Microcracking behavior transition in thermally treated granite under mode I loading
TL;DR: In this article, the effect of thermal treatment on microcracking behavior of thermally treated granite under mode I loading was investigated by performing three-point bending tests on a set of pre-notched semi-circular specimens.
About: This article is published in Engineering Geology.The article was published on 2021-03-05. It has received 22 citations till now.
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TL;DR: In this article, the authors measured the uniaxial compression strength (UCS) and p-wave velocity (Vp) of granite samples after they were heated to various temperatures as high as 500°C and allowed to cool to room temperature.
25 citations
TL;DR: In this paper, the mixed mode I/II fracture characteristics of heat-treated granite were investigated by means of the extended finite element method (XFEM), which is based on the cohesive zone model (CZM).
15 citations
TL;DR: In this article, the authors investigate the effect of the loading condition and granite heterogeneity on the cracking mechanism and find that the microcracks under mixed-mode I-II loading do not nucleate as easily as compared with that in mode I case.
14 citations
TL;DR: In this paper, the authors analyzed the effects of pre-existing thermal microcracks on the microcracking mechanisms of Hong Kong granite under mode I loading, and found that the presence of the thermal micro-cracks aggravates the micro crack damage.
13 citations
TL;DR: In this paper , the authors used acoustic emission (AE) and digital image correlation (DIC) techniques to monitor the fracture behaviors of the notched semi-circular bend specimens during the test.
11 citations
References
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TL;DR: A new approach for modelling discrete cracks in meshfree methods is described, in which the crack can be arbitrarily oriented, but its growth is represented discretely by activation of crack surfaces at individual particles, so no representation of the crack's topology is needed.
Abstract: A new approach for modelling discrete cracks in meshfree methods is described. In this method, the crack can be arbitrarily oriented, but its growth is represented discretely by activation of crack surfaces at individual particles, so no representation of the crack's topology is needed. The crack is modelled by a local enrichment of the test and trial functions with a sign function (a variant of the Heaviside step function), so that the discontinuities are along the direction of the crack. The discontinuity consists of cylindrical planes centred at the particles in three dimensions, lines centred at the particles in two dimensions. The model is applied to several 2D problems and compared to experimental data. Copyright © 2004 John Wiley & Sons, Ltd.
1,274 citations
TL;DR: A review of the successes and limitations of acoustic emission (AE) studies as applied to the fracture process in rock with emphasis on our ability to predict rock failure is presented in this paper.
867 citations
TL;DR: A review of recent work on microcracks in rock can be found in this paper, with a focus on the morphogenesis, kinematics, dynamics, population statistics and observational techniques.
812 citations
01 Dec 1993
TL;DR: A review of the successes and limitations of acoustic emission (AE) studies as applied to the fracture process in rock with emphasis on our ability to predict rock failure is presented in this paper, where application of laboratory AE studies to larger scale problems related to the understanding of earthquake processes is also discussed.
Abstract: The development of faults and shear fracture systems over a broad range of temperature and pressure and for a variety of rock types involves the growth and interaction of microcracks. Acoustic emission (AE), which is produced by rapid microcrack growth, is a ubiquitous phenomenon associated with brittle fracture and has provided a wealth of information regarding the failure process in rock. This paper reviews the successes and limitations of AE studies as applied to the fracture process in rock with emphasis on our ability to predict rock failure. Application of laboratory AE studies to larger scale problems related to the understanding of earthquake processes is also discussed. In this context, laboratory studies can be divided into the following categories. 1) Simple counting of the number of AE events prior to sample failure shows a correlation between AE rate and inelastic strain rate. Additional sorting of events by amplitude has shown that AE events obey the power law frequency-magnitude relation observed for earthquakes. These cumulative event count techniques are being used in conjunction with damage mechanics models to determine how damage accumulates during loading and to predict failure. 2) A second area of research involves the location of hypocenters of AE source events. This technique requires precise arrival time data of AE signals recorded over an array of sensors that are essentially a miniature seismic net. Analysis of the spatial and temporal variation of event hypocenters has improved our understanding of the progression of microcrack growth and clustering leading to rock failure. Recently, fracture nucleation and growth have been studied under conditions of quasi-static fault propagation by controlling stress to maintain constant AE rate. 3) A third area of study involves the analysis of full waveform data as recorded at receiver sites. One aspect of this research has been to determine fault plane solutions of AE source events from first motion data. These studies show that in addition to pure tensile and double couple events, a significant number of more complex event types occur in the period leading to fault nucleation. 4) P and S wave velocities (including spatial variations) and attenuation have been obtained by artificially generating acoustic pulses which are modified during passage through the sample. (A) This paper was presented at the 34th U.S. Symposium on rock mechanics, 27-30 June 1993, University of Wisconsin-Madison. For the covering abstract see IRRD 863389.
696 citations
TL;DR: In this article, a dual-horizon peridynamics (DH-PD) formulation is proposed to solve the ghost force issue by considering the unbalanced interactions between the particles with different horizon sizes.
Abstract: Summary
In this paper, we develop a dual-horizon peridynamics (DH-PD) formulation that naturally includes varying horizon sizes and completely solves the ‘ghost force’ issue Therefore, the concept of dual horizon is introduced to consider the unbalanced interactions between the particles with different horizon sizes The present formulation fulfills both the balances of linear momentum and angular momentum exactly Neither the ‘partial stress tensor’ nor the ‘slice’ technique is needed to ameliorate the ghost force issue We will show that the traditional peridynamics can be derived as a special case of the present DH-PD All three peridynamic formulations, namely, bond-based, ordinary state-based, and non-ordinary state-based peridynamics, can be implemented within the DH-PD framework Our DH-PD formulation allows for h-adaptivity and can be implemented in any existing peridynamics code with minimal changes A simple adaptive refinement procedure is proposed, reducing the computational cost Both two-dimensional and three-dimensional examples including the Kalthoff–Winkler experiment and plate with branching cracks are tested to demonstrate the capability of the method Copyright © 2016 John Wiley & Sons, Ltd
508 citations