A Whole-Rate-Region Fatigue Crack Growth Model Incorporating Nonlinear Rate Evolution Characteristics Based on a Peridynamic Approach

The traditional peridynamic fatigue model is capable of simulating the fatigue behaviors in stable region because of its correlation to the Paris law, which describes the stable evolution of fatigue crack growth rate. Hence, the traditional model exhibits pronounced inaccuracies in the near-threshold and unstable growth regions due to its linear constraint. To address this problem, we proposed a whole-rate-region fatigue crack growth model (WRR model) that incorporates both linear and nonlinear regions. To integrate the effects of fatigue threshold and fracture toughness within this model, the threshold cyclic bond strain and the critical bond strain parameters are introduced. Consequently, the nonlinear evolution of crack growth rates in the near-threshold and unstable growth regions could be characterized by the WRR model. Validation of the WRR model’s efficacy and precision is achieved through comparative analysis between simulated fatigue behaviors and experimental data. The fatigue crack propagation behavior under biaxial loading is further analyzed based on the proposed model. Relative to a traditional model, the WRR model provides a more accurate and realistic simulation of crack behaviors.