Numerical analysis of composite preform structure based on flat cross-linked braiding

Composite materials are widely used in aerospace, automotive industry and medical equipment, where most of the structural parts are made of fiber laminates. Rotary braiding is one of the most important methods to prepare composite preforms. The ordinary rotary braided preforms have low porosity and dense yarns, but are single-layer structures after molding, which do not meet the needs of most applications. To solve the problem that traditional laminates are prone to delamination, this paper designs a flat cross-linked braiding process for the preparation of multilayer-interlocking composite panels. The carrier trajectory is analyzed, and the spatial coordinate system of the braided chassis is established by combining the effect of the end traction system on the morphology of the preform yarns. The numerical model of the preform is initially obtained by using cubic B-spline curve fitting, and an algorithm for gathering yarns towards the fabric center is proposed to optimize the numerical model. Experimental samples of flat cross-linked preforms are prepared according to the braiding process, and the reliability of the optimization algorithm is verified by comparing the yarn coordinates of the experimental samples with those of the optimized numerical model.