Effect of different temperatures on the fatigue behavior of interference fitted plates of Al-alloy 7075-T6

The effect of short time exposure to thermal cycle on the fatigue life of interference fitted fastener holes was evaluated by experimental and numerical method in Al-alloy 7075-T6. When interference fitted holes are subjected to temperature, the pre-stresses produced by interference fit may be considerably redistributed. To investigate the pre-stresses redistribution and its effect on the fatigue life of interference fitted specimens, two different temperatures (i.e. 60 celcius and 120 celcius), apart from room temperature, were selected. The fatigue tests were performed to obtain S-N curves. Tangential pre-stress distribution was analyzed by the finite element method. Three-dimensional stress distributions of interference fit process have been determined around the hole at three temperatures: 25 celcius, 60 celcius, and 120 celcius. The finite element analyses justify the experimentally observed fatigue test behavior. The results show that the short period thermal cycle could improve the fatigue life of the prepared samples.