增强相形态对复合材料微区力学状态影响的有限元分析

Effect of Reinforcement's Shape on the Local Stress Field of Metal Matrix Composites

采用三维有限元方法模拟了非连续增强金属基复合材料的应力场 ,得到了不同长径比的椭球形增强体周围的最大主应力场和应力球张量场的分布 ,分析了增强体长径比对非连续增强金属基复合材料的应力场、应力集中、界面应力过渡及材料内部最危险位置的影响。与仅适用于稀疏夹杂的Eshelby单夹杂模型相比 ,本文模型 (体积分数约为 2 0 % - 6 0 % )与工程实际更加接近 。

The stress fields of discontinuously reinforced metal matrix composites (MMCs) are simulated using a three-dimension finite element method. We obtain the maximum principal stress fields and hydrostatic stress fields of MMCs which have ellipsoidal reinforcements with different slenderness ratios. The influence of the slenderness ratio on the stress field distribution, stress concentration, stress transmission over interface, and the most dangerous point are investigated. The analysis carried out by finite element method (FEM) shows that the stress field inside the reinforcement is non-uniform, which is different from the Eshelby's classical result, the uniform distribution of stress from the hypothesis of uniform distribution of strain inside the reinforcement.