Effect of Consolidation Pressure on the Transverse Compressive Strength of UHMWPE Composites at High Strain-rates

Abstract

UHMWPE (Ultra-High Molecular Weight Polyethylene) composites are commonly utilized as protective materials against fragments and projectiles. They are composed of UHMWPE fibers and a thermoplastic elastomeric matrix, typically Styrene- Isoprene-Styrene (SIS) or Thermoplastic Polyurethane (TPU). The dynamic mechanical performance of these composites is known to scale with consolidation pressure, but the underlying mechanisms are poorly understood. The majority of the experiments on this material described in the literature are performed at quasi-static strain-rates, even though the composite is loaded at ballistic strain-rates (10􀵯 – 106 s-1) when used in protective applications. In this work, Dyneema® HB80 laminates consolidated at two different pressures are loaded in uniaxial out-of-plane compression at strain rates of the order of 103 s-1 in a Kolsky bar. Using high speed optical imaging, we are able to visualize the dynamic damage evolution in the composite as a function of the applied stress.