Comparison of symmetrical double sided and stepped patches for repairing cracked metallic structures

The ability to determine an acceptable improvement in performance after maintenance operations on high reliable damaged structures is vital and crucial in such a way that it has to meet damage tolerance criteria and maintain a proper service for which the structure is initially designed for. In this regard the aim of the present study compares the performance of a double sided patch and a stepped patch. This study evaluates the performance of each repair type and shows that a stepped patch gives better results. The investigation is accomplished via a two dimensional finite element method of a centre cracked metallic panel repaired using an externally bonded composite patch. In practice, it is recommended to choose a symmetrical double patch which offers the best guarantee and a better stability. Rose’s formula and the method of finite element method permit to lead and reach this goal.