Dr Luca Vecchiato is a research associate at the Department of Industrial Engineering, University of Padua. His research mainly focuses on local approaches for the fatigue design of metallic components and welded structures, the experimental characterization of the short fatigue crack propagation threshold and potential drop-based non-destructive testing on metals.
One of the simplest and most efficient ways to design lightweight structural components is the combination of welding and aluminum alloys. However, aluminum welded joints are extremely sensitive to fatigue failure and making accurate lifetime predictions is still challenging when Variable Amplitude (VA) loading conditions are involved. Among all design criteria available in the literature for the fatigue strength assessment of welded structures, the present work focuses on the Peak Stress Method (PSM), which is an engineering finite element (FE)-oriented technique to rapidly estimate the notch stress intensity factors (NSIFs) at the weld toe or weld root, both modeled as sharp V-notches having null tip radius. The fatigue strength of welded components under Constant Amplitude (CA) loading is then evaluated by combining the simplicity and rapidity of the PSM in evaluating the NSIFs with a robust fatigue strength criterion such as the one based on the averaged Strain Energy Density (SED), which can be written as a function of the relevant NSIFs. The theoretical formulation of the PSM for the fatigue strength assessment of welded joints made of steel and subjected to VA loadings has been recently proposed by combining its CA formulation with the Palmgren-Miner’s cumulative linear damage rule. In the present contribution, the VA formulation of the PSM has been further extended and validated against experimental data taken from the literature and generated by testing welded joints made of aluminum alloys.