一种韧性断裂准则中材料常数的计算模型及其应用

为确定符合板材变形规律的韧性断裂准则中的材料常数,基于传统M-K模型框架并进行修正,结合单向拉伸和平面应变试验数据,提出一种新的韧性断裂准则材料常数计算模型。利用MATLAB软件编写该计算模型的算法程序,得到应用于铝镁合金5A06-O板材的不同韧性断裂准则材料常数。同时将CL韧性断裂准则嵌入Abaqus/Explicit显示模块的用户材料子程序VUMAT。在200℃的条件下,对铝镁合金5A06-O板材在热介质胀形和充液热拉深中的断裂行为进行数值模拟,并与相同工艺参数下的试验所得结果作对比。结果表明,热介质胀形高度误差为6.2%,充液热拉深深度误差为8.5%,验证了韧性断裂准则材料常数计算模型的正确性,表明了CL韧性断裂准则在板材充液热成形中的适用性。

A calculating model of material constants in ductile fracture criterion and its applications

To determine material constants of ductile fracture criteria which are in accord with sheet deforming regularity, based on the theoretical framework of the conventional M-K model and some reasonable modification, a new computational model is derived by combining data of uniaxial tension with that of plane strain tests. Through compiling the algorithm program in MATLAB, material constants of various ductile fracture criteria are determined by using data of aluminium magnesium alloy 5A06-O sheet. The C&;L ductile fracture criterion is written into the subroutine VUMAT which is embedded in Abaqus/Explicit. Then, numerical simulations of aluminium magnesium alloy 5A06-O sheet warm hydrobulging and hydroforming are conducted at 200℃. Compared with the experimental results with the same processing parameter, the errors of warm hydrobulging height and warm hydroforming height do not exceed 6.2% and 8.5% respectively. Thus, the results show that the validity of the model is verified and the application of the C&;L ductile fracture criterion in sheet warm hydrobulging and hydroforming is effective.