A large diameter split Hopkinson pressure bar for testing rocks

Cellular materials such as wood are widely and advantageously used as shock absorbers in various transport applications. The design and manufacturing of structures made of these materials require the knowledge of their dynamic compressive properties at various strain rates and stress states. Therefore, it is challenging to conduct dynamic multiaxial stress state experiments and especially on split-Hopkinson pressure bar apparatus where stress hardening increases as a function of velocity. This paper presents the so-called verification and validation methodology for confining solutions dedicated to impact on viscoelastic split-Hopkinson pressure bar system with large diameter bars. The method is a hybrid approach combining finite element analysis and an original experimental validation. Based on finite element results, particular attention is given to the mass, the material and the geometry to minimize the confining device influence on the propagation of elastic waves and thus on the material response of the tested specimens. It is essential to avoid spurious reflected waves at the new interfaces of the system in order to ensure the validity of the experimentation. The numerically predicted solutions are experimentally validated and preliminary results in the context of dynamic loadings using wood material are presented.

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Ø100mm SHPB Equipment and its Application

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.99-100.891 ◽

2011 ◽

Vol 99-100 ◽

pp. 891-895

Author(s):

Zhi Gang Zhang ◽

Meng Shen Li ◽

Xiao Long Wang ◽

Xiao Lei Zhong ◽

Qing Li

Keyword(s):

Performance Index ◽

Split Hopkinson Pressure Bar ◽

Large Diameter ◽

Hopkinson Pressure Bar ◽

Study Material ◽

Split Hopkinson ◽

And Performance ◽

Pressure Bar ◽

Further Development ◽

Nonhomogeneous Materials

Hopkinson Pressure Bar (HPB) is one of the main sets to study material dynamic mechanic properties. Large diameter HPB is mainly used for nonhomogeneous materials. In this paper the properties of Split Hopkinson Pressure Bar (SHPB) of Ø100mm are introduced, including its structure and performance index. The main problems of large diameter SHPB are analyzed. The further development and application of SHPB are also explored.

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Influence of Early Age on the Wave Velocity and Dynamic Compressive Strength of Concrete Based on Split Hopkinson Pressure Bar Tests

Shock and Vibration ◽

10.1155/2018/8206287 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Shiming Wang ◽

Longjun Dong ◽

Jian Zhou

Keyword(s):

Critical Incident ◽

Incident Energy ◽

Split Hopkinson Pressure Bar ◽

Large Diameter ◽

Threshold Value ◽

Early Age ◽

Uniaxial Compression Test ◽

Hopkinson Pressure Bar ◽

Split Hopkinson ◽

Pressure Bar

The effect of early age on the mechanical properties of concrete was investigated in this study. A uniaxial compression test was performed on split Hopkinson pressure bar (SHPB) equipment with a large diameter of 75 mm. The experimental results indicated that before 7 days, concrete showed viscoelasticity and had good deformation ability and low sensitivity to incident energy. In addition, the concrete exhibited the characteristics of quasi-brittle materials, and the sensitivity of the incident energy improved with age. The threshold value of the incident energy at early ages had an insignificant effect on the stable age concrete. The threshold value was 50% of the corresponding age’s critical incident energy, while it was 75% after 7 days.

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Analysis of the Impact of the Frequency Range of the Tensometer Bridge and Projectile Geometry on the Results of Measurements by the Split Hopkinson Pressure Bar Method

Metrology and Measurement Systems ◽

10.2478/mms-2013-0047 ◽

2013 ◽

Vol 20 (4) ◽

pp. 555-564 ◽

Cited By ~ 12

Author(s):

Wojciech Moćko

Keyword(s):

Test Bench ◽

Split Hopkinson Pressure Bar ◽

Dynamic Deformation ◽

Spectral Width ◽

Hopkinson Pressure Bar ◽

Computing Environment ◽

Split Hopkinson ◽

Pressure Bar ◽

The Impact ◽

Bench Model

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient

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