Mesoscale analysis of aging mechanical behaviors of 3D woven composites

3D orthogonal woven composites (3DOWCs) are inevitably subjected to the severe cyclic hygrothermal aging environment in the application of supersonic aircraft structures and their durability should be proven. However, most current works relating to the hygrothermal aging of 3DOWCs rely on the experimental methods which are of high cost. To address this issue, a matrix-yarn mesoscale model of 3DOWCs was established to investigate the cyclic hygrothermal aging mechanical behaviors in this paper. High-fidelity mesoscale representative volume element (RVE) was constructed with realistic geometric configuration of the reinforcement. Only the aging properties of pure resin were needed in the mesoscale model. The aging properties of fiber yarns were calculated with Chamis formulas accounting for resin aging. Tension-compression asymmetry behavior of resin matrix was accounted in the constitutive model. The damage initiation and propagation of resin matrix, yarn and cohesive interface were modeled by the progressive 3D damage model. The mechanical properties of 3DOWCs before and after aging were predicted by the mesoscale model and validated with experiment. This work can provide effective tool for the design of 3DOWCs applied in harsh environments.