Ballistic performance of multilayered armor with intermediate polyester composite reinforced with fique natural fabric and fibers

Multilayered Armor Systems (MASs) with a front ceramic followed by synthetic fabric are currently used against high velocity ammunition. In these armors, the front layer, which shatters the ceramic and spalls the bullet, is followed by an intermediate layer, usually plies of synthetic aramid fabric (Kevlar (R)). In the present work, the intermediate Kevlar (R) layer was replaced by an equal thickness layer of two configuration of fique fibers, as fabric or aligned fibers. Both fique fabric and aligned fibers in amounts of 10, 20 and 30 vol% were used to reinforced polyester matrix composite. Ballistic impact tests against high velocity 7.62 caliber ammunition revealed that the plain polyester as well as the fique fabric and aligned fiber composites have a relatively similar shock impedance performance as that of the Kevlar (R). Indentation around 16-20 mm in witness clay for MASs with fique fabric and aligned fique fiber polyester composites as second layer, were better than that of 23 mm for Kevlar (R). These values attended the US National Institute Justice standard, which requires a maximum of 44 mm for body protection. The energy dissipation mechanisms related to the contribution of fique fabric and fibers composites were analyzed in terms of distinct failure modes, visually supported by scanning electron microscopy. These were found to be the same mechanisms recently disclosed for aramid fabric and other natural fibers composites. (C) 2019 Instituto Militar de Engenharia. Published by Elsevier B.V.