Abstract
In the present manuscript, the importance of support type on accurate determination of rock fracture toughness in semi-circular bending (SCB) test is demonstrated. First, by employing the finite element (FE) method, a detailed study is conducted to assess the effect of support friction on the mode I stress intensity factor (SIF) in the SCB specimen. Then, three different rocks and three various support types are utilized to investigate the support type effect experimentally. Both the FE and experimental results show that utilization of different types of supports results in different friction coefficients between the SCB specimen and the bottom supports. This can generate significant errors in calculations of SIF and fracture toughness of rock samples. It is shown that using the fixed or roller-in-groove support types can generate a large amount of error in rock fracture toughness calculations, although, these types of supports are still commonly being used by researchers.
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Abbreviations
- S :
-
Support span
- a :
-
Crack length
- R :
-
Radius of the specimen
- P :
-
External load
- t :
-
Specimen thickness
- r :
-
Radius of the support rollers
- K I :
-
Mode I stress intensity factor
- K Ic :
-
Mode I fracture toughness
- Y I :
-
Normalized mode I stress intensity factor
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Acknowledgements
This research was funded by Universiti Teknologi Malaysia under Grant Number of HIR - QJ130000.2424.04G40.
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Bahrami, B., Ayatollahi, M.R., Mirzaei, A.M. et al. Support Type Influence on Rock Fracture Toughness Measurement Using Semi-circular Bending Specimen. Rock Mech Rock Eng 53, 2175–2183 (2020). https://doi.org/10.1007/s00603-019-02023-z
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DOI: https://doi.org/10.1007/s00603-019-02023-z