13th International Conference on Fracture June 16–21, 2013, Beijing, China -5- Figure 5. Crack and inhomogeneity Figure 6. Crack and debonded inhomogenity 4. Conclusions A pseudo-incident wave method is developed to predict the dynamic interaction effects between cracks and inhomogeneities. This approach enabled us to reduce the original interaction problem into the solution of coupled single crack/inhomogeneity subproblems, for which analytical solutions could be easily obtained which are coupled through the scattered waves. The steady state solution of the crack problem is obtained using integral transform method and the solution of the inhomogeneity problem is determined using Fourier expansion. The dynamic stress intensity factors (SIFs) at the matrix crack are obtained and numerical examples are provided to show the effect of the frequency, geometry of microdefects and material properties upon the dynamic SIFs. Both shielding and amplification effects are experienced and discussed. Acknowledgements This research is supported by the Natural Sciences and Engineering Research Council of Canada. References [1] R. G. Hoagland, G. T. Hahn and A. R. Rosenfield, Influence of microstructure on the fracture propagation in rock. Rock Mech. 5, (1973), 77-106. [2] N. Claussen, J. Steeb, R. F. Pabst, Effect of inducted micro-cracking on the fracture toughness of ceramics. Bull. Am. Ceram. Soc. 56, (1977), 559-562. [3] A. G. Evans, K. T. Faber, Crack-growth resistance of micro cracking brittle materials. J. Am. Ceram. Soc., 67, (1984), 255-260. [4] M. Ruhle, A. G. Evans, R. M. McMeeking, P. G. Charalambides, J. W. Hutchinson, Microcrack toughening in alumina/Zirconia. Acta Metall. 35, (1987), 1701-1710. [5] D.K.L. Tsang, S.O. Oyadiji, A.Y.T. Leung, Multiple penny-shaped cracks interaction in a finite body and their effect on stress intensity factor. Eng. Frac. Mech. 70, (2003), 2199-2214. [6] X. Yan, C. Miao, A numerical method for a void-crack interaction under cyclic loads, Acta Mech 223, (2012), 1015-1029. [7] D. Gross, Ch. Zhang, Diffraction of SH waves by a system of cracks: solution by an integral equation method. Int. J. Solids Structures. 24, (1988), 41-49. [8] S. A. Meguid, X. D. Wang, On the dynamic interaction between a microdefect and a main crack. Proc. R. Soc., Lond. A409, (1995), 449-464.
RkJQdWJsaXNoZXIy MjM0NDE=