プレス成形シミュレーションのための移動硬化則の材料パラメータ決定

抄録

Cyclic bending experiment has been proposed in order to investigate cyclic response of sheet metals such as high strength steel sheet. This experiment has advantage that buckling, which often cases error in tension-compression test, does not take place. On the other hand, stress-strain curve cannot be obtained from bending test due to the inhomogeneous stress and strain distribution along thickness direction. In this study, therefore, obtained punch load vs. stroke curve was combined with the inverse approach to determine Yoshida-Uemori model parameters. In the inverse analysis, the optimization problem was solved by gradient based optimization technique called Sequential Quadratic Programming to achieve the automatic parameter identification system, which does not rely on the skill or experience of the engineer. In order to validate the proposed parameter identification system, 590 and 980MPa class high strength steel sheet was employed. The optimization results showed that inverse approach was successfully solved, and the obtained load-stroke curves were correlated with the experimental results. Moreover, the identified parameters were found to be reasonably well by comparing with the stress-strain curves obtained by tension-compression test.