Bending behavior of multilayered and multidirectional stitched aramid woven fabric structures

Abstract

The aim of this study was to experimentally determine the bending behavior of developed multilayered and multistitched ballistic structures which could affect the comfort for the wearer. For this reason, the bending rigidity test was conducted on all developed multilayered and multistitched ballistic structures after the impact test. Fabric density and crimp ratio influenced the bending rigidity of single layer fabric. On the other hand, the bending rigidities of multilayered and multistitched ballistic structures depended on the number of fabric layers and stitching directions. Generally, multilayered four directional stitched ballistic structures showed the highest bending rigidity compared to the two and one directional stitching. Multilayered and multistitched ballistic structures showed high bending rigidity compared to multilayered and unstitched ballistic structures. This indicated that the number of stitching directions affected the bending rigidity of the developed ballistic structures. In addition, multilayered and multistitched structures showed a low order of bending curvatures compared to the multilayered unstitched structure. On the other hand, after all structures were impacted by one type of projectile but varied speeds, multistitched structures had low conical depth compared to those of the unstitched structures. This was because stitching increased the bending rigidity of the ballistic structures and reduced the structural deformation to the out-of-plane direction. It could not, however, be easily formed and it could decrease the ballistic comfort to the wearer.