通过2.5D-C/SiC陶瓷基复合材料的面内拉伸试验,研究了材料在拉伸载荷作用下的力学性能和损伤演化过程,建立了2.5D-C/SiC复合材料的应力型和应变型拉伸损伤演化模型.结果表明,材料沿纵向和横向的拉伸应力-应变曲线相似,损伤过程基本相同.对应于拉伸应力应变曲线的三个特征切线模量,面内拉伸的损伤演化过程可以分为三个阶段:初始损伤阶段、损伤加速阶段和损伤减缓阶段.由应力型损伤演化模型可以推导出三个损伤阶段的两个特征应力,其中第一特征应力可以作为工程比例极限的参考值.
Based on experimental analysis of 2.5D-C/SiC composite, mechanical behavior and damage evolution process under tensile loading were investigated. Tensile damage evolution models in terms of stress and strain for 2.5D-C/SiC composite were presented to disclosure tensile damage evolution law. Experiment shows that the tensile damage process of 2.5D-C/SiC composite along longitudinal and transverse direction is similar, and that tensile stress-strain curve is nonlinear and approximately consists of 3 fold lines corresponding to three specific tangential moduli. The damage process includes three stages: the first is initial damage stage in which the initial micro-cracks of composite cracking;'the second is accelerating stage that new micro-cracks appears and opens; the last is decelerating stage that the deflection of micro-cracks and debonding of fiber/matrix interface are major damage mechanisms.