Validating ballistic impact limits of fiber-metal laminated GLARE composites as lightweight aerospace-grade material: Experimental and simulation studies

Fiber-metal laminate composite materials offer unique advantages over traditional aerospace materials like monolithic aluminum or carbon fiber composites. GLARE composites are utilized in aerospace applications for its exceptional damage tolerance and lightweight properties to address sustainability concerns. This study offers a machine-learning based prediction of ballistic impact limit of aerospace-grade GLARE 4A-3/2-0.4 composites. Finite element analysis models were calibrated for two-dimensional ballistic phase diagram for conical projectile impacts on aerospace-grade Al 2024-T3. The ballistic response of the GLARE configuration was investigated under high-velocity impacts by spherical projectiles, with ballistic limit velocities determined through simulation and confirmed by gas-gun experiments. Post-impact damages were characterized using non-destructive ultrasonic inspection, optical microscopy and computed tomography to provide insights into failure mechanisms. A 3-D ballistic limit diagram was constructed to analyze the effects of aluminum layer thickness and projectile diameter on impact resistance. The ballistic limit diagram topology strongly correlates with predictions from support vector regression-based machine learning models. The outcome of this study offers a valuable toolset for optimizing the structural design and enhancing the impact resilience of sustainable aerospace-grade laminated materials.