Investigation of failure modes and influence on ballistic performance of Ultra-High Molecular Weight Polyethylene (UHMWPE) uni-directional laminate for hybrid design

For hybrid design of soft body armour, material selection must be based on ballistic characteristics of materials. This study aims to identify ballistic characteristics of Ultra-High Molecular Weight Polyethylene (UHMWPE) uni-directional (UD) laminate, including failure modes of UHMWPE fibres during ballistic impact and its influence on ballistic performance of UD laminate. According to fractorgraphic analysis, thermal damage of UHMWPE fibres is obvious and more significant for front layers at the striking face, which results in material properties degradation during impact. Ballistic test results showed when Dyneema UD laminate was placed on the striking face before Twaron fabric, ballistic performance including energy absorption and Backface signature (BFS) exhibits obvious degradation. Finite Element (FE) results showed when material properties degradation of Dyneema UD induced by thermal damage is taken into account, stress wave propagation and transverse deflection of Dyneema UD is highly constrained, which leads to quick perforation. As a result, energy absorption of whole hybrid panel is decreased.