An experimental investigation on the effect of short time exposure to elevated temperature on fatigue life of cold expanded fastener holes

An experimental study has been carried out to investigate the effect of short time exposure to elevated temperature on fatigue life of cold expanded fastener holes. When cold expanded holes are subjected to temperature variations their fatigue life changes remarkably. However the exact governing mechanism has not been clearly addressed before. In this study, another stress relaxation mechanism rather than creep has been introduced which happens at a short time due to temperature rise. Results of fatigue tests on Al 7075-T6 show that the effect of this mechanism can be beneficial or detrimental. This research has sought to clarify this issue.