A new low-cycle and high-cycle fatigue life prediction criterion based on crystal plasticity finite element method

The present study proposes a novel physically-based criterion for simultaneously predicting both high-cycle and low-cycle fatigue life by incorporating slip irreversibility. Considering the damage induced by irreversible plastic deformation on the foundation of cumulative dissipation energy, this criterion serves as an effective tool for assessing fatigue life. Based on the construction of multiple RVE models combined with crystal plastic finite element method, we successfully predicted the high- and low-cycle fatigue life of micro-grain K4169 alloy within a scatter band of ± 1.5 by this new fatigue parameter indicator. Notably, the prediction error of high-cycle fatigue life is within 10 %, a 70 % reduction compared to the cumulative dissipated energy criterion. On such basis, the slip irreversible coefficients (p) at different loading conditions were predicated precisely and validated by experimental data obtained from atom force microscope. Then a double logarithmic linear relationship between p and fatigue life of the alloy was established with the equation $p=1.2\times {10}^{-3}\bullet N_f^{-0.4079}$. In addition, the high-cycle fatigue life of fine-grain K4169 alloy was also precisely predicted within a scatter band of ± 2.5 by adjusting grain size in RVE models.