A hybrid deterministic-problemistic model for vibroacoustic studies
A hybrid deterministic-problemistic model for vibroacoustic studies
The acoustic field inside a hard-walled acoustic cavity due to the random vibration of one flexible wall is analysed by a novel hybrid deterministic-probabilistic model. This approach implies that the flexible wall is not amenable to a deterministic treatment due to its high modal density and uncertainties concerning its exact geometric and material properties. Thus an original probabilistic treatment based on the vibration field correlation characteristics is proposed for the flexible wall. On the other hand, full information is available for the acoustic cavity making it tractable by deterministic modal techniques. A coupling coefficient between each acoustic mode and the plate bending wave field is employed to represent the vibroacoustic interaction and the response obtained from a model summation due to contributions from each acoustic mode.
Information concerning the spatial distribution of the plate response is provided by the probabilistic model and expressed in terms of correlation coefficients or normalised cross-power spectral densities of normal acceleration. Expressions for these two coefficients are derived based on an approximate modal representation and on a free wave model. Particular attention is paid to the plate boundary conditions and results are derived for plates with clamped, simply-supported, guided or free edges. A general boundary condition which solely depends on the edge stiffness is employed to model the effect of stiffeners on the plate vibration field. Information about curvature and type of excitation applied to the plate are also incorporated in this model. It is found that the derived correlation coefficients and normalised cross-power spectral densities are valid as frequency average estimates in bands in which more than eight plate modes are available. However, when the plate model overlap factor is higher than unity they can also be employed in narrow bands.
University of Southampton
Bonilha, Murilo Weingarten
a681ef88-1247-42b1-a3fb-df5e993560b1
1996
Bonilha, Murilo Weingarten
a681ef88-1247-42b1-a3fb-df5e993560b1
Bonilha, Murilo Weingarten
(1996)
A hybrid deterministic-problemistic model for vibroacoustic studies.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The acoustic field inside a hard-walled acoustic cavity due to the random vibration of one flexible wall is analysed by a novel hybrid deterministic-probabilistic model. This approach implies that the flexible wall is not amenable to a deterministic treatment due to its high modal density and uncertainties concerning its exact geometric and material properties. Thus an original probabilistic treatment based on the vibration field correlation characteristics is proposed for the flexible wall. On the other hand, full information is available for the acoustic cavity making it tractable by deterministic modal techniques. A coupling coefficient between each acoustic mode and the plate bending wave field is employed to represent the vibroacoustic interaction and the response obtained from a model summation due to contributions from each acoustic mode.
Information concerning the spatial distribution of the plate response is provided by the probabilistic model and expressed in terms of correlation coefficients or normalised cross-power spectral densities of normal acceleration. Expressions for these two coefficients are derived based on an approximate modal representation and on a free wave model. Particular attention is paid to the plate boundary conditions and results are derived for plates with clamped, simply-supported, guided or free edges. A general boundary condition which solely depends on the edge stiffness is employed to model the effect of stiffeners on the plate vibration field. Information about curvature and type of excitation applied to the plate are also incorporated in this model. It is found that the derived correlation coefficients and normalised cross-power spectral densities are valid as frequency average estimates in bands in which more than eight plate modes are available. However, when the plate model overlap factor is higher than unity they can also be employed in narrow bands.
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Published date: 1996
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Local EPrints ID: 459916
URI: http://eprints.soton.ac.uk/id/eprint/459916
PURE UUID: a8e75912-ea73-49a6-90aa-42e31da87e66
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Date deposited: 04 Jul 2022 17:27
Last modified: 16 Mar 2024 18:34
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Author:
Murilo Weingarten Bonilha
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