A novel numerical simulation method for predicting compressive properties of 3D multiaxial braided composites considering various defects

This paper reports a novel manufacturing process of preparing the Three-Dimensional Multiaxial Braided Composites (3DMBCs) and the effects of various defects generated in the manufacturing process on the compressive mechanical properties of 3DMBCs through the experimental and numerical methods. The five-step fabrication process of the 3D multiaxial braided preform was firstly introduced in detail. Then, the influences of various defects such as voids, waviness, and fiber breakage defects on the compressive properties of 3DMBCs were discussed. It is found that the fiber breakage defect and waviness defects were the two primary factors on the decrease of compressive properties of 3DMBCs. However, void defects in the resin and interface had little effect on the composites. When the fiber breakage defect content was 25% and the waviness was 7°, the composite compressive modulus decreased by 51%. The progressive damage process and failure mechanism of the composite under 90° compressive loading confirmed the validity of the numerical model by comparing with the experiments.