Scattering of ultrasonic compression waves by particulate filler in a cured epoxy continuum

Challis, R.E.; Holmes, A.K.; Tebbutt, J.S.; Cocker, R.P.

doi:10.1121/1.421281

Cited by 16 publications

(10 citation statements)

References 15 publications

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“…Allowance for different sizes of spheres are considered. Numerical examples are computed using data taken from [2,3,7]. The material properties are isotropic.…”

Section: Discussionmentioning

confidence: 99%

“…In the realm of nondestructive evaluation of composites the need to clearly identify ultrasonic signals in adhesive materials has taken a step forward in analysing the problem of multiple scattering by particulate composites both theoretically and experimentally [2,3]. The material characteristics of the constituents considered here have thermoelastic properties, and the inclusions may have different sizes.…”

Section: Introductionmentioning

confidence: 99%

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Dispersion and attenuation in thermoelastic multisize particulate composites

2008

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This paper deals with the problem of multiple scattering by a random distribution of spherical solid particles in a solid. The material properties of both media are taken as thermoelastic. The radii of the inclusions may be different. The self-consistent method in its variant of the effective medium is used to find the dispersion and attenuation of quasi-elastic, quasi-thermal and shear waves. The single scattering problem required by this technique is solved approximately by means of the Galerkin method applied to an integral equation using the Green function. Numerical results display a characteristic resonance phenomena which appears in the interval where the results are approximately valid, that is, for very long waves down to wavelengths about twice the largest diameter of the spheres. Examples are shown, for composites with two sets of inclusions, which have either a very similar or dissimilar size. Comparisons are made with the elastic counterpart. Among the material properties, the mass density ratio, inclusion to matrix, seems to play an important and simple role. Frequency intervals are distinguished and shown to depend on that ratio, where the attenuation and dispersion of quasi-elastic and P-waves are either very close to each other or not at all. The same applies to shear waves in either composite. The mass density ratio also displays a simple monotonic decreasing behaviour as a function of the frequency at the first attenuation maximum and velocity minimum. These results may be of interest for the nondestructive testing characterization of particulate composites.

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“…Allowance for different sizes of spheres are considered. Numerical examples are computed using data taken from [2,3,7]. The material properties are isotropic.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dispersion and attenuation in thermoelastic multisize particulate composites

2008

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“…Similar phenomena have been observed for polymers loaded with glass spheres 36 and talc filler. 37 In the materials presented the wavelength is in the range 2.9-3.4 mm and the Expancel dimensions were in the range 20-40 m. The reductions in the density and acoustic impedance are varying approximately linearly with the filler content. The minimum acoustic impedance reached is 0.88 MRayls, which is low enough for the design of a matching layer for an air coupled piezoelectric composite transducer.…”

Section: Low Density Filled Systemsmentioning

confidence: 99%

Properties of photocured epoxy resin materials for application in piezoelectric ultrasonic transducer matching layers

Troge

O'Leary

Hayward

et al. 2010

The Journal of the Acoustical Society of America

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This paper describes the acoustic properties of a range of epoxy resins prepared by photocuring that are suitable for application in piezoelectric ultrasonic transducer matching layers. Materials, based on blends of diglycidyl ether of Bisphenol A and 1,4-cyclohexanedimethanol diglycidyl ether, are described. Furthermore, in order to vary the elastic character of the base resin, samples containing polymer microspheres or barium sulfate particles are also described. The acoustic properties of the materials are determined by a liquid coupled through transmission methodology, capable of determining the velocity and attenuation of longitudinal and shear waves propagating in an isotropic layer. Measured acoustic properties are reported which demonstrate materials with specific acoustic impedance varying in the range 0.88-6.25 MRayls. In the samples comprising blends of resin types, a linear variation in the acoustic velocities and density was observed. In the barium sulfate filled samples, acoustic impedance showed an approximately linear variation with composition, reflecting the dominance of the density variation. While such variations can be predicted by simple mixing laws, relaxation and scattering effects influence the attenuation in both the blended and filled resins. These phenomena are discussed with reference to dynamic mechanical thermal analysis and differential scanning calorimetry of the samples.

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“…Krautkraemer and Krautkraemer [11]), including the study of the curing process [12]. Fundamental work was undertaken by Alig and coworkers [13][14][15][16][17][18][19], and Challis et al [20][21][22][23][24]. A good overview on methods for cure monitoring including ultrasound is given in Lodeiro and Mulligan [25].…”

Section: Online Process Monitoring Using Ultrasoundmentioning

confidence: 99%