Issue 52

A.V. Tumanov et alii, Frattura ed Integrità Strutturale, 52 (2020) 299-309; DOI: 10.3221/IGF-ESIS.52.23 299 Crack growth rate prediction based on damage accumulation functions for creep-fatigue interaction A.V. Tumanov, V.N. Shlyannikov, A.P. Zakharov Institute of Power Engineering and Advanced Technologies, FRC Kazan Scientific Center, Russian Academy of Sciences, Russia tymanoff@rambler.ru , shlyannikov@mail.ru , alex.zakharov88@mail.ru A BSTRACT . The present study is concerned with formulation of a model for the creep–fatigue crack growth rate prediction on the base of fracture damage zone concepts. It is supposed that crack growth rate can be determined by integration of damage accumulation rate equations into the fracture process zone for low-cycle fatigue and creep loading independently. In the case of low-cycle fatigue loading the damage accumulation function proposed by Ye and Wang was used as well as a classical Kachanov-Rabotnov power law was employment for the creep damage accumulation characterization. Fracture process zone size is calculated on the base of the nonlinear stress intensity factors concept proposed by Shlyannikov. The background for the proposed general model of crack growth rate under creep and fatigue interaction is given in order to comparison with the experimental data. Experimental study of crack growth rate under creep and fatigue interaction is performed for compact tension specimen made from 20CrMoV5. Crack growth rate carried out at the elevated temperature of 550°C according to ASTM E2760 standard. The predictions of the crack growth rate were compared with the experimental data for the 20CrMoV5 steel obtained at an elevated temperature, and the agreement was found to be satisfactory. K EYWORDS . Creep-fatigue interaction; Crack growth rate prediction; Nonlinear stress intensity factors. Citation: Tumanov A.V., Shlyannikov V.N., Zakharov A.P., Crack growth rate prediction based on damage accumulation functions for creep-fatigue interaction, Frattura ed Integrità Strutturale, 52 (2020) 299-309. Received: 02.03.2020 Accepted: 13.3.2020 Published: 01.04.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION tructures in the aviation, space flight, power generation, and petrochemical industries are typically exposed to elevated temperatures. Damage accumulation and growth considerations at creep and fatigue owing to changes in the material microstructure, void nucleation, interaction, and growth on the grain boundaries are important in the design and operation of such components in order to ensure structural integrity. It is well known that the creep damage accumulation from the damage caused by cyclic loading is different. At the moment, there are many models in literature allow to take into account the damage accumulation, both during creep and cyclic loading. S