Characterization of fretting fatigue in self-piercing riveted aluminium alloy sheets

A study was conducted to characterize fretting fatigue in self-piercing riveted single-lap joints of aluminium alloy 5754 sheets. The experimental results showed that fretting occurred at three different positions in the joint. It was established that fretting led to surface work-hardening and crack initiation as well as early stage crack propagation. Crack initiated at the surface of the riveted sheets as a result of high stress concentration and propagated oblique to the mating surface under the effect of fretting fatigue. The depth of damage due to fretting depended on the applied load and the cycle time. Microhardness measurements allowed the estimation of the depth of damage due to fretting. These results were observed to correlate well with the length of crack propagation.