 4 rd HeeChung Nho**, 5 rd TaeHyun Park**, 6 rd InSik Cho **, 7 rd InGyu Park** *1 st ILJIN GROUP. **4 nd SUN MOON University Key Words: Ultrasonic Fatigue Testing( 초음파피로시험 ), Bearing Steel ( 베어링스틸 ), Accelerated test method ( 가속시험방법 ), Dynamic Elastic Modulus( 동탄성계수 ) Abstract: Depending on the speed of the machine the incidence of premature failure due to fatigue of bearings is increased where a higher resistance to fatigue of the material development is required. The quality of bearing materials is to be accompanied by a quality assurance and in current steels oxygen content and non-metallic listing are directly related to the evaluation of the cleanliness and fatigue performance. The evaluation of fatigue performance of bearing steel ensures the quality stability through establishing industry standards for reliability of bearing steel quality and life expectancy. Therefore, in this paper, a critical evaluation of accelerated ultrasonic fatigue testing (UFT) was performed according to ASM HANDBOOK Vol. 8, where 20kHz ultrasonic fatigue test method and piezoelectric ceramic (PZT) fatigue test method of a displacement control method using the acoustic resonance vibration system, and the elastic modulus is measured according to ASTM E1875, KS F 2437 standards. It was found that the specimen is an important factor to design and change in stress. The mechanical properties and ultrasonic fatigue test results before and after heat treatment for SAE 52100 bearing steel through a proprietary UFT and dynamic elastic modulus measurement technology were performed in Korea. The results related to the mechanical properties and fatigue life cycle of the study was to enhance the fatigue strength as described destructive fatigue theory. 초록 : 베어링은부품소재산업에서없어서는안되는매우중요한요소부품으로서베어링의강성과내구성향상지표인 Dynamic Load Rating/Static Load Rating 의향상을위해제조기술에서는소재, 가공, 열처리, 표면처리등모든기계기술이집약되어지며, 가장원천적인소재기술과표면처리기술이점점부각되고있다. 특히각종기계의고속화에따라베어링의피로로인한조기파손의발생빈도가증가하므로피로에대한저항성이더욱높은소재개발이요구되고있다. 이에베어링의품질확보를위해서는소재의품질평가가수반되어야하며, 현재강중산소함량및비금속게재물등청정도와관련되피로성능을평가하여베어링강의품질평가및소재수명예측에더나아가베어링의신뢰성확보를위한산업표준화구축을통해품질안정성을확보하여야한다. 이러한피로수명은굽힘이나비틀림에의한피로파괴, 마모에의한성능저하, 마찰특성악화에의한성능및효율저하등제품의사용환경에따라개별적또는복합적요인에의해발생하는아주복잡하고어려운기술및학문분야이다. 따라서본논문에서소개하고자하는핵심적인평가기술은 ASM HANDBOOK Vol. 8 에있는초음파가속피로 (UFT : Ultrasonic Fatigue Test) 시험법으로 20kHz 압전세라믹 (PZT) 탄성공진진동방식을이용한변위제어방식의피로시험방법이며, 기본적으로 ASTM E1875, KS F 2437 규격의동탄성계수측정이수반되어야한다. 이는시험편설계와응력환산에중요한인자로결정된다. 이에국내에서독자적으로개발한초음파피로시험기와동탄성계수측정기술을통해 SAE 52100 베어링강에대한열처리전후의기계적특성및초음파피로시험결과를확인하고자하였으며, 이와관련된피로강도향상에대한기계적특성및기가사이클피로수명에대한결과를피로파괴적이론으로설명하고자하였다. 후기 " 본논문은제천자동차 ( 수송기계 ) 부품산업클러스터육성사업으로지원된연구결과입니다 [ 제품공정기술개발, 자동차용휠베어링강기가사이클신뢰성시험기술개발 ]" (1) Cho, I. S., Shin, C. S., Kim, J. Y. and Jeon, Y. H., 2012, "Accelerated Ultrasonic Fatigue Testing Appications and Reserch Trends," Trans. Korean Soc. Mech. Eng. A, Vol. 36, No. 6, pp. 707~712. (2) Wagner, D., Cavalieri, F. J., Bathias, C., Ranc, N., 2012, " Ultrasonic fatigue tests at high temperature on an austenitic steel," PropulsionandPowerResearch,Vol.1,pp.29~35. (3) www.mbrosia.co.kr true8297@nate.com - 56 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 57 KSME15RE-T 상온에서 Alloy 617 모재와용접부재의저사이클피로거동과수명예측 Rando Tungga Dewa * 황정준 * 김태수 * 김우곤 ** 김민환 ** 김병탁 *** 김선진 *** * 부경대학교대학원, ** 한국원자력연구원, *** 부경대학교, Low Cycle Fatigue Behavior and Life Prediction of Alloy 617 Base Metal and the Welded Joints at Room Temperature Rando T. D.*, Jeong Jun Hwang*, Tae Su Kim*, Woo Gon Kim**, Min Hwan Kim**, Byung Tag Kim*** and Seon Jin Kim*** *Graduate School of Department of Mechanical Design Engineering, Pukyong National University ** Korea Atomic Energy Research Institute (KAERI) Department of Mechanical & Automotive Engineering, Pukyong National University Key Words: Alloy 617, Coffin-Manson Relationship, Fatigue Life, Low Cycle Fatigue, Welded Joint Abstract: The Very High Temperature (VHTR) is one of the most promising reactor between the Generation-IV reactors for producing electricity, process heat and hydrogen. Alloy 617 is a primary candidate material for the VHTR main component, intermediate heat exchanger, due to its good properties for components of power generating plants with high temperature strength. Furthermore, system start-ups and start-downs as well as power transients will produce low cycle fatigue (LCF) loadings of components. These considerations used to determine the material resistance of cyclic loading and the properties of Alloy 617 under LCF loadings. However, many researchers have been conducted LCF tests for base material only, they did not investigate the weld joint material. In this investigation, The LCF behaviour of Alloy 617 base metal (BM) and weld joint (WJ) which is fabricated by a gas tungsten arc weld (GTAW) process, have been studied under continuous cyclic loading. Through the Coffin-Manson relationship or better known as the strain-life relationship that is always used to describe the strain-controlled LCF behavior. Alloy 617 was solution treated hot rolled plate with thickness of 25 mm. Cylindrical LCF specimens were machined from base metal and weld pad configuration with 6.0 mm diameter in the reduced section with a gage length of 12.5 mm. The shape of the weld joint has a single V-groove with an angle of 80 o and 10 mm root gap. A filler metal was used for