A Numerical Analysis of Riveted Lap Joint Containing Multiple-site Damage

The evaluation of stress intensity factors (SIFs) for cracks in mechanically fastened joints is one of the central issues in a damage tolerance analysis. Accurate stress intensity solutions may be difficult to determine due to geometric complexity along with variations in fastener load transfer and fastener interference and material thickness because of corrosion. Detailed finite element models that include specific aspects of fastener for lap joints analysis, but such representations are often impractical for large lap joints involving many fasteners. In order to reduce the number of degrees of freedom in a particular model, a methodology was implemented that efficiently depicts mechanical fasteners in lap joints using finite elements. Uncorroded and corroded lap joints with three crack scenarios were studied by the computationally efficient model. The effects of pillowing corrosion and fastener interference were also included in the model. The results show that the effect of MSD and thinning of the material is to increase substantially stress intensity factors (SIFs) values compare to that of a single crack without corrosion. For a given cyclic stress range, SIF decreases with increasing rivet interference level. This is particularly true for shorter crack lengths. SIF values for the longer crack are not sensitive to the length of shorter crack on the opposite side of the rivet hole. The effects of corrosion pillowing cause SIF values on the faying surface to be larger than those on the opposing surface, and the crack front distorts from the straight front. Moreover, stresses on the faying surface may exceed the yield strength of the material.