Analysis of glass reinforced aluminum composite's energy dissipation behaviour during low-velocity impacts

Glass-Reinforced Aluminum (GLARE) laminates combine low density, high specific strength, and excellent fatigue resistance, yet their performance under combined thermal and impact loads remains insufficiently characterized. This study investigates GLARE 4A 3/2-0.4 panels subjected to low-velocity drop-weight impacts at three temperatures (25 °C, 60 °C, and 90 °C) and three energy levels (40 J, 60 J, and 90 J). Temperature-dependent input data for modeling were obtained through uniaxial tensile tests in 0° and 90° fiber orientations, Dynamic Mechanical Analysis (ASTM D3039, EN 6032), and Thermomechanical Analysis (ASTM D696). An LS-DYNA finite element model simulated the impact event at room temperature, serving as a baseline for interpreting experimental trends. Post-impact damage was assessed using ultrasonic C-scanning, X-ray computed tomography, macro-fractography, and active thermography, enabling correlation of dent depth with internal cracking, fiber rupture, and delamination. Thermal-fatigue exposures at 80 °C for up to four days were applied to both constituent materials (Al 2024-T3, FM 94 epoxy) and full laminates, followed by interlaminar shear testing (ASTM D2344) to evaluate residual interface integrity. Results indicate that elevated temperatures increase energy absorption but also exacerbate delamination and surface indentation, while prolonged heating further reduces shear strength due to intensified interfacial stresses. By integrating controlled impact testing, thermomechanical characterization, advanced non-destructive evaluation, and validated numerical modeling, this work provides a comprehensive framework for understanding GLARE's coupled thermo-impact response, offering insights relevant to design optimization, maintenance scheduling, and structural reliability in aerospace applications.