Experimental investigation of fatigue damage accumulation in 1100 Al alloy

Abstract

The cumulative fatigue damage characeristics of 1100 Al alloy were studied to gain a better understanding of the effects of the loading sequence, the percentage of initial applied load cycles and the stress ratio. Two-level cumulative fatigue damage tests were performed on notched specimens that consisted of a basic one-block loading sequence that was either a high load followed by a low load or a low load followed by a high load. The experimental data were examined on the basis of Miner's cumulative damage rule, the double linear damage rule and an alternative approach to the double linear damage rule. The experimental results showed that the sequence of loading and the stress ratio had a definite effect on the fatigue damage life. For the high-to-low loading sequence, Miner's cumulative additions were consistently less than one; for the low-to-high two-step case the additions were greater than one.