Impact dynamics simulation for multilayer fabrics

Abstract

SUMMARYHigh-strength fabrics are employed in a wide range of ballistic protection and blast mitigation applications. They are normally used in a multilayer configuration. General numerical models of impact, perforation, and fragmentation processes in multilayer fabrics must account for complex contact-impact dynamics and include general thermomechanical coupling. A hybrid particle-element formulation has been developed to simulate impact and perforation in plain weave fabrics. Simulation results show good agreement with experiment, for fragment simulating projectile impacts on both aramid and ultra high molecular weight polyethelene soft armor materials.

Simulation of Large Fragment Impacts on Shear-Thickening Fluid Kevlar Fabric Barriers

“…The method incorporates general thermomechanical constitutive models for all of the interacting materials, including analytic or tabular equations of state and irreversible entropy production associated with dissipative processes such as friction and plasticity. Note that the Kevlar KM-2 [26] material model described in a previous paper [11] was used in conducting the simulations presented in this paper. Hence, the material modeling descriptions that follow are only those newly developed for the present research.…”

“…edges, and 2) fabric clamped on all four edges. As a preliminary to the parameter study, validation simulations were performed using impact data for single-layer 4 2 in: fabric targets clamped on two edges and impacted by 0.22-caliber fragment simulating projectiles (data previously reported by the authors) [11]. Figure B1 compares the validation simulations to the test data, showing good agreement for the target configuration of principal interest.…”

“…2 shows graphics for the corresponding simulation. Note that the graphics draw the bar or hex elements that link the particles rather than the particles themselves [11]. The graphics illustrate a number of important features of the hybrid-particle-element formulation.…”

“…This section outlines the hybrid-particle-element method developed by the authors [11] to model impact dynamics in highperformance fabrics, and it describes new constitutive augmentations developed for that method in order to represent the thermodynamic and dissipative properties of STF Kevlar. The constitutive augmentations include a mixture equation of state and a generalized Bingham fluid model of STF effects.…”

“…In recent research, Shivarama and Fahrenthold [10] and Rabb and Fahrenthold [11] have extended a hybrid-particle-element computational technique, developed originally to model perforation and fragmentation in solid materials, in order to simulate impact and penetration dynamics in high-performance fabrics. The extended formulation was validated by modeling experiments involving 0.22-caliber fragment simulating projectile impacts on aramid and UHMWPE materials for targets up to four fabric layers in thickness.…”