A method to obtain flow stress in the plastic deformation state is investigated in this study. The flow stress prior to necking is calculated based on Hollomon’s constitutive equation using the strain rate and stress obtained from a tensile test, whereas the strain hardening coefficient after necking is obtained using the stress and strain rate obtained from a compression test; subsequently, the two flow stresses are combined. Two-dimensional rigid plastic finite element analysis considering ductile fracture in the stress test is conducted by inputting the proposed flow stress. It is confirmed that the shape and dimensions of the necking part on the load–displacement curve from the finite element analysis are similar to those obtained experimentally, thereby confirming the validity of the proposed flow stress calculation.

本研究研究了一种在塑性变形状态下获得流动应力的方法。颈缩前的流动应力是根据 Hollomon 的本构方程使用拉伸试验获得的应变率和应力计算的，而颈缩后的应变硬化系数是使用压缩试验获得的应力和应变率获得的；随后，两个流动应力合并。应力试验中考虑延性断裂的二维刚塑性有限元分析是通过输入建议的流动应力进行的。有限元分析证实，载荷-位移曲线上颈缩部分的形状和尺寸与实验获得的相似，从而证实了所提出的流动应力计算的有效性。