Oscillation elimination in the Hopkinson bar apparatus and resultant complete dynamic stress-strain curves for rocks

By Xibing Li, T. Lok, Jian Zhao, P. Zhao. 2000

229 citations recorded by the source corpus.

Abstract This paper highlights an improved experimental approach for eliminating oscillation that exists in the dynamic stress–strain response of rocks and other brittle materials obtained from tests using a split Hopkinson pressure bar (SHPB). Both analytical and experimental results for a number of rock types are presented to verify the idea. Results from the investigation indicate that oscillation in the dynamic stress–strain response of these materials originates from the Pochhammer–Chree dispersion of the loading incident wave, and more evidently from the relatively low strength and elastic modulus of the samples compared with metallic materials. In order to control the oscillation effectively, it is proposed that a half-sine loading waveform should be used instead of the conventional rectangular loading waveform in SHPB tests. Experimental results obtained from both the conventional and the improved methods are presented, including dynamic complete stress–strain curves for granite, sandstone and limestone. The improved method eliminates oscillation in the tests, provides better stability of strain rate and more representative results than those obtained from the conventional rectangular loading waveform shape.

Subfields: Civil and Structural Engineering, Geophysics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/04c9c9a0caf8c3dbfe2652e5f451d19ccb7a07ed

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Civil and Structural Engineering

1. Qianbing Zhang
2. Jian Zhao
3. Zilong Zhou
4. Xibing Li
5. Y. Zou
6. Feng Dai
7. Yuan Xu
8. Guowei Ma

In Geophysics

1. Qianbing Zhang
2. Jian Zhao
3. Feng Dai
4. Yuan Xu
5. Xibing Li
6. Zilong Zhou
7. Y. Zou
8. Kaiwen Xia

In Materials Chemistry

1. Qianbing Zhang
2. Jian Zhao
3. Xibing Li
4. Zilong Zhou
5. Y. Zou
6. Feng Dai
7. Kaiwen Xia
8. Yuan Xu

Citations in the corpus

• Numerical Simulation of the Rock SHPB Test with a Special Shape Striker Based on the Discrete Element Method (2014, methodology): “(1) difficulty in achieving stress uniformity and equilibrium in the specimen; (2) premature failure of the specimen before stress equilibrium; (3) high oscillation of the incident wave; and (4) difficulty in ensuring the specimen’s deformation at a constant strain rate (Lok et al. 2002; Frew et al.”
• Dynamic Response and Failure Mechanism of Brittle Rocks Under Combined Compression-Shear Loading Experiments (2018, methodology): “2010), or alternatively using a shaped striker (Christensen et al. 1972; Li et al. 2000).”
• Determination of mechanical properties and full-field strain measurements of rock material under dynamic loads (2013, methodology): “Two kinds of pulse shaping techniques, the pulse shaper [24] and a cone-shaped striker [5,25,26], have been used to reduce wave dispersion effect and overcome premature failure of specimen using traditional SHPB [27].”
• Suggested Methods for Determining the Dynamic Strength Parameters and Mode-I Fracture Toughness of Rock Materials (2012, background): “1, consists of a striker bar, an input bar, an output bar, a damper, a gas gun and a data acquisition unit [1–3].”
• A Review of Dynamic Experimental Techniques and Mechanical Behaviour of Rock Materials (2014, methodology): “Analytical, numerical and experimental corrections for wave dispersion were first proposed for testing of ductile materials by Follansbee and Frantz (1983) and Gorham (1983), for concrete by Gong et al. (1990) and for rock by Li et al. (2000b).”
• Dynamic Characteristics of Granite Subjected to Intermediate Loading Rate (2005, methodology): “Further investigation by the authors shows that the half-sine loading waveform enables the test material to be in a state of uniform stress or strain during the entire loading duration (Li et al., 2000; Lok et al., 2002; Li et al., 2001).”