KW-T617 that was prepared according to AWS specifications. Fully reversed axial total strain controlled LCF tests were conducted in air at room temperature condition at four different total strain-controlled ranges, i.e. 0.6, 0.9, 1.2 and 1.5% using a servo hydraulic machine equipped with frequency of 0.25 Hz. The waveform is chosen in triangular shape and the fatigue life was taken as the cycle number corresponding to a 100% drop in the peak tensile stress. LCF data was taken automatically by a personal computer through an extensometer attached to the gauge section of specimen. In the strain-controlled LCF testing, the cyclic stress response is an important feature of a material as it presents the path of the stress amplitude. In engineering materials usually exhibits an initial cyclic hardening or softening to some level in cyclic plastic deformation process. The higher stress generate a crack is to nucleate. For higher total strain range cyclic softening are observed until the rapid stress drop to failure. At the lower total strain range the more likely constant saturation phase stabilized during the cyclic loading and decrease slowly until failure. Therefore, along under the same total strain range, the fatigue life exhibited that BM specimens was longer than WJ specimens and fatigue life was decreasing with increasing in strain range level. The LCF testing results were evaluated at half-life according to Coffin-Manson equation via universal slope method. The transition of fatigue life is 4395 cycles for BM exhibited a longer life than 766 cycles for WJ. All cyclic lives are predicted within a factor of ±1.5 and the predicted results are in a good agreement with error of accuracy about 17%. The higher strain levels for room temperature condition showed a significant error when the plastic strain range is so small. In conclusion, this two kind of materials experienced a similar cyclic softening phase throughout almost the entire life and the cyclic hardening occurred at a short period of the fatigue life. It was found that the Coffin-Manson provided a good adaptation results for the life prediction of Alloy 617 BM and WJ at room temperature. (1) Seon Jin Kim, Pil-ho Choi, Rando Tungga Dewa, Woo Gon Kim, Min-Hwan Kim, Norway, 2014, "Low Cycle Fatigue Properties of Alloy 617 Base Metal and Weld joint at Room Temperature," Procedia Materials Science in European Conf. on Fracture, Vol. 3, pp. 2201~2206. (2) Rando Tungga Dewa, Seon-Jin Kim, Woo-Gon Kim and Min-Hwan Kim, October 2014, "Evaluation of Fatigue Life on Alloy 617 Base Metal and Alloy 617/Alloy 617 Weld Joints under Low Cycle Fatigue Loading," J. of the Korean Society for Power System Engineering, Vol. 18, No. 5, pp. 122~128. (3) Pil-Ho Choi, Seon-Jin Kim, Woo-Gon Kim and Min-Hwan Kim, October 2014, "An Experimental Investigation on Low Cycle Fatigue Behavior of Alloy 617 Base Metal and Alloy 617/Alloy 617 Weld Joints," J. of the Korean Society for Power System Engineering, Vol. 18, No. 5, pp. 115~121. Seon Jin Kim, sjkim@pknu.ac.kr - 57 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 58 KSME15RE-T DIC 기법을이용한 GFRP 복합재의피로손상특성화 김종일 허용학 * 김용환 ** 한국표준과학연구원, * 한국표준과학연구원, ** 충남대학교 Fatigue damage characterization of GFRP composite using DIC technique Jong Il Kim, Yong Hak Huh* and Yong Hwan Kim** Korea Research Institute of Standard and Science * Korea Research Institute of Standard and Science ** Chungnam National University Key Words: DIC(digital image correlation), GFRP composite(gfrp 복합재 ), Fatigue test ( 피로시험 ), Notch( 노치 ), Strain( 변형률 ) Abstract: The aim of presented investigations was to measure fatigue characteristic in GFRP composites with a notch using DIC technique. The full-field strain distribution around a notch was measured with DIC technique under cyclic loading at 3 Hz. The notch of GFRP composites was introduced by artificial hole and edge with optional radius in the four-ply laminated GFRP composites with the unidirectional(0 ) and three directional(0 /±45 ) fiber orientations. The full-field stress was determined with the strain results. 초록 : 항공우주및신재생에너지분야에서는금속재료에비해서비강성 강도등기계적물성이뛰어난복합재료가많이사용되고있다. 그중에서도섬유강화복합재료 (fiber-reinforced plastic composite) 가지배적으로사용되며, 이러한섬유강화복합재료는섬유의방향, 밀도, 배열형상, 프리프레그 (prepreg) 의적층수에따라손상의발생및진전의메커니즘이다르다. 따라서제조및운용상의결함과손상은재료및제품의신뢰성에큰영향을미친다. 본연구에서는피로하중하에서노치를포함하고있는 GFRP 복합재료의변형률거동측정함으로써손상의발생및진전에따른피로특성을조사하였다. 본연구에서는 GFRP 복합재료의노치주위의변형률을측정하기위해 3D DIC 기법을사용하였으며, 3D DIC 기법은두대의 CCD(coupled charge device) 카메라를사용하여시험편표면의변형전이미지와변형후이미지의비교를통해전체영역의변위및변형률을계산하게된다. 본시험에사용된시험편은시험편길이방향 (0 ) 에대해서각각 1 축 (0 ) 및 3 축 (0 /±45 ) 의 4 ply 로적층된 GFRP 복합재료를이용하여두께 3.5 mm, 너비 25 mm, 길이 250 mm 의판재형으로제작되었다. 또한, 시험편의노치부는핸드드릴을이용하여건전한시험편에지름 1.5 mm 의구멍을뚫어형성한노치와추가로시험편폭방향으로뾰족한노치의두종류를시험하였다. 피로하중하에서손상의발생및진전따른변형률분포를측정하기위해시험편길이방향으로 3 Hz 속도로피로하중을부하하였다. DIC 이미지는반복하중의최대점 (peak load) 에서취득하였다. GFRP 복합재의손상발생및진전에따른피로특성을고찰하기위해, 시험편길이및폭방향, 전단 (shear) 및 von-mises 변형률을조사하였으며, 얻어진변형률을이용하여시험편표면의응력장을계산하였다. 1 축시험편에서는노치양끝단에서부터각각시험편길이방향으로띠형태의변형률분포가나타나시험편길이방향보다는폭방향으로변형률구배가큼을확인할수있었다. 3 축시험편에서는시험편길이방향에대해 ±45 방향으로변형률띠형태의변형률분포가지배적으로나타났지만, 0 의섬유방향의영향으로인해상대적으로 1 축시험편에비해폭방향으로의변형률구배가작게나타났다. 또한, 피로하중및사이클이증가할수록두시험편모두변형률의구배가크게나타난영역이시험편길이방향으로증가하였다. 그러나 3 축시험편에서는 ±45 의섬유방향으로인해시험편폭방향으로도그영역이발전함을확인하였다. 