Effect of stitching on the mechanical and impact properties of woven laminate composite

Abstract

Mechanical and impact-resistant properties of stitched woven laminate composite have been studied. The S-2 Glass/Polyester, Kevlar/PVB-Phenol and Spectra/Vinylester composites were stitched at different stitch densities to improve its mechanical and impact properties of the composite. Both chain and plain stitches were used for reinforcing the laminate in the Z-axis of the composite. The mechanical properties of woven laminate composite were improved at the optimum stitch density compared to those of conventional unstitched one. Energy absorption capability of stitched composite was also higher than that of unstitched composite, and the stitched composite showed a significant increase in energy absorption capability under repeated impact. The damaged areas caused by the repeated impact or by the penetration of projectile were far smaller in the stitched composite than in the unstitched laminate one. The stitched composite showed about 10% improvement in ballistic efficiency over the conventional woven laminate composite at the optimum stitch design.