Fatigue Tests and Numerical Analyses of Partial-Load and Full-Load Carrying Fillet Welds at Cover Plates and Lap Joints

Abstract

The fatigue strength of fillet welds is dependent on the amount of loads transferred. This is considered in the approaches for fatigue assessment in different ways. Particularly in the structural stress approaches, modified stress distributions in thickness direction of the parent plate have recently been proposed to consider the amount of load carried by the fillet weld in the fatigue assessment. In order to validate the approaches, fatigue tests have been performed with cover plates having partial-load carrying fillet welds and lap joints having full-load carrying fillet welds. The thickness of all plates was 12 mm, while two throat thicknesses with 3 and 7 mm were realized. The approaches for fatigue strength assessment include different structural stress approaches and the effective notch stress approach. Conclusions are drawn from a comparison of the approaches and from the fatigue lives obtained with respect to the consideration of the amount of load carried by fillet welds.