Experimental and numerical study on ballistic response of stitched aramid woven fabrics under normal and oblique dynamic impact

The objective of this study was to examine the influence of impact angle and stitching method on the ballistic properties of fabrics. Multi-layer stitched fabrics and multi-layer unstitched fabrics were designed and manufactured. Subsequent pull-out tests, as well as positive and oblique impact ballistic tests, were conducted. A validated yarn-level ballistic impact finite element model was established to analyze the effects of impact angle and stitching methods on ballistic properties, including stress distribution, back deformation, and energy absorption. The results of experiments and simulations demonstrate that impact angle and stitching methods significantly affect the impact resistance and response mechanism of the fabric. The suture treatment significantly enhanced the energy absorption capacity of PW4, with an average energy absorption ratio of 16.72% at various angles. This treatment facilitates stress propagation within the yarn, resulting in a maximum reduction of 576.00 mm² in the low-stress area, thereby maximizing the yarn's load-bearing potential. The peak value of back deformation is decreased. In comparison to PW4–0, the peak value of out-of-plane deformation displacement of PWS4–0 is reduced by 17.89%. Additionally, the energy absorption mechanism of the fabric varied with the incident angle, showing a "falling-rising-falling" trend in total energy absorbed.