Detection of plate vibration modes by means of Near-field Acoustic Holography in the presence of reflective surfaces
2012 (English)In: International Conference on Noise and Vibration Engineering 2012, ISMA 2012, including USD 2012: International Conference on Uncertainty in Structure Dynamics, Katholieke Universiteit Leuven , 2012, Vol. 5, 3571-3584 p.Conference paper (Refereed)
A numerical and experimental study is presented on the influence of reflections on the reconstruction accuracy of the surface velocity of vibrating plates by means of Fourier-based Planar Near-field Acoustic Holography (PNAH) and a single-layer microphone array. At low frequencies (well below coincidence), it is shown that the effect of the presence of the reflective surface on the reconstruction depends on the source. When measuring close to the source, the classical PNAH transformation, based on the free-field radiation assumption, provides a good quantitative reconstruction of the surface vibration velocity. The effectiveness of a modified propagator is investigated which includes the effect of reflections on the inverse propagation from measured pressure at the hologram plane to surface vibration velocity at the source plane. This is done by simulations and measurements for sources that differ in velocity profile and size and that are radiating well below coincidence. Measurements are performed for a free plate in a large baffle in front of a granite block which is less than one acoustic wavelength apart.
Place, publisher, year, edition, pages
Katholieke Universiteit Leuven , 2012. Vol. 5, 3571-3584 p.
Acoustic holography, Acoustic noise, Plates (structural components), Structural dynamics, Surface reconstruction, Velocity, Acoustic wavelength, Free-field radiations, Inverse propagation, Nearfield Acoustic Holography, Numerical and experimental study, Plate vibration modes, Reconstruction accuracy, Simulations and measurements
Other Engineering and Technologies
IdentifiersURN: urn:nbn:se:kth:diva-165134ISI: 000321063903047ScopusID: 2-s2.0-84906355695ISBN: 9781622768257OAI: oai:DiVA.org:kth-165134DiVA: diva2:807778
25th International Conference on Noise and Vibration engineering, ISMA2012 in conjunction with the 4th International Conference on Uncertainty in Structural Dynamics, USD 2012, 17 September 2012 through 19 September 2012, Leuven, Belgium
QC 201504242015-04-242015-04-232015-04-24Bibliographically approved