A procedure for fatigue life prediction of spot welded joints

The problem of predicting the fatigue life of spot welded joints has not yet been satisfactorily resolved. Several approaches exist, but many of them are difficult to apply to general structures, which are widely different from simple laboratory specimens. A general criterion is proposed in this paper, based on a theoretical extrapolation of the radial stress. The criterion must be used together with a Finite Element model of the joint and so this paper presents the steps required to get the necessary FE data; steps that are also applicable to the case of complex joints. The advantage of the proposed method is its independence of notch effects near the spot-weld edge. The suggested procedure is applied to several specimens of different materials and the results obtained are successfully compared with experimental data.