Institute of Fundamental Technological Research
Polish Academy of Sciences

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K. Attenborough

The Open University (GB)


Recent publications
1.  Zieliński T.G., Venegas R., Perrot C., Červenka M., Chevillotte F., Attenborough K., Benchmarks for microstructure-based modelling of sound absorbing rigid-frame porous media, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2020.115441, Vol.483, pp.115441-1-38, 2020

Abstract:
This work presents benchmark examples related to the modelling of sound absorbing porous media with rigid frame based on the periodic geometry of their microstructures. To this end, rigorous mathematical derivations are recalled to provide all necessary equations, useful relations, and formulae for the so-called direct multi-scale computations, as well as for the hybrid multi-scale calculations based on the numerically determined transport parameters of porous materials. The results of such direct and hybrid multi-scale calculations are not only cross verified, but also confirmed by direct numerical simulations based on the linearised Navier-Stokes-Fourier equations. In addition, relevant theoretical and numerical issues are discussed, and some practical hints are given.

Keywords:
porous media, periodic microstructure, wave propagation, sound absorption

Affiliations:
Zieliński T.G. - IPPT PAN
Venegas R. - other affiliation
Perrot C. - other affiliation
Červenka M. - Czech Technical University in Prague (CZ)
Chevillotte F. - MATELYS – Research Lab (FR)
Attenborough K. - The Open University (GB)
2.  Aygün H., Attenborough K., Postema M., A review of the state of art in applying Biot theory to acoustic propagation through the bone, Open Access Library Journal, ISSN: 2333-9705, DOI: 10.4236/oalib.1100994, Vol.e994, pp.1-12, 2014

Abstract:
Understanding the propagation of acoustic waves through a liquid-perfused porous solid frame- work such as cancellous bone is an important pre-requisite to improve the diagnosis of osteoporosis by ultrasound. In order to elucidate the propagation dependence upon the material and structural properties of cancellous bone, several theoretical models have been considered to date, with Biot-based models demonstrating the greatest potential. This paper describes the fundamental basis of these models and reviews their performance.

Keywords:
Acoustic, Propagation, Bone, Theoretical Model

Affiliations:
Aygün H. - Southampton Solent University (GB)
Attenborough K. - The Open University (GB)
Postema M. - other affiliation
3.  Aygün H., Attenborough K., Postema M., Lauriks W., Langton Ch.M., Predictions of angle dependent tortuosity and elasticity effects on sound propagation in cancellous bone, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, ISSN: 0001-4966, DOI: 10.1121/1.3242358, Vol.126, No.6, pp.3286-3290, 2009

Abstract:
The anisotropic pore structure and elasticity of cancellous bone cause wave speeds and attenuation in cancellous bone to vary with angle. Previously published predictions of the variation in wave speed with angle are reviewed. Predictions that allow tortuosity to be angle dependent but assume isotropic elasticity compare well with available data on wave speeds at large angles but less well for small angles near the normal to the trabeculae. Claims for predictions that only include angle-dependence in elasticity are found to be misleading. Audio-frequency data obtained at audio-frequencies in air-filled bone replicas are used to derive an empirical expression for the angle-and porosity-dependence of tortuosity. Predictions that allow for either angle dependent tortuosity or angle dependent elasticity or both are compared with existing data for all angles and porosities.

Affiliations:
Aygün H. - Southampton Solent University (GB)
Attenborough K. - The Open University (GB)
Postema M. - other affiliation
Lauriks W. - other affiliation
Langton Ch.M. - other affiliation

List of recent monographs
1. 
Attenborough K., Postema M., A Pocket-sized Introduction to Dynamics, University of Hull, pp.1-52, 2008
2. 
Attenborough K., Postema M., A Pocket-sized Introduction to Acoustics, University of Hull, pp.1-79, 2008

List of chapters in recent monographs
1. 
Postema M., Attenborough K., Fundamentals of Medical Ultrasonics, rozdział: Vibrations, Spon Press, pp.51-61, 2011
2. 
Postema M., Attenborough K., Fundamentals of Medical Ultrasonics, rozdział: Waves and sound, Spon Press, pp.63-87, 2011

Conference papers
1.  Opiela K.C., Zieliński T.G., Attenborough K., Manufacturing, modeling, and experimental verification of slitted sound absorbers, ISMA2020 / USD2020, International Conference on Noise and Vibration Engineering / International Conference on Uncertainty in Structural Dynamics, 2020-09-07/09-09, Leuven (BE), pp.409-420, 2020

Abstract:
Designs with uniformly distributed slits normal or inclined to the incident surface exhibit a great potential because of their simplicity and good acoustical performance. However, production of materials of this sort is challenging as the required fabrication precision is very high. This paper deals with additive manufacturing, modeling, and impedance tube testing of a few slitted geometries and their variations, including cases where the dividing walls between slits are perforated. They were designed to be producible with current 3D printing technology and provide reliable measurements using standardized equipment. The normal incidence sound absorption curves predicted analytically and numerically were verified experimentally. It is observed that such simple configurations may lead to absorption properties comparable to porous acoustic treatments with more complex microstructure. The good agreement between the predictions and measurements supports the validity of the multi-scale modeling employed.

Affiliations:
Opiela K.C. - IPPT PAN
Zieliński T.G. - IPPT PAN
Attenborough K. - The Open University (GB)

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