Influences of sound scattering by elastic cylindrical shell on the directivity of vector sensor

2013 ◽  
Author(s):  
Liang Guolong ◽  
Zhang Guangpu ◽  
Pang Fubin
Keyword(s):  
Cylindrical Shell ◽  
Elastic Cylindrical Shell ◽  
Sound Scattering ◽  
Vector Sensor

Acoustic wave diffraction by an elastic cylindrical shell with viscous filling

1989 ◽  
Vol 25 (7) ◽  
pp. 662-667 ◽  
Author(s):  
O. B. Kachaenko ◽  
L. S. Pal'ko ◽  
N. A. Shul'ga
Keyword(s):  
Cylindrical Shell ◽  
Acoustic Wave ◽  
Wave Diffraction ◽  
Elastic Cylindrical Shell

scholarly journals An Evaluation of Active Noise Control in a Cylindrical Shell

1989 ◽  
Vol 111 (3) ◽  
pp. 337-342 ◽  
Author(s):  
R. J. Silcox ◽  
H. C. Lester ◽  
S. B. Abler
Keyword(s):  
Cylindrical Shell ◽  
Analytical