또한피로하중에따른손상부분을절단하여 SEM 측정을통해시험편표면및절단면을관찰하여손상의종류와진전단계및그형태등을확인할수있었다. (1) Caminero, M. A., Lopez-Pedrosa, M., Pinna, C. and Soutis, C., 2013, "Damage monitoring and analysis of composite laminates with an open hole and adhesively bonded repairs using digital image correlation," Composite: Part B, Vol. 53, pp. 76~91. (2) Nixon-Pearson, O. J., Hallett, S. R., Withers, P. J. and Rouse, J., 2013, "Damage development in open-hole composite specimens in fatigue. Part 1: Experimental investigation," Composite Structures, Vol. 106, pp. 882~889. (3) Huang, Y., Bu, Y., Zhou, L., Zhu, J., Shi, H., Xie, H. and Feng, X., 2013, "Fatigue crack growth and propagation along the adhesive interface between fiber-reinforced composites," Engineering Fracture Mechanics, Vol. 110, pp. 290~299. 김종일, isumilov@naver.com - 58 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 59 KSME15RE-T 소형풍력발전기용 AFPMG 의스톨영역을고려한최대출력제어에관한연구 김성안 변상인 조윤현동아대학교 A Study on Maximum Power Control Considering Stall Region of AFPMG for Small Wind Turbine Sung An Kim, Sang In Byun and Yun Hyun Cho Electrical Engineering, University of Dong-A, Key Words: Wind Turbine( 풍력터빈 ), Generator( 발전기 ), Maximum Power Control( 최대출력제어 ), Stall Control( 스톨제어 ), Axial Flux Permanent Magnet Generator( 축방향자속영구자석형발전기 ), Constant Speed Control( 일정속도제어 ), Flux Weakening Control( 약자속제어 ). Abstract: Blades of small wind turbines are being applied to the pitch angle to a minimum in order to obtain a maximum power below the rated wind speed. This occurs high speed rotating blade and excessive output of generator over the rated wind speed. To prevent these problems, mechanical control methods, such as a pitch control of blade and brake and electrical control methods, such as a constant speed control and flux-weakening control have been applied. These methods have disadvantages, such as rise in unit cost, additional space requirements and over torque of shaft. Therefore, this paper proposes maximum power control considering stall region of AFPMG for small wind turbine. The maximum output control of AFPMG are separated by low-speed, medium speed, high speed and still region in accordance with speed variations. Further, this control should be considered high torque- acceleration and low torquedeceleration according to torque variations. Compared with the conventional method, the proposed control method can be expanded as a power generation regions and has the effect of preventing the overload that accumulated in the blade and rotating shaft in a high speed areas. 초록 : 소형풍력터빈의블레이드는정격풍속이하에서최대출력을얻기위해피치각을최소로적용되고있다. 이는정격풍속이상에서블레이드의고속회전및발전기의과출력위험이발생한다. 이러한문제점을방지하기위해서는피치제어시스템과브레이크설치등의기계적제어와발전기의일정속도제어와약 - 자속제어등의전기적제어를적용하고있다. 이는시스템의단가상승, 추가공간요구및회전자축의과토크가발생하는단점이있다. 그러므로, 본논문에서는풍력터빈의스톨영역을고려한 AFPMG 의최대출력제어를위한방법을제안한다. AFPMG 의최대출력제어는속도변화에따라저속, 중속, 고속및정지영역으로구분된다. 또한, 각각의속도영역에서발전기의토크변화에따라고토크 - 가속과저토크 - 감속으로나누어제어한다. 저속영역에서는발전기의최대출력을위해서발전기의속도지령값을최대로증가하여 q 축전류지령값을주속비에따라비례적으로증가시킨다. 중속영역에서는고토크 - 가속영역과저토크 - 감속영역으로나누어 q 축전류지령값을제어한다. 마지막으로, 고속영역에서는고토크가속영역으로발전기의속도를감속시켜최대출력일정제어를한다. 제안된방식의타당성을입증하기위해서, 선행연구된 3kW AFPM 발전기와풍력발전기시스템의실험데이터를기반으로컴퓨터시뮬레이션을수행하였다. 시뮬레이션을통해서기존방식의문제점을파악하고제안된방식의알고리즘을적용하여비교분석하였다. 제안된스톨영역을고려한최대출력제어는기존의방식에비해서발전이가능한속도영역이확장되며고풍속영역에서블레이드와회전축에누적되는과부하를방지하는효과를확인하였다. 후기 이논문은 2014 년도정부 ( 미래창조과학부 ) 의재원으로한국연구재단의지원을받아수행된기초연구사업임 (No. NRF-2014R1A2A2A01003368). 본연구는 2014 년도산업통산자원부의재원으로한국에너지기술평가원 (KETEP) 의지원을받아수행한연구과제 (No. 20134030200320) 입니다. (1) Lee, K. K., Han, S. H., 2012, "Optimization of Wind Turbine Pitch Controller by Neural Network Model Based on Latin Hypercube," Trans. of the KSME(B), Vol. 36, No. 9, pp. 1065~1071. Presenting author name, e-mail address - 59 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 60 KSME15RE-T 직접구동형축방향자속형영구자석풍력발전기에관한연구 변상인 전효근 조윤현동아대학교 A Study on Axial Flux Permanent Magnet Synchronous Generator for Direct-Driven Wind Turbine Sang-In Byun, Hyo-Keun Jeon and Yun-Hyun Cho Electrical Engineering, Dong-A University Key Words: Axial Flux Permanent Magnet Generator( 축방향자속형영구자석발전기 ), Radial Flux( 경방향자속형 ) Direct-Driven( 직접구동형 ), Finite Element Methodology( 유한요소법 ), Wind Turbine System( 풍력발전시스템 ) Abstract: This paper presents a study on fractional slot axial-flux permanent magnet generator for direct-driven wind turbines. Radial flux and axial flux PM machines are compared based on the same machine diameter in terms of volume, efficiency, and cost of active material. The AFPM found to be a light, low cost and high performance solution for direct-driven wind turbines. For fast and accurate calculation of performance in the preliminary evaluation of AFPM generators for large power DD wind turbines, a d-q model of AFPM is then developed to calculate the generating performance. To verify the design and analysis methodology, a 3kW prototype was constructed and tested at the end of this study and the measurement results generally agree well with the analysis results. 초록 : 최근자원고갈과원자력발전의안전성문제점등의대안으로풍력, 조력, 태양광발전등의친환경에너지자원의개발이중요시되고있다. 풍력시스템분야에서다양한발전시스템을비교해보면직접구동형영구자석발전기를적용한시스템이손실이적으며, 가격대비연간에너지생산량이높은장점을가진다. 이러한흐름에따라최근산업에서의주관심사는고성능저가격의발전기를개발하는데주목하고있다. 본논문에서는풍력발전시스템용직접구동축방향자속형영구자석발전기에대하여연구하였다. 경방향및축방향자속형발전기의체적, 효율그리고제작비용등을동일한치수를두고비교한결과축방향자속형발전기가가격및무게, 성능면에서우수하고직접구동풍력발전시스템에적합하다는결론을얻을수있었다. 권선계수, 병렬회로수, 코딩토크의주기성, 기자력고조파함유율, 회전자손실등을고려하여설계하였으며, 대용량직접구동풍력발전기에적용한축방향자속형영구자석발전기의성능분석을보다빠르고정확하게하기위해, d-q 모델을제안하였으며, 이를통해발전기의성능을예측할수있었다. 