Finite element analysis and life modeling of a notched superalloy under thermal mechanical fatigue loading. (August 2018)

• Record Type: Journal Article
• Authors: Hu, Xiaoan; Zhao, Gaole; Yang, Xiaoguang; Shi, Duoqi
• Is Part Of: International journal of pressure vessels and piping. Volume 165(2018)
• Page Start: 51
• Page End: 58
• Publication Date: 2018-08
• Subjects: Superalloy -- Life prediction -- Thermal mechanical fatigue -- Viscoplastic -- Notch; Pressure vessels -- Periodicals; Pipe -- Periodicals; Récipients sous pression -- Périodiques; Tuyaux -- Périodiques; Pipe; Pressure vessels; Periodicals; 681.76041
• DOI: 10.1016/j.ijpvp.2018.06.004
• Languages: English
• ISSNs: 0308-0161

Abstract

Abstract: Notched thermal mechanical fatigue (TMF) of a directionally solidified (DS) superalloy applied for turbine blades has been studied experimentally and numerically. The test results, failure analysis, constitutive model and life prediction method of the notched superalloy were presented. Two types of notched specimens with the theory stress concentration (Kt) of 1.5 and 2 were designed. The temperature applied to the specimens ranged from 500 to 1000 °C. With a developed constitutive model for TMF, the cyclic stress and strain responses at the notches were analyzed. The dominated damage area which was defined as 1 mm zone was identified with the basis of the scanning electron microscope (SEM) observations as well as the finite element analysis results. Finally, an averaged stress based life model corresponding to the damage process zone was proposed with good accuracy to prediction TMF lives with or without notches. Highlights: The damage process zone was identified by the fracture mechanism and stress analysis. A modified constitutive model was developed to capture the TMF response of the superalloy. The effective stresses in fatigue damage process zone correlated the TMF life very well.