Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance

The fracture toughness of a rock often varies depending on the specimen shape and the loading type used to measure it. To investigate the mode I fracture toughness using semi-circular bend (SCB) specimens, we experimentally studied the fracture toughness using SCB and chevron bend (CB) specimens, th...

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Main Authors: Funatsu, T, Shimizu, N., Kuruppu, Mahinda, Matsui, K.
Format: Journal Article
Published: Springer 2015
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/7989
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author Funatsu, T
Shimizu, N.
Kuruppu, Mahinda
Matsui, K.
author_facet Funatsu, T
Shimizu, N.
Kuruppu, Mahinda
Matsui, K.
author_sort Funatsu, T
building Curtin Institutional Repository
collection Online Access
description The fracture toughness of a rock often varies depending on the specimen shape and the loading type used to measure it. To investigate the mode I fracture toughness using semi-circular bend (SCB) specimens, we experimentally studied the fracture toughness using SCB and chevron bend (CB) specimens, the latter being one of the specimens used extensively as an International Society for Rock Mechanics (ISRM) suggested method, for comparison. The mode I fracture toughness measured using SCB specimens is lower than both the level I and level II fracture toughness values measured using CB specimens. A numerical study based on discontinuum mechanics was conducted using a two-dimensional distinct element method (DEM) for evaluating crack propagation in the SCB specimen during loading. The numerical results indicate subcritical crack growth as well as sudden crack propagation when the load reaches the maximum. A K-resistance curve is drawn using the crack extension and the load at the point of evaluation. The fracture toughness evaluated by the K-resistance curve is in agreement with the level II fracture toughness measured using CB specimens. Therefore, the SCB specimen yields an improved value for fracture toughness when the increase of K-resistance with stable crack propagation is considered.
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spelling curtin-20.500.11937-79892017-09-13T14:35:06Z Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance Funatsu, T Shimizu, N. Kuruppu, Mahinda Matsui, K. K-resistance curve Fracture process zone DEM SCB specimen Fracture toughness The fracture toughness of a rock often varies depending on the specimen shape and the loading type used to measure it. To investigate the mode I fracture toughness using semi-circular bend (SCB) specimens, we experimentally studied the fracture toughness using SCB and chevron bend (CB) specimens, the latter being one of the specimens used extensively as an International Society for Rock Mechanics (ISRM) suggested method, for comparison. The mode I fracture toughness measured using SCB specimens is lower than both the level I and level II fracture toughness values measured using CB specimens. A numerical study based on discontinuum mechanics was conducted using a two-dimensional distinct element method (DEM) for evaluating crack propagation in the SCB specimen during loading. The numerical results indicate subcritical crack growth as well as sudden crack propagation when the load reaches the maximum. A K-resistance curve is drawn using the crack extension and the load at the point of evaluation. The fracture toughness evaluated by the K-resistance curve is in agreement with the level II fracture toughness measured using CB specimens. Therefore, the SCB specimen yields an improved value for fracture toughness when the increase of K-resistance with stable crack propagation is considered. 2015 Journal Article http://hdl.handle.net/20.500.11937/7989 10.1007/s00603-014-0550-8 Springer fulltext
spellingShingle K-resistance curve
Fracture process zone
DEM
SCB specimen
Fracture toughness
Funatsu, T
Shimizu, N.
Kuruppu, Mahinda
Matsui, K.
Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance
title Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance
title_full Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance
title_fullStr Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance
title_full_unstemmed Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance
title_short Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance
title_sort evaluation of mode i fracture toughness assisted by the numerical determination of k-resistance
topic K-resistance curve
Fracture process zone
DEM
SCB specimen
Fracture toughness
url http://hdl.handle.net/20.500.11937/7989