Numerical prediction for the elastic properties of three dimensional and five directional braided composites

The finite element model is established based on the micro-structure of three dimensional and five directional braided composites and the assumption of the braiding yarn with the hexagon section and the axial yarn with the square section and the analysis of geometrical relationship of yarns in three dimensions. The elastic constants of three dimensional and five directional braided composites are calculated by the finite element method and compared with the corresponding results of three dimensional and four directional braided composites. The influences of the braiding angle and fiber volume fraction on the elastic constants are also analyzed. In addition, the predictions were compared with the experiment results which verified the validity of the finite element analysis. The results show that three dimensional and five directional braided composite has good mechanical properties and it improves the axial mechanical performance of the material by joining the axial yarns.