Prediction of fatigue life for multi-spot welded joints with different arrangements using different multiaxial fatigue criteria

In this paper, the effects of weld arrangement on the fatigue behavior of the multi-spot welded joints have been investigated via experimental and multiaxial fatigue analysis. To do so, three sets of the spot welded specimens with different arrangements were prepared and fatigue tests were conducted under the various cyclic loads. Experimental tests revealed that the spot welded arrangement effect has a considerable role in fatigue strength of multi-spot welded joints. A nonlinear finite element code was used to obtain the stress and strain distributions near the roots of the nuggets for the three kinds of the specimens. Fatigue lives of the specimens were predicted by means of six different multiaxial fatigue criteria using the local stress and strain values obtained from the finite element simulations. It was found that the SWT and Crossland criteria have the best accuracy for all types of the specimens among the applied criteria. (C) 2015 Elsevier Ltd. All rights reserved.