Multi-scale elastic properties of 2.5D woven composites with void defects

2.5D woven composite material inevitably produces void defects in itsproduction process, which will seriously reduce its mechanical properties andreduce its service life. In this paper, the effects of void defects on the mechani-cal properties of 2.5D woven composites were studied by multi-scale analysis.An improved Halpin-Tsai semi-empirical model is proposed to calculate theelastic properties of yarns with porous defects and verified by finite elementmethod. A microscale representative volume unit (RVE) for predicting theelastic constants of composites with pore defects is established. Theoreticalanalysis and finite element analysis were used to verify the micro scale, andfinite element analysis and experiment were used to verify the micro scale.The effect of porosity on the elastic properties of micro-scale RVE was studiedin detail. The results show that the model is reasonable and accurate inpredicting the mechanical properties of yarns and composites. In addition, theeffect of porosity on the mechanical properties of 2.5D woven composites issignificant