Dynamic shear properties of some rubber-like materials

Fletcher, W. P.; Gent, A. N.

doi:10.1088/0508-3443/8/5/303

Cited by 20 publications

(18 citation statements)

References 18 publications

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“…Results from Nashif & Lewis (1991) are also compared in the figure but the curves were read at 500 Hz. The G ′ value of Nashif et al (1985) is higher by a factor of 3 than that from Fletcher & Gent (1973). The loss factors also differ considerably but all are well above the required minimum.…”

Section: Butyl Rubber (Iir)mentioning

confidence: 86%

“…The dynamic properties of butyl rubber in the ranges of temperature and frequency mentioned previously for the rail absorber are given by Fletcher & Gent (1973); Nashif et al (1985). Figure 2.42 shows the dynamic properties from Nashif et al (1985) and Fletcher & Gent (1973) at 1000 Hz for temperatures -20 to 40 .…”

Section: Butyl Rubber (Iir)mentioning

confidence: 94%

“…On the other hand, reinforcing fillers such as carbon black with small particle size and silica are used in both natural and synthetic rubber to improve their physical properties. Rubber containing reinforcing filler exhibits some non-linear characteristics (Fletcher & Gent, 1973). The hysteresis loops (Lindley, 1992).…”

Section: Filler Reinforcementmentioning

confidence: 99%

“…Figure 2.42 shows the dynamic properties from Nashif et al (1985) and Fletcher & Gent (1973) at 1000 Hz for temperatures -20 to 40 . Results from Nashif & Lewis (1991) are also compared in the figure but the curves were read at 500 Hz.…”

Section: Butyl Rubber (Iir)mentioning

confidence: 99%

“…The shear modulus from (Nashif et al, 1985) and Nashif & Lewis (1991) were calculated using interpolation from the master curve, while the shear modulus from Fletcher & Gent (1973) is calculated using time temperature superposition. Ideally they should give similar behaviour; the source of this discrepancy is not known.…”

Section: Butyl Rubber (Iir)mentioning

confidence: 99%

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A methodology for developing high damping materials with application to noise reduction of railway track

Ahmad

2009

The Journal of the Acoustical Society of America

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For application in damping treatments, elastomeric materials should have a high damping loss factor, but this is inevitably linked to a strong temperature-dependence of the dynamic properties. A methodology is developed that allows a material to be formulated for a particular damping application where temperature-dependence has to be taken into account. The methodology is applied to the case of a tuned absorber system used for damping the vibration of a railway track. This is required to be effective over a temperature range -20 to 40 .To investigate the effect of the temperature on the performance of a rail damper, a simple Timoshenko beam model of the track vibration is used, to which are added single-frequency and dual-frequency tuned absorbers. The results show that a high noise reduction can be achieved for the optimum stiffness, provided that the loss factor is between about 0.25 and 0.4.In order to study the generic effects of high damping versus constant stiffness, the time-temperature superposition principle is used to convert frequency-dependence to temperature-dependence for a notional material with constant loss factor. This is used in the prediction of decay rates and thereby noise reduction. In addition, a weighted noise reduction is studied by using measured rail temperature distributions. This temperatureweighted noise reduction allows a single number measure of performance to be obtained which can be used to assess various elastomeric materials in order to determine the optimum material for a given situation.Two types of viscoelastic material, butyl and EPDM rubbers with various amount of fillers and plasticisers are investigated. The properties of both rubbers have been measured over the range of temperatures for frequencies 300-3000 Hz. For this a test rig had to be modified. For butyl, the best combination of filler and plasticiser gives temperature weighted noise reductions up to 5.9 dB(A). Butyl rubber is suitable for use in the rail absorber giving high noise reductions between 0 and 40 . The best EPDM compound gives a temperature-weighted noise reduction up to 6.2 dB(A). Comparing these two rubbers, EPDM is more suitable for low temperatures below 10 and butyl is more suitable for higher temperatures above 10 .

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Section: Butyl Rubber (Iir)mentioning

confidence: 86%

Section: Butyl Rubber (Iir)mentioning

confidence: 94%

Section: Filler Reinforcementmentioning

confidence: 99%

Section: Butyl Rubber (Iir)mentioning

confidence: 99%

Section: Butyl Rubber (Iir)mentioning

confidence: 99%

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A methodology for developing high damping materials with application to noise reduction of railway track

Ahmad

2009

The Journal of the Acoustical Society of America

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Physical Constants of Rubbery Polymers

Furuta

Kimura

Iwama

1999

The Wiley Database of Polymer Properties

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The strain dependence of rubber viscoelasticity. Part II. The influence of carbon black

Mason

1960

J of Applied Polymer Sci

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In Part I of this series it was shown how variations in the dynamic Young's modulus with extension could be represented by linear relations for gum rubbers in the region of 0 to 100% extension.' The present work uses a similar treatment to examine how the viscoelastic behavior of natural rubber within this extension region is affected by the incorporation of two carbon blacks of widely differing colloidal activity. One of these materials, MT black, consists substantially of spherical particles with a mean diameter of about 0.4 microns: electron microscopy of cut surfaces of the black-rubber compound showed that the individual particles were welldispersed. The finer material, HAF black, has a mean particle diameter of about 0.04 microns but exists in the rubber compound in a flocculated condit,ion with aggregates up to about 0.3 microns in diameter.The rubber containing the coarse, &IT black yielded linear strain relations enabling a direct comparison to be made with the behavior of the gum: the HAF material did not give linear relations for either the dynamic or the equilibrium Young's modulus. To facilitate discussion of this behavior it is desirable to set out more explicitly than in Part I the model underlying the analysis. Figure 1 shows the model used to formalize the c. -dependence of dynamic behavior upon extension. The series modulus E , represents the normal Hookean elasticity of a solid. This will be a slowly decreasing function of temperature and probably a slowly increasing function of strain12 but its magnitude will generally be well in excess of 1Olo dyne/ so that the deformation in this element will be relatively small under conditions where there is an appreciable rubberlike contribution to the elasticity. The rest of the model comprises an equilibrium modulus Eo in parallel with a number of Maxwellian elements typified by the modulus Er damped by the series viscosity T~ES, T , being the relaxation time of the element.It is now supposed that the system is stretched to a finite extension ratio X and allowed to relax at this extension so that Em, Eo, E,, and T , all take up equilibrium values dependent on X and, in general, differing from their values in the unstrained stat,e. In the present work the frequency and temperature are such that the dynamic Young's modulus E*( = E' + iE") is always much smaller than Em, and under this conditionwhere w / 2~ is the frequency and the other variables all relate to the extension ratio X.In amorphous viscoelasticity theory the moduli Eo and E , are treated as rubberlike moduli, being directly proportional to the absolute temperature and to the density. If it is now assumed that these moduli all have the same strain dependence, viz : Eo(X) = Eo(l)f(X)Et(X) = Et(l)f(X) for all i

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Dynamic shear properties of some rubber-like materials

Cited by 20 publications

References 18 publications

A methodology for developing high damping materials with application to noise reduction of railway track

A methodology for developing high damping materials with application to noise reduction of railway track

Physical Constants of Rubbery Polymers

The strain dependence of rubber viscoelasticity. Part II. The influence of carbon black

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