Crack nucleation threshold under fretting loading by a thermal method

The aim of this study is to develop a new, non-destructive, experimental method, based on the thermal response of materials, to determine crack nucleation threshold during a fretting test in a cylinder on flat contact configuration. The temperature evolution during a fretting test with constant loading showed that the latter can be decomposed into three parts: an overall thermal drift and two periodic signals at f_L and 2f_L; where f_L is the loading frequency. The results showed that the stabilized value of the drift and the periodic signals' amplitudes can be empirically related to the crack nucleation threshold; with result differences of less than 10% from those determined by destructive methods.