Impact dynamics of magnetorheological fluid saturated Kevlar and magnetostrictive composite coated Kevlar

High strength, light weight and flexibility have made fabrics the preferred material for personal body armor and other impact protection applications such as passenger airbags, turbine blade containment systems, military and motorcycle helmets, and space debris shields. Recently, a shear thickening fluid has been used to treat a Kevlar fabric for an additional enhancement to the ballistic resistance of the neat fabric. Motivated by this technique of dissipation augmentation to high strength fabrics, this research aims at investigating the incorporation of other energy-dissipative materials into high strength fabrics. Specifically, two magnetic field-responsive materials (a magnetorheological fluid and Terfenol-D) have been used as a dissipation augmentation of Kevlar fabrics. No previous work has reported either experimental or computational research on the impact dynamics of Kevlar fabric treated with magnetorheological fluids or magnetostrictive solids. This research has investigated both computational modeling and experimental evaluation of the impact dynamics of textile composite armor, treated with magnetic field-responsive materials. Fragment simulating projectile impact tests have been conducted for the fabricated composite targets under an applied magnetic field. A computational model based on a hybrid particle-element method has been developed, to simulate the impact dynamics of composite fabric targets embodying magnetorheological fluids. This model is a mesoscale multiphysics model which can simulate impact dynamics including complex magneto-thermo-mechanical coupling effects as well as interactions among a projectile, fabric yarns, and magnetorheological fluid particles. Computer simulations have been performed to validate the hybrid particle-element method against experimental results. The computational method developed in this research has shown good agreement with the experimental data, in terms of the ballistic limit and residual velocity of a striking projectile. As fabric impact protection systems become more complex, and more expensive materials are introduced, computation may play a more important role in design. Therefore, the hybrid particle-element model in this dissertation may contribute to the improvement of the computational capability for virtual prototyping of fabric-interstitial fluid composites.