The energy absorption characteristics and structural optimization of titanium/UHMWPE fiber metal laminates under high-speed impact

Fiber-metal laminates (FMLs), known for their lightweight and high strength, are widely used in structural protection in the fields of shipbuilding, military, and aerospace. Experiments were conducted using 12.7 mm hard spherical projectiles at speeds ranging from 915.7 – 1290 6 m per second to study the high-speed impact on FMLs composed of titanium and Ultra-high Molecular Weight Polyethylene(UHMWPE). The primary failure modes of the fibers were tensile failure and compressive shear failure. With increasing impact velocity, the proportion of tensile failures in the fibers gradually decreased, transitioning to shear plug failure as the main failure mode, while the titanium alloy primarily experienced erosive perforation and petal-shaped tearing. At a speed of 1290 6 m/s, the titanium alloy began to exhibit significant adiabatic shear tearing in four directions. Further, a three-dimensional numerical model was established, which, through theoretical analysis and experimental validation, proved to be highly reliable. Using this theoretical model, a deeper analysis of the dynamic response and penetration mechanism of the structure was conducted, explaining the energy distribution mechanism and dynamic response mechanisms of various parts. Based on this model, improvements and optimizations were made to the laminar structure of the UHMWPE/titanium alloy FML. Placing metal at the back maximized energy absorption but led to more pronounced bulging.