Robust Design of Crankshaft

Abstract : Finite element analysis along with DOE scheme has been performed to obtain robust design of crankshaft assembly. This study focused on obtaining optimized fillet radius of crankshaft mainly by statistical approach. 27 design cases using 3 factors with 3 levels are constructed by design of experiment. Changes of design factors and noise factor may influence the durability of crankshaft system. General two stages of robust design may enhance the durability of crankshaft model. Increasing crank arm thickness was adopted as a shrink step and change of fillet radius was used as a shift step. By combining these two steps, the stress concentration at the fillet area is reduced and adequate fillet radius is determined for the robust design of crankshaft. Key words :Crankshaft(크랭크샤프트), Finite element analysis( 유한요소해석), Bending stress(굽힘응력), Torsion stress(비틀림응력), Computational design of experiment( 실험계획법), Robust design(강건설계) 1. 서 론 1) 크랭크샤프트는 크랭크저널, 크랭크암, 크랭크핀 등으로 구성되어 있으며, 커넥팅로드에 연결되어 엔진 폭발 하중에 의한 주기적인 하중을 받는 엔진 주요 구성품의 하나이다. 엔진 구동 중에 지속적으로 발생하는 반복적인 굽힙 응력(bending stress)과 비틀림 응력(torsion stress)은 크랭크샤프트에 복합적으로 작용한다. 취약부에 누적된 응력집중은 크랙의 발생과 전파를 야기할 수 있으며, 그 결과로 엔진에 치명적인 손상을 유발할 수 있다.