一种新的各向同性金属材料屈服函数

A new yield function on isotropic metals

材料的屈服函数是建立相应的塑性本构关系以及进行塑性分析的首要条件,文章基于静水压对金属材料屈服无影响以及各向同性假设,将一般屈服函数进行泰勒展开,推导出包含应力1次~4次项的新型各向同性金属材料屈服函数以及相应八阶塑性张量。通过对该屈服函数退化,得到各向同性金属材料拉压屈服性能相同和不同条件下的屈服函数。利用Lode实验结果进行验证,结果表明,该屈服函数仅包含3个材料参数,并且对拉压屈服性能相同和不同的金属材料都有较好的适用性,具有较高的工程应用价值。

The yield function is very important in establishing the plastic constitutive relation and analyzing the plastic deformation.Based on the hypothesis of isotropy and hydrostatic pressure insensitivity,this article derives a new yield function for isotropic metals with the degree term from one to four by Taylor,and corresponding eight-order plastic tensor is also established.This yield function can be degenerated to the yield functions for symmetry and asymmetry in tension-compression yield.By means of the results of Lode test,it is proved that this yield function is very suitable for metal materials with tension-compression symmetry or asymmetry.And there are three material parameters in the yield function,hence,the form is simple and has higher value in engineering