Fatigue analysis of laser welded Al-alloy joints with the fictitious notch radius of rf = 0.05 mm

The fatigue strengths for EN AW-6156 Al-alloy laser welded butt joints and T-joints are unified in local stress system with the fictitious radius of rf = 0.05 mm. The reference SN-curve is obtained, which can be used for fatigue design for laser welded Al-alloy joints with a plate thickness of less than or equal to 5 mm. Fatigue lives under two variable amplitude loading sequences are calculated by taking into account the influence of mean stress on fatigue life for EN AW-6156 Al-alloy laser welded butt joints and T-joints. The results showed that the calculated fatigue lives agree well with experimental data. However, when the mean stresses are not taken into account, a relatively larger deviation between calculated lives with experimental results is shown. Therefore, it is suggested that the mean stress in laser welded Al-alloy structures cannot be ignored in fatigue life assessment.