유한요소 역 해석을 이용한 축대칭 다단계 박판성형에서의 공정변수 설계에 관한 연구

Abstract

A finite element inverse method is introduced for direct prediction of blank shapes, strain distributions, and reliable intermediate shapes from desired final shapes in axisymmetric multi-step deep drawing processes. This mothod enables the determination of process disign. The approach deals with the Henckys deformation theory. Hills second order yield criterion, simplified boundary conditions, and minimization of plastic work with constraints. The algorithm developed is applied to motor case forming, and cylindrical cup drawing with the large limit drawing ratio so that it confirms its validity by demonstrating resonably accurate numerical results of each problem. Numerical examples reveal the reason of difficulties in motor case forming with corresponding limit diagrams.