A study on the fatigue crack growth behavior of thick aluminum panels repaired with a composite patch

Experimental investigations on the effect of composite material patch repairing were conducted to characterize the fatigue crack growth behavior in a thick Al6061-T6 (6 mm) panels with a single sided fiber reinforced composite patch. Four different patch lengths and an un-patched plate were examined. Using three-dimensional finite element analysis, the stress intensity factors were calculated, from which the fatigue crack growth rates were experimentally measured. For the patched panels, different crack growth ratios according to the different plate thickness were investigated experimentally and analytically. The results demonstrate that the size of composite patch size affect fatigue life. While the crack reaches the patch end, retardation of crack growth is found in the bonded repair.