Damage simulation of composite materials based on strain invariant failure theory

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.