Comparison Between Composite Patches and Bolt Clamping Force to Repair an Edge Crack in Aluminum Alloy 2024-T3 Specimens

Many of components in various industries are working under multiaxial stresses, and since the cracks can be the source of the failure, therefore, the strength analysis of the cracked structures under mixed- mode loads and trying to increase the strength and stability of them is very important. In this paper, the effect of the composite patch and clamping force resulted from torque tightening a nut and bolt on the fracture strength of an aluminum alloy 2024-T3 plate having an edge crack has been compared experimentally and numerically. The cracked test specimens were loaded using modified Arcan fixture to create pure opening fracture mode (mode I), pure in-plane shear fracture mode (mode II) and mixed mode of (I and II). In the numerical part, Ansys finite element package was used to simulate the test specimens performance. The results of this study showed a significant increase in tensile strength of the repaired components by using these two methods compared to simply cracked specimens. Thus, an increase of 44% in the tensile strength of mode I can be achieved with a composite patch, however, the strength increase is reduced to 18% in pure shear mode. Clamping force also increases the fracture strength in mixed mode. This increase is 24% for pure shear mode and it reaches 9% in the pure tensile mode.