比例/非比例加载路径下5754O汽车用铝合金板各向异性变形行为的精确解析

With the increasing demand for lightweight automobiles, the aluminum alloy sheets are becoming more and more widespread in the modern automotive industry. The 5754O aluminum alloy sheet has complex anisotropy rules in plastic forming process under different loading paths, including proportional and non-proportional loading paths. Experimental results show that the anisotropy will change with the increase of deformation. Therefore, it is difficult to describe the anisotropic behavior accurately during the whole deformation process based on single curve hypothesis. Due to this problem, Yld2000-2d yield function is modified considering the stability during the large deformation process. The stress-strain curve along different directions based on the modified yield function and single curve hypothesis. Comparing the theoretical and experimental results, shows that the modified Yld2000-2d yield function fits for the anisotropy of 5754O aluminum alloy sheet based on single curve hypothesis whereas the original Yld2000-2d does not. The unity and variation of different hardening models under proportional and non-proportional loading paths are proved respectively. Based on the modified Yld2000-2d yield function and different loading mods (isotropic and mixed hardening), the stress-strain curves under non-proportional loading paths are deduced. The resulting theoretical curves are validated with experimental results. The anisotropic deformation behaviors of 5754O aluminum alloy sheet under proportional and non-proportional loading paths are described accurately, which will provide important theoretical support for its industrial application.