Probabilistic fatigue crack growth analysis of spot-welded joints.

This paper presents a probabilistic fatigue crack growth life prediction methodology for spot-welded joints under variable amplitude loading history. The loading is multi-axial and is obtained from transient response analysis of a vehicle model using finite-element analysis. A three-dimensional (3D) finite element model of a simplified joint with four spot welds is developed, and the static stress analysis of this joint is performed. Then the fatigue crack inside the base material sheet is modelled as a surface crack. Probabilistic crack growth model is combined with the stress analysis result to develop a probabilistic fatigue crack growth life prediction methodology for spot welds. This new method is implemented with MSC/NASTRAN and MSC/FATIGUE and is useful for the reliability assessment of spot-welded joints against fatigue crack growth. [ABSTRACT FROM AUTHOR]