Influence of the radius of curvature at the weld toe in the fatigue strength of fillet welded joints

An experimental and theoretical study was carried out on the influence of the radius of curvature at the weld toe, ϱ, in the fatigue strength of transverse non-load-carrying fillet welded joints loaded in bending and in tension. For fatigue life computation, stress intensity factor solutions were obtained by the weight function method and J-integral calculation and the difference in results was found to be negligible. Comparison of K results obtained by the weight function method with results quoted in the literature obtained with the collapsable crack tip element indicated only a 1–2% difference. The experimental work included a statistical analysis of the values of ϱ measured in welded specimens and S N data obtained in T joints with plate thickness values of 4, 6, 12 and 20 mm and with constant joint proportions. Some differences were obtained between the experimental results and the theoretical predictions, but these can be explained by the absence in the derived model of both crack tip ellipsity and a crack initiation term.