발전기 d-q 모델의파라메터는회전방향으로요소분할한 3D 모델을이용하여계산되엇으며, 분수스롯을가지는축방향발전기를소형풍력발전기에적용하여제안한방법을검증하였다. 3kW 급발전기는동일한치수로설계되었으며, 슬롯수와극수의조합을달리두어각타입별발전기출력, 전압, 효율그리고역률등이비교분석되었으며, 결과적으로분수슬롯구조의다층권선법이축방향자속형풍력발전기에적합하다는결론을얻을수있었다. 발전기설계및분석을검증하기위해서 3kW 급소형풍력발전기의시제품제작및성능평가를거쳤으며, 마지막으로제안된설계및해석기법을통한해석치와성능평가를통한실험치의비교검증을통하여제안된방법을통해분수슬롯의축방향자속형발전기의성능예측이가능하다는것을얻을수있었다. 후기 본연구는 2014 년도산업통산자원부의재원으로한국에너지기술평가원 (KETEP) 의지원을받아수행한연구과제 (No.20134030200320) 입니다. 이논문은 2014 년도정부 ( 미래창조과학부 ) 의재원으로한국연구재단의지원을받아수행된연구임 (No.NRF-2014R1A2A2A01003368). (1) A. D. Hansen, L. H. Hansen, 2007, "Wind Turbine Concept Market Pencentration over 10 years(1995-2004), " Wind Energy, vol. 10, pp. 81-97. (2) H. Polinder, et al., 2006, "Comparison of Direct-driven and Geared Generator Concept for Wind Turbines, " IEEE Transactions on, vol. 21, pp. 725-733. Hyo keun Jeon, hyokeun6876@gmail.com - 60 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 61 KSME15RE-T 대용량풍력발전기용하이브리드다단직접구동형발전기 김양균 * 김태영 * 박정민 * 조윤현 ** 한승호 * * 동아대학교기계공학과, ** 동아대학교전기공학과 Hybrid Multi-Stage Direct-Drive Generator for Large-Scale Wind Turbine Yang Gyun Kim*, Tae Young Kim*, Jeong Min Park*, Yun Hyun Cho** and Seung Ho Han* * Dept. of Mechanical Engineering, Dong-A Univ., Busan, Korea ** Dept. of Electrical Engineering, Dong-A Univ., Busan, Korea Key Words: Hybrid multi-stage direct-drive generator( 하이브리드다단직접구동형발전기 ), Wind turbine( 풍력발전기 ), Axial flux permanent magnet-type machine( 축방향자속영구자석형발전기 ), Radial flux permanent magnet-type machine( 반경방향자속영구자석형발전기 ) Abstract: A direct-drive generator for offshore large-scale wind turbine has attracted interest because of a higher energy density in comparison with a gear train type generator. The direct-drive generator in the ways of magnetic flux direction are divided into AFPM(Axial Flux Permanent Magnet)- and RFPM(Radial Flux Permanent Magnet)-type machine. The AFPM-type machine is highly efficient in generating electricity due to its structural feature such as narrow width in comparison with the RFPM-type machine. If the AFPM-type machine is applied, an increase of electric power production through multi-stage in axial direction is easily achieved. On the other hand, the RFPM-type machine can be applied to a geometric feature of wide width. In this study, a hybrid two-stage direct-drive generator for 6MW was proposed, in which the two-stage AFPM-type machine for 5 MW was composed of each topology model for 2.5MW with hollow shape of the rotor with annular disc, the stator and the main shaft mounted on coupled slew bearings. In addition, the RFPM-type machine with a capacity of 1MW was added to the hollow shape of the rotor. Analytic results obtained from an electro-magnetic and structural interaction analysis showed that the structural weight of the proposed hybrid two-stage direct-drive generator can be achieved under a total weight of 150tonf in a condition satisfying the requirements of structural behaviors such as allowable air-gap clearance and strength. 초록 : 해상풍력용대용량직접구동형발전기는증속기가필요한간접구동형발전기에비해전력밀도와유지보수측면에서유리하여, 관련기업에서많은관심을갖고개발되어지고있다. 직접구동형발전기는자속방향에따라 AFPM(Axial Flux Permanent Magnet) 및 RFPM(Radial Flux Permanent Magnet) 방식으로나누어지며서로다른구조적인특징을가지고있다. AFPM 방식발전기는폭이좁은형상적인특징을가지고있어, 축방향으로의적층을통해전력생산을증대시키기에용이하다. 이에반하여 RFPM 방식발전기는폭이넓은경우에적용할수있는특징을갖고있다. 본연구에서는축방향으로의적층이용이한중공축과한쌍의선회베어링으로구성된 2.5MW 급 AFPM 방식발전기를 2 단으로적층하고, 추가적으로중공축에 1MW 급 RFPM 방식발전기가장착된 6MW 급하이브리드직접구동형발전기를제안하였다. 전자기해석과구조연성해석을통하여, 허용공극과강도를만족하는조건에서제안된 6MW 급하이브리드직접구동형발전기의총중량이 150tonf 미만임을확인하였다. 후기 본연구는 2014 년도산업통산자원부의한국에너지기술평가원 (No.20134030200320) 및지역혁신센터사업인고기능성밸브기술지원센터의지원을받아수행되었습니다. (1) D. Bang, H. Polinder, G. Shrestha and J. A. Ferreira, 2008, Review of Generator Systems for Direct-Drive Wind Turbines, European Wind Energy Conference & Exhibition, pp. 1~11. (2) Staffan Engstrom and Stefan Lindgren, 2006, Design of NewGen direct drive generator for demonstration in a 3.5 MW Wind Turbine, EWEC(European Wind Evergy Conference & Exhibition, pp. 137. Corresponding Author : Seung Ho Han, shhan85@dau.ac.kr - 61 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 62 KSME15RE-T 대용량풍력발전기용직접구동형발전기의냉각장치 김태영 * 김양균 * 이명곤 * 조윤현 ** 한승호 * * 동아대학교기계공학과, ** 동아대학교전기공학과 Cooling System for Direct-Drive Generator with AFPM-Type Machine in Large- Scale Wind Turbine Tae Young Kim*, Yang Gyun Kim*, Myeong Gon Lee*, Yun Hyun Cho** and Seung Ho Han* * Dept. of Mechanical Engineering, Dong-A Univ., Busan, Korea ** Dept. of Electrical Engineering, Dong-A Univ., Busan, Korea Key Words: Cooling system( 냉각장치 ), Direct-drive generator( 직접구동형발전기 ), Axial flux permanent magnettype machine( 축방향자속영구자석형발전기 ), Heat transfer( 열전달 ) Abstract: Direct-drive generator with AFPM(Axial Flux Permanent Magnet)-type machine in a large-scale wind turbine has drawn interest of renewable energy industries due to its higher torque density and relatively simple structure compared with geared-type generator. The AFPM-type machine, however, has a history of overheating on the surface of the stator, so that power production decreases significantly. A proper cooling system, therefore, is necessary. In this paper, performance evaluation by means of numerical heat transfer analysis was carried out for the 2.5MW AFPM-type machine with air-cooled type cooling system equipped with an air-blower and water-cooled type cooling system using a heat pipe wound at top-side of the stator. The numerical results showed that the temperatures on the stator surface using the air- and water-cooled type cooling system were 60 and 76 o C, respectively. The temperatures of the permanent magnet caused by the radiant heating from the stator surface were 53 and 66 o C, respectively, in each cooling system, which met the requirements for a given power production. As a result, the permanent magnet did not reach the malfunction temperature. Although the water-cooled type cooling system didn t show better performance in terms of the cooling condition, it gave even better effect in the aspect of the light-weight design due to relatively small size of water pumps and peripheral device. 