Multiaxial fatigue assessments of welded joints

The present paper reports on the in-field procedure specifically devised to apply the Modified Wöhler Curve Method (MWCM) along with the Theory of Critical Distances (TCD) to estimate fatigue lifetime of steel and aluminium welded joints subjected to in-service constant (CA) and variable amplitude (VA) multiaxial fatigue loading. The accuracy and reliability of the MWCM was systematically checked through a large number of experimental results taken from the literature and generated by testing, under CA/VA biaxial nominal loading, welded samples having different geometry. Such a systematic validation exercise allowed us to prove that our method is successful in designing welded joints against CA/VA multiaxial fatigue. This result is very interesting because it suggests that our approach can be used in situations of practical interest by performing a fatigue assessment which fully complies with the recommendations of the available Standard Codes.