Probabilistic assessment of weld fatigue damage for a nonlinear combination of correlated stress components

Estimation of fatigue damage for welds which are subjected to multiple stress components is addressed. Each component is represented by a separate stress cycle distribution of the Weibull type, and the effect of correlation between the different components is addressed. Three different types of bivariate Weibull distributions are considered. These are of the following categories: (i) The Nataf model (ii) The NKR model and (iii) The Plackett model. Comparison is made between the fatigue damage obtained by application of the different models for different levels of correlation and with different SN-curve exponents. Extension from the bivariate case to higher dimensions is also briefly discussed.