A system approach for studying the engine dynamic characteristics requires a cranktrain flexible body dynamic model including crankshaft, connecting rod and piston. By using a multi-body dynamics code, LMS Virtual Lab, rigid body dynamic model and flexible multi-body dynamic model were established. From these models, the dynamic loads acting on the crankshaft were calculated. Rigid model for V12 engine cranktrain with components connected by kinematical constraints was transformed into a flexible model by replacing rigid crankshaft and connecting rods with flexible ones. And to secure the credibility of flexible body model, three kinds of flexible models were tried, i.e. a model with a fully flexible crankshaft, model with a partially flexible crankshaft(1/6 of the whole length), and a partial detailed flexible model(with finer meshes). The results from each model were compared, and a partial detailed model with finer meshes was found to give reasonable stress values within relatively short period of computing time.

원자력발전소중 안전과 관련된 구조물은 지진의 가능성에 대비하여 그의 구조적 안전성과 가용성이 검중되어야 한다. 본 논문은 원자력발전소 보호시스댐 캐비넷올 예롤 들어 그에 대한 내진검증 방법올 보였다. 캐비넷의 유한요소모델을 작성하여 통특성올 구하였고 그 모우드값을 입력지진스펙트럼과 비교한 결과 구조물의 1 차모우드가 입력스펙트럼의 야앓와 일치함으로써 셜계변경의 필요성이 대두되었다. 이 peak 값을 피하기 위하여 캐비넷의 구조를 변경하였고 변경된 구조물에 대하여 웅답스텍트럽해석과 시간 이력해석올 수행하여 구조적 건전성과 가용성올 보임으로써 설계변경된 캐비넷의 내진검증을 확인하였 다