Dynamic Brazilian Test of Rock Under Intermediate Strain Rate: Pendulum Hammer-Driven SHPB Test and Numerical Simulation

Zhu, Wancheng; Niu, Leilei; Li, S. H.; Xu, Zigan

doi:10.1007/s00603-014-0677-7

Cited by 77 publications

(17 citation statements)

References 31 publications

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“…According to Hertz contacting theory, Zou et al [37] have presented a nonlinear theory model of partial deformation on longitudinally impacted surfaces of bars to theoretically analyze the hammer impact process and, based on the principle of one-dimensional wave propagation, a one-dimensional stress wave program has been developed [35] to simulate wave propagation in rock specimens and bars during SHPB tests driven by a pendulum hammer (Figure 3).…”

Section: The Parameter Analysismentioning

confidence: 99%

Constant Strain Rate Uniaxial Compression of Green Sandstone during SHPB Tests Driven by Pendulum Hammer

Zhu

Niu

et al. 2017

Shock and Vibration

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During the Split-Hopkinson pressure bar (SHPB) tests driven by pendulum hammer, employing a proper special shape striker is an effective way to obtain dynamic stress equilibrium condition and to get constant strain rate of the rock specimen. To find the proper special shape striker, a striker with a cambered surface was introduced and eight geometrically different hammers were designed to analyze the effect of hammer geometry on the waveform of excited incident stress waves. Based on experiments and simulations, parameter effects, including the cambered hammer curvature radius and hammer diameter, length, and impact velocity, on the incident wave shape were examined. These parametric studies provided guidelines for achieving constant strain rates in rock specimens during SHPB tests. The use of different diameter hammers was noted for shaping stress-time curves to follow the stress-strain behavior of green sandstone. Finally, to examine the applicability of using hammer geometry for shaping incident waves to achieve constant strain rate, SHPB tests on green sandstone specimens were conducted. The results demonstrated that a constant strain rate (100 s −1 ) lasting for 70 s was achieved with the 8# hammer (3.7 kg; curvature radius, diameter, and length of 100, 70, and 126.3 mm, resp.). In addition, dynamic experiments on green sandstone were carried out under various strain rates and the results showed that the initial tangential modulus was almost unaffected by strain rate. The strain at peak stress tended to increase with rising strain rate and the dynamic strength of green sandstone showed an apparent rate dependency.

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Section: The Parameter Analysismentioning

confidence: 99%

Constant Strain Rate Uniaxial Compression of Green Sandstone during SHPB Tests Driven by Pendulum Hammer

Zhu

Niu

et al. 2017

Shock and Vibration

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“…With respect to the logarithmic scale of strain rate, the strength increases slowly at a lower strain rate, but after a critical strain rate, the strength increases sharply, as shown in Figure . The critical strain rate depends on the type of rock and is generally in the range of 10 −1 and 10 3 s −1, which coincides with the range of intermediate strain rates . The dynamic behaviour of rocks within this range of strain rates is, therefore, the focus of this work, and the understanding of such behaviour can help predict the critical strain rate.…”

Section: Introductionmentioning

confidence: 87%

A particle mechanics approach for the dynamic strength model of the jointed rock mass considering the joint orientation

Zhou

Karakus

et al. 2019

Num Anal Meth Geomechanics

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Summary In nature, there exist several forms of anisotropy in rock masses due to the presence of bedding planes, joints, and weak layers. It is well understood that the anisotropic properties of jointed rock masses significantly affect the stability of surface and underground excavations. However, these critical anisotropic characteristics are often ignored in existing uniaxial dynamic failure criteria. This study investigates the effect of a pre‐existing persistent joint on the rate‐dependent mechanical behaviours of a rock mass using a particle mechanics approach, namely, bonded particle model (BPM), to realistically replicate the mechanical response of the rock mass. Firstly, in order to capture the rate‐dependent response of the jointed rock mass, the BPM model is validated using published experimental data. Then, a dynamic strength model is proposed based on the Jaeger criterion and simulation results. To further investigate the dynamic behaviours, the dynamic uniaxial compressive strength (UCS) for anisotropic rock masses with various joint orientations is investigated by subjecting the BPM models to uniaxial compression numerical tests with various strain rate. The proposed dynamic strength model is validated based on numerical simulation results. Finally, the fragmentation characteristics of the jointed rock masses are analysed, which demonstrate that the failure mode affects the dynamic UCS. This is further confirmed by the analysis of the orientations of microscopic cracks generated by the compression loading.

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“…e pneumatichydraulic testing machine has been developed for studying the strain rate ranging from 10 0 s −1 to 10 1 s −1 , and dropweight machines have been used to achieve strain rate ranging from 10 0 s −1 to 10 2 s −1 [15]. e dynamic Brazilian test of rock specimens was conducted with the pendulum hammer-driven SHPB test in order to determine the tensile strength of rock under an intermediate strain rate ranging from 5.2 to 12.9 s −1 [101].…”

Section: Rock Damage and Failure Induced By Dynamic Loadingmentioning

confidence: 99%

Numerical Simulation on Damage and Failure Mechanism of Rock under Combined Multiple Strain Rates

Zhu

Wei

Niu

et al. 2018

Shock and Vibration

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During underground hard-rock mining, the drilling and blasting method currently remains the most economical excavation method, and the rock may experience a multistrain-rate spectrum under quasi-static, dynamic, and rheological loading conditions and their combination as well. The study on the damage mechanism of rock under multistrain-rate condition that induced by mining excavation is the fundamental issue for predicting the mining-induced hazards such as rockburst. In this study, the state of the art of rock damage and failure under different strain rates is reviewed first. Then, the numerical model for rock failure under multiple strain rates is formulated when the rock damage is taken as the main thread. Meanwhile, we summarize our work in this area over the past ten years, and the constitutive law for the damage and failure of rock under multistrain rates is presented. Finally, several numerical examples, i.e., rock damage and failure under combined static and dynamic load, rock damage and failure triggered by dynamic stress redistribution due to excavation, rock damage and failure induced by blasting, and rock damage and failure due to the combination of dynamic disturbance and rheological load, are presented. Based on these numerical simulations, the associated rock damage mechanism and failure behaviors under differently combined multiple strain rates are clarified, which may provide a theoretical basis for clarifying the rock failure mechanism during rockbursts and rock blasting. Also, further studies on the damage and failure of rock under multiple strain rates are suggested.

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Dynamic Brazilian Test of Rock Under Intermediate Strain Rate: Pendulum Hammer-Driven SHPB Test and Numerical Simulation

Cited by 77 publications

References 31 publications

Constant Strain Rate Uniaxial Compression of Green Sandstone during SHPB Tests Driven by Pendulum Hammer

Constant Strain Rate Uniaxial Compression of Green Sandstone during SHPB Tests Driven by Pendulum Hammer

A particle mechanics approach for the dynamic strength model of the jointed rock mass considering the joint orientation

Numerical Simulation on Damage and Failure Mechanism of Rock under Combined Multiple Strain Rates

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