An Experimental and Numerical Study on the Effect of Loading Type and Specimen Geometry on Mode-I Fracture Toughness of Rock

Document Type : Research Article

Authors

Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract

ABSTRACT: As fracture toughness (KIC) is one of the most practical parameters in fracture mechanics of rock, this article aims to investigate this parameter both experimentally and numerically. In the current research, mode-I fracture toughness of a kind of limestone was investigated by performing Brazilian disc, cylinder direct tension and under bending cubs. Through performing some tests on straight notched Brazilian disc specimen (SNBD), the effect of specimen diameter and crack length on the rock mode-I fracture toughness was investigated. Moreover, in order to determine the effect of the loading type on the mode I fracture toughness; two other tests were conducted on the cylinder direct tension specimens and cubic specimens (DT and SENB). Then, the effect of the crack length and the specimen diameter on the rocks mode-I fracture toughness was investigated through conducting the statistical analysis of variance (ANOVA) on the results obtained in DT and SNBD tests. In order to determine the required
parameters of DT and SNBD specimens for fracture toughness, finite-element software was used. The results showed that by increasing the diameter from 75 mm to 95 mm, for Brazilian disc specimens the average fracture toughness increases by 30%. Also it seems that factors such as the test and loading type as well as the crack geometry can affect the fracture roughness parameter.

Highlights

[1] A. Fahimifar, M. Malekpour, Experimental and numerical analysis of indirect and direct tensile strength using fracture mechanics concepts, Bulletin of Engineering Geology and the Environment, 71(2) (2012) 269-283.

[2] M. Iqbal, B. Mohanty, Experimental calibration of stress intensity factors of the ISRM suggested cracked chevron-notched Brazilian disc specimen used for determination of mode-I fracture toughness, International Journal of Rock Mechanics and Mining Sciences, 43(8) (2006) 1270-1276.

[3] M. Aliha, M. Sistaninia, D. Smith, M. Pavier, M. Ayatollahi, Geometry effects and statistical analysis of mode I fracture in guiting limestone, International Journal of Rock Mechanics and Mining Sciences, 51 (2012) 128-135.

[4] L. Tutluoglu, C. Keles, Mode I fracture toughness determination with straight notched disk bending method, International Journal of Rock Mechanics and Mining Sciences, 48(8) (2011) 1248-1261.

[5] F. Ouchterlony, Extension of the compliance and stress intensity formulas for the single edge crack round bar in bending, in: Fracture Mechanics for Ceramics, Rocks, and Concrete, AStM International, 1981.

[6] K. Khan, N. Al-Shayea, Effect of specimen geometry and testing method on mixed mode I-II fracture toughness of a limestone rock from Saudi Arabia, Rock mechanics and rock engineering, 33(3) (2000) 179-206.

[7] E.J. Hansen, V.E. Saouma, Numerical simulation of reinforced concrete deterioration: Part 2-Steel corrosion and concrete cracking, ACI Materials Journal, 96 (1999) 331-338.

[8] S. Mohammadi, Extended finite element method: for fracture analysis of structures, John Wiley & Sons, 2008.

[9] A.L. Amarasiri, J.K. Kodikara, Determination of cohesive properties for mode I fracture from beams of soft rock, International Journal of Rock Mechanics and Mining Sciences, 48(2) (2011) 336-340.

[10] V. Birtel, P. Mark, Parameterised finite element modelling of RC beam shear failure, in: ABAQUS Users’ Conference, 2006, pp. 95-108.

Keywords

References

[1] A. Fahimifar, M. Malekpour, Experimental and numerical analysis of indirect and direct tensile strength using fracture mechanics concepts, Bulletin of Engineering Geology and the Environment, 71(2) (2012) 269-283.
[2] M. Iqbal, B. Mohanty, Experimental calibration of stress intensity factors of the ISRM suggested cracked chevron-notched Brazilian disc specimen used for determination of mode-I fracture toughness, International Journal of Rock Mechanics and Mining Sciences, 43(8) (2006) 1270-1276.
[3] M. Aliha, M. Sistaninia, D. Smith, M. Pavier, M. Ayatollahi, Geometry effects and statistical analysis of mode I fracture in guiting limestone, International Journal of Rock Mechanics and Mining Sciences, 51 (2012) 128-135.
[4] L. Tutluoglu, C. Keles, Mode I fracture toughness determination with straight notched disk bending method, International Journal of Rock Mechanics and Mining Sciences, 48(8) (2011) 1248-1261.
[5] F. Ouchterlony, Extension of the compliance and stress intensity formulas for the single edge crack round bar in bending, in: Fracture Mechanics for Ceramics, Rocks, and Concrete, AStM International, 1981.
[6] K. Khan, N. Al-Shayea, Effect of specimen geometry and testing method on mixed mode I-II fracture toughness of a limestone rock from Saudi Arabia, Rock mechanics and rock engineering, 33(3) (2000) 179-206.
[7] E.J. Hansen, V.E. Saouma, Numerical simulation of reinforced concrete deterioration: Part 2-Steel corrosion and concrete cracking, ACI Materials Journal, 96 (1999) 331-338.
[8] S. Mohammadi, Extended finite element method: for fracture analysis of structures, John Wiley & Sons, 2008.
[9] A.L. Amarasiri, J.K. Kodikara, Determination of cohesive properties for mode I fracture from beams of soft rock, International Journal of Rock Mechanics and Mining Sciences, 48(2) (2011) 336-340.
[10] V. Birtel, P. Mark, Parameterised finite element modelling of RC beam shear failure, in: ABAQUS Users’ Conference, 2006, pp. 95-108.
AUT Journal of Civil Engineering
Volume 1, Issue 1
May 2017
Pages 45-54

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