The influence of load correlation on vibration fatigue damage of symmetrical notched cantilever beam structures

Abstract

This paper aims to develop an innovative multiaxial fatigue criterion based on the stress invariant, in order to perform the fatigue damage analysis of engineering structures subjected to random vibrations. First, the change rule of structural vibration fatigue lifetime under different load correlation conditions is systemically studied by experiments. Then, the finite element analysis of such a structure, including the modal analysis and the spectral analysis, is implemented in order to compute the response stress power spectral density (PSD) functions at the critical fatigue‐prone location under coupled random acceleration base excitations. Finally, the influence rule of load correlation on the vibration fatigue damage of such a symmetrical structure is theoretically illustrated through formula derivation. Moreover, combined with the critical distance theory point method, the proposed time/frequency‐domain multiaxial fatigue criterion is applied for vibration fatigue lifetime evaluation of the structure. The lifetime prediction accuracy of the proposed multiaxial fatigue criterion is verified by comparing with the vibration fatigue test results.