Characterization of three Himalayan rocks using a split Hopkinson pressure bar

Chakraborty, Tanusree; Mishra, SK; Loukus, Josh; Halonen, Brent; Bekkala, Brady

doi:10.1016/j.ijrmms.2016.03.005

Cited by 58 publications

(19 citation statements)

References 27 publications

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“…Wave theory is adopted to express the stress‐strain curve of the coal material:

({, \begin{matrix} γ ()(, t) = \frac{C_{b}}{L_{s}} ()(, ε_{i} - ε_{r} - ε_{t}) \\ ε ()(, t) = \frac{C_{b}}{L_{s}} \int_{0}^{t} (ε_{i} - ε_{r} - ε_{t}) d t \\ σ ()(, t) = \frac{A_{b}}{2 A_{s}} E_{b} ()(, ε_{i} + ε_{r} + ε_{t}) \end{matrix})

where γ is strain rate; E b is elastic modulus of the pressure bar, GPa; C b is the velocity of the stress wave in the pressure bar, m/s; A b is the cross‐sectional area of the pressure bar, m 2 ; A s is the original cross‐sectional area of the coal specimen, m 2 ; and L s is the length of coal specimen, m.…”

Section: Experimental Setup and Observationsmentioning

confidence: 99%

“…5 Dynamic properties of interest include the following: density, wave velocity, porosity, strength, scale effect, bedding effect, the influence of moisture, and energy dissipation. 15,[33][34][35][36][37][38][39][40][41][42][43][44][45] Very high loading rate dynamic tests are usually conducted by using split Hopkinson pressure bar (SHPB) systems, 30,46 to determine dynamic properties of brittle materials including concretes, ceramics, rocks, and coals under wide range of impact loadings or strain rates of 10 1 -10 4 /s. [47][48][49][50][51][52][53] For determination of dynamic properties of different coals, the principal attributes are to recovery the dynamic magnitudes of Young's modulus and compressive/tensile strength based on the stress-strain curves at very high strain rates.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Fan

Elsworth

et al. 2019

Energy Science & Engineering

106

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We report laboratory experiments to investigate the dynamic failure characteristics of outburst‐prone coal using a split Hopkinson pressure bar (SHPB). For comparison, two groups of experiments are completed on contrasting coals—the first outburst‐prone and the second outburst‐resistant. The dynamic mechanical properties, failure processes, and energy dissipation of both outburst‐prone and outburst‐resistant coals are comparatively analyzed according to the obtained dynamic compressive and tensile stress‐strain curves. Results show that the dynamic stress‐strain response of both outburst‐prone and outburst‐resistant coal specimens comprises stages of compression, linear elastic deformation, then microfracture evolution, followed by unstable fracture propagation culminating in rapid unloading. The mechanical properties of both outburst‐prone and outburst‐resistant coal specimens exhibit similar features: The uniaxial compressive strength and indirect tensile strength increase linearly with the applied strain rate, and the peak strain increases nonlinearly with the strain rate, whereas the elastic modulus does not exhibit any clear strain rate dependency. Differences in the dynamic failure characteristics between outburst‐prone and outburst‐resistant coals also exist. The hardening effect of strain rate on outburst‐prone coal is more apparent than on outburst‐resistant coal, which is reflected in the dynamic increase factor at the same strain rate. However, the dynamic strength of outburst‐prone coals is still lower than that of outburst‐resistant coals due to its low quasi‐static strength. The dissipated energy of outburst‐prone coal is smaller than that of outburst‐resistant coal. Therefore, the outburst‐prone coal, characterized by low strength, high deformability, and small energy dissipation when dynamically loaded to failure, is more favorably disposed to the triggering and propagation of gas outbursts.

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“…Wave theory is adopted to express the stress‐strain curve of the coal material:

({, \begin{matrix} γ ()(, t) = \frac{C_{b}}{L_{s}} ()(, ε_{i} - ε_{r} - ε_{t}) \\ ε ()(, t) = \frac{C_{b}}{L_{s}} \int_{0}^{t} (ε_{i} - ε_{r} - ε_{t}) d t \\ σ ()(, t) = \frac{A_{b}}{2 A_{s}} E_{b} ()(, ε_{i} + ε_{r} + ε_{t}) \end{matrix})

Section: Experimental Setup and Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Fan

