基于应变不变量失效理论的复合材料损伤模拟

Damage simulation of composite materials based on strain invariant failure theory

应变不变量失效理论基于物理失效模式判断纤维和基体的损伤,适于研究纤维与基体的细观相互作用及固化残余应力的影响.介绍了应变不变量失效理论的物理背景,建立了正方形、六边形和钻石型细观代表体积单元模型,给出了宏观应变到细观应变的转换方法,提出了相应的失效模式和损伤演化准则.基于应变不变量失效理论求得了CCF300/5228材料体系的机械应变放大系数和热应变放大系数,对CCF300/5228复合材料开孔层合板的拉伸破坏过程进行了模拟,分析了纤维和基体的失效过程.计算与试验结果取得了较好的一致性,证明了该理论的适用性.

Strain invariant failure theory（SIFT） estimates failure in fiber and matrix based on mechanical failure modes,which is suitable to study meso-interaction between fiber and matrix,and to evaluate influence of curing residual stress.Mechanical theory background of SIFT was introduced.Square,hexagon and diamond representative volume element（RVE） model in meso level were established.Transition method between macro and meso level was given.Failure mode and damage evolution criteria were proposed.Based on this theory,mechanical strain amplification factors and thermal strain amplification factors of CCF300/5228 were obtained,open hole tensile performance of CCF300/5228 was calculated,fracture process of fiber and matrix was analyzed.Good agreement between numerical results and experiments is observed,which demonstrates the applicability of this theory.