Multilayer composites for application in bulletproof vests

Abstract

The quest for lighter and more flexible body armour solutions demands for the development of new materials or the application of existing materials not traditionally used in this field. An example is Shear Thickening Fluids (STFs), which have been the subject of research for the past two decades, but despite the results obtained so far, considering the potential adoption of STF for ballistic strength enhancement of fabrics, it has not yet been applied in practice. More recently, thermoplastic matrix composites have also been investigated. Taking into account the current state of the art, this study evaluates the low-velocity impact performance of composites using two different matrices: UHMWPE GUR® 5113 and Shear Thickening Fluid DIC701N, both reinforced with two types of Twaron® fabrics. It was demonstrated that the partial impregnation by the UHMWPE matrix provided higher energy absorption by allowing generate mechanisms contributing to its dissipation, such as fibre/matrix debonding, delamination, and fibre stretching. Excessive impregnation contributed to increase the composite's fragility and lower energy absorption. For a single layer of fabric, the absorbed energy was 37% higher for STF/fabric composite than for the neat fabric at the same areal density.