Back
 GM  Vol.3 No.4 , October 2013
Numerical Crack Analysis of Blunt Rock Indenters by an Indirect Boundary Element Method
Abstract: Linear elastic fracture mechanics principles are widely applied for the analysis of crack problems in rock fracture mechanics. Rock indentation is an important and complicated problem among rock engineering issues. In this paper, in addition to the fracture criterion of maximum tangential stress adjacent to crack tip, the higher order displacement discontinuity method (which is a version of the indirect boundary element method) has been used for modeling the crack propagation mechanism under blunt indenters. In order to achieve more accurate results, higher order boundary elements i.e. quadratic elements, has been used to calculate displacement discontinuities and also to reduce the singularities of stress and displacement fields near the crack tip, the special crack tip elements has been used to calculate the stress intensity factors (SIF) at the crack tips. In this modeling, the effect of crack angle on stress intensity factors has been investigated. The numerical results of stress intensity factors obtained from some example problems were compared to the theoretical and experimental results cited in the literature which always show a percentage error less than one percent. The simulated results may pave the way for increasing the efficiency of mining and drilling by improving the design of tools and indentation equipments.
Cite this paper: N. Sadat Tayarani and M. Fatehi Marji, "Numerical Crack Analysis of Blunt Rock Indenters by an Indirect Boundary Element Method," Geomaterials, Vol. 3 No. 4, 2013, pp. 132-137. doi: 10.4236/gm.2013.34017.
References

[1]   F. F. Roxborough and H. R. Phillips, “Rock excavation by disc cutter,” International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 12, No. 12, 1975, pp. 361-366. http://dx.doi.org/10.1016/0148-9062(75)90547-1

[2]   X. C. Tan, S. Q. Kou and P. A. Lindqvist, “Application of The DDM and Fracture Mechanics Model On The Simulation of Rock Breakage by Mechanical Tools,” Engi- neering Geology, Vol. 49, No. 3-4, 1998, pp. 277-284.

[3]   M. Hood, “Phenomena Relating to the Failure of Hard Rock Adjacent to an Indenter,” Journal of the South African Institute of Mining and Metallurgy, 1977, pp. 113- 123.

[4]   H. Alehossein, E. Detournay and H. Huang, “An Analytical Model for the Indentation of Rocks by Blunt Tools,” International Journal of Rock Mechanics and Mining Sciences, Vol. 33, No. 4, 2000, pp. 267-284.

[5]   A. W. Momber, “Deformation and Fracture of Rocks Loaded with Spherical Indenters,” International Journal of Fracture. Vol. 125, No. 3-4, 2004, pp. 263-279. http://dx.doi.org/10.1023/B:FRAC.0000022240.64448.2f

[6]   L. H. Chen and J. F. Labuz, “Indentation of Rock by Wedge Shaped Tools,” International Journal of Rock Mechanics and Mining Sciences, Vol. 43, No. 7, 2006, pp. 1023-1033.

[7]   D. F. Howarth and F. F. Roxborough, “Some Fundamental Aspects of the Use of Disc Cutters in Hard Rock Excavation,” Journal of the South African Institute of Mining and Metallurgy, 1982, pp. 309-315.

[8]   H. Liu, “Numerical Modeling of the Rock Fracture Process under Mechanical Loading,” Ph.D. Thesis, Lulea University of Technology, Lulea, 2002.

[9]   N. G. W. Cook, M. Hood and F. Tsai “Observations of Crack Growth in Hard Rock Loaded by an Indenter,” International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 21, No. 2, 1984, pp. 97-107. http://dx.doi.org/10.1016/0148-9062(84)91177-X

[10]   V. E. Saouma and M. Kleinosky, “Finite Element Simula- tion of Rock Cutting: A Fracture Mechanics Approach,” Proceedings of the 25th US Symposium on Rock Me- chanics, ASCE, Evanston, 25-27 June, 1984, pp. 792-799.

[11]   H. Alehossein and M. Hood, “State of the Art Review of Rock Models for Disc Roller Cutters,” In: Aubertin, Hassani and Mitri, Eds., Rock Mechanics, Balkema, Rotterdam, 1996, pp. 693-700.

[12]   B. Mishra and A. Khair, “Numerical Simulation of Rock Indentation and Heat Generation During Linear Rock Cutting Process Golden Rocks,” The 41st US Symposium on Rock Mechanics (USRMS), June 2006, pp. 17-21.

[13]   H. Liu, S. Q. Kou and P. A. Lindqvist, “Numerical Studies on Bit-Rock Fragmentation Mechanisms,” International Journal of Geomechanics, Vol. 8, No. 1, 2008, pp. 45-67. http://dx.doi.org/10.1061/(ASCE)1532-3641(2008)8:1(45)

[14]   Q. Gong, J. Zhao and Y. Yong Jiao, “Numerical Modeling of the Effects of Joint Orientatio on Rock Fragmentation by TBM Cutter,” Tunnelling and Underground Space Technology, Vol. 20, No. 2, 2006, pp. 183-191. http://dx.doi.org/10.1016/j.tust.2004.08.006

[15]   Y. Mi and M. H. Aliabadi, “Dual Boundary Element Method for Three-Dimensional Fracture Mechanics Analysis,” Engineering Analysis with Boundary Elements, Vol. 10, No. 2, 1992, pp. 161-171.

[16]   A. Portela, M. H. Aliabadi and D. P. Rooke, “Dual Boundary Element Incremental Analysis of Crack Propagation,” International Journal Computers and Structures, Vol. 46, No. 2, 1993, pp. 237-247.

[17]   M. Fatehi Marji, H. Hosseini Nasab and A. H. Kohsary, “On the Uses of Special Crack Tip Elements in Numerical Rock Fracture Mechanics,” International Journal of Solids and Structures, Vol. 43, No. 6, 2006, pp. 1669-1692.

[18]   M. Fatehi Marji, H. Hosseini Nasab and A. H. Kohsary, “A New Cubic Element Formulation of the Displacement Discontinuity Method Using Three Special Crack Tip Elements for Crack Analysis,” International Journal of Solids and Structures, Vol. 1, No. 1, 2007, pp. 61-91.

[19]   H. Hosseini Nasab and M. Fatehi Marji, “A Semi-Infinite Higher-Order Displacement Discontinuity. Method and Its Application to the Quasistatic Analysis of Radial Cracks Produced by Blasting,” International Journal of Solids and Structures, Vol. 3, No. 2, 2007, pp. 439-458.

[20]   M. Fatehi Marji, H. Hosseini Nasab and H. morshedy, “Numerical Modeling of the Mechanism of Crack Propagation in Rocks under TBM Disc Cutters,” International Journal of Solids and Structures, Vol. 4, No. 3, 2009, pp. 605-627.

[21]   M. Fatehi Marji and I. Dehghani, “Kinked Crack Analysis by a Hybridized Boundary Element/Boundary Collocation Method,” International Journal of Solids and Structures, Vol. 47, No. 7-8, 2010, pp. 922-933.

[22]   B. N. Whittaker, R. N. Singh and G. Sun, “Rock Fracture Mechanics, Principles, Design and Applications,” Elsevier, Netherlands, 1992.

 
 
Top