不同应力三维度条件下孔洞的演变及修正的Gurson模型

本文对含不同形状孔洞的幂硬化材料的圆柱体胞模型，运用控制宏观应力三维工的方法进行了有限元分析。计算结果表明：１．孔洞初始形状，应力三维度对孔洞的长大有重要影响；２．Ｇｕｓｏｎ模型对孔洞长大规律的描述是不准确的，不准确度与孔洞初始形状，应力三维度有关，修正后的Ｇｕｒｓｏｎ模型与有限元结果吻合较好；３．在低应力三维度区，孔洞以及形状改变为主，在高应力三维度区，孔洞以扩张为主；

THE DEVELOPMENT OF VOID UNDER DIFFERENT STRESS TRIAXIALITY AND MODIFIED CURSON MODEL

In this paper, the cell model containing nonspherical voids in an isotropically exponential hardening elastoplastic matrix is analyzed by the finite element method. From the analysis, it shows that: (1) the shape of the void and the stress triaxiality have an importment effect on the growth of the void, (2) Gurson model is unable to describe the growth of the void accurately, the inaccuracy being relative to the shape of the void and the stress trixiality and the modified Gurson model by authors fitting well with the result of FEM analysis, (3) in low stress triaxiality, the change of shape of void is important, but in high stress triaxiality, the change of volume is important. It is not approprite to adopt that the volume fraction fc is considered as the fracture criterion, instead the shape factor of void should be considered in the fracture criterion.