Journal of the Korean Society of Mineral and Energy Resources Engineers (한국자원공학회지)

The Korean Society of Mineral and Energy Resources Engineers (한국자원공학회)
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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

Ko, Tae-Young;Kemeny, J.;Moon, Hyun-Koo
고태영;;문현구

  • Published : 2008.06.28
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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.

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.

Keywords

References

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