PSI - Issue 23

Antunes et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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F.V. Antunes et al. / Procedia Structural Integrity 23 (2019) 571–576

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4. Conclusions

Crack tip phenomena is studied here using CTOD versus load plots obtained numerically. The aspects studied are the crack closure level, the elastic regime of  K and the crack tip plastic deformation, which was related with fatigue crack propagation. The elastic load range,  K el , was found to increase linearly with material’s yield stress. Well defined relations were found between the elastic and the plastic deformations, which greatly depend on material. The fatigue crack growth rate, obtained experimentally, was plotted versus plastic CTOD range,  p , for the different materials. Acknowledgements This work was financially supported by: Project PTDC/CTM-CTM/29101/2017 – POCI-01-0145-FEDER-029101 funded by FEDER funds through COMPETE2020 - Programa Operacion al Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES. Antunes, F.V., Rodrigues, S.M., Branco, R., Camas, D., 2016. A numerical analysis of CTOD in constant amplitude fatigue crack growth, Theoretical and Applied Fracture Mechanics 85, 45 – 55. Antunes, F.V., Branco, R., Prates, P.A., Borrego, L., 2017. Fatigue crack growth modelling based on CTOD for the 7050-T6 alloy, Fatigue Fract Engng Mater Struct 40, 1309 – 1320. Antunes, F.V., Serrano, S., Branco, R., Prates, P., Lorenzino, P., 2018. Fatigue crack growth in the 2050-T8 aluminium alloy, International journal of fatigue 115, 79 – 88. Chaboche, J.L., 2008. A review of some plasticity and viscoplasticity constitutive theories. International Journal of Plasticity 24, 1642 – 1693. Yusof F., Lopez-Crespo P., Withers P.J., 2013. Effect of overload on crack closure in thick and thin specimens via digital image correlation. International Journal of Fatigue 56, 17 – 24. Lopez-Crespo, P., Steuwer, A. Buslaps, T., Tai, Y.H., Lopez-Moreno, A., Yates, J.R., Withers, P.J., 2015. Measuring overload effects during fatigue crack growth in bainitic steel by synchrotron X-ray diffraction, International Journal of Fatigue 71, 11 – 16. Matos, P.F.P., Nowell, D., 2007. On the accurate assessment of crack opening and closing stresses in plasticity-induced fatigue crack closure problems. Engineering Fracture Mechanics 74, 1579 – 1601. Mokhtarishirazabad, M., Lopez-Crespo P., Moreno, B., Lopez-Moreno, A., Zanganeh, M., 2016. Evaluation of crack-tip fields from DIC data: A parametric study, International Journal of Fatigue 89, 11 – 19. Oliveira, M.C., Alves, J.L. Menezes, L.F., 2008. Algorithms and Strategies for Treatment of Large Deformation Frictional Contact in the Numerical Simulation of Deep Drawing Process. Archives of Computational Methods in Engineering 15, 113-162. Pommier, S., Risbet, M., 2005. Time derivative equations for mode I fatigue crack growth in metals, International Journal of Fatigue 27, 1297 – 1306. Santos, L.M.S., Ferreira, J.A.M., Jesus, J.S., Costa, J.M., Capela, C., 2016. Fatigue behaviour of selective laser melting steel components, Theoretical and Applied Fracture Mechanics 85, 9-15. Sunder, R., 2012Unraveling the Science of Variable Amplitude Fatigue, Journal of ASTM International 9(1), 1-32. Vasco-Olmo, J.M. , Díaz , F.A., Antunes, F.V., James M.N., 2019. Characterisation of fatigue crack growth using digital image correlation measurements of plastic CTOD, Theoretical and Applied Fracture Mechanics 101, 332 – 341. Voce, E., 1948. The relationship between stress and strain for homogeneous deformation. Journal of the Institute of Metals 74, 537 – 562. Yan, L., Fan, J., 2016. In-situ SEM study of fatigue crack initiation and propagation behavior in2524 aluminum alloy, Materials and Design, 110, 592-601. Zhang, W., Liu, Y., 2012. Investigation of incremental fatigue crack growth mechanisms using in situ SEM testing, International Journal of Fatigue 42, 14 – 23. References