A Virtual-Strain-Energy-Density-Based Critical-Plane Criterion to Multiaxial Fatigue Life Prediction

The Smith-Watson-Topper (SWT) fatigue damage parameter has been discussed based on the critical-plane concept. It was found that the fatigue life prediction obtained by the SWT model tended to be unconservative during the non-proportional loading as only the tensile components on the plane of maximum principal strain range has been considered. To overcome this shortcoming, a virtual strain energy density model has been proposed using the von-Mises criterion, where the shear component on the plane of maximum principal strain range can be included during the non-proportional loading conditions. However, on the other hand, this model will be equivalent to the SWT model under the uniaxial and/or proportional loading conditions.