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Journal ArticleDOI

A Review of Dynamic Experimental Techniques and Mechanical Behaviour of Rock Materials

01 Jul 2014-Rock Mechanics and Rock Engineering (Springer Vienna)-Vol. 47, Iss: 4, pp 1411-1478
TL;DR: A review of the development and the state of the art in dynamic testing techniques and dynamic mechanical behaviour of rock materials can be found in this article, where a detailed description of various dynamic mechanical properties (e.g., uniaxial and triaxial compressive strength, tensile strength, shear strength and fracture toughness) and corresponding fracture behaviour are discussed.
Abstract: The purpose of this review is to discuss the development and the state of the art in dynamic testing techniques and dynamic mechanical behaviour of rock materials. The review begins by briefly introducing the history of rock dynamics and explaining the significance of studying these issues. Loading techniques commonly used for both intermediate and high strain rate tests and measurement techniques for dynamic stress and deformation are critically assessed in Sects. 2 and 3. In Sect. 4, methods of dynamic testing and estimation to obtain stress–strain curves at high strain rate are summarized, followed by an in-depth description of various dynamic mechanical properties (e.g. uniaxial and triaxial compressive strength, tensile strength, shear strength and fracture toughness) and corresponding fracture behaviour. Some influencing rock structural features (i.e. microstructure, size and shape) and testing conditions (i.e. confining pressure, temperature and water saturation) are considered, ending with some popular semi-empirical rate-dependent equations for the enhancement of dynamic mechanical properties. Section 5 discusses physical mechanisms of strain rate effects. Section 6 describes phenomenological and mechanically based rate-dependent constitutive models established from the knowledge of the stress–strain behaviour and physical mechanisms. Section 7 presents dynamic fracture criteria for quasi-brittle materials. Finally, a brief summary and some aspects of prospective research are presented.

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Citations
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Journal ArticleDOI
TL;DR: In this paper, a detailed review of the detailed procedures and principles of techniques for dynamic rock tests using split Hopkinson bars is presented, followed by the key loading techniques that are useful for dynamic tests with SHPB (i.e., pulse shaping, momentum-trap and multi-axial loading techniques).
Abstract: Dynamic properties of rocks are important in a variety of rock mechanics and rock engineering problems. Due to the transient nature of the loading, dynamic tests of rock materials are very different from and much more challenging than their static counterparts. Dynamic tests are usually conducted using the split Hopkinson bar or Kolsky bar systems, which include both split Hopkinson pressure bar (SHPB) and split Hopkinson tension bar (SHTB) systems. Significant progress has been made on the quantification of various rock dynamic properties, owing to the advances in the experimental techniques of SHPB system. This review aims to fully describe and critically assess the detailed procedures and principles of techniques for dynamic rock tests using split Hopkinson bars. The history and principles of SHPB are outlined, followed by the key loading techniques that are useful for dynamic rock tests with SHPB (i.e. pulse shaping, momentum-trap and multi-axial loading techniques). Various measurement techniques for rock tests in SHPB (i.e. X-ray micro computed tomography (CT), laser gap gauge (LGG), digital image correlation (DIC), Moire method, caustics method, photoelastic coating method, dynamic infrared thermography) are then discussed. As the main objective of the review, various dynamic measurement techniques for rocks using SHPB are described, including dynamic rock strength measurements (i.e. dynamic compression, tension, bending and shear tests), dynamic fracture measurements (i.e. dynamic imitation and propagation fracture toughness, dynamic fracture energy and fracture velocity), and dynamic techniques for studying the influences of temperature and pore water.

356 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluate the thermal effects on the geophysical properties of granite and show that the dynamic strength decreases linearly as temperature increases but increases as the impact pressure increases.

212 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of water content on mechanical properties of sandstone specimens with different water contents in both saturation and drying processes was investigated using the Nuclear Magnetic Resonance (NMR) technique.
Abstract: Water content has a pronounced influence on the properties of rock materials, which is responsible for many rock engineering hazards, such as landslides and karst collapse. Meanwhile, water injection is also used for the prevention of some engineering disasters like rock-bursts. To comprehensively investigate the effect of water content on mechanical properties of rocks, laboratory tests were carried out on sandstone specimens with different water contents in both saturation and drying processes. The Nuclear Magnetic Resonance technique was applied to study the water distribution in specimens with variation of water contents. The servo-controlled rock mechanics testing machine and Split Hopkinson Pressure Bar technique were used to conduct both compressive and tensile tests on sandstone specimens with different water contents. From the laboratory tests, reductions of the compressive and tensile strength of sandstone under static and dynamic states in different saturation processes were observed. In the drying process, all of the saturated specimens could basically regain their mechanical properties and recover its strength as in the dry state. However, for partially saturated specimens in the saturation and drying processes, the tensile strength of specimens with the same water content was different, which could be related to different water distributions in specimens.

