FATIGUE LIFE PREDICTION OF WELDED JOINTS AT SUB-ZERO TEMPERATURES USING MODIFIED PARIS-ERDOGAN PARAMETERS

The fatigue life of welded steel components is usually determined by the weldment; in these cases, fracture mechanical approaches are widely used for their prediction. Ferritic steels are known to have a fatigue strength that is dependent on temperature. Therefore, this study evaluates fatigue tests of cruciform joints and transverse stiffeners at different sub-zero temperature levels, with regard to fatigue life. Simultaneously, the stress intensity factors over the crack length are calculated for the individual experiments using analytical solutions. Then, using the Paris-Erdogan relation with temperature and material adjusted C and m parameters as well as tabular values, the fatigue lives are calculated with analytical solutions and compared with the experimental results. It is shown that, the prediction accuracy is significantly increased for the sub-zero temperature range by using temperature-adjusted Paris-Erdogan parameters, as long as the temperature are above the fatigue transition temperature.
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