延性材料损伤演化及材料软化的孔洞尺寸影响  

VOID SIZE INFLUENCE ON DAMAGE EVOLUTION AND STRAIN SOFTENING

作　　者：李晓红[1] 张克实[1] 

机构地区：[1]西北工业大学工程力学系

出　　处：《机械强度》2003年第1期81-84,共4页Journal of Mechanical Strength

基　　金：国家自然科学基金 (1 9972 0 55);航空基础科学基金 (0 0C530 2 2 )资助项目~~

摘　　要：应用有限元方法 ,对延性材料孔洞型细观损伤演化进行探讨。考察具有相同初始孔洞体积分数f0 、不同相对尺寸孔洞长大和对材料软化的影响。三种体胞分别为简单立方体胞、体心立方体胞以及非均匀孔洞群状分布体胞。体胞基体为Mises等向强化材料。采用大变形有限元方法 ,简单加载 ,应力三维度保持定值。分析结果发现 ,孔洞群状分布体胞模型所代表小尺寸孔洞的长大速度较慢 。Three types of cubic cell models containing one void, two voids and nine voids respectively are used originally to investigate the problems of void size effects on the damage evolution of ductile materials. The cells have equal initial void volume fractions f 0 (0.01%), but the different void sizes with relative radius 2.0,1.6,0.96 and different spaces. The stress state parameter ( T =1/3,1,3) represents the loading conditions of uniaxial tensile round smooth bars, round notched bars and crack tip fracture process zones. The results are obtained by using FEM software ABAQUS 5.8(1998) and discussed completely. By comparing the results, it is found that the relative void volume fractions f/f 0 and the stress carrying capacity of material with different void sizes can be very different. For the larger void, the ratio f/f 0 increases faster and the stress carrying capacity drops more rapidly especially when the stress state parameter and higher. It means that the ductile materials with larger, voids can fail earlier than those with the smaller ones. The void damage evolution processes accompany the plastic deformation of materials. The difference of void sizes may change the ways of macro scope and meso scope plastic deformation of materials. The void size effects on damage of ductile materials may not be ignored. If initial different void sizes refer to inclusion and second phase particle sizes in real materials, it will be beneficial to increase the strength of materials by decreasing the inclusion and particle sizes in metallurgic processes.

关 键 词：延性损伤 有限元 损伤尺寸影响 

分 类 号：O344.1[理学—固体力学] O346.5[理学—力学]