13th International Conference on Fracture June 16–21, 2013, Beijing, China -8- perfectly. With interface bond strength increasing for example between 35-70MPa, the overall stiffness of the specimen is increased obviously. And the yield strength is higher than 90MPa. So in this situation the spacemen can work very well. And the gradient performance of the functionally gradient materials is not obviously affected by the interfacial crack. 4. Conclusion In this study, the modeling of fatigue crack initiation and propagation for particulate reinforced composites is facilitated with new Voronoi Cell Finite Element Method (VCFEM), considering the matrix-inclusion interfacial fatigue cracks, matrix fatigue cracks and crack closures. In the new element, all possible contacts on the crack edge is considered by contact seeking and remeshing methods, when the crack is closing under all possible changing loads. The fatigue crack initiates when the fatigue damage exceeds certain critical damage value, and fatigue crack propagation are simulated by gradual seeking crack propagating directions and new crack tips in a remeshing method. The second example of Particle-reinforced metal-matrix composites with 20 elliptical inclusions shows that the VCFEM has considerable accuracy and high efficiency in dealing with the initiation and propagation of the fatigue crack. Good agreements are obtained between the results of VCFEM and the general finite element method, not given in this paper. This kind of VCFEM method can predict functionally gradient material particles’ interfacial crack accurately. The particles’ size, topological structure, and interfacial deboning strength will influence FMES’ mechanical behavior. With the interface cracking the overall stiffness of functionally gradient materials is gradually reduced. Acknowledgements The financial support by the National Natural Science Foundations of China (Nos. 11072092 and Nos. 11262007) is gratefully acknowledged. References [1] J. Zhang, and N. Katsube, A hybrid finite element method for heterogeneous materials with randomly dispersed rigid inclusions. Int J Numer Methods Eng, 38 (1995) 1635–1653. [2] S. Ghosh, and S. N. Mukhopadhyay, Material based finite element analysis of heterogeneous media involving dirichlet tessellations. Comput Methods Appl Mech Eng, 104 (1993) 211–247. [3] S. Ghosh, and S. Moorthy, Elastic-plastic analysis of arbitrary heterogeneous materials with the voronoi-cell finite-element method. Comput Methods Appl, 121 (1995) 373–409. [4] S.Ghosh, Y. Ling, et al., Interfacial debonding analysis in multiple fiber reinforced composites. Mech mater, 32 (2000) 561–591. [5] R. Guo, H. J. Shi and Z. H. Yao, Numerical simulation of thermo-mechanical fatigue properties for particulate reinforced composites. Acta Mechanica Sinica, 21(2) (2005) 160–168. [6] R. Guo, H. J. Shi and Z. H. Yao, The modeling of interfacial debonding crack in particle reinforced composites using Voronoi cell finite element method. Comput Mech, 32(1-2) (2003) 52–59.
RkJQdWJsaXNoZXIy MjM0NDE=