单向短纤维复合材料中热残余应力研究

基于单向短纤维增强金属基复合材料的单纤维模型，利用轴对称弹塑性有限元分析方法，研究了该类复合材料中热残余应力的大小和分布情况以及各种微结构参数的变化对它的影响，同时还讨论了热残余应力的存在对基体与纤维之间应力传递的影响。研究表明，热应变的不匹配导致纤维受压、基体受拉，界面法向受压。热残余应力的存在降低了基体与纤维间的应力传递，不利于复合材料整体性能的提高。

Thermal Residual Stresses in Aligned Short Fiber Reinforced Metal Matrix Composites

Based on the single fiber model of aligned short fiber reinforced metal matrix composites, the thermal residual stresses and their distribution are calculated with the axi-symmetrical elasto-plastic finite element method. The effects of various microstructural parameters on thermal residual stresses are discussed. The effects of thermal residual stresses on stress transfer in aligned short fiber composite under axially applied load are analyzed. It is shown that the unmatched thermal strain results in compressional stresses in the fibers, tensile stresses in the matrix, and compressional normal stresses on interfaces. Thermal residual stresses degrades the degree of stress transfer between matrix and fibers, and harmful to the improvement of the mechanical properties of the composite.