Prediction of fatigue life in cold expanded Al-alloy 2024-T3 plates used in double shear lap joints

To predict fatigue crack initiation and fatigue crack growth lives in cold expanded double shear lap joints a numerical method has been employed. The total estimated fatigue lives were compared with available experimental fatigue test results for plain hole and cold expanded hole specimens of Al 2024-T3 in double shear lap joints. Three-dimensional finite element simulations have been performed in order to obtain the created residual stresses field due to cold expansion and subsequent far field longitudinal loading in the double shear lap joint. The obtained stress and strain distributions from the finite element analyses were employed to predict stress concentration factors to calculate fatigue crack initiation and fatigue crack growth lives using AFGROW computer code. The predicted fatigue lives demonstrate that there is a good agreement between the proposed method and experimental fatigue test results.