Effects of composite patching on cyclic crack tip deformation of cracked pinned metallic joints

Advanced composite patching has been used to rehabilitate cracked structures. In this work, the effects of bonded carbon fiber-reinforced polymer (CFRP) patch on reducing the crack tip driving forces, namelyJ-integral, crack tip plastic zone, and crack tip opening displacement, of a crack emanating from a fastener hole, under cyclic loading, was studied. The number of CFRP layers, the orientation of the fiber with respect to the direction of the path of the crack, and the pinned joint configurations are the main parameters studied in this research. A three-dimensional finite element model was employed in this work, using ABAQUS. The double-sided CFRP patch-repaired pinned joint is simulated in order to study crack retardation behavior under two different combinations of loading,i.e. Modes I and II. The results of the study show that the stiffness of the cracked pinned joint is increased by using a CFRP composite patch. The reduction in theJ-integral ranged from 25% to 45%, depending on the length of the crack and the mode of the crack. Moreover, the monotonic and cyclic crack tip plastic zones decreased by 5% to 45%, depending on the length of the crack.