Towards optimization of patch shape on the performance of bonded composite repair using FEM

Composite repair is gaining importance for extending the service life of aging aircrafts. There are many parameters like patch thickness, patch layup configuration and patch shape influencing the performance of composite repair. Therefore a need exists to prioritize them. In this work a 3-D finite element analysis has been conducted to get an optimum composite patch shape applied on an inclined center cracked panel, repaired by symmetrical patch. The patch shapes considered are circle, rectangle, square, ellipse and octagon. Also SIF reduction is compared for the same volume of patch. It is observed that extended octagonal patch shape performs better in case of SIF reduction