13th International Conference on Fracture June 16–21, 2013, Beijing, China -8- 5. Conclusion The non-local DP model is a useful methodology in the rate-independent, non-linear modelling of fracture in Gilsocarbon. The significance of the result is both theoretical and practical: On the theoretical plane, though the conventional EPFM methodology has been shown to be limited in the application in nuclear graphite, it was demonstrated that the fracture parameters calculated using EPFM are relevant as they describe the inherent failure behviour. Since the model allows for the bulk degradation of material ahead of the crack tip, fracture is not constrained to a singularity, but is simulated as the degradation of the material ahead of the crack tip. The practical significance is that the DP model has shown excellent agreement with experimental results and hence motivates for further investigations of using non local DP models to simulate quasi-brittle fracture in nuclear graphite that has been degraded by operation in reactor environments. Acknowledgments TH Becker would like to express his appreciation for the University of Cape Town and the people involved in facilitating this research and to the University of Manchester for providing the required experimental equipment, such as the mechanical testing apparatuses as well as for the use of the server cluster. References [1] M.P. Hindley, M.N. Mitchell, C. Erasmus, R. McMurtry, T.H. Becker, D.C. Blaine, A.A. Groenwold, Journal of Nuclear Materials, Available online 30 October 2012, ISSN 0022-3115, 10.1016/j.jnucmat.2012.10.030. [2] J. Brocklehurst, M. Darby, Materials Science and Engineering 16 (1974) 91–106. [3] B. Mitchell, J. Smart, S. Fok, B. Marsden, Journal of Nuclear Materials 322 (2003) 126–137. [4] J.P. Strizak, IAEA-TECDOC-690 (Ed.), 1991, p. 16. [5] P. Ouagne, G.B. Neighbour, B. McEnaney, Journal of Physics D: Applied Physics 35 (2002) 927–934. [6] A. Hodgkins, T. Marrow, P. Mummery, B. Marsden, A. Fok, Materials Science and Technology 22 (2006) 1051. [7] A.D. Hodgkin, Crack Propagation in Nuclear Graphite, PhD Thesis, The University of Manchester, 2006. [8] S. Fazluddin, Crack Growth Resistance in Nuclear Graphite, University of Sheffield, 2002. [9] M. Sakai, K. Urashima, M. Inagaki, Journal of the American Ceramic Society 66 (1983) 868– 874. [10] M. Sakai, J. Yoshimura, Y. Goto, M. Inagaki, Journal of the American Ceramic Society 71 (1988) 609–616. [11] M.R. Ayatollahi, a. R. Torabi, Carbon 48 (2010) 2255–2265. [12] P.J. Heard, M.R. Wootton, R. Moskovic, P.E.J. Flewitt, Journal of Nuclear Materials 401 (2010) 71–77. [13] W. Weibull, Roy. Swedish Ins. Eng. Res. 153 (n.d.) 1–55. [14] M.P. Hindley, M.N. Mitchell, D.C. Blaine, A.A. Groenwold, Journal of Nuclear Materials 420 (2012) 110–115. [15] T.H. Becker, T.J. Marrow, R.B. Tait, Journal of Nuclear Materials 414 (2011) 32–43. [16] M. Mostafavi, T.J. Marrow, Engineering Fracture Mechanics 78 (2011) 1756–1770. [17] T.H. Becker, T.J. Marrow, R.B. Tait, Experimental Mechanics 51 (2011) 1511–1526.
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