Fatigue life evaluation of welded joints under multiaxial loading for different stress concepts using an extended Gough-Pollard criterion

Abstract

Abstract Fatigue life evaluation of welded joints under multiaxial loading usually refers to stresses normal to the weld and shear stresses. Stresses parallel to the weld are not considered in most experiments, nor in the well-known Gough-Pollard criterion. Hence, the Gough-Pollard criterion has recently been extended in order to include all stress components at the weld surface. In this paper, both the original and, for the first time, the extended Gough-Pollard criterion are applied to different welded specimens under multiaxial stresses that include stresses parallel to the weld. As shown, the original Gough-Pollard equation is not sufficient to evaluate such stress states. The reason is that the calculated fatigue life becomes less conservative as the stresses parallel to the weld become more significant. The extended Gough-Pollard criterion, on the other hand, shows greatly improved accuracy while significantly reducing the likelihood of non-conservative results. In conclusion, the extended Gough-Pollard criterion is able to describe fatigue life under multiaxial stress better than the original version and provides reliable and conservative results for welded joints. The main findings are shown to be valid for the nominal, the hot spot, and the notch stress concept.