A multi-axial vibration fatigue evaluation procedure for welded structures in frequency domain

Modeling of vibration fatigue of welded structures in the frequency domain can be particularly challenging. For instance, the stress singularity at weld locations causes finite element size sensitivity in stress determination. Furthermore, the interactions of multiple vibration modes at a weld location can generate non-proportional multiaxial stresses. Here we present a comprehensive procedure for modeling multiaxial fatigue behaviors of welded structures in the frequency domain to address some of these issues. The procedure utilizes a robust mesh-insensitive method and modal decomposition approach to determine the normal and shear traction stress responses. We proposed a non-proportionality correlation function to interrelate the resulting power spectrum density (PSD) of normal and shear traction stresses and their cross-PSD (CPSD) for establishing an effective stress parameter. The correlation function is determined and validated based on the well-established time-domain path-dependent maximum range (PDMR) method through a small-scale data-driven approach.

Automated summary

Modeling vibration fatigue of welded structures in the frequency domain is challenging due to stress singularity at weld locations and interactions of multiple vibration modes. A comprehensive procedure utilizing mesh-insensitive method and modal decomposition approach is proposed to address these issues. A non-proportionality correlation function is introduced to relate the power spectrum density of normal and shear traction stresses, establishing an effective stress parameter.