Predicting mechanical properties of 3D braided composites using a helix geometry model

On the basis of available studies, a helix geometry cell model of 3D braided composites is proposed. The yarns in the helix geometry model have been curved to avoid collision at the center of the unit cell and this coincides with the actual configuration of 3D braided composites. Based on the model, the mechanical properties, such as Young's modulus and Poisson's ratio, were calculated by a finite multiphase element method (FMEM). Compared with the experiment results, the study revealed that the helix geometry model predictions are more accurate than the conventional unit cell model.