DIC-based constant amplitude and two-block loading fatigue life prediction of open hole GLARE laminate

The constant amplitude fatigue life is predicted using the normalized fatigue stress with the goodness of fit above 0.98. The crack initiation life was estimated based on the stress concen-tration factor and the surface axial strain measured by DIC. The high-low amplitude sequence two-block loading fatigue life was predicted using an iterative calculation method based on the corrected crack tip effective stress intensity factor range, almost all results are in a 1.3-scatter band. The previous nonlinear fatigue damage cumulative model was further modified for two -block loading, the life prediction results are within a 1.2-scatter band.