Influence Of Amplitude Loading And Stress Ratio On Fatigue Life Of Aluminum 2024 T3 Alloy
A systematic study of the effects of stress ratio on small fatigue crack growth in Al 2024 T3 was conducted under constant amplitude loading. Specimens were tested axially at room temperature under three amplitude loading and with three different stress ratios (R) of 0, 0.1, and -0.1at a frequency of 20 Hz. For a given material and environment, the fatigue crack growth behavior is essentially the same for different specimens or components because the stress intensity factor range is the principal controlling factor in fatigue crack growth. Variable loading effect was also analyzed in step down order to study the fatigue growth rate. Thus the fatigue crack growth rate (da/dN) versus K data obtained on simple specimen configurations, under constant amplitude conditions can be used for engineering design.
Keywords: Crack length (a), Fatigue Crack Growth Rate (da/dn), Number of cycles (N), Stress ratio (SR).