Linear Damage Rule Life Prediction for Stress Controlled Fatigue-Creep Interaction of Aluminum Alloys

Abstract

The fatigue-creep interaction performance of 5086 and 6061-T651 aluminum alloys were investigated for specimens tested under control stress rotating bending at a stress ratio R=-1 and 250°C temperature. The fatigue endurance limit for both alloys reduced at 250°C. The fatigue and creep damage was evaluated based on the linear damage rule, where the fatigue damage was determined as the number of cycles to failure and the creep damage was evaluated based on the time applied experimentally for low to high and high to low amplitude stress. The cumulative fatigue-creep interaction damage was found to around 0.5 i.e DF +Dc =0.5 Fatigue – creep interaction lives predicted by the linear damage rule were compared to the actual lives. The results show that the linear damage rule gave an overestimated predictions.

Keywords

• stress controlled fatigue creep interaction
• life prediction
• linear damage rule
• aluminum alloys