Normalized creep–fatigue life prediction model based on the energy dissipation during hold time

Multi-axial creep-fatigue life prediction considering history-dependent damage evolution: A new numerical procedure and experimental validation

“…The phenomenological Jeong's stress relaxation equation (Jeong et al, 2007) including the elastic follow-up factor is rewritten as…”

A New Ductility Exhaustion Model for High Temperature Low Cycle Fatigue Life Prediction of Turbine Disk Alloys

“…Over the past several decades, the issue of accurately predicting HTLCF life of these hot section components has been an area of interest. Many life prediction methods have been reported [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However because of the complex damaging mechanisms involved, a unified model that can provide accurate life prediction for HTLCF does not exist [1].…”

“…They depend on various test and material parameters, such as temperature, stress or strain rate, loading frequency and loading waveform. Several researchers have reported the influence of the cyclic frequency [2], hold period [3], strain range [4], loading waveform [5], strain rate [6,7], heat treatment [8], testing temperature [9] and environment [10,11] on the cyclic stress response, deformation mode, and fatigue life of superalloys during HTLCF. Increasing attention has been paid to the study of fatigue and creep interaction in either isothermal or thermal-mechanical fatigue conditions [12].…”

“…For example, considering the dynamic viscosity as the damage parameter to describe the flow behavior, Goswami [14] proposed the Ductility Exhaustion (DE) approach for HTLCF life prediction which is based on extensive research of CrMo steels. Recently, with the assumption that the creep effect of stress relaxation leads to the reduction of fatigue life, Jeong [3,15] developed a stress relaxation range model (SRR). This model suggests that the relaxed stress range can be used as a creep-fatigue damage function and the Manson-Coffin curves under different conditions can be normalized to construct a master curve under strain controlled fatigue tests.…”

“…Their limitations can be summarized as follows: (a) some cannot accurately describe the effects of different loading waveforms, for example, LDS, FMMC and FMDF; (b) most of them ignore the effects of mean strain or mean stress on the fatigue life, such as LDS, FS, DRA, SRR [3,15], DE [14] and the models presented in [7,18]; (c) many of the existing models are not applicable under stress controlled conditions, for example, SRP and SEP, DE [14] and SRR [3,15]. The methods reported in [15][16][17] are limited to evaluation of HTLCF life under strain controlled conditions.…”