초록 : 대용량풍력터빈에서사용되고있는직접구동형발전기중 AFPM(Axial Flux Permanent Magnet) 방식발전기는증속기를사용하는간접구동형발전기에비해높은토크밀도와단순한구조형상때문에신재생에너지산업에서많은관심을두고개발하고있다. 그러나 AFPM 방식발전기의대형화에따라고정자표면에발생하는높은열로인해발전효율이급격하게감소하는문제가있어이에적합한냉각장치의필요성이대두하고있다. 본연구에서는 2.5MW 급 AFPM 방식발전기에적용되는과급기를이용한공랭식냉각장치와고정자주위에히트파이프를감아냉각하는수랭식냉각장치를대상으로열 - 유동연성해석을통한냉각성능을평가하였다. 고정자표면에대한수치해석결과공랭식냉각장치의경우온도가 60 o C 에도달하였으며, 수랭식냉각장치의경우 76 o C 를나타내었다. 아울러고정자표면의복사열에의한영구자석온도는공랭식냉각장치에서 53 o C, 수랭식냉각장치에서 66 o C 로나타났다. 이는전력생산을위한영구자석의허용온도요구조건을충족하는수치이다. 결과적으로각각의냉각장치에서영구자석의표면온도가발전성능에크게영향을미치는고장온도에도달하지않았다. 수랭식냉각장치는공랭식냉각장치보다냉각성능은좋지않지만, 발전효율에영향을미치지않는범위에서비교적작은용량의물펌프및주변장치가요구되어경량설계의관점에서유리하다고판단된다. 후기본연구는 2014 년도산업통산자원부의한국에너지기술평가원 (No.20134030200320) 및지역혁신센터사업인고기능성밸브기술지원센터의지원을받아수행되었습니다. (1) Hong Gi Lee, 2005, "Development of 800kW class Direct Drive Synchronous Generator for WECS," Applied Thermal Engineering., vol.24, No.4, pp. 76-79. (2) Janne Nerg, 2013, "Lumped-Parameter-based Thermal Analysis of a Doubly Radial forced-air-cooled Direct- Driven Permanent Magnet Wind Generator," Applied Mathematics and Computers in Simulation, pp. 218-229. Corresponding Author : Seung Ho Han, shhan85@dau.ac.kr, - 62 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 63 KSME15RE-T 풍력발전기기어박스를위한전달오차기반스퍼기어의결함진단연구 박성호 유자원 박정호 * 윤병동 * 최주호 한국항공대학교항공우주및기계공학부, * 서울대학교기계항공공학부, A Study on the Transmission Error based Fault Daignosis of Spur Gear Transmission for Wind turbine 1 st Sung Ho Park, 2 nd Jawon Yoo, 3 rd Jung Ho Park*, 4 th Byeng D. Youn*, and 3 rd Joo Ho Choi 1 st, 2 nd & 5 th School of Aerospace & Mechanical Engineering, Korea Aerospace University *3 rd & 4 th School of Mechanical and Aerospace Engineering, Seoul National University Key Words: Wind turbine( 풍력발전 ), Diagnosis( 고장진단 ), Gear fault( 기어결함 ), Transmission error( 전달오차 ), Order analysis( 오더분석 ), Lumped parameter model( 집중변수모델 ), Fault severity assessment( 고장심각성평가 ). Abstract: Gear fault diagnosis of a spur gear transmission is carried out as a preliminary research for the purpose of applying it to the wind turbine. A simple test bed is installed to illustrate the approach, which consists of motors and a pair of spur gears. Several faults of spall and crack with differing size are artificially imbedded at the tooth of a gear. During the operation, transmission error (TE) is measured, which is the discrepancy of rotation angle between the ideal and real value due to the finite gear stiffness. The fault feature is identified and estimated by way of signal processing of TE, which includes the order analysis, time synchronous averaging, high pass filtering. Dynamic lumped parameter model and finite element analysis are used to relate the feature with the fault at the tooth, based on the knowledge that the gear mesh stiffness is reduced by the fault existence and affects the TE behavior during the operation. As a result, fault is successfully diagnosed, in which the type is characterized and the size is estimated using the measured TE under various operating conditions). 초록 : 안정적인풍력발전기시스템은설계단계에서뿐만아니라, 지속적인운영에서도유지관리가요구된다. 이러한비용을줄기이기위해상태기반정비가관심을받고있다. 본연구에서는풍력발전기에상태기반정비를적용하기위한관련한기초연구로서풍력발전기의전달오차 (transmission error) 를통한기어균열의고장진단을수행하였다. 풍력발전기의기어박스를대신하여두개의평기어 (spur gear) 로구성된간단테스트베드를구축하고입출력회전축사이에발생하는전달오차 (Transmission Error) 를측정하여, 이것을통해서결함을진단하고자하였다. 전달오차는기어맞물림시유한한기어강성때문에발생하는이상적회전각과의차이를뜻하는것으로기어에결함이존재하면이값이더증가하며결함의크기에비례하게된다. 본연구에서는기어에결함을인위적으로인가하였는데, 이뿌리균열 (crack 2mm, 5mm), 점식 (spall 6.5mm 1.3mm, 6.5mm 2.6mm) 그리고부분파손 (breakage) 들을인가하고, 30rpm, 450Nm 의조건으로운전중전달오차를측정하였다. 신호처리를통해적절한특징을추출함으로써이로부터결함의크기를추정하고자하였다. 신호의재현성확보를위해분해조립을반복하여이로인한오차를정량화하였고, 이것과결함신호와의차별성을확보하기위한분석을수행하였다. 신호처리에서는오더분석, residual signal, TSA 및 band pass filtering 등의기법을이용하였다. 상대적으로작은 spall, crack, breakage 에서는분해조립의오차와비슷한수준의차이가있었다. 하지만큰결함의기어이빨에서는정상기어이빨과비교했을때눈에띄는전달오차의차이를관찰할수있었고이를 FEM 해석결과와비교하여 FEM 결과를바탕으로바탕으로결함을예측할수있게되었다. FEM 해석은상용소프트웨어인 ANSYS 를통하여기어의정적전달오차의해석값을얻었다. 실제기어의형상을고려하여이끝의 tip relief 를측정 FEM 해석에서도적용하여진행하였다. 실험과 FEM 해석을바탕으로얻은결과를바탕으로결함의종류에따라 TE 주는영향이다르게된다는것을알게되었고. spall 은접촉강성, crack 은굽힘강성에영향을줘서전달오차신호의형상에영향을미치게되고이를바탕으로결함종류를판별할수있게된다. 후기 본연구는한국에너지기술평가원 (KETEP) 의지원하에진행되었습니다. (1) H. Endo a,, R.B.Randall a, C.Gosselin, Differential diagnosis of spall vs. cracks in the gear tooth fillet region - Experimental validation, vol.23, Mechanical Systems and Signal Processing,2009, pp 636 651. (2) C. James Lia,, Hyungdae Lee, Gear fatigue crack prognosis using embedded model, gear dynamic model and fracture mechanics,vol 19, Mechanical Systems and Signal Processing, 2005,pp 836 846 Presenting author name, e-mail address - 63 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 64 KSME15RE-T 라이다 (LiDAR) 측정을이용한나셀전달함수의유도 김현구 강용혁 윤창열한국에너지기술연구원, 신재생에너지자원센터 Derivation of Nacelle Transfer Function Using LiDAR Measurements Hyun-Goo Kim, Yong-Heack Kang and Chang-Yeol Yun Korea Institute of Energy Research, New-Renewable Energy Resource Center Key Words: Nacelle Transfer Function( 나셀전단함수 ), Wind Turbine( 풍력터빈 ), Nacelle Anemometer( 나셀풍속계 ), LiDAR(Light Detection And Ranging, 라이다 ), Wind Speed Calibration( 풍속보정 ) 초록 : 일반적으로 MW 급풍력터빈의나셀 (nacelle) 상부에는풍력터빈제어목적으로풍속계, 풍향계, 기압, 기온, 습도등을측정하는기상관측센서가설치되어있다. 