PSI - Issue 22

Meng-Fei Hao et al. / Procedia Structural Integrity 22 (2019) 78–83 Meng-Fei Hao et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 4 Model predictions and errors for TC4 alloys under asymmetric loadings Figs. 1-3 show that fatigue life predictions and distribution fall within different scatter bands for the three alloys, respectively. Note from Figs. 1-3(a), nearly all of fatigue life predicted by the proposed model are within a life scatter of ± 3 for the three alloys. Noticed from Figs. 1-3(b) that, considering the lower mean and scatter of for TC4, GH4169 and 7050 T7451, and the overall performance of each model mentioned above, it is worth noting that the proposed model shows better model applicability than others. In addition, it shows better accuracy by combining the strain energy aspect with critical plane approach. Accordingly, Fig. 4 presents five model predictions for TC4 alloys under asymmetric loadings. Note that both the proposed and MSWT models give acceptable fatigue life predictions comparing with the other three ones. In particular, nearly all of predictions by these two models are within a life scatter of ± 3, as indicated by the lower mean of in Fig. 4(b). 4 Conclusions In the current analysis, a new strain energy-based critical plane model is developed for multiaxial fatigue analysis. Model validation and comparison are conducted by employing experimental data of three alloys under different loading conditions. Then, the following conclusions can be drawn: 1) For the TC4, GH4169 and Al7050-T7451 alloys, the proposed model yields better correlations on experimental lives than others, showing that the equivalent shear strain and equivalent shear stress can be utilized as damage parameter for fatigue failure analysis. 2) Comparing with the other four models, the proposed model indicates better model applicability. Moreover, it shows good prospects by combining critical plane approach with stress/strain-based damage parameters to reflect both influences of loading histories and multiaxial stress-strain states. Acknowledgement The authors would like to acknowledge the financial support of the National Natural Science Foundation of China (No. 11672070), Sichuan Provincial Key Research and Development Program (No. 2019YFG0348) and Science and Technology Program of Guangzhou, China (No. 201904010463). References [1] Hu D, Wang R, Fan J, et al. Probabilistic damage tolerance analysis on turbine disk through experimental data. Engineering Fracture Mechanics, 2012, 87: 73-82. [2] Zhu SP, Huang HZ, Peng W, et al. Probabilistic physics of failure-based framework for fatigue life prediction of aircraft gas turbine discs under uncertainty. Reliability Engineering & System Safety, 2016, 146: 1-12. [3] Liao D, Zhu SP, Qian G. Multiaxial fatigue analysis of notched components using combined critical plane and critical distance approach. International Journal of Mechanical Sciences, 2019, 160: 38-50. [4] Liao D, Zhu SP. Energy field intensity approach for notch fatigue analysis. International Journal of Fatigue, 2019, 127: 190-202. [5] Zhu SP, Yu ZY, Liu Q, et al. Strain energy-based multiaxial fatigue life prediction under normal-shear stress interaction. International Journal of Damage Mechanics, 2019, 28(5): 708-739