Implementation of the Peak Stress Method for the automated FEM-assisted design of welded joints subjected to constant amplitude multiaxial fatigue loads

The Peak Stress Method (PSM) is a local approach to the fatigue strength assessment of welded structures. Starting from FE-calculated opening, in-plane shear and out-of-plane shear peak stresses at the weld toe and weld root, the PSM defines an equivalent peak stress for estimating the fatigue failure location and fatigue life of welded structures, in compliance with properly defined design curves. An interactive tool has been developed in Ansys® Mechanical to automate all calculation tasks required to apply the PSM to generic welded structures. The developed application allows to identify and analyse all weld toe and weld root lines of the structure in a full-automated way, performing fatigue life estimation on each analysed node. Finally, fatigue life results can be visualized directly on the model’s geometry through dedicated contour plots. In this work, some joint geometries taken from the literature and related to steel welded joints subjected to multiaxial fatigue loads are re-analysed taking advantage of two design procedures: (i) manual application of the PSM, (ii) automated implementation of the PSM. Taking advantage of the tool developed in Ansys®, a remarkable reduction in analysis time and effort can be achieved, with respect to manual PSM analyses.