Abstract
Owing to the importance of crack patching in fracture mechanics analysis, the aim of this study is to analyse numerically by the finite element method the advantage of the use of the bonded symmetric composite patch for repairing cracks in metallic sheets in mode I and mixed mode. The obtained results show that there is a considerable reduction of the asymptotic value of the stress intensity factor at the crack tip in the case of the use of the double symmetric patch compared with the single patch. In addition the gain of the composite thickness obtained by the double patch is also considerable in both mode one and mixed mode.