Fracture mechanics analysis of cracked plate repaired by composite patch

The enhancement of service life of damaged or cracked structures is currently major issue to the researchers and engineers. In order to evaluate the life of cracked aging aircraft structures, the repair technique which uses adhesively bonded boron/epoxy composite patched is being widely considered as a cost-effective and reliable method. But, this repair method contains many shortcomings. One of these shortcomings, debonding is major issue. When the adhesive shear stress increases, debonding is caused at the end of patch and plate interface. And this debonding is another defect except crack propagation. In this paper, we assess safety at the cracked Al-plate repaired by Br/Epoxy composite patch. Firstly, the reduction of stress intensity factors near the crack-tip are determined to the effects of various non-dimensional design parameters. Secondly, using the finite element analysis, the distribution of adhesive shear stresses are acquired. Finally, the problem of how to optimize the geometric configurations of the patch has been discussed.