Radiation efficiency of damped plates

Kou, Yiwei; Liu, Bilong; Tian, Jing

doi:10.1121/1.4906186

Cited by 14 publications

(5 citation statements)

References 10 publications

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“…With all driving points, i.e., in all rows, the driving point has a stronger amplitude and can much more clearly be seen when damping is higher, while with lower damping, the driving point is not so prominent. This is in accordance with the increased damping, as already nicely discussed in [31] Section II. With large damping, the waves leaving the driving point are damped considerably and are, therefore, weaker on all other parts of the plate.…”

Section: Forced Oscillation Patterns Vs Eigenmodessupporting

confidence: 90%

“…Therefore, increasing the damping decreases so-called dead spots on a soundboard, notes which are low in volume. This is a general and important finding studied before [31,38]. When damping is increased, the eigenmodes disappear.…”

Section: Forced Oscillation Patterns Vs Eigenmodessupporting

confidence: 61%

“…This is an important mechanism when driving the soundboard with frequencies that are not eigenfrequencies of this soundboard, which is considerably the case with lower frequencies. Models so far of an aluminum plate predict up to 8 dB [31], that of a layered plate up to 15 dB sound radiation increase [38]. Heavily damped vibrating systems, such as wood, therefore, are still able to radiate low frequencies that are not eigenfrequencies of the system loud and strong.…”

Section: Forced Oscillation Patterns Vs Eigenmodesmentioning

confidence: 99%

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Impact of Damping on Oscillation Patterns on the Plain Piano Soundboard

Bader

Plath

2022

Acoustics

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The influence of internal damping on the vibration of a piano soundboard is investigated using a Finite-Difference Time Domain (FDTD) physical model and experimental measurements. The damping constant of the model is varied according to a range similar to those found with measurements on a real grand piano at different production stages. With strong damping, a clear driving-point dependency of the forced string oscillation on the oscillation pattern of the soundboard is found. When decreasing the damping, this driving-point dependency is decreasing, nevertheless, it is still present. High damping, therefore, decreases soundboard vibration when strings drive the soundboard at the soundboard’s eigenfrequencies. However, such large damping increases soundboard vibrations when strings drive the soundboard at frequencies which are not eigenfrequencies. Therefore, strong damping smooths out the frequency response spectrum of an instrument. Extreme damping without any presence of distinct eigenmodes leads to a radiation of the strings sound spectrum without soundboard filtering. Low damping leads to a strong influence of the soundboard on the string’s radiated sound. Therefore, the amount of soundboard characteristics can be designed to alter internal damping process by choice of materials, including wood or varnish, and geometry. Additionally, damping reduces the presence of ’dead spots’, notes which are considerably lower in volume compared to other notes.

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Section: Forced Oscillation Patterns Vs Eigenmodessupporting

confidence: 90%

Section: Forced Oscillation Patterns Vs Eigenmodessupporting

confidence: 61%

Section: Forced Oscillation Patterns Vs Eigenmodesmentioning

confidence: 99%

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Impact of Damping on Oscillation Patterns on the Plain Piano Soundboard

Bader

Plath

2022

Acoustics

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“…Wallace [9] derived an integral formula based on far-field acoustic radiation power to calculate the modal acoustic radiation efficiency of a finite plate. Kou et al [10] proposed modifications to the classical formulas given by Cremer and Leppington, regarding the influence of structural damping on the radiation efficiency.…”

Section: Introductionmentioning

confidence: 99%

TBL-Induced Structural Vibration and Noise

Xilong¹,

Kou²,

Liu³

2020

Boundary Layer Flows - Theory, Applications and Numerical Methods

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One of most import noise sources in a jet powered aircraft is turbulent boundary layer (TBL) induced structural vibration. In this chapter, the general model for the prediction of TBL-induced plate vibration and noise is described in detail. Then numerical examples for a typical plate are illustrated. Comparisons of plate vibration and radiated noise between numerical results and wind tunnel test are presented. The effects of structural parameters on modal-averaged radiation efficiency and therefore the radiated noise are discussed. The result indicates that an increment of flow velocity will increase the acoustic radiation efficiency below the hydrodynamic coincidence frequency range. The main reason for this phenomenon is that a higher convection velocity will coincide with lower order modes which have higher radiation efficiencies.

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“…The constrained layer damping (CLD) is a typical material extensively applied to suppress vibration and sound radiation for thin-walled structure in automobile, subway, aviation and so on [1]. Foreign and domestic researchers have done much work on testing and analyzing CLD's mechanic characteristics, vibro-acoustic characteristics and optimization by analytic method [2,3], numerical method [4,5] and test method [6]. These work most focus on vibration suppression and sound radiation of beam or panel structure with CLD.…”

Section: Introductionmentioning

confidence: 99%

The Effects on Acoustic Characteristics of Aircraft with Constrained Layer Damping

2019

Proceedings of 2019 the 9th International Workshop on Computer Science and Engineering

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The constrained layer damping(CLD) could suppress vibration and sound radiation of thinwalled structure like aircraft fuselage. By calculating the sound transmission loss of panel with CLD based on finite element analysis method and sound pressure level of aircraft with CLD based on statistical energy analysis method, and compared with experimental results from standing wave tube and reverberationanechoic chamber, the acoustic characteristics of aircraft and panel with CLD and the effect of CLD's parameters such as density and coverage have been investigated. The experimental and simulation results show good consistency and trend.

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Radiation efficiency of damped plates

Cited by 14 publications

References 10 publications

Impact of Damping on Oscillation Patterns on the Plain Piano Soundboard

Impact of Damping on Oscillation Patterns on the Plain Piano Soundboard

TBL-Induced Structural Vibration and Noise

The Effects on Acoustic Characteristics of Aircraft with Constrained Layer Damping

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