Computer geometry simulation of spatial structure of three-dimensional braided composites

For 4-step square braiding structures, a representative geometric model of unit cell was presented through studying the actual braiding process, as well as fabrics spatial geometry model. It is composed of a series of yarns, the structure of which is formed when yarn carriers wind a full cycle and return back to the initial start position, such a model ensures continuity of yarn bunches and integrity of braided composite structure. For each yarn, control points were assigned properly in all regions of braided volume, then the cubic B-spline curves were constructed by passing these control points, forming the central axes of yarn spatial structure. Finally the structure of yarns and the braided cell was generated, which was quite suitable for the next FEM analysis of the mechanical properties of the braided composites.