Round-Robin Study on Stress Analysis for the Effective Notch Stress Approach

Abstract

The effective notch stress approach for the fatigue strength assessment of welded structures as included in the Fatigue Design Recommendations of the IIW requires the numerical analysis of the elastic notch stress in the weld toe and/or weld root which is fictitiously rounded with a radius of 1 mm. In order to establish guidelines for modelling the structure and evaluating the results, several numerical analyses have been performed in a round robin. This covers three welded details of different complexity where either the weld toe or the weld root is the potential crack location. The first example is a cruciform joint with non-load carrying fillet welds in one load case and load carrying in the other. The second is a complex T-joint of rectangular hollow section (RHS) members which was also subject of the so-called SAE-FDE weld challenge to predict fatigue life. The third is the fillet-welded end connection of a RHS joint being prone to fatigue failure at the weld root with non-fused root faces. The results are compared with each other and conclusions are drawn with regard to appropriate modelling and to the scatter of results to be expected.