The influence of mean stress on fatigue crack propagation in aluminium alloys

Various equations to account for the mean stress dependence of crack propagation data have been described. They have been fitted to data from the aluminium alloys 7075-T6, 2024-T3 and 6082-T6, and their applicability to these alloys has been discussed. In addition, two mean stress equations were applied to crack propagation threshold data for the 5083-H321 aluminium alloy. Finally, a new equation to account for the mean stress dependence of crack propagation data has been suggested and its excellent applicability has been shown.