Predicting Crack Growth under Thermo-mechanical Cycling
Load-controlled tests were conducted on Inconel 718 under thermo-mechanical fatigue (TMF) to evaluate crack growth rate as a function of phase angle between load and temperature. A model is developed to predict TMF crack growth rates based solely on isothermal data. The model uses a linear summation concept based on contributions to crack growth of the two dominant mechanisms which are active at the minimum and maximum temperature of the cycle: mechanical fatigue and environmentally assisted crack growth. It was found that damage which contributes significantly to crack growth occurs only during the increasing load portion of a TMF cycle and only while the time-dependent contribution is an increasing function. A discussion of the dominant mechanisms and a comprehensive review of the literature in TMF crack growth is presented. Applicability of the modeling concepts to other materials is discussed.
International Journal of Fatigue
Nicholas, Theodore; Heil, Michael L.; and Haritos, George K., "Predicting Crack Growth under Thermo-mechanical Cycling" (1989). Mechanical Engineering Faculty Research. 827.