Analytical theory for fatigue crack propagation rates of mixed-mode I-II cracks and its application

The Manson-Coffin law for the low-cycle fatigue (LCF) of a representative volume element (RVE) and fatigue crack propagation (FCP) rate of cracked components can characterize material fatigue resistance. This paper proposes an LCF-FCP model for predicting the FCP rate of plane-stress mixed-mode I-II cracks. A semi-analytical model is also proposed for the Je integral of mixed-mode I-II compact tension shear (CTS) specimens based on energy equivalence method. The combination of these two models predicted the FCP rates of CTS specimens made from 30Cr2Ni4MoV rotor steel with mixed-mode I-II cracks and subjected to four different loading angles. The theoretical results were consistent with the experimental results.