Fatigue crack propagation prediction by cyclic plasticity damage accumulation models

Different analytical models of damage accumulation by cyclic plasticity have been developed to predict fatigue crack growth from monotonic, cyclic, fracture toughness and crack propagation threshold properties. The models' development logic is condensed as a flowchart, which emphasizes, in a clear and easily comprehensive way, all the required modeling steps. 1020 and API 5L X60 steels and 7075‐T6 aluminum alloy were used in the experimental verification of the models. Samples were extracted from materials of the same heat, in order to have a reliable comparison. The experimental results are better predicted by the models that use the plastic part of Coffin–Manson's equation to calculate the fatigue life of small volume elements ahead of the crack tip, and expressions of the HRR type to represent the elastic–plastic strain amplitude in the cyclic plastic zone.