材料内部孔洞压实机理的研究

STUDY ON CLOSING OF INTERNAL VOIDS OF MATERIALS

采用损伤细观力学中的Gurson模型,从理论上分析了材料内部孔洞的闭合压实过程。理论结果和实验结果基本符合。发现当用该模型分析孔洞完全闭合的条件时,会出现应力或应变的奇异性。因此提出了一种新的、有限体积的椭球体中含椭球形孔洞的损伤细观模型。通过引入孔洞形状改变因子对Gurson方程进行了修正,建立了含孔洞材料的本构关系,推出了材料内部孔洞完全闭合的条件。

A theoretical analysis on the closing process of internal voids in materials is carried out by using Gurson's model of damage micromechanics and a better agreement between theory and experiment is obtained. However, it is also found that stress or strain tend to have singularities when voids are closed entirely, so a new microscopic damage model is developed and Gurson's equation is modified by introducing the void shape change factor. According to the constitutive relation for materials containing voids established in the new model, the condition of the entire closing of voids is given.