CONICET | Buscador de Institutos y Recursos Humanos

Current fracture mechanics methods for fatigue assessment are based on long cracks behaviour, including those that consider thresholds for crack propagation. The present work aims at predicting the fatigue strength of welded joints by means of a fracture mechanics approach that takes into account the fatigue behaviour of short cracks. The methodology estimates the fatigue crack propagation rate as a function of the difference between the applied driving force (function of crack length) and the material threshold for crack propagation. The fatigue strength of butt-welded specimens transversely stressed was analysed. Experimental results from the literature were used for comparisons. Good estimations are obtained by using only the fatigue limit and the fatigue propagation threshold for long cracks that correspond to the base metal, and the applied crack driving force distribution along the crack path obtained from simple FE models. The influence of plate thickness, material and initial crack length on fatigue strength of butt-welded joints was analysed. Results show good agreement with experimental trends.