陶瓷基复合材料三维有效应力强度失效模型

基于陶瓷基复合材料在多轴应力作用下的各向异性损伤演化机制，提出损伤解耦分析的模型和方法，实现定量描述损伤分量之间的耦合影响效应。考虑损伤引起的内应力强化，通过引入有效应力的概念，对微细观损伤造成的材料承载性能衰减进行了表征，并提出复杂应力条件下强度失效判别的最大有效应力判据和二次有效应力判据。采用平纹编织C/SiC复合材料，开展了轴向拉伸加卸载、偏轴拉伸加卸载和面内剪切加卸载试验，进行了损伤演化和强度失效分析。模型和试验结果对比分析表明，本文提出的强度理论具有合理性，预测结果准确。 

Effective stress based three-dimensional strength failure model for ceramic matrix composites

Based on the anisotropic damage evolution mechanisms of ceramic matrix composites under multiaxial stress, analytical model and methodology have been proposed for damage decoupling investigation, through which the interaction effects among damage components can be quantificationally characterized. Considering that the internal stresses of the load carrying material would be enhanced by mechanical damage, the parameter of effective stress was introduced in order to describe the degradation of load bearing capacity induced by micro-damage. Moreover, the maximum effective stress criterion and the quadratic effective stress criterion were suggested for strength failure discrimination under complex stress state. The damage evolution and strength failure analysis was performed with plain-weave C/SiC composites subjected to incremental cyclic tests of on-axis and off-axis tension and in-plane shear. Comparison between experimental and theoretical data demonstrates that the established strength theory is reasonable, and the predicted results are accurate.