An Experimental Method for considering Dispersion and Attenuation in a         Viscoelastic Hopkinson Bar

Bacon, C.

doi:10.1177/001448519803800402

Cited by 45 publications

(62 citation statements)

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“…However, as PMMA is a viscoelastic material and the wave dispersion effect cannot be neglected when stress wave propagates in the bar, the signals need correction before being used. Bacon [5] developed an experimental method to correct the dispersion effect. If the lateral motion can be neglected in a straight cylindrical bar, the normal stress σ (x, t) and the longitudinal strain ε(x, t) are related to the axial displacement u(x, t) at cross-section x and at time t by ∂σ (x, t)…”

Section: Experimental Methodsmentioning

confidence: 99%

Indentation of aluminium foam at low velocity

Shi

Miao

Liu

et al. 2015

EPJ Web of Conferences

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Abstract. The indentation behaviour of aluminium foams at low velocity (10 m/s ∼ 30 m/s) was investigated both in experiments and numerical simulation in this paper. A flat-ended indenter was used and the force-displacement history was recorded. The Split Hopkinson Pressure bar was used to obtain the indentation velocity and forces in the dynamic experiments. Because of the low strength of the aluminium foam, PMMA bar was used, and the experimental data were corrected using Bacon's method. The energy absorption characteristics varying with impact velocity were then obtained. It was found that the energy absorption ability of aluminium foam gradually increases in the quasi-static regime and shows a significant increase at ∼10 m/s velocity. Numerical simulation was also conducted to investigate this process. A 3D Voronoi model was used and models with different relative densities were investigated as well as those with different failure strain. The indentation energy increases with both the relative density and failure strain. The analysis of the FE model implies that the significant change in energy absorption ability of aluminium foam in indentation at ∼10 m/s velocity may be caused by plastic wave effect.

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Section: Experimental Methodsmentioning

confidence: 99%

Indentation of aluminium foam at low velocity

Shi

Miao

Liu

et al. 2015

EPJ Web of Conferences

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“…titanium, magnesium alloy or aluminum, or a polymer, e.g. polymethylmethacrylate (PMMA), PC, or nylon [77][78][79][80][81][82][83][84][85][86][87][88]. Low impedance metallic bars do not require any changes to the experimental apparatus or data reduction.…”

Section: Dynamic Loading: Split Hopkinson Pressure Barmentioning

confidence: 99%

High Strain Rate Mechanics of Polymers: A Review

Siviour

Jordan

2016

J. dynamic behavior mater.

265

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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“…The data were used to calculate the experimentally determined wave transfer function and wave propagation coefficient in frequency domain, according to Bacon's method and its modification. [34,35] Wave propagation coefficient was calculated separately for incident and transmission bars using "bars together" and "incident bar apart" void tests.…”

Section: Shpb Data Processingmentioning

confidence: 99%

Impact Testing of Polymer‐filled Auxetics Using Split Hopkinson Pressure Bar

et al. 2017

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In this paper, impact testing of auxetic structures filled with strain rate sensitive material is presented. Two dimensional missing rib, 2D re-entrant honeycomb, and 3D re-entrant honeycomb lattices are investigated. Structures are divided into three groups according to type of filling: no filling, low expansion polyurethane foam, and ordnance gelatine. Samples from each group are tested under quasistatic loading and dynamic compression using Split Hopkinson Pressure Bar. Digital image correlation is used for assessment of in-plane displacement and strain fields. Ratios between quasistatic and dynamic results for plateau stresses and specific energy absorption in the plateau are calculated. It is found out that not only the manufactured structures, but also the wrought material exhibit strain rate dependent properties. Evaluation of influence of filling on mechanical properties shows that polyurethane increases specific absorbed energy by a factor of 1.05-1.4, whereas the effect of gelatine leads to increase of only 5-10%. Analysis of the Poisson's function reveals influence of filling on achievable (negative) values of Poisson's ratio, when compared to unfilled specimens. The results for the Poisson's function yielded apparently different values as the assessed minima of quasi-static Poisson's ratio in small deformations are constrained by a factor of 15.

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An Experimental Method for considering Dispersion and Attenuation in a Viscoelastic Hopkinson Bar

Cited by 45 publications

References 0 publications

Indentation of aluminium foam at low velocity

Indentation of aluminium foam at low velocity

High Strain Rate Mechanics of Polymers: A Review

Impact Testing of Polymer‐filled Auxetics Using Split Hopkinson Pressure Bar

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