受有两级空洞损伤时韧性材料的力学行为

本文利用大应变有限元方法研究了两级空洞对韧性材料的损伤作用.模型是以轴对称圆柱基体作为胞元,内含一初始的球型空洞.基体内的应力/应变随胞元外载的增大而达到临界状态,从而在围绕初级空洞的基体内将萌生次级空洞.后者是由空单元实现的.两级空洞的交互作用被证明将促进材料中的空洞化现象从而加速损伤并导至材料的总体弹性模量值在临近破断时急剧下降.

THE MECHANICAL BEHAVIOUR OF DUCTILE MATERIALS DAMAGED BY SECOND GENERATIONS OF VOIDS

Large strain finite element method is employed to investigate the damaging effect of two generations of voids in ductile materials. An axisymmetric cylinder embedding an initially spherical void is chosen as the model cell. Secondary voids will initiate around the initial void when the local stress/strain in the matrix increases to certain critical conditions. This event is numerically simulated through an empty element technique. The interaction between these two generations of voids has been proved to be favourable to the voiding condition, thus accelerating the material damage, characterized by the value of the overall elastic modulus which may undergo drastic drop when nearing final fracture.