Formulation of multiaxial fatigue failure criteria for spectral method

Fatigue life assessment under multiaxial loading requires the use of multiaxial fatigue failure criteria which are defined in time and frequency domain. Frequency domain criteria are created via formulations using former criteria in the time domain. Therefore, there is a need for a general approach to formulate criteria in the frequency domain based on existing proposals. We discuss methods to determine parameters appearing in the frequency domain criteria; in particular, we present the critical plane approach proposed by Macha and other proposals based on stress invariants. An attempt to generalize the problem is presented and discussed in the section of conclusions.