Fatigue Life Estimation of Spot-Welded Joints Using Several Multiaxial Fatigue Criteria

In this study, the effects of electrode clamping force on the fatigue strength of 5083-0 aluminum alloy spot-welded joints have been investigated via experimental and multiaxial fatigue analysis. To do so, three sets of the specimens—with different amounts of the sheet spacing—which have been fabricated using different values of the electrode clamping force, were selected, and then fatigue tests were performed under various cyclic longitudinal load levels. A nonlinear finite element code was used to obtain the stress and strain distribution near the roots of the nuggets as a result of longitudinal applied loads. Fatigue lives of the specimens were estimated with Crossland, Kandil–Brown–Miller, Glinka, Varvani-Farahani, Fatemi–Socie, and Smith–Watson–Topper multiaxial fatigue criteria by means of the local stress and strain distribution obtained from the finite element analysis. It was shown that, the fatigue lives of spot-welded joints were improved by increasing the electrode clamping force. Also, the comparison between experimental results and multiaxial fatigue predictions revealed that among the applied criteria, the Crossland and Glinka approaches had the best accuracy for all types of the specimens.