金属基复合材料疲劳寿命细观预测

MICROMECHANICAL PREDICTIONS OF FATIGUE LIFE FOR METAL-MATRIX COMPOSITES

本文以细观力学的平均场理论为基础,利用增量方法分析了金属基复合材料的疲劳性能,在每个增量过程把基体看作各向异性弹性材料来处理。首先利用数值方法求得了任意椭球夹杂在各向异性基体中的Eshelby张量,然后利用Mori-Tanaka平均场理论建立了复合材料应力与应变的增量关系。应用上述方法和基体的塑性混合强化模型及基体的疲劳寿命关系,本文分析了SiC/Al金属基复合材料的疲劳性能与微观结构的联系,并对复合材料的低周疲劳寿命进行预测。分析和预测结果和文献的实验相符合。

A new incremental method is proposed to predict the cyclic behavior of metal-matrix composites. In each incremental step, the matrix is considered to be an anisotropic material whose stiffness tensor is chosen as the tangent moduli of the studied matrix. The Eshelby tensor for an ellipsoidal inclusion embedded in an anisotropic matrix is calculated numerically. With the aid of Mori-Tanaka mean field theory and numerical solution of the Eshelby tensor, the incremental stress and strain relation of the composite is derived. With the aid of the matrix mixed hardening law and the matrix fatigue properties, the tensile, cyclic hardening behavior and the fatigue life for a particulate reinforced are analyzed in detail; the predicted results agree quantitatively well with the ones given in the literature. In the end, the method is applied to predict the fatigue life for metal matrix composites. The comparison with experiment is also given.