Retardation of fatigue crack growth in aircraft aluminium alloys via laser heating – Numerical prediction of fatigue crack growth

The presented study discusses a quantitative numerical approach for predicting the fatigue crack growth in AA2198-T8 C(T)100 specimens containing one line of laser heating. By heating with a defocused laser residual stresses are introduced and the fatigue crack growth is retarded. The developed methodology, which investigates coupling of the structural process simulation, the extraction of the total stress intensity Ktot and the prediction of the resulting fatigue crack growth rates by an empirical crack growth law is stepwise validated on the basis of experimental results. The prediction is found to be highly accurate. Special attention needs to be given to the quality of the process simulation results because the prediction of fatigue crack growth is highly sensitive to the results obtained in this simulation step.