Determination of the Mode I Fracture Toughness of Rock Using the Compact Tension Specimen and the Effect of Specimen Size and Loading Rate on the Fracture Toughness

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2008 Vol.45, Issue 3 Preview Page Next Page

Determination of the Mode I Fracture Toughness of Rock Using the Compact Tension Specimen and the Effect of Specimen Size and Loading Rate on the Fracture Toughness 컴팩트 시험편을 이용한 암석의 모드 I 파괴인성 측정 및 시험편의 크기와 재하속도가 파괴인성에 미치는 영향: 고태영, J. Kemeny, 문현구
Tae Young Ko, J. Kemeny and Hyun-Koo Moon

30 June 2008. pp. 234-241

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Abstract

The fracture toughness is a quantitative expression of a material resistance to failure and it is an important parameter in fracture mechanics. The fracture toughness can be used in many rock mechanics applications such as blasting, hydraulic fracturing, and excavation. In this study the mode I fracture toughness of Coconino sandstone is determined using the Compact Tension (CT) type specimens. A new stress intensity factor formula for the CT specimen is developed using the finite element program, FRANC2D/L. The effects of the specimen size and the loading rate on the fracture toughness are also investigated. Three specimen sizes are used for the size effect and four loading rates are employed for the loading rate effect. The experimental results show that the fracture toughness increases with increasing specimen size. Also, the fracture toughness increases with increasing loading rate.

Keywords

Mode I fracture toughness

Compact tension specimen

Stress intensity factor

Finite element method

Size effect

Loading rate effect

파괴인성은 재료가 파괴에 저항하는 정도를 나타내는 재료 고유의 상수로서 파괴역학에서 중요한 요소 중의 하나이다. 이러한 파괴인성은 암석역학의 여러 분야 중, 특히 발파, 수압파쇄 그리고 굴착 등에 활용될 수 있다. 본 연구에서는 Coconino 사암의 모드 I 파괴인성을 컴팩트 인장 시험편을 이용하여 구하였다. 유한요소 프로그램인 FRANC2D/L을 이용하여 컴팩트 인장 시험편의 응력확대계수를 결정하였다. 시험편의 크기와 재하속도가 파괴인성에 미치는 영향을 분석하였다. 실험 결과, 파괴인성은 시험편의 크기가 증가함에 따라 증가하는 경향을 보였다. 또한 재하속도가 빠를수록 파괴인성도 같이 증가하였다.

키워드

파괴인성

컴팩트 인장 시험편

유한요소법

응력확대계수

크기효과

재하속도 효과

References

ASTM E399-06e1, 2006, Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness KIC of Metallic Materials, In: Annual book of ASTM standards. American Society for Testing and Materials.
Barton, C.C., 1982, “Variables in fracture energy and toughness testing of rock,” Proc. of 23rd US Symp. on Rock Mech., The Univ. of California, Berkeley, California, pp. 449-462.
Bažant, Z.P., Bai, S-P and Gettu, R., 1993, “Fracture of Rock: Effect of Loading Rate,” Eng. Fract. Mech., Vol. 45, No. 3, pp. 393-398.
Donovan, J.G. and Karfakis, M.G., 2004, “Adaptation of a Simple Wedge Test for the Rapid Determination of Mode I Fracture Toughness and the Assessment of Relative Fracture Resistance,” Int. J. Rock Mech. Min. Sci., Vol. 41, No. 4, pp. 695-701.
Dyskin, A.V. and Galybin, A.N., 1996, “A Mechanism of Size Effect in Facture Toughness Measurements,” Proc. of the 2nd North American Rock Mechanics Symposium, Montreal, QC, Canada, June 19-21, pp. 655-662.
Fowell, R.J., 1995, “Suggested Method for Determining Mode I Fracture Toughness Using Cracked Chevron Notched Brazilian Disc Specimens,” Int. J. Rock Mech. Min. Sci. & Geomech. Abstr., Vol. 32, No. 1, pp. 57-64.
Gross, B., 1970, Some Plane Elastostatic Solutions for Plates Having a V-Notch, Ph.D. Dissertation, Case Western Reserve University, USA.
Ko, T.Y. and Kemeny, J., 2007, “Effect of Confining Stress and Loading Rate on Fracture Toughness on Rocks,” Proc. of the 1st Canada-US Rock Mechanics Symposium, Vancouver, Canada, May 27-31, pp. 625-629.
Ouchterlony, F., 1988, “Suggested Methods for Determining the Fracture Toughness of Rock,” Int. J. Rock Mech. Min. Sci. & Geomech. Abstr., Vol. 25, No. 2, pp. 71-96.
Roegiers, J.C. and Zhao, X.L., 1991, “Determination of the Fracture Toughness of a Saturated Soft Rock: Discussion,” Can. Geotech. J. Vol. 28, pp. 470-471.
Schmidt, R.A., 1980, “A Microcrack Model and Its Significance to Hydraulic Fracturing and Fracture Toughness Testing. Proc. of the 21st U.S. Rock Mechanics Symposium, The University of Missouri - Rolla, May 28-30, pp. 581-590.
Srawley, J.E. and Gross, B., 1972, “Stress Intensity Factors for Bend and Compact Specimens,” Eng. Fract. Mech., Vol. 4, No. 3, pp. 587-589.
Tada, H., Paris, P.C., and Irwin, G.R., 2000. The Stress Analysis of Cracks Handbook. 3rd Ed., ASME Press, New York.
Whittaker, B.N., Singh, R.N., and Sun, G., 1992, Rock Fracture Mechanics: Principles, Design and Applications, Elsevier Publishing Company, Amsterdam ; New York.

