摘要
根据电镜断面考察结果,以Gurson模型为本构方程的有限单元法对包体模型及三维非均匀模型进行了详细分析.为了评价应力-应变关系及损伤的主要因素,考虑了基体中SiC粒子的体积率和径比的非均匀分布.其结果表明,用这种非均匀模型能很好地仿真铝基体在大量塑性变形之后所发生的韧窝破坏过程.SiC粒子体积率、径比及其位置的非均匀性,对局部和整体损伤过程与应力-应变关系的影响相当大.当Sic粒子径比为1.0,并在基体中均匀分布时,断裂应变会大幅度增大.
In this study, based on the fracture surface observations using an SEM (Scanning Electron Microscope), a numerical unit model and 3-dimensional non-uniform model for FEM (Finite Element Method) analysis are proposed with Gur-son's model as the constitutive equation. The non-uniform distribution of the SiC particle volume fraction in the matrix and the aspect ratio are considered for the evaluation of the stress-strain relationship and the damage. The results show that the dimple fracture process of the matrix aluminum alloy is well simulated, with large amount of plastic deformation. The non-uniformity of the SiC particle volume fraction, aspect ratio and its locations have a strong effect on the local and global damage behavior and stress-strain relations. It is shown that the fracture strain becomes very large when the aspect ratio of SiC particles is 1.0 and they are distributed uniformly in the matrix.
出处
《力学与实践》
CSCD
北大核心
2002年第6期30-32,共3页
Mechanics in Engineering
