Integrated fracture mechanics approach to analyze the fatigue behaviour of welded joints

MIRCO DANIEL CHAPETTI; J BELMONTE; TAGAWA, T; MIYATA, T

SCIENCE AND TECHNOLOGY OF WELDING AND JOINING

The Charlesworth Group

Año: 2004 vol. 9 p. 430 - 439

1362-1718

Current fracture mechanics methods for fatigue assessment are based on long crack behaviour, including those that consider thresholds for crack propagation. The present work is concerned with an attempt to predict 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 and the material threshold for crack propagation, function of crack length. The fatigue strength of butt-welded specimens stressed transversely was analysed. Experimental results from the literature were used for comparisons. Estimations are obtained by using only the fatigue limit and the fatigue propagation threshold for long cracks, and the applied stress distribution along the crack path obtained from simple FE models. The influence of plate thickness, initial crack length and reinforcement angle on fatigue strength of butt-welded joints was analysed. Results show good agreement with experimental trends