Experimental investigation and numerical prediction of fatigue crack growth of 2024-T4 aluminum alloy

Compact specimens were employed to study fatigue crack growth of 2024-T4 aluminum alloy under constant/variable amplitude loading. Apparent R-ratio effect under constant amplitude loading was identified with the nominal stress intensity factor range. Fatigue crack growth rates predicted by a unified model agreed with the experimental data well. Single tensile overload resulted in significant retardation of crack growth which was fully recovered after propagating out of overload-affected zone. Retarded crack growth induced by three-step sequence loading was heavily dependent on two sequence loading parameters. The influence of variable amplitude loading on crack growth was reasonably characterized by Wheeler’s model.