Study on the Yoshida-Uemori Material Model of High-Tensile Steel Sheets by Shear Tests

In this research, the Yoshida-Uemori material models for four kinds of high-tensile steel sheet were analyzed by shear tests. The Yoshida-Uemori (Y-U) material model is currently the most important model in the simulation of stamp forming high-tensile steel sheets. It can comprehensively describe the Bauschinger effect and strain hardening behavior of metal during severe plastic deformation. Several commercial simulation software have built-in Y-U material models such as DYNAFORM and Pam-Stamp. The experimental curves must be obtained by the cyclic tension and compression test, and then the Y-U material parameters can be calculated by the regression operation. However, the parameters of the Y-U material model are difficult to obtain because the cyclic tension and compression test of thin sheet is prone to buckling phenomenon. This study first discuss the transform relation between shear test and tensile test, and then the Y-U material model is established by cyclic shear tests to avoid buckling. LS-DYNA numerical simulations of the shear tests were used to verify the accuracy of the material models. Four kinds of high-tensile steel sheet produced by China Steel Corporation are discussed, including JSC1180Y, JSC980Y, JAC590R and JSC440P, which cover a wide range of strength of the stamping plate. It further confirmed that the proposed research method does work.