Studies on Shape Optimization of Repair Patches for Damaged Composites

Due to the increasing development of health monitoring and damage detection techniques, the assessment of damage presence and its shape is a viable option to continuously evaluate the structural integrity of composite components. Along with such tool, one could employ repair patch techniques in order to restore (or locally improve) the originally designed strength of a damaged composite component. This approach would imply in the use of a composite repair patch capable of increasing the stiffness of a damaged component with minimal material addition, resulting in the minimization of costs with component replacements and extend the structures life. In this context, the present work exposes initial studies concerning simple repair shapes optimization applied to damaged composite materials. The main objective of this research is to propose an optimization procedure capable of specifying suitable patch shapes to be applied in a pre-assessed damaged area of a laminated component. The optimization formulation was defined considering as objective function the minimization of the error with respect to the structure first natural frequencies. Linear programming along with an interior point algorithm was employed in order to obtain an optimized repair patch shape. The analyzed model was a rectangular multilayered plate with a predefined damaged zone. Epoxi-graphene composite with transversely isotropic material behavior was considered for all components. A shell finite elements model was used to solve the associated modal problem.