界面层对C/SiC复合材料热残余应力影响的模拟及分析

摘要

针对平纹编织C/SiC复合材料的C纤维束,通过对其扫描电子显微镜(Scanning electronmicroscope,SEM)照片的测量,考虑纤维排布以及选择合适的界面模型,建立了包含界面层的三维三相的代表特征体元(Representative volume element,RVE)的有限元模型.采用间接耦合的降温法,在考虑温度对组分弹性常数的影响以及施加合适的周期性边界条件的基础上模拟了C纤维束轴向的热残余应力.分析可知,对于SiC基体的热残余应力,其随着界面层厚度的减小而增大,随着界面层模量的增大而增大.引入一维应力分布轴,将振荡幅值作为选择最佳参数的一个条件,据此可知选用热膨胀系数小的界面层材料可更好的降低组分间热残余应力变化的梯度.%For carbon fiber bundle of plain weave C/SiC composites,the three dimensional and three phase finite element model of representative volume element (RVE) with interface is established by using the scanning electron microscope (SEM) pictures,and considering fiber arrangement and selection of appropriate interface model.The axial TRS of carbon fiber bundle is simulated by using cooling method with indirect coupling,considering the influence of temperature on the elastic constants of the components and applying appropriate periodic boundary conditions.The analysis shows that the TRS of SiC matrix increases with the decrease of the thickness of interlace,and increases with the increase of the interface modulus.Introducing the one-dimensional stress distribution axis and using oscillation amplitude of stress as one condition of choosing the best parameters,it is considered that it's better to reduce the gradient of the change of TRS among the components by choosing interface with small thermal expansion coefficient.