Hypervelocity Impact Response of Polyethylene Plates

When developing protective structures to defend against hypervelocity impacts (HVIs), optimizing specific energy dissipation is critical. Incorporation of lightweight materials, such as polymers, into novel layered shielding concepts could improve HVI performance in space and military applications without compromising cost or weight. One key challenge is developing a fundamental understanding of the effects of molecular architecture on the macroscopic dynamic material response and damage formation. In this work, two common and affordable thermoplastics, namely ultra-high molecular weight polyethylene (UHMWPE) and high density polyethylene (HDPE), were assessed. Flat rectangular targets of fixed geometries were subjected to a series of normal HVIs with spherical 10 mm diameter aluminum 1050 projectiles at velocities in the range 2-6.5 km/s. The back face debris cloud velocity, mass loss, and perforation radius were found to be functions of impact velocity for both materials. Additional post-impact forensic analyses were performed to provide insight into the distinct failure modes of the two polyethylenes.