Effects of external patch configuration on repaired composite laminates subjected to multi-impacts

Abstract

This work intends to study the impact performance of repaired composites by the overlap patch technique and, for this purpose, experimental tests were carried out on single and double-patch specimens. In order to evaluate the impact fatigue strength, both configurations were submitted to multi-impacts, until the full perforation occurs. It was possible to conclude that the double-patch geometry supports higher maximum loads, lower displacements and promotes higher elastic energies. Relatively to the impact energy of 6 J, for example, the maximum load and the elastic energy is 97.1% and 51.2% higher, respectively, but the maximum displacement is about 50% lower than the values obtained with the single-patch geometry. Higher impact fatigue life was also observed, as consequence of its higher stiffness. The impact bending stiffness confirms the difference of stiffness between them, and shows to be a parameter able to monitor the damage progression.