基于应力的断裂准则对AA7075-T6韧性断裂行为的预测研究

Study on ductile fracture behavior prediction of AA7075-T6 with stress-based fracture criterion

通过试验研究了AA7075-T6在剪切、单轴拉伸和平面应变拉伸应力状态下的塑性变形和韧性断裂行为。然后采用Swift-Voce硬化定律和pDrucker屈服函数表征了板材在不同加载状态下的塑性变形特性。最后,采用基于应力的pDrucker韧性断裂准则表征了不同应力状态下塑性变形过程中的韧性断裂行为。为了提高数值模拟预测精度,塑性本构模型和pDrucker韧性断裂准则参数均采用试验-模拟相结合的逆向工程方法进行优化标定。将有限元预测的韧性断裂位移与不同试件载荷-行程曲线进行了比较。结果表明,通过逆向工程优化的pDrucker韧性断裂准则能够准确描述AA7075-T6不同应力状态下的韧性断裂行为。

The plastic deformation and ductile fracture behaviors of AA7075-T6 under shear,uniaxial tensile and plane strain tensile stress states were studied by tests.Then the Swift-Voce hardening law and pDrucker yield function were used to characterize the plastic deformation characteristics of sheets under different loading conditions.Finally,pDrucker ductile fracture criterion based on stress was used to characterize ductile fracture behaviors in plastic deformation under different stress states.To improve the prediction accuracy of numerical simulation,the parameters of plastic constitutive model and pDrucker ductile fracture criterion were optimized and calibrated by inverse engineering method combining test and simulation.The ductile fracture displacement predicted by finite element method was compared with load-stroke curves of different specimens.The results show that pDrucker duckile fracture criterion optimized by inverse engineering can accurately describe the ductile fracture behaviors of AA7075-T6 under different stress states.