A comprehensive analysis of FML based on UHMWPE against ballistic impact: An Experimental and Numerical Approach

Ballistic protection in light vehicles has traditionally been implemented through add-on armor panels, which increases the areal density of the structural system and reduces mobility and maneuverability in operational environments. As an alternative, the development of structural components that integrate protective functions within the load-bearing element itself allows for maintaining structural integrity while providing impact resistance. In this context, stainless steel-based Fiber Metal Laminates (FMLs) represent a potential solution to combine load-bearing capacity and ballistic protection into a single integrated system and constitute a promising architecture for the preliminary assessment of lightweight structural protection concepts. This work addresses a comprehensive experimental and numerical study of the impact behavior of FMLs consisting of AISI 304 stainless steel as the metallic phase and UHMWPE composite material as reinforcement. The analysis is structured in two stages. First, the constituent materials are studied independently through small-caliber projectile ballistic impact tests to characterize their ballistic response and the damage induced by the energy absorption mechanisms inherent to each material. These results are used to calibrate and validate specific numerical models for each constituent. Damage assessment is performed using computed tomography (CT) and 3D scanning techniques, enabling both internal and external characterization. In the second stage, the validated constituent models are integrated into multilayer FML configurations. Two laminates of different thicknesses are subjected to ballistic impact and damage analysis, using experimental results to validate the predictive capability of the developed numerical model. The proposed procedure provides a validated modeling framework capable of predicting the impact behavior of stainless steel–UHMWPE FMLs in various configurations, aimed at the preliminary assessment of lightweight structural protection concepts and future vehicle-oriented applications.