Experimental and analytical investigation of damage initiation and propagation in fiber metal laminates under static tensile loading

Abstract This study investigates the influence of metal plasticity on the initiation and propagation of cracks within the 90‐degree carbon/epoxy layers of fiber metal laminates (FMLs) under static uniaxial tensile loading. The research combines experimental observations and analytical modeling to assess key damage mechanisms, including matrix cracking, crack saturation, delamination, and stiffness degradation. An energy‐based analytical model, rooted in variational principles, is developed to predict stress distribution, plastic deformation in metal layers, and the onset of matrix crack initiation. Experimental tests employing a new technique on Carbon Reinforced Aluminum Laminates (CARAL) with [AL/903]s and [AL/902]s configurations demonstrate that plasticity in the metal layers triggers damage, leading to matrix cracking, followed by delamination. A good agreement between the analytical predictions and experimental data validates the model's capability to capture FML behavior. Key findings indicate that increasing the 90‐degree layers reduces stiffness, failure stress, and saturated matrix crack density in FMLs. These insights contribute to a deeper understanding of FML performance and failure mechanisms under tensile loading conditions. Highlights The metal plasticity affects the initiation and propagation of cracks in FML. Using an energy‐based analytical model, damage in FML was predicted. Damage was presented at any loading moment with a known applied stress.