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

The PSM is an engineering FE-oriented local approach to estimate the fatigue lifetime of steel welded structures under constant amplitude (CA) loads and has been previously validated against more than 1300 experimental data. The PSM has been recently reformulated to account for Variable Amplitude (VA) uniaxial as well as multiaxial loadings. To this purpose, it has been combined with Palmgren-Miner's Linear Damage Rule and the extended formulation has been successfully validated against a large bulk of VA fatigue data available in the literature. In addition, an automated analysis tool has recently been developed in Ansys® Mechanical, taking advantage of Ansys® Customization Toolkit, to support the FE analyst in the fatigue design of welded structures according to the PSM. In the present investigation, the automated algorithm has been extended to the newly developed multiaxial VA formulation of the PSM. The output of the automated tool are edge-contour plots and graphs of the fatigue life, allowing the analyst to rapidly single out the most critical point in the structure among all competing crack initiation sites.