Numerical simulations of the effect of stitching reinforcement on composite laminates with a circular hole

A calculation model of stitching yarn was proposed, and the elastic properties parameter of stitching yarn were obtained based on the numerical simulation and the experiment results. The finite element simulating calculation was carried out on the stitching reinforcement for composite laminates containing a circular hole. The strain distribution near the hole edge were investigated analytically. The hole edge coefficients of strain concentration were calculated for different stitching parameters, such as stitching needle distance, row spacing, edge distance, diameter and modulus. A stitching design parameters on the edge of hole are obtained.