Optimum Patch Repair Shapes for Cracked Members

In the present paper the problem of finding the optimal patch repair shape in a cracked structural component with respect to a given objective function, is investigated by using a biological-based procedure known as Genetic Algorithm (GA) in conjunction with a penalty constraint. The search for an optimal patch shape, which can be regarded also as an optimal topology problem, is obtained by determining the corresponding patch’s continuous material’s density distribution: the design optimisation considered in the present study takes into account the minimisation of some mechanical desired performance of the structure’s while keeping constant the total available patched area (optimal constrained problem). The proposed optimisation model is implemented in a F.E. code and some numerical simulations are performed in order to assess its reliability in optimal topology design of patch repairs, applied to mode I cracked members, with respect to some expected performances. For the considered problems, the optimisation algorithm allows a quite important improvement (in reducing the stress intensity factor) with respect to cracked components repaired with simple shape (i.e. rectangular) bonded patches.