Strain-based probabilistic fatigue life prediction of spot-welded joints

This paper develops a strain-based probabilistic fatigue life prediction methodology for spot-welded joints under variable amplitude loading history. The loading history is multi-axial and is obtained from transient response analysis of a vehicle model. A 3D FE model of a simplified joint with four spot welds is developed and a static stress–strain analysis is performed first. Then a probabilistic Miner’s rule is combined with randomized strain–life curve family and the stress–strain analysis result to develop a strain-based probabilistic fatigue life prediction methodology for the spot weld. This new method is implemented and combined with FEA software, and is useful for reliability assessment of spot-welded joints against fatigue.