Complete Determination Of Structural Intensity In Plates Using Laser Vibrometers

Structural power flow is an alternative way of analyzing vibrations, where, differently from traditional techniques, the emphasis is put on the active part of the vibration energy instead of the total. The active vibration energy is directly related to the injection and dissipation of energy in the structure and can, therefore, be a valuable tool for solving vibroacoustical problems. However, measuring the active part of the vibration energy in the presence of a highly reverberant field is often impractical. This paper presents an experimental method especially adapted for the computation of structural power flow using spatially dense vibration data measured with scanning laser Doppler vibrometers. In the proposed method, an operational deflection shape measured over the surface of the structure is curve-fitted using a two-dimensional discrete Fourier series approximation. This approximation minimizes the effects of spatial leakage. From the wavenumber-frequency domain data thus obtained, it is straightforward to compute the spatial derivatives that are necessary to determine the structural power flow. An example consisting of a rectangular aluminum plate supported by four rubber mounts and excited by an electrodynamic shaker is used to appraise the proposed method. Both numerically simulated data and experimental data are used. keywords: structural power flow, vibration intensity, laser vibrometers, plate structures, operational deflection shapes 0-81 94-2264-9/96/$6.OO SPIE Vol. 2868 / 149 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/04/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx =0 if in which case it can be shown that V x (wVw*) =0 . With this assumption, Eqs. (10) may be rewritten as: SPIE Vol. 2868 / 151 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/04/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

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“…(8)(9)(10), and using the finite difference approximations in Eqs. (8)(9)(10), and using the finite difference approximations in Eqs.…”

Section: Finite Difference Approximationsmentioning

confidence: 99%

“…7,8 have proposed the use of spatial Fourier transforms to compute the power flow in the wavenumber domain. Pascal et a!.…”

Section: Introductionmentioning

confidence: 99%

<title>Predicting and measuring flexural power flow in plates</title>

Arruda

Mas

1996

SPIE Proceedings

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“…The energy quantities (structural intensity and energy densities) associated with flexural waves in a plate are directly computed from vibration velocity data which are measured using a scanning laser vibrometer [8,9]. An advanced wavenumber-domain technique has been developed to eliminate leakage effects [9].…”

Section: Introductionmentioning

confidence: 99%

Characterisation of a dissipative assembly using structural intensity measurements and energy conservation equation

Pascal

Carniel

Li³

2006

Mechanical Systems and Signal Processing

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“…The identification of preferential structural paths for optimal vibration energy transfer was regarded as powerful information to optimize the location of vibration and noise control devices. Since its original formulation 1,2 several numerical and experimental techniques were presented to evaluate the SI field in plates 3,4 and solids 5 in presence of deterministic or random excitations. 6 Only in recent years, SI was investigated as a possible tool for damage detection.…”

Section: Introductionmentioning

confidence: 99%

Structural damage identification in plates via nonlinear structural intensity maps

Semperlotti

Conlon

2010

The Journal of the Acoustical Society of America

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A nonlinear structural intensity concept is presented as an approach for the identification of defects displaying nonlinear vibration behavior. The nonlinear structural dynamic response exhibited by a riveted joint with loosened fasteners connecting a stiffener with a flat panel is investigated. The excitation, generating elastic waves with dominant bending components, triggers the nonlinear contact between the plate and the stiffener inducing a dynamic response rich with nonlinear harmonics. Experimental structural intensity maps are evaluated at the super-harmonic frequencies. This technique provides an experimental approach for the characterization and two dimensional visualization of nonlinear types of defects.

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Complete Determination Of Structural Intensity In Plates Using Laser Vibrometers

Cited by 27 publications

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<title>Predicting and measuring flexural power flow in plates</title>

<title>Predicting and measuring flexural power flow in plates</title>

Characterisation of a dissipative assembly using structural intensity measurements and energy conservation equation

Structural damage identification in plates via nonlinear structural intensity maps

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