풍향계는풍력터빈회전축이입사되는자연풍의풍향과일직선이되도록요각도 (yaw angle) 를추종하기위함이고, 풍속계는풍력터빈의기동및정지풍속 (cut-in and cut-out wind speed) 을판단하기위함이다. 나셀풍속계는풍력터빈의블레이드뿌리 (blade root) 후방에설치되기때문에풍력터빈에입사되는자연풍의풍속이아니라블레이드회전에의한후류 (wake) 및나셀형상에의해변형되는풍속을측정하게된다. 이에따라자연풍풍속과는다른풍속과난류강도 (turbulence intensity) 를측정하게되므로, 풍속값을풍력터빈의운전제어에적용하게됨에따라시스템운전효율의저하가발생하게되며, 운전소음및피로하중 (fatigue load) 의증가가발생하게된다. 한편고가의제품인풍력터빈은성능평가를통해제품성능이입증되어야하는데, 이를위해서는정확한입사풍풍속을알아야한다. 풍력터빈국제표준인 IEC 61400-12-2 에서는풍력터빈풍상부에기상탑 (meteorological tower) 를설치하고허브높이 (hub height) 에서입사풍풍속을측정하여나셀전달함수 (NTF) 즉나셀풍속을자연풍풍속으로변환하는함수를유도하여나셀풍속계를보정 (calibration) 하도록규정하고있다. 그러나 IEC 61400-12-2 풍력터빈성능평가방법은추가적비용과시간이소모되기때문에훨씬간편한방법인나셀풍속계를보정하여사용하기위한연구가다수진행되었다 (Antonius and Pedersen, 1997; Hunter et al., 2001; Smith et al., 2002; Kim, 2013). 본연구에서는나셀풍속계의왜곡된측정값을풍력터빈에입사되는자연풍풍속으로보정하기위한나셀전달함수를유도하는새로운방법을제안하고자한다. 즉, 기존의지점 (point) 풍속만을측정하는것이아니라풍력터빈블레이드회전면의면적평균풍속을측정할수있는 LiDAR 측정을활용하고, 나셀전달함수를유도할때다중회귀분석을통하여기존의선형나셀전달함수보다더우수한비선형 (nonlinear) 나셀전달함수를유도하였다. 후기 본연구는한국에너지기술연구원의주요사업 (GP2014-0030) 으로수행한결과입니다. (1) Antonius, I., Pedersen, T. F., 1997, Nacelle Anemometry on a 1MW Wind Turbine: Comparing the Power Performance Results by Use of the Nacelle or Mast Anemometer, Risoe National Laboratory, Rosie-R-941. (2) Hunter, R., Pedersen, T. F., Dunbabin, P., Antoniou, I., Frandsen, S., Klug, H., Albers, A., Lee. W. K., 2001, European Wind Turbine Testing Procedure Developments, Task 1: Measurement Method to Verify Wind Turbine Performance Characteristics," Risoe National Laboratory, Risø-R-1209. (3) International Electrotechnical Commission, 2008, WIND TURBINES Part 12-2: Power performance of electricity producing wind turbines based on nacelle anemometry, IEC 61400-12-2. (4) Kim, H. W., 2013, Wind Turbine Power Performance Testing Using Nacelle Transfer Function and Uncertainty Analysis, Master Thesis, Jeju National University, Korea. (5) Smith, B., Link, H., Randall, G., McCoy, T., 2002, Applicability of Nacelle Anemometer Measurements for Use in Turbine Power Performance Tests, National Renewable Energy Laboratory, NREL/CP-500-32494. Hyun-Goo Kim, hyungoo@kier.re.kr - 64 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 65 KSME15RE-T 바이오디젤혼합연료의정량적배기특성평가 윤정환 * 염정국 * * 동아대학교기계공학과 Estimation of Quantitative Emission Characteristics of Biodiesel Blended Fuel Jeonghwan Yoon* and Jeongkuk Yeom* * Dept. of Mechanical Engineering, Dong-A Univ. Key Words: Biodiesel Fuel( 바이오디젤연료 ), Pearson Correlation Coefficient( 피어슨상관계수 ), Spearman Rank order Correlation Coefficient( 스피어만상관계수 ), Trade-Off( 상충관계 ) Abstract: In this study, exhaust gas according to the mixing ratio of biodiesel(soybean oil) was investigated and fuels mixing ratio range from BD(biodiesel)3 to BD100. Also, condition of injection pressure was change as 400bar, 600bar, 800bar, 1000bar and 1200bar. To analyze engine emission of NOx and Soot quantitatively according to fuel mixing ratio and injection pressure, Pearson correlation coefficient and Spearman rank-order correlation coefficient based on statistics were used in this study. Consequently, Pearson correlation coefficient of data of NOx and Soot according to mixing ratio and injection pressure in experiment variable was -0.8 and Spearman rank-order correlation coefficient was -0.862, which indicated that correlation of the emission of NOx and Soot was linear and relation of NOx and Soot was trade-off. Also, in the variable of injection pressure at 400bar, it can be possible to reduce NOx, Soot simultaneously through control of biodiesel mixing ratio because the Pearson correlation coefficient was 0.7 at 400bar that indicated direct proportion relation between NOx and Soot. 초록 : 본연구는경유와바이오디젤 ( 대두유 ) 혼합연료의디젤엔진배기특성을조사하였고, 연료혼합비는 BD(biodiesel)3, BD5, BD20, BD50 및 BD100 이며, 또한분사압력조건을 400bar, 600bar, 800bar, 1000bar 및 1200bar 로변화시켰다. 그리고연료혼합비및분사압력에따른엔진배출물인 NOx 와 Soot 의정량적인분석을위해통계학에기초한피어슨상관계수와스피어만상관계수를이용하였다. 본연구의결과로서실험변수인혼합비와분사압력에대한 NOx 및 Soot 발생량의피어슨상관계수는 -0.8 이며, 스피어만상관계수는 -0.862 로 NOx 와 Soot 발생량관계가선형적이며, 이것은 trade-off 관계를나타낸다. 또한분사압력의경우 400bar 조건에서피어슨상관계수가 0.7 로양의상관관계를나타내며이것은 NOx 와 Soot 배출관계가정비례적인것을나타낸다. 따라서 400bar 조건에서혼합비제어를통한 NOx 와 Soot 의동시저감이가능할것으로판단된다. 