Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Stress controlled fatigue creep interaction

Experimental Study of the Effect of Shot Peening on Elevated Temperature Fatigue Behavior of 7075-T651 Al. alloy

Hussain J. Al-Alkawi; Shakir Sakran Hassan; Salah F. Abd-El-Jabbar

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 416-433

There is a general interest in increasing the fatigue life of materials. Shot peening is the process commonly used in order to increase the fatigue strength and life of 7075-T651. The effect of a combination of processes, fatigue-creep interaction and shot peening has not been thoroughly investigated so far. The aim of the present investigation was whether further improvements can be achieved by a comb/*ination of the two treatments. Two level experiments (cumulative fatigue damage programe) were used in order to determine the optimal set of process. It was found that the combination of shot peening and fatigue-creep interaction could be applied successfully in order to increase fatigue life for some specimens. Results of variable loading test clearly indicate that Miner rule does not give accurate and reliable predictions on fatigue lives.

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

Salah F. Abd-El-Jabbar; Shakir Sakran Hassan; Hussain J. Al-Alkawi

Engineering and Technology Journal, 2012, Volume 30, Issue 5, Pages 729-743

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.