Damage Evolution and Energy Absorption of FRP Plates Subjected to Ballistic Impact Using a Numerical Model

High velocity transverse impact to laminated fiber reinforced composites is of interest in military and structural applications. Damage evaluation of the targets during impact based upon experimental work can be prohibitively expensive. However recent advances in the field of numerical simulation provide a means of predicting the performance characteristics of layered materials for ballistic protection. There is however, limited information about the ballistic response of reinforced thermoplastic composite materials. The overall objective of this work is to investigate the behavior of a plain weave laminated composites of varying thicknesses under high velocity impact both from an experimental and modeling view point. To analyze this problem, a series of ballistic impact tests have been performed on plain weave E-glass/polypropylene laminated composites of different thicknesses with a 0.50 caliber cylindrical shaped flat nose projectiles. A gas gun with a sabot stripper mechanism is employed to impact the panels. To analyze the perforation mechanism, ballistic limit and damage evaluation, an explicit three- dimensional finite element code LS-DYNA is being used. Selecting proper material models and contact definition is one of the major criteria for accuracy of the numerical simulation. During high velocity impact, composite laminates undergo progressive damage failure and hence, Material Model 161, a progressive failure model based on Hashin’s criteria, has been assigned to predict failure of the laminates. The projectile is modeled using a Material Model 3 (MAT_PLASTIC_KINEMATIC). The laminates and the projectile are meshed using brick elements with single integration points. The impact velocity ranged from 187 to 332 m s-1. A good correlation between the numerical and experimental results has been drawn in terms of predicting ballistic limit, delamination and energy absorption during impact.