후기 이논문은 2013 년도정부 ( 교육부 ) 의재원으로한국연구재단의기초연구사업지원을받아수행된것임 (NRF-2013R1A1A2011842). (1) Lin, Y., Wu, Y. G. and Chang, C., 2007, "Combustion Characteristics of Waste-Oil Produced Biodiesel/Diesel Fuel Blends," Fuels, Vol. 86, pp. 1772~1780. (2) Hass, M. J., Scott, K. M., Alleman, T. L. and McCormick, R. L., 2001, "Engine Performance of Biodiesel Fuel Prepared from Soybean Soapstock: A High Quality Renewable Fuel Produced from a Waste Feedstock," Energy & Fuels, Vol. 15, pp. 1207~1212. (3) No, S. Y., 2009, Bioenergy Engineering, ABCNURI, Chungbuk National University, pp. 47~60. (4) Yeom, J. K., 2011, "Basic Experimental Study on the Application of Biofuel to a Diesel Engine," Trans. of the KSME(B), Vol. 35, No. 11, pp. 1163~1168. (5) Kim, W. C., 2006, Modern Statistical, YONUNGCHI MUNHWASA, Seoul, pp. 256~325. (6) Jeon, C. H., Jeong, M. G. and Lee, H. S., 2004, Applied Statistics for Engineers, HONGRUNG PUBLISHING COMPANY, Seoul, pp. 12~132. (7) Seong, T. J., 2009, Understanding and Applying Modern Basic Statistics, KYOYOOKBOOK, Paju, pp. 361~365. (8) MINITAB Help Anderson Darling Statistic release 16.2.3, Minitab Inc., Pennsylvania, 2012. Jeongkuk Yeom, laser355@dau.ac.kr - 65 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 66 KSME15RE-T 에멀젼연료충돌분무의거동특성에관한연구 김학민 * 염정국 * * 동아대학교기계공학과 Study of Behavior Characteristics of Impinging Spray of Emulsified Fuel Hakmin Kim* and Jeongkuk Yeom* * Dept. of Mechanical Engineering, Dong-A Univ. Key Words: Emulsified Fuel( 에멀젼연료 ), Impinging Spray( 충돌분무 ), Oil in Water( 수중유형 ), Schlieren Method( 쉴리렌방법 ), Water in Oil( 유중수형 ) Abstract: In this study, the mixing ratio of emulsified fuel through impinging spray was investigated effect of spray behavior characteristics. The emulsified fuel was made by mixing diesel and hydrogen peroxide(h 2 O 2 ). The temperature of heating plate was set at 150, 200 and 250. The injection pressures were set at 400bar, 600bar, 800bar and 1000bar. Surfactants for the emulsified fuel mixture were mixed span80 and tween80 mixed as 9:1, was fixed to 3% of the total volume of the emulsified fuel. The mixing ratio of hydrogen peroxide in emulsified fuel was set as EF(Emulsified fuel)0, EF2, EF12 and EF22. Also, for visualization of the evaporation impinging spray was applied to the Schlieren method. As a result of this study, it was found that the higher temperature and injection pressure of the heating plate impingement becomes active diffusion of the fuel vapor to promoting emulsified fuel evaporation. These results, when using the emulsified fuel in the actual engine, due to the temperature drop effect of combustion chamber by evaporation of hydrogen peroxide in fuel and faster mixture formation is expected to decrease the engine emissions. 초록 : 본연구는디젤 - 과산화수소에멀젼연료의충돌분무를대상으로과산화수소의혼합비가분무거동특성에미치는영향을조사하였다. 에멀젼연료의증발을위해온도조절이가능한가열판을사용하여온도를 150, 200 및 250 로각각설정하였고, 그리고연료분사압력을 400bar, 600bar, 800bar 및 1000bar 로설정하여분사압력이에멀젼연료의증발특성에미치는영향을확인하였다. 에멀젼연료의혼합을위한계면활성제로 span80 과 tween80 을 9:1 의비율로혼합하여에멀젼연료전체체적의 3% 로고정하였고과산화수소의혼합비율을 EF(Emulsified Fuel)0, EF2, EF12 및 EF22 로설정하여디젤연료와혼합하였다. 또한에멀젼연료증발충돌분무의가시화를위해쉴리렌방법을적용하였다. 본연구의결과로서충돌하는가열판의온도와분사압력이높을수록에멀젼연료증발촉진으로연료기상의확산이활발해지는것을알수있었다. 이러한결과로부터실제엔진에에멀젼연료를사용할경우연료내과산화수소증발에의한연소실온도저하효과와함께보다신속한혼합기형성으로인하여엔진배출물감소가기대된다. 후기 이논문은 2013 년도정부 ( 교육부 ) 의재원으로한국연구재단의기초연구사업지원을받아수행된것임 (NRF-2013R1A1A2011842). (1) Kim, M. C. and Lee C. S., 2008, "It s Effects for Engine Emission of Water/Oil Emulsified Fuel," Journal of Korean Society of Analytical Science, Vol. 21, No. 3, pp. 159~166. (2) Lif, A. and Holmberg, K., 2006, "Water-in-Diesel Emulsions and Related Systems," Advances in Colloid and Interface Science, Vol. 123-126, pp. 231~239. (3) Seo, H. J., Oh, S. M. and Huh, H. I., 2002, "Spray Characteristics and Exhaust Emission Tests for a Diesel Engine Using Emulsified Fuels," Trans. of the KSAE, Vol. 10, No. 4, pp. 60~68. (4) Koc, A. B. and Abdullah, M., 2013, "Performance and NO X Emissions of a Diesel Engine Fueled with Biodiesel- Diesel-Water Nanoemulsions," Fuel Processing Technology, Vol. 109, pp. 70~77. (5) Raheman, H. and Kumari, S., 2014, "Combustion Characteristics and Emissions of a Compression Ignition Engine Using Emulsified Jatropha Biodiesel Blend," Biosystems Engineering, Vol. 123, pp. 29~39. (6) Ashok, M. P. and Saravanan, C. G., 2008, "Role of Hydrogen Peroxide in a Selected Emulsified Fuel Ratio and Comparing It to Diesel Fuel," Energy & Fuels, Vol. 22, No. 3, pp. 2099~2103. (7) Ithnin, A. M., Ahmad, M. A., Bakar, M. A. A., Rajoo, S. and Yahya, W. J., 2015, "Combustion Performance and Emission Analysis of Diesel Engine Fuelled with Water-in-Diesel Emulsion Fuel Made from Low-Grade Diesel Fuel," Energy Conversion and Management, Vol. 90, pp. 375~382. Jeongkuk Yeom, laser355@dau.ac.kr - 66 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 67 KSME15RE-F 3 세대휠베어링내구시험방법차이에따른내구손상도분석 김대성 이승표 * 여준철 ** 자동차부품연구원, * 일진글로벌, ** 일진베어링 Damage Analysis of 3 rd GEN Wheel Bearing under the Durability Test Modes Daesung Kim, Seungpyo Lee, * and Juncheol Yeo** Korea Automotive Technology Research Institute *Iljin Global Co. **Iljin Bearing Co. Key Words: Wheel bearing ( 휠베어링 ), Durability( 내구성 ), Multi-axis load condition ( 다축하중환경 ) Abstract: In the 3 rd generation of wheel bearing, the functional integration of vicinity components around wheel bearing. As a result, it increased the stiffness of bearing structure significantly and reduced the wheel bearing components. It is very important to improve the durability of wheel hub bearing by analyzing its failure mode. Because a failure mode are come from not only the fatigue failure of flange but also the fatigue failure of race and hub due to the contact friction between ball and orbital surface. In this study, strain measurement system was constructed, and carried out a variety of multi-axial loading test mode. The analysis results of damage on the multi-axis load conditions of wheel bearing will be used to make a more accurate multi axis test mode. 