Estimation of fatigue performance of welded joints by local approaches

The fatigue assessment using the Dang Van criterion by local approaches was studied according to the results of fatigue tests of 16Mn non-carrying-load cruciform welded joints.It is shown that the minimum element size of EFA in the stress concentration zone has apparent effects on the calculation of the local parameters.When the radius of the weld toes ranges from 0.15 to 0.8 mm,the reasonable predicting results can be obtained if the local parameters are calculated by selecting the minimal element size in the range of 0.32-0.62 mm,and the local approaches using the Dang Van criterion can reasonably assess the fatigue behavior of welded joints,but the value of β is conservative.Additional,we find that the radius of weld toes mainly affect the local distributions of stress concentration in the small region (r<0.5 mm),and there is the stable stress concentration when the depth is above the value (r≥0.5 mm).Thus it will be more reasonable if the local stress parameters at the point away from the site of the maximal stress are used to calculate the Dang Van local parameters.This could reduce the dependence of Dang Van local parameters on the geometries of welded toe and local element sizes.