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金属板料成形过程的仿真需要定义材料在大应变处对应的流动应力曲线,即真应力-应变曲线。文章介绍了一种逆向识别方法,通过结合单向拉伸试验和有限元仿真分析来获得金属板料在大应变区间内的流动应力曲线。仿真分析过程中通过构建合适的有限元模型,正确模拟分散性失稳期间的各向异性塑性变形行为。在得出材料完整的直至颈缩阶段的流动应力曲线后,建立多个不同的硬化模型描述该曲线,并比较拟合结果,发现改进的Hockett-Sherby模型效果最好。
The simulation of metal sheet forming process needs to define the corresponding flow stress curve of the material at large strain, that is, the true stress-strain curve. In this paper, a reverse identification method is introduced, and the flow stress curve of sheet metal in the large strain range is obtained by uniaxial tensile test and finite element simulation analysis. During the process of simulation analysis, an appropriate finite element model is constructed to correctly simulate the anisotropic plastic deformation behavior during dispersion instability. After obtaining the complete flow stress curve of the material up to the necking stage, a number of different hardening models were established to describe the curve and the fitting results were compared. The improved Hockett-Sherby model was found to be the best.