TY - JOUR
T1 - Subcycle fatigue crack growth and equivalent initial flaw size model for fatigue life assessment under arbitrary loadings for Al-7075
AU - Shivankar, Sushant
AU - Chen, Jie
AU - Liu, Yongming
N1 - Funding Information: The research is partially supported by a fund from NAVAIR through a subcontract from Technical Data Analysis, Inc (TDA) (contract No. N68-335-18-C-0748, program manager: Krishan Goel). The support is greatly appreciated. Publisher Copyright: © 2021 Elsevier Ltd
PY - 2022/3
Y1 - 2022/3
N2 - A novel fatigue-life prediction methodology combining a subcycle fatigue crack growth (FCG) analysis and equivalent initial flaw size (EIFS) concept is proposed in this paper. This research focuses on extending a previously developed time-based subcycle fatigue crack growth model to a near-threshold regime and under multiaxial loadings. First, the threshold FCG behavior using subcycle FCG is discussed, and a new temporal kernel function to include intensity factor corresponding to the near-threshold region is proposed. Following this formulation, the multiaxial load case scenario is considered for mixed-mode FCG using a critical plane approach. Next, the general multiaxial loading is converted to an equivalent uniaxial loading for life prediction. Next, model predictions under arbitrary loadings (e.g., uniaxial and multiaxial, constant and variable amplitude loading, and random spectrums) are compared with experimental data from open literature and internal testing. Multiple conclusions and potential future work have been suggested using the proposed model.
AB - A novel fatigue-life prediction methodology combining a subcycle fatigue crack growth (FCG) analysis and equivalent initial flaw size (EIFS) concept is proposed in this paper. This research focuses on extending a previously developed time-based subcycle fatigue crack growth model to a near-threshold regime and under multiaxial loadings. First, the threshold FCG behavior using subcycle FCG is discussed, and a new temporal kernel function to include intensity factor corresponding to the near-threshold region is proposed. Following this formulation, the multiaxial load case scenario is considered for mixed-mode FCG using a critical plane approach. Next, the general multiaxial loading is converted to an equivalent uniaxial loading for life prediction. Next, model predictions under arbitrary loadings (e.g., uniaxial and multiaxial, constant and variable amplitude loading, and random spectrums) are compared with experimental data from open literature and internal testing. Multiple conclusions and potential future work have been suggested using the proposed model.
KW - Equivalent initial flaw size
KW - Fatigue crack growth
KW - Life prediction
KW - Random
KW - Subcycle
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U2 - 10.1016/j.ijfatigue.2021.106685
DO - 10.1016/j.ijfatigue.2021.106685
M3 - Article
SN - 0142-1123
VL - 156
JO - International Journal of Fatigue
JF - International Journal of Fatigue
M1 - 106685
ER -