Effect of Rubber particles on Kevlar Fiber Reinforced Polymer composite against High Velocity Impact

Abstract

Bullet proof vests have been designed for decades to provide protection against different type of threats like small arms ammunition. Although pure fabric is being used in most of bullet proof vests but back face signature is very high in plain fabric. This back face signature or blunt can causes severe damage to body parts resulting in internal bleeding and sometimes even causing death. So it is also an important factor to be considered while designing a bullet proof vest. A lot of different methods are being used in literature to upsurge the impact response of Kevlar Fiber Reinforced Polymer (KFRP) composite like addition of Nano-clay, change of fiber orientation, use of toughened epoxy etc. In this research, effect of different matrix combinations on blunt trauma and energy absorbed by KFRP laminates are studied. KFRP composite samples are prepared with epoxy and different percentages of rubber + epoxy, and are experimentally tested against 9mm Full Metal Jacketed (FMJ) bullet.
The ballistic impact behavior and back face signature measurement of Kevlar/epoxy composite and Kevlar/epoxy with different percentages of rubber are compared with that of pure fabric. Results from the experiments have shown positive effect, of adding rubber in matrix, in terms of energy absorption (i.e. penetration), reduction in back face signature and damage mechanism for ballistic impact event. During experiment it is found that failure of primary yarn, elastic deformation of secondary yarn, delamination and matrix cracking are the main energy absorption mechanisms. The results have shown that the laminates with a combination of rubber and epoxy give optimum results i.e. better impact resistance with lesser blunt trauma or back signature. Among these samples the sample with 12.5% rubber has best results.