13th International Conference on Fracture June 16–21, 2013, Beijing, China -9- of crack paths distribution breaks. While, for the models of 160mm and 320mm height, the crack path solutions are almost the same, which indicates that the designed boundary disturbance has ignorable effect on crack growth for these models sizes. The reasons are: (i), with the same boundary disturbance, the bigger the model is, the smaller the additional stress generated; (ii), as the distance from disturbance becomes bigger, the distribution of additional stress becomes more and more uniform; see the stress distribution comparison between different model sizes in Fig. 5. 5. Conclusion Nowadays, the observation technology still has some distance to be accuracy enough to generate a numerical model fully describing the real world. With limited data, the differences between numerical modelling and reality exist. For crack propagation problem, which is high non-linear, the effect of the differences is numerically examined by using a simple setting in this paper. For a 3D linear elastic dynamic problem, the near field disturbances lead to significant changes to crack path solution in the invested cases. While, the effect of far field disturbance becomes weaker as the distance from crack tips becomes larger, and becomes stronger as the degree of heterogeneity becomes larger. The Saint-Venant principle still holds in the studied crack growth problem. Acknowledgements This research is partially supported by the Central Public-interest Scientific Institution Basal Research Fund of China (Grant No. 2011B-05), China postdoctoral Science Foundation, and Natural Science Foundation of Hei Longjiang Province of China (Grant No. LC2012C32). These supports are greatly appreciated. References [1] J. Oliver, Modelling strong discontinuities in solid mechanics via strain softening constitutive equations. Part 1: Fundamentals. Int. J. Num. Meth. Eng., 39(21), (1996) 3575-3600. [2] K. Ravi-Chandar, and W. Knauss, An experimental investigation into dynamic fracture: III. On steady-state crack propagation and crack branching. International Journal of Fracture, 26(2), (1984) 141-154. [3] K. Oguni, L. Wijerathne, T. Okinaka and M. Hori, Crack propagation analysis using PDS-FEM and comparison with fracture experiment. Mech. Mater. Phys. Solid, 41(11), (2009) 1242-1252. [4] J. Oliver, A. Huespe and P. Sanchez, A comparative study on finite elements for capturing strong discontinuities: E-FEM vs X-FEM. Comput. Method Appl. M., 195(37), (2006) 4732-4752. [5] F. Stan, Discontinuous Galerkin method for interface crack propagation. Int. J. Mater. Forming 1, (2008) 1127-1130. [6] W.K. Liu, S. Hao, T. Belytschko, S.F. Li, and C.T. Chang, Multiple scale meshfree methods for damage fracture and localization. Comp. Mater. Sci., 16(1), (1999) 197-205. [7] M. Hori, K. Oguni, and H. Sakaguchi, Proposal of FEM implemented with particle discretization for analysis of failure phenomena. J. Mech. Phys. Solids: 53(3), (2005) 681-703. [8] H. Chen, L. Wijrathne, M. Hori, and T. Ichimura, Stability analysis of dynamic crack growth using PDS-FEM. Struct. Eng. Earthq. Eng., 29(1), (2012) 1s-8s. [9] L. Casett, Efficient symplectic algorithms for numerical simulations of Hamiltonian flows. Phys. Scripta, 51, (1995) 29-34. [10]H. Hausmann, S. Hoyer, B. Schurr et al., New seismic data improve earthquake location in the Vienna basin area, Austria. Austrian Journal of earth sciences, 103(2), (2010) 2-14 [11] J. Tarasewicz, R. S. White, B. Brandsdóttir and B. Thorbjarnardóttir, Location accuracy of earthquake hypocentres beneath Eyjafjallajkull, Iceland, prior to the 2010 eruptions. JKULL, 61, (2011) 33-50
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