192 citations


Cites background from "A Review of Dynamic Experimental Te..."

  • ...Due to the rate dependence of rock materials, the strain rate must be controlled to make the strength more comparable (Zhou et al. 2010; Zhang and Zhao 2014)....

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Journal ArticleDOI
TL;DR: In this article, the impact tests were conducted on sandstone subjected to axial static pre-stresses varying from 0 to 75 MPa by a modified split Hopkinson pressure bar.
Abstract: To deeply understand the rock failure characteristics under actual engineering condition, in which static geo-stress and dynamic disturbance usually act simultaneously, impact tests were conducted on sandstone subjected to axial static pre-stresses varying from 0 to 75 MPa by a modified split Hopkinson pressure bar. The fracturing process of specimens was recorded by a high speed camera. Dynamic parameters of sandstone, such as strain rate, dynamic strength and energy partition were acquired. Fracture mechanisms of pulverized specimens were identified by the method combining the displacement trend line and digital image correlation technique. Moreover, fragments of failed specimens were sieved to obtain the fragment size distribution. Test results revealed that, under the same incident energy, the dynamic compressive strength increases first, then decreases slowly and at last drops rapidly with the increase of pre-stress, and reaches the maximum under 24.4% of uniaxial compressive strength due to the closure of initial defects. Four final patterns were observed, namely intact, axial split, rock burst, and pulverization. The rock burst only occurs when the pre-stress lies in the elastic deformation stage or initial stable crack growth stage and the incident energy is intermediate. For pulverized specimens, the fracture mechanism is transformed into shear/tensile equivalent from tensile-dominated mixed mode as the pre-stress increases. Specimens with 75 MPa pre-stress release strain energy during failure process, contrary to specimens with lower pre-stresses absorbing energy from outside. The crushing degree of pulverized specimens exhibits a positive correlation with the pre-stress as a consequence of higher damage development in rock.

185 citations

Journal ArticleDOI
TL;DR: In this paper, the failure behaviors of different rock types (granite, red sandstone, and cement mortar) were investigated using a novel testing system coupled to true-triaxial static loads and local dynamic disturbances.
Abstract: Slabbing/spalling and rockburst are unconventional types of failure of hard rocks under conditions of unloading and various dynamic loads in environments with high and complex initial stresses. In this study, the failure behaviors of different rock types (granite, red sandstone, and cement mortar) were investigated using a novel testing system coupled to true-triaxial static loads and local dynamic disturbances. An acoustic emission system and a high-speed camera were used to record the real-time fracturing processes. The true-triaxial unloading test results indicate that slabbing occurred in the granite and sandstone, whereas the cement mortar underwent shear failure. Under local dynamically disturbed loading, none of the specimens displayed obvious fracturing at low-amplitude local dynamic loading; however, the degree of rock failure increased as the local dynamic loading amplitude increased. The cement mortar displayed no failure during testing, showing a considerable load-carrying capacity after testing. The sandstone underwent a relatively stable fracturing process, whereas violent rockbursts occurred in the granite specimen. The fracturing process does not appear to depend on the direction of local dynamic loading, and the acoustic emission count rate during rock fragmentation shows that similar crack evolution occurred under the two test scenarios (true-triaxial unloading and local dynamically disturbed loading).

180 citations


Cites background from "A Review of Dynamic Experimental Te..."

  • ...…al. 2013; Nasseri et al. 2014), different excavation rates (Tao et al. 2012; Zhao et al. 2014), dynamic loading (Okubo et al. 1997; Li et al. 2005; Zhang and Zhao 2014b), dynamic uniaxial cyclic loading (Bagde and Petroš 2005; Kittitep and Decho 2005; Tang et al. 2014), and true-triaxial…...

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  • ...The mechanical behavior of rocks under triaxial quasi-static and dynamic loading conditions has attracted widespread attention in the field of rock engineering and was critically reviewed by Jaeger et al. (2009) and Zhang and Zhao (2014a)....

