Experimental and numerical investigation in failure of cracked aluminum plates repaired with bonded FML composite patch, under impact loading

In this paper, Charpy impact tests were conducted on cracked aluminum plates repaired with FML composite patches. The effects of the crack characteristics and patch lay-up sequence on the energy absorption of the specimens were investigated experimentally. In order to reduce the test numbers, the design of experiments method was used, and the results were predicted by response surface method. The effect of repairing on the fracture parameters [stress intensity factor (SIF), J-integral, and crack propagation direction (CPD)] at the crack front was calculated using three-dimensional (3D) finite element analysis. The results show that the value of the energy absorption increases when the crack angle increases and that the patch lay-up sequence has a significant role on the efficiency of the repair. When the location of the metal layer of the patch is near the repaired surface of the specimen, the value of the energy absorption increases