An Energy-Based Axial Isothermal-Mechanical Fatigue Lifing Method

作者：Wertz John; Letcher Todd; Shen M H Herman^*; Scott Emuakpor Onome; George Tommy; Cross Charles

来源：Journal of Engineering for Gas Turbines and Power-Transactions of the ASME, 2012, 134(10): 102502.

DOI：10.1115/1.4007121

An energy-based fatigue lifing method for the determination of the full-life and criticallife of in-service structures subjected to axial isothermal-mechanical fatigue (IMF) has been developed. The foundation of this procedure is the energy-based axial room-temperature lifing model, which states: the total strain energy dissipated during both a quasi-static process and a dynamic (fatigue) process is the same material property. The axial IMF lifing framework is composed of the following entities: (1) the development of an axial IMF testing capability; (2) the creation of a testing procedure capable of assessing the strain energy dissipated during both a quasi-static process and a dynamic process at elevated temperatures; and (3) the incorporation of the effect of thermal loading into the axial fatigue lifing model. Both an axial IMF capability and a detailed testing procedure were created. The axial IMF capability was employed to produce full-life and critical-life predictions as functions of temperature, which were shown to have an excellent correlation with experimental fatigue data. For the highest operating temperature, the axial IMF full-life prediction was compared to lifing predictions made by both the universal slopes and the uniform material law prediction and was found to be more accurate at an elevated temperature. [DOI: 10.1115/1.4007121]

• 出版日期2012-10