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References
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Book
27 Sep 1994
TL;DR: In this paper, the authors present a method to produce dynamic deformation at high strain rates by using Shear Bands (Thermoplastic Shear Instabilities) and dynamic fracture.
Abstract: Dynamic Deformation and Waves. Elastic Waves. Plastic Waves. Shock Waves. Shock Waves: Equations of State. Differential Form of Conservation Equations and Numerical Solutions to More Complex Problems. Shock Wave Attenuation, Interaction, and Reflection. Shock Wave-Induced Phase Transformations and Chemical Changes. Explosive-Material Interactions. Detonation. Experimental Techniques: Diagnostic Tools. Experimental Techniques: Methods to Produce Dynamic Deformation. Plastic Deformation at High Strain Rates. Plastic Deformation in Shock Waves. Shear Bands (Thermoplastic Shear Instabilities). Dynamic Fracture. Applications. Indexes.

2,609 citations


"A Review of Dynamic Experimental Te..." refers methods in this paper

  • ...In this study, impact loading studies are not included; the interested reader is referred to the excellent book by Meyers (1994) and critical review by Field et al. (2004) for the general principle and experimental techniques, and a recent PhD thesis (Braithwaite 2009) for knowledge of impact…...

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Journal ArticleDOI
01 Nov 1949
TL;DR: In this article, a method of determining the stress-strain relation of materials when stresses are applied for times of the order of 20 microseconds is described, using a modification of the Hopkinson pressure bar and detonators were used to produce large transient stresses.
Abstract: A method of determining the stress-strain relation of materials when stresses are applied for times of the order of 20 microseconds is described. The apparatus employed was a modification of the Hopkinson pressure bar, and detonators were used to produce large transient stresses. Thin specimens of rubbers, plastics and metals were investigated and the compressions produced were as high as 20% with the softer materials. It was found that whilst Perspex recovered almost as soon as the stress was removed, rubbers and polythene showed delayed recovery, and copper and lead showed irrecoverable flow. The phenomenon of delayed recovery is discussed in terms of the theory of mechanical relaxation and memory effects in the material.

2,596 citations


"A Review of Dynamic Experimental Te..." refers methods in this paper

  • ...…of rock materials has been extensively studied; in particular, significant progress in experimental methodology has been made with the advent of HSR loading techniques starting from the work of Kolsky (1949), as well as high-speed and high-resolution measurement techniques (Perkins and Green 1968)....

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  • ...2.2 Techniques for High Strain Rate Testing One of the most widely used loading techniques at HSR is the split Hopkinson bar (SHB), or the Kolsky bar developed by Kolsky (1949)....

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Book
26 Mar 2009
TL;DR: In this paper, a comprehensive overview of image correlation for shape, motion and deformation measurements is provided. But, the authors do not discuss the effect of out-of-plane motion on 2D measurements.
Abstract: Image Correlation for Shape, Motion and Deformation Measurements provides a comprehensive overview of data extraction through image analysis. Readers will find and in-depth look into various single- and multi-camera models (2D-DIC and 3D-DIC), two- and three-dimensional computer vision, and volumetric digital image correlation (VDIC). Fundamentals of accurate image matching are described, along with presentations of both new methods for quantitative error estimates in correlation-based motion measurements, and the effect of out-of-plane motion on 2D measurements. Thorough appendices offer descriptions of continuum mechanics formulations, methods for local surface strain estimation and non-linear optimization, as well as terminology in statistics and probability. With equal treatment of computer vision fundamentals and techniques for practical applications, this volume is both a reference for academic and industry-based researchers and engineers, as well as a valuable companion text for appropriate vision-based educational offerings.

2,454 citations

Journal ArticleDOI
TL;DR: In this paper, an experiment was designed to check the equivalence of the effects of changes in strain rate and in temperature on the stress-strain relation in metal deformation.
Abstract: An experiment has been designed to check a previously proposed equivalence of the effects of changes in strain rate and in temperature upon the stress‐strain relation in metals. It is found that this equivalence is valid for the typical steels investigated. The behavior of these steels at very high rates of deformation may, therefore, be obtained by tests at moderate rates of deformation performed at low temperatures. The results of such tests are described. Aside from changing the isothermal stress‐strain relation, an increase of strain rate tends to change the conditions from isothermal to adiabatic. It is found that at low temperatures, the adiabatic stress‐strain relation in the plastic range is radically different from the isothermal, having an initial negative rather than a positive slope. This initial negative slope renders unstable homogeneous plastic deformation.

2,263 citations

Journal ArticleDOI
TL;DR: In this paper, a self-consistent method for the elastic moduli of bodies containing randomly distributed flat cracks, with or without fluid in their interiors, is proposed and general concepts are outlined for arbitrary cracks and explicit derivations together with numerical results are given.

1,840 citations