Elsworth

et al. 2019

Energy Science & Engineering

106

View full text Add to dashboard Cite

show abstract

“…In the initial phase of stress wave propagation, the area under the curve (AUC) represents the total impact energy of the bullet. After the specimen was damaged, the residual impact energy was transferred to the transmitted bar or reflected to the incident bar in the form of stress wave [19], creating the transmitted wave and the reflected wave. Most of the residual impact energy is represented by the AUC of the transmitted wave.…”

Section: Energy Absorption Of the Sfrhscmentioning

confidence: 99%

Split-Hopkinson Pressure Bar Test and Numerical Simulation of Steel Fiber-reinforced High-strength Concrete

Ji¹,

Shi²,

He³

et al. 2019

RCMA

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The fabrication and optimization of the shelter layer are critical to the performance of the protective works. The novel shelter layer made of steel fiber-reinforced high-strength concrete (SFRHSC) is much more advantageous than that of ordinary concrete. This paper carries out a split-Hopkinson pressure bar (SHPB) test on the steel fiber and high-strength concrete, two main components of the SFRHSC, aiming to disclose the failure features and dynamic compressive strength of the SFRHSC under dynamic conditions. Specifically, the SFRHSC specimens with 0 %, 0.5 % and 1.0 % of steel fiber were subjected to impact compression test under the air pressures of 0.7, 0.9 and 1.0MPa, respectively. In addition, the impact compression process was also numerically simulated on the finite-element software LS-DYNA. The research results show that: the increase in strain rate pushed up the dynamic compressive strength of the SFRHSC, that is, the failure degree of the specimen was greatly enhanced by the strain rate; under the air pressure of 0.7MPa, the specimen with 1.0 % of steel fiber had the highest dynamic compressive strength (180.9MPa), 22.6 % higher than that of the specimen with no steel fiber; the numerical simulation reproduced the one-dimensional (1D) propagation of the stress wave in the bars, which proves the hypothesis of 1D elastic stress wave, and restaged the impact compression process on the SFRHSC, outputting results similar to the test data. Keywords: steel fiber-reinforced high-strength concrete (SFRHSC), impact compression, strain rate effect, numerical simulation Camouflaged layer Bursting layer Distribution layer Supporting structure Revue des Composites et des Matériaux Avancés

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“…Although Split Hopkinson Pressure Bar (SHPB) test system has been extensively applied in the study of dynamic fracture, the specimen dimension conducted by SHPB is relatively small, and the crack propagation behavior may be affected by reflected waves. In this study, a new test system, i.e.…”

Section: Introductionmentioning

confidence: 99%

The effect of a pre‐existing crack on a running crack in brittle material under dynamic loads

Zhou

Zhu

Wang

et al. 2019

Fatigue Fract Eng Mat Struct

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Brittle material usually contains plenty of cracks or micro‐cracks, which raises a question that how a pre‐existing crack affects a running crack as they are approaching. In order to investigate such issue, impact experiments were conducted by using double crack semi‐circle (DCSC) specimens. Polymethyl methacrylate (PMMA) was selected to make the DCSC specimens, and a modified SHPB system was used to perform the impact tests. The finite difference code AUTODYN was employed to simulate the crack propagation behavior and propagation path, and the simulated crack paths agree well with the impact test results. Meanwhile the stresses around the crack tips were analyzed and the crack propagation direction was investigated. To calculate the crack dynamic stress intensity factors (DSIFs), finite element code ABAQUS was employed. The results show that the spacing D between the vertical crack tip and the inclined crack center affects the stress distribution and fracture behavior of the vertical crack largely. As the vertical crack approaches the inclined crack, the crack speed is slow down, and tensile stress appears at the inclined crack tip. As the spacing D is small than 50 mm, the vertical crack connects with the middle area of the inclined crack. As the spacing D is 50 mm, the vertical crack connects with either the middle area or the upper tip of the inclined crack. As the spacing D is larger than 50 mm, the vertical crack coalesces with the upper crack tip.

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Characterization of three Himalayan rocks using a split Hopkinson pressure bar

Cited by 58 publications

References 27 publications

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Experimental investigation on dynamic strength and energy dissipation characteristics of gas outburst‐prone coal

Split-Hopkinson Pressure Bar Test and Numerical Simulation of Steel Fiber-reinforced High-strength Concrete

The effect of a pre‐existing crack on a running crack in brittle material under dynamic loads

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