초록 : 자동차용휠베어링은단순베어링인 1 세대베어링부터주변부품이기능적으로결합되어다양한세대의휠베어링으로진화하고있다. 이들중허브와플렌지가결합된 3 세대휠허브베어링은허브와볼궤도면을통합하여강성을크게높이면서도중량을절감할수있으며, 고장수리비용또한적절하여현재가장많은차량에채택되어사용되고있다. 1 세대휠베어링은볼궤도면의접촉피로에의해파손되어단순회전피로시험만으로도이의내구성을평가할수있지만, 3 세대휠허브베어링의파손모드는궤도면접촉피로파손뿐아니라모듈화된허브와플랜지의피로파손까지포함하기때문에이를평가하기위해서는좀더실사용환경에근접한시험법이요구된다. 이에따라, 완성차업체에서는단순회전피로시험뿐만아니라휠베어링시뮬레이터를이용한다축하중피로시험에대한시험사양을보유하고이를이용하여휠허브베어링의내구성을평가하고있다. 본연구에서는휠허브베어링의허브, 플랜지등각부위별변형율을측정할수있는변형율측정시스템을구축하고다양한시험모드기반의다축하중피로시험을수행하였다. 이를통해다축시험모드에따른시험조건별하중특징을확인하고하고, 내구손상도분석을수행하였다. 본연구를통해분석된피로손상도비교분석결과는기존에진행되는다양한다축시험사양을통합하여가속시험평가를수행할수있는시험방법개발에기반데이터로사용할수있을것이다 후기 본연구는 2014 년산업기술혁신사업중 World Class 300 프로젝트인 1.5 Nm 이하의 drag 토크, 현중량대비 90% 이하의중량, 500,000 km 이상의수명, 5,500 Nm/deg. 이상의강성을갖는승용차용휠베어링기술개발 과제의 2 차년도수행결과이며과제수행과관련해도움주신관계자분들께감사드립니다. (1) Kim, D. S., Choi, S. J., Nam, C. H. Lee, S. P. and Park, J. Y., 2014, "Effectiveness Analysis of Durability for The Third Generation Wheel Bearing under The Multi-axial Fatigue Loading Condition," Annual con. KSME, pp. 780~782. (2) J. A. Bannantine, J.J. Comer, and J.L.Handrock, 1989, "Fundamentals of metal fatigue analysis," Prentice hall, pp. 200~201. Daesung Kim, dskim@katech.re.kr - 67 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 68 KSME15RE-F 철도차량필드데이터에의한고장빈도영향요인분석사례연구 김종운 한국철도기술연구원 A case study of influence factor analysis on failure frequency using field data for rolling stock Jongwoon Kim Korea Railroad Research Institute Key Words: rolling stock( 철도차량 ), field data( 필드데이터 ), failure frequency( 고장빈도 ), influence factor( 영향인자 ), reliability( 신뢰성 ) Abstract: There are various influence factors on the failure frequency of rolling stocks such as calendar time, operating time, service line, manufacturer, maintenance date, and temperature. The influence factors is analyzed using field data for rolling stocks in this work. Items of high failure frequency are identified. Trend and factor analysis is performed for the identified items. As a result, calendar time, operating time, and the elapsed time after heavy maintenance are important factors and their degrees of influence are different for items. For some items, seasonal impact is high. For other items, the failure rate increases as operating time and the elapsed time after heavy maintenance go on. Further research for the expected lifetime and maintenance interval might be needed for the items. 초록 : 철도차량의고장빈도에미치는영향요인들은다양하다. 계절적영향에의해달력시간 (Calendar time) 이중요한요인이되기도하고, 때로는달력시간보다운영시간및거리 (Operating time and distance) 가더중요한영향을미치기도한다. 이뿐아니라운행노선, 제작사, 유지보수일자, 기온등철도차량고장빈도에영향을주는다양한요인들이있다. 본연구에서는특정노선및철도차량에대한필드데이터를분석하여고장빈도에영향을주는요인들을분석하였다. 고장발생빈도가높은장치들을도출하였고, 주요장치에대한고장빈도영향요인및추세분석을수행하였다. 그결과달력시간 ( 계절 ), 운영시간, 중정비후경과시간이고장발생빈도에영향을크게주었고, 그영향의정도는하위장치에따라상이하였다. 계절적영향이큰장치들을확인할수있었으며, 운영시간및중정비후시간이경과함에따라단위시간당고장빈도가증가하는경향을보인장치들도있었다. 이러한장치들은기대수명의산정및유지보수주기조정등에대한추후연구가필요할것으로판단된다. 후기 본연구는한국철도기술연구원주요사업인 철도시스템글로벌시장진출체계및기반구축 과제의일환으로수행되었습니다. Jongwoon Kim, jong@krri.re.kr - 68 -

2015 년도대한기계학회신뢰성부문춘계학술대회논문집 pp. 69 KSME15RE-F 승용차용하이드로엔진마운트열화메커니즘분석성대운 류용현 현대자동차 Analysis of Degradation Mechanism of Hydro Engine Mounts Sung, Dae Un Ryu, Young Hyun* HYUNDAI KIA Motors * HYUNDAI KIA Motors Key Words: Hydro Engine Mounts( 하이드로엔진마운트 ), Elastomers( 방진고무 ), Thermal Ageing( 열노화 ), Degradation( 열화 ), Noise and Vibration( 소음진동 ) Abstract: The elastomers such as engine mounts are the primary factor controlling the vibration induced by the vehicle engine and transmission. The field issues have been made by the degradation of vibrational and damping properties of elastomers after the long term customer s usage. Due to the heat generated by an engine, an elastomeric rubber could be thermally aged. Moreover, hydro-mounts can be degraded by the hydro devices within the hydro mounts. In this paper, the mechanism of degradation of elastomeric rubber and hydro mounts. The major influencing design factors for the degradation of vibrational properties could be found by identifying the ageing mechanism. The robust design guideline could be established for elastomers. 초록 : 지난 10 년간은 BRICs 등신흥시장의차량판매량이증가하면서세계각지역의다양한환경조건에서균열과파손등의내구성이중요한화두였다. 최근에는시장이성숙단계에접어들면서고객의요구조건은더욱까다로워지고있으며클레임이나고객불만은고장보다는소음 / 이음과같은열화 (degradation) 문제가이슈가되고있다. 중고차의소음 / 진동열화도평가결과를보면공차시 (idle) 진동과소음이두드러지게열화되는것을알수있었다. 신품과고품교환을통한부품별기여도를분석한결과엔진마운트 (engine mounts) 와같은방진고무 (elastomers) 의진동절연율악화의기여도가가장높았다. 고무부품은주변의열과산소에의한화학반응으로고무분자간의가교밀도 (crosslink density) 가증가하고기계적물성이변화하게된다. 이로인하여고부품의정적 / 동적탄성계수와댐핑특성이변화하게된다. 중고차엔진마운트고품의가교밀도증가량을균형팽창 (equilibrium swelling) 방법으로측정한결과를 Fig. 1 에서나타내었다. 고무두께를따라 2mm 단위로시편을절개하여측정한결과, 신품대비가교밀도가 20~35% 증가함을확인할수있다. 하이드로마운트 (hydro engine mounts) 의열화는방진고무자체의열화뿐만아니라, 엔진마운트내부의디커플러 (decoupler) 구성부품들의열화가수반된다. 중고차고품분석을통하여하이드로마운트열화메커니즘및이에영향을주는인자를파악하였다. Fig. 2 는 A 차종엔진마운트의동탄성계수 (dynamic stiffness) 열화량을계측한결과이며신품대비 +53% 증가함을확인할수있었다. 본연구에서는하이드로마운트의열화에영향을주는구성부품인멤브레인 (membrane) 과마운트액 (mount fluid) 및방진고무의열화메커니즘을분석하였다. (1) Ernst, S. and Weltin, U., Ageing under preload, Constitutive Models for Rubber VIII, 2013. (2) A. Gent, Engineering with Rubber (3rd edition) Cincinnati: hanser Publications (3) Wei, Y., L. Nasdala, H. Rothert and Z. Xie, Study on the dynamic mechanical properties of aged rubbers, Constitutive Models for Rubber III, 2003. (4) W. David, Failure of Plastics and Rubber Products, Rapra Technology Limited, 2001. Presenting Author, dusung@hyundai.com - 69 -