Resonance theory of acoustic waves interacting with an elastic plate

1979 ◽  
Vol 66 (6) ◽  
pp. 1857-1866 ◽  
Author(s):  
Ralph Fiorito ◽  
Walter Madigosky ◽  
Herbert Überall
Keyword(s):  
Elastic Plate ◽  
Acoustic Waves ◽  
Resonance Theory

Acoustic scattering by a finite nonlinear elastic plate. I Primary, secondary and combination resonances

1987 ◽  
Vol 414 (1846) ◽  
pp. 237-253 ◽  
Keyword(s):  
Incident Wave ◽  
Elastic Plate ◽  
Scattered Field ◽  
Acoustic Waves ◽  
Multiple Scales ◽  
Acoustic Scattering ◽  
Scattered Wave ◽  
Thin Elastic Plate ◽  
Finite Width ◽  
Wave Angle

A thin elastic plate of finite width is irradiated by time-harmonic acoustic waves. The fluid is assumed light compared with the plate mass, and the forcing term is of sufficient amplitude to necessitate the inclusion of a nonlinear term (due to mid-plane stretching) in the plate equation. The order-one scattered field is determined by the method of multiple scales when the forcing frequency approaches a free oscillation frequency (eigenfrequency) of the plate. This solution is shown to agree with previous work, for the linear problem, and can be multivalued for particular values of the plate-fluid parameters. The scattered wave may also exhibit jumps in its amplitude and phase angle as it varies with frequency, incident-wave angle or incident-wave amplitude. The non-linear term further allows the possibility of secondary and combination resonances. These are investigated and the scattered field is shown to contain terms of different frequencies to those of the incident waves. Multivalued solutions and the associated jump phenomenon are again found for these resonant cases.

RESONANCES OF ACOUSTIC WAVES INTERACTING WITH AN ELASTIC SEABED

2001 ◽  
Vol 09 (03) ◽  
pp. 1079-1093 ◽  
Author(s):  
MARGARETE S. FOKINA ◽  
VLADIMIR N. FOKIN
Keyword(s):  
Reflection Coefficient ◽  
Half Space ◽  
Acoustic Waves ◽  
Elastic Half Space ◽  
Exact Expression ◽  
Ocean Bottom ◽  
Sediment Layer ◽  
Resonance Theory ◽  
Space Characteristic ◽  
Exact Calculations

An exact expression for the reflection coefficient is obtained with the Thomson–Haskell technique for the geoacoustical model of an ocean bottom consisting of an elastic homogeneous sediment layer overlying an elastic half-space. Characteristic equations for explicit determination of the position of each individual resonance contribution to the reflection coefficient are derived. Analytical expressions for the angular and frequency resonance positions are found. The resonance expression for the reflection coefficient is written in the form of a sum of resonance terms. Comparison between resonance theory and exact calculations for the elastic layer covering the elastic half-space is presented. The results of resonance formalism show excellent agreement with exact theory in all the cases.

The damping of flexural and acoustic waves by a bias-flow perforated elastic plate

1995 ◽  
Vol 6 (4) ◽  
pp. 307-328 ◽  
Author(s):  
M. S. Howe
Keyword(s):  
Wave Equation ◽  
Elastic Plate ◽  
Acoustic Waves ◽  
Homogeneous Distribution ◽  
Circular Aperture ◽  
Fluid Loading ◽  
Numerical Predictions ◽  
Bias Flow ◽  
Vorticity Production ◽  
Bending Wave

An analysis is made of the damping of sound and structural vibrations by vorticity production in the apertures of a bias flow, perforated elastic plate. Unsteady motion causes vorticity to be generated at the aperture edges; the vorticity and its energy are swept away by the bias flow and result in a net loss of acoustic and vibrational energy. In this paper we investigate the interaction of an arbitrary fluid-structure disturbance with a small circular aperture in the presence of a high Reynolds number, low Mach number bias flow. By considering the limit in which the aperture is small compared to the length scale of the impinging disturbance, it is shown that the effect of the interaction can be represented by a concentrated source in the plate bending wave equation consisting of a delta function and two of its axisymmetric derivatives. A generalized bending wave equation is then formulated for a plate perforated with an homogeneous distribution of small, bias flow circular apertures. This equation is used to predict the attenuation of sound and resonant bending waves by vorticity production. Acoustic damping is found to be significant provided the fluid loading is sufficiently small for the plate to be regarded as rigid (e.g. for an aluminium plate in air when the frequency is not too small). On the other hand, a bending wave is effectively damped only when the fluid loading is large enough for the wave to produce a substantial pressure drop across the plate; when this occurs the predicted attenuations are comparable with those usually achieved by the application of elastomeric damping materials. Numerical predictions are presented for steel and aluminium plates in air and water.

Resonant transmission of acoustic waves through an elastic plate quasiperiodically corrugated on surfaces

2011 ◽  
Vol 375 (45) ◽  
pp. 4081-4084 ◽  
Author(s):  
Rui Hao ◽  
Chunyin Qiu ◽  
Yanyun Hu ◽  
Kun Tang ◽  
Zhengyou Liu
Keyword(s):  
Elastic Plate ◽  
Acoustic Waves ◽  
Resonant Transmission

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

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