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society for Geosystem Engineering
Journal Title(Ko) :한국지구시스템공학회지
Volume : 45
No :3
Pages :234-241

[1] ASTM E399-06e1, 2006, Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness KIC of Metallic Materials, In: Annual book of ASTM standards. American Society for Testing and Materials.

[2] Barton, C.C., 1982, “Variables in fracture energy and toughness testing of rock,” Proc. of 23rd US Symp. on Rock Mech., The Univ. of California, Berkeley, California, pp. 449-462.

[3] Bažant, Z.P., Bai, S-P and Gettu, R., 1993, “Fracture of Rock: Effect of Loading Rate,” Eng. Fract. Mech., Vol. 45, No. 3, pp. 393-398.

[4] Donovan, J.G. and Karfakis, M.G., 2004, “Adaptation of a Simple Wedge Test for the Rapid Determination of Mode I Fracture Toughness and the Assessment of Relative Fracture Resistance,” Int. J. Rock Mech. Min. Sci., Vol. 41, No. 4, pp. 695-701.

[5] Dyskin, A.V. and Galybin, A.N., 1996, “A Mechanism of Size Effect in Facture Toughness Measurements,” Proc. of the 2nd North American Rock Mechanics Symposium, Montreal, QC, Canada, June 19-21, pp. 655-662.

[6] Fowell, R.J., 1995, “Suggested Method for Determining Mode I Fracture Toughness Using Cracked Chevron Notched Brazilian Disc Specimens,” Int. J. Rock Mech. Min. Sci. & Geomech. Abstr., Vol. 32, No. 1, pp. 57-64.

[7] Gross, B., 1970, Some Plane Elastostatic Solutions for Plates Having a V-Notch, Ph.D. Dissertation, Case Western Reserve University, USA.

[8] Ko, T.Y. and Kemeny, J., 2007, “Effect of Confining Stress and Loading Rate on Fracture Toughness on Rocks,” Proc. of the 1st Canada-US Rock Mechanics Symposium, Vancouver, Canada, May 27-31, pp. 625-629.

[9] Ouchterlony, F., 1988, “Suggested Methods for Determining the Fracture Toughness of Rock,” Int. J. Rock Mech. Min. Sci. & Geomech. Abstr., Vol. 25, No. 2, pp. 71-96.

[10] Roegiers, J.C. and Zhao, X.L., 1991, “Determination of the Fracture Toughness of a Saturated Soft Rock: Discussion,” Can. Geotech. J. Vol. 28, pp. 470-471.

[11] Schmidt, R.A., 1980, “A Microcrack Model and Its Significance to Hydraulic Fracturing and Fracture Toughness Testing. Proc. of the 21st U.S. Rock Mechanics Symposium, The University of Missouri - Rolla, May 28-30, pp. 581-590.

[12] Srawley, J.E. and Gross, B., 1972, “Stress Intensity Factors for Bend and Compact Specimens,” Eng. Fract. Mech., Vol. 4, No. 3, pp. 587-589.

[13] Tada, H., Paris, P.C., and Irwin, G.R., 2000. The Stress Analysis of Cracks Handbook. 3rd Ed., ASME Press, New York.

[14] Whittaker, B.N., Singh, R.N., and Sun, G., 1992, Rock Fracture Mechanics: Principles, Design and Applications, Elsevier Publishing Company, Amsterdam ; New York.

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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