参数求解方法对屈服准则的各向异性行为描述能力的影响

Effect of the Solving Method of Parameters on the Description Ability of the Yield Criterion about the Anisotropic Behavior

详细分析基于应力各向异性和变形各向异性两种求解Hill48屈服准则参数的方法。在给出两种各向异性参数求解表达式的基础上,具体分析Hill48屈服准则本身的局限性。以5754O铝合金板为研究对象,进行不同方向的单向拉伸试验。采用两种各向异性参数求解方法,基于Hill48屈服准则推导不同方向拉伸过程中的理论应力-应变曲线和拉伸过程中的变形规律。通过对比理论与试验结果具体分析参数求解方法对屈服准则精度的影响。基于两种参数求解方法,进行5754O铝合金板拉深试验的有限元模拟,讨论不同求解方法对凸耳现象的描述精度。得出结论:当对应力各向异性为主的问题进行分析时,应采用应力各向异性法求解;当对变形各向异性为主的问题进行分析时,则应采用变形各向异性法求解。研究结果对屈服准则在板料成形方面的合理应用具有重要的参考价值。

Two solving methods of Hi1148 yield criterion based on stress anisotropy and deformation anisotropy, respectively, are analyzed in detail. The limitation of Hi1148 yield criterion is discussed with presenting two kinds of expressions of the solving method of the anisotropic parameters. The uniaxial tensile tests of 57540 aluminum alloy sheet along different directions are carried out. With different solving methods of anisotropic parameters, the theoretical stress-strain curves and the deformation rule during the tension process along different directions are derived. By comparing the theoretical and experimental results, the effect of the solving method on the accuracy of the yield criterion is analyzed. Based on two kinds of solving methods of the parameters the finite element simulations of the deep drawing test of 57540 aluminum alloy sheet are carded out and the accuracy of different solving methods on describing the earing phenomenon is discussed. It is concluded that the solving problem based on stress anisotropy should be used for the research object mainly related to stress anisotropy, while that based on deformation anisotropy should be used for the research objecet mainly related to deformation anisotropy. This research has important reference value for the reasonable application of yield criterion on sheet metal forming.