Crushing and intrusion resistance improvement of aluminum beams by carbon/epoxy composite patches

This study investigates the intrusion and crushing performance of hybrid fiber metal laminates based on aluminum and carbon fiber reinforced polymers, in comparison to reference aluminum parts, made from AA6451 or AA7075 automotive grade alloys. A first set of crushing tests and intrusion tests were performed to assess the influence of several parameters: aluminum thickness (0.9, 1.5 and 2.5 mm) and aluminum composition (AA6451 and AA7075), the thickness of carbon composite patch (2 or 3) and the area of composite coverage, patch or strips. Intrusion test results of hybrid structures were correlated to validate and refine a Finite Element Model. Then, a range of configurations was numerically modelled to determine the optimum aluminum-composite lay-up architectures and the ideal locations of the patches leading to the best absorbed energy/weight ratio for a given load. Results demonstrate that localized composite patches improve the intrusion properties of tubes without penalizing the overall part weight.