The Experts below are selected from a list of 6474 Experts worldwide ranked by ideXlab platform
Abigail Hackston - One of the best experts on this subject based on the ideXlab platform.
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the mohr Coulomb Criterion for intact rock strength and friction a re evaluation and consideration of failure under polyaxial stresses
Solid Earth, 2016Co-Authors: Abigail Hackston, E H RutterAbstract:Abstract. Darley Dale and Pennant sandstones were tested under conditions of both axisymmetric shortening and extension normal to bedding. These are the two extremes of loading under polyaxial stress conditions. Failure under generalized stress conditions can be predicted from the Mohr–Coulomb failure Criterion under axisymmetric shortening conditions, provided the best form of polyaxial failure Criterion is known. The sandstone data are best reconciled using the Mogi (1967) empirical Criterion. Fault plane orientations produced vary greatly with respect to the maximum compressive stress direction in the two loading configurations. The normals to the Mohr–Coulomb failure envelopes do not predict the orientations of the fault planes eventually produced. Frictional sliding on variously inclined saw cuts and failure surfaces produced in intact rock samples was also investigated. Friction coefficient is not affected by fault plane orientation in a given loading configuration, but friction coefficients in extension were systematically lower than in compression for both rock types. Friction data for these and other porous sandstones accord well with the Byerlee (1978) generalization about rock friction being largely independent of rock type. For engineering and geodynamic modelling purposes, the stress-state-dependent friction coefficient should be used for sandstones, but it is not known to what extent this might apply to other rock types.
Liang-shih Fan - One of the best experts on this subject based on the ideXlab platform.
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Coulomb Criterion - bounding crustal stress limit and intact rock failure: Perspectives
Powder Technology, 2020Co-Authors: Martin O. Saar, Liang-shih FanAbstract:Abstract In this perspective article, we illustrate the importance and versatility of the Coulomb Criterion that serves as a bridge between the fields of powder technology and the rock mechanics/geomechanics. We first describe the essence of the Coulomb Criterion and its physical meaning, revealing surprising similarities regarding its applications between both fields. We then discuss the rock mechanics applications and limitations at two extreme scales, the Earth's crust (tens of kilometers) and intact rocks (meters). We finally offer thoughts on bridging these scales. The context of the article is essential not only to the rock mechanics/geomechanics community but also to a broader powder technology community.
E H Rutter - One of the best experts on this subject based on the ideXlab platform.
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the mohr Coulomb Criterion for intact rock strength and friction a re evaluation and consideration of failure under polyaxial stresses
Solid Earth, 2016Co-Authors: Abigail Hackston, E H RutterAbstract:Abstract. Darley Dale and Pennant sandstones were tested under conditions of both axisymmetric shortening and extension normal to bedding. These are the two extremes of loading under polyaxial stress conditions. Failure under generalized stress conditions can be predicted from the Mohr–Coulomb failure Criterion under axisymmetric shortening conditions, provided the best form of polyaxial failure Criterion is known. The sandstone data are best reconciled using the Mogi (1967) empirical Criterion. Fault plane orientations produced vary greatly with respect to the maximum compressive stress direction in the two loading configurations. The normals to the Mohr–Coulomb failure envelopes do not predict the orientations of the fault planes eventually produced. Frictional sliding on variously inclined saw cuts and failure surfaces produced in intact rock samples was also investigated. Friction coefficient is not affected by fault plane orientation in a given loading configuration, but friction coefficients in extension were systematically lower than in compression for both rock types. Friction data for these and other porous sandstones accord well with the Byerlee (1978) generalization about rock friction being largely independent of rock type. For engineering and geodynamic modelling purposes, the stress-state-dependent friction coefficient should be used for sandstones, but it is not known to what extent this might apply to other rock types.
Tomasz Wierzbicki - One of the best experts on this subject based on the ideXlab platform.
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strain capacity of x70 pipeline steel subjected to biaxial loading condition
ASME 2015 34th International Conference on Ocean Offshore and Arctic Engineering, 2015Co-Authors: Marcelo Paredes, Tomasz WierzbickiAbstract:In this work the tensile capacity of circumferentially pressurized cracked pipes with varying crack parameters and pipe dimensions are numerically investigated. The biaxial loading mode includes internal pressure and tensile load, which are applied in sequence. The present physics-inspired fracture model based upon the original Mohr-Coulomb Criterion enables not only the computation of global fracture response of pipe subjected to complex loading condition but also a thorough determination of the local evolving stress state around the growing cracks.Copyright © 2015 by ASME
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application of extended mohr Coulomb Criterion to ductile fracture
International Journal of Fracture, 2010Co-Authors: Tomasz WierzbickiAbstract:The Mohr–Coulomb (M–C) fracture Criterion is revisited with an objective of describing ductile fracture of isotropic crack-free solids. This Criterion has been extensively used in rock and soil mechanics as it correctly accounts for the effects of hydrostatic pressure as well as the Lode angle parameter. It turns out that these two parameters, which are critical for characterizing fracture of geo-materials, also control fracture of ductile metals (Bai and Wierzbicki 2008; Xue 2007; Barsoum 2006; Wilkins et al. 1980). The local form of the M–C Criterion is transformed/extended to the spherical coordinate system, where the axes are the equivalent strain to fracture \({\bar \varepsilon_f}\) , the stress triaxiality η, and the normalized Lode angle parameter \({\bar \theta}\) . For a proportional loading, the fracture surface is shown to be an asymmetric function of \({\bar \theta}\). A detailed parametric study is performed to demonstrate the effect of model parameters on the fracture locus. It was found that the M–C fracture locus predicts almost exactly the exponential decay of the material ductility with stress triaxiality, which is in accord with theoretical analysis of Rice and Tracey (1969) and the empirical equation of Hancock and Mackenzie (1976), Johnson and Cook (1985). The M–C Criterion also predicts a form of Lode angle dependence which is close to parabolic. Test results of two materials, 2024-T351 aluminum alloy and TRIP RA-K40/70 (TRIP690) high strength steel sheets, are used to calibrate and validate the proposed M–C fracture model. Another advantage of the M–C fracture model is that it predicts uniquely the orientation of the fracture surface. It is shown that the direction cosines of the unit normal vector to the fracture surface are functions of the “friction” coefficient in the M–C Criterion. The phenomenological and physical sound M–C Criterion has a great potential to be used as an engineering tool for predicting ductile fracture.
Martin O. Saar - One of the best experts on this subject based on the ideXlab platform.
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Coulomb Criterion - bounding crustal stress limit and intact rock failure: Perspectives
Powder Technology, 2020Co-Authors: Martin O. Saar, Liang-shih FanAbstract:Abstract In this perspective article, we illustrate the importance and versatility of the Coulomb Criterion that serves as a bridge between the fields of powder technology and the rock mechanics/geomechanics. We first describe the essence of the Coulomb Criterion and its physical meaning, revealing surprising similarities regarding its applications between both fields. We then discuss the rock mechanics applications and limitations at two extreme scales, the Earth's crust (tens of kilometers) and intact rocks (meters). We finally offer thoughts on bridging these scales. The context of the article is essential not only to the rock mechanics/geomechanics community but also to a broader powder technology community.
