A split Hopkinson bar technique for low-impedance materials

Chen, W.; Zhang, B.; Forrestal, M. J.

doi:10.1007/bf02331109

Cited by 330 publications

(169 citation statements)

References 11 publications

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“…Increasing the cross-sectional area of the specimens to obtain a larger signal poses difficulties since it would require larger bars, which may be prohibited by the available laboratory facilities. Chen et al [76] pioneered the use of hollow, aluminum transmitted bars. Using aluminum reduces the impedance of the bar material itself, and the hollow bar provides a reduced cross-sectional area.…”

Section: Dynamic Loading: Split Hopkinson Pressure Barmentioning

confidence: 99%

“…However, rubbers were some of the first materials to be characterized in split Hopkinson bar experiments [1,2], and more recently a number of authors have proposed techniques to address these difficulties through modifications to the Hopkinson bar or other similar systems [57,66]. These include pulse shaping [62], low impedance Hopkinson bar materials to increase the transmitted force [76,77,81,82,148] or use of more sensitive force gauges to directly measure the force at the specimen bar interface [62][63][64]. Longer Hopkinson bars may be used to increase the duration of the experiment [53], as can direct impact systems [149], in addition, if stress gauges are combined with optical measurements of specimen deformation, the experiment duration is no longer limited by wave overlapping in the bars and longer durations can be achieved [150].…”

Section: Rubbery Amorphous Polymersmentioning

confidence: 99%

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High Strain Rate Mechanics of Polymers: A Review

Siviour

Jordan

2016

J. dynamic behavior mater.

285

121

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The mechanical properties of polymers are becoming increasingly important as they are used in structural applications, both on their own and as matrix materials for composites. It has long been known that these mechanical properties are dependent on strain rate, temperature, and pressure. In this paper, the methods for dynamic loading of polymers will be briefly reviewed. The high strain rate mechanical properties of several classes of polymers, i.e. glassy and rubbery amorphous polymers and semi-crystalline polymers will be reviewed. Additionally, time-temperature superposition for rate dependent large strain properties and pressure dependence in polymers will be discussed. Constitutive modeling and shock properties of polymers will not be discussed in this review.

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Section: Dynamic Loading: Split Hopkinson Pressure Barmentioning

confidence: 99%

Section: Rubbery Amorphous Polymersmentioning

confidence: 99%

High Strain Rate Mechanics of Polymers: A Review

Siviour

Jordan

2016

J. dynamic behavior mater.

285

121

View full text Add to dashboard Cite

show abstract

“…This configuration works better than the configuration by Chen [7], where the front end reflections interfere adversely with the sample, causing ringing in the data, which cannot be corrected. These configurations are shown in As a result of replacement of solid bar with hollow bar, the signal at the transmitter bar is doubled.…”

Section: Methodsmentioning

confidence: 91%

High strain rate behavior of polyurea compositions

Joshi¹,

Milby²

2012

AIP Conference Proceedings

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Estimation of two-dimensional strain rate based on high frame rate ultrasound imaging method Proceedings of Meetings on Acoustics 14, 020001 (2011) Abstract. High-strain-rate response of three polyurea compositions with varying molecular weights has been investigated using a Split Hopkinson Pressure Bar arrangement equipped with aluminum bars. Three polyurea compositions were synthesized from polyamines (Versalink, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Amines with molecular weights of 1000, 650, and a blend of 250/1000 have been used in the current investigation. These materials have been tested to strain rates of over 6000/s. High strain rate results from these tests have shown varying trends as a function of increasing strain. While higher molecular weight composition show lower yield, they do not show dominant hardening behavior at lower strain. On the other hand, the blend of 250/1000 show higher load bearing capability but lower strain hardening effects than the 600 and 1000 molecular weight amine based materials. Results indicate that the initial increase in the modulus of the blend of 250/1000 may lead to the loss of strain hardening characteristics as the material is compressed to 50% strain, compared to 1000 molecular weight amine based material.

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“…Hence, the effective use of a rubber can only be achieved when its dynamic mechanical properties are well characterized. Several studies have included high speed experiments on rubbers in compression and tension using the split Hopkinson bars [2][3][4] and newly developed techniques [5,6]. Although many improvements have been made to this traditional technique, the inherent softness of rubber produces experimental difficulties in achieving precise force measurements and a static stress equilibrium state.…”

Section: Introductionmentioning

confidence: 99%

The dynamic Virtual Fields Method on rubbers at medium and high strain rates

Yoon

Siviour

2015

EPJ Web of Conferences

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Abstract. Elastomeric materials are widely used for energy absorption applications, often experiencing high strain rate deformations. The mechanical characterization of rubbers at high strain rates presents several experimental difficulties, especially associated with achieving adequate signal to noise ratio and static stress equilibrium, when using a conventional technique such as the split Hopkinson pressure bar. In the present study, these problems are avoided by using the dynamic Virtual Fields Method (VFM) in which acceleration fields, clearly generated by the non-equilibrium state, are utilized as a force measurement with in the frame work of the principle of virtual work equation. In this paper, two dynamic VFM based techniques are used to characterise an EPDM rubber. These are denoted as the linear and nonlinear VFM and are developed for (respectively) medium (drop-weight) and high (gas-gun) strain-rate experiments. The use of the two VFMs combined with high-speed imaging analysed by digital imaging correlation allows the identification of the parameters of a given rubber mechanical model; in this case the Ogden model is used.

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A split Hopkinson bar technique for low-impedance materials

Cited by 330 publications

References 11 publications

High Strain Rate Mechanics of Polymers: A Review

High Strain Rate Mechanics of Polymers: A Review

High strain rate behavior of polyurea compositions

The dynamic Virtual Fields Method on rubbers at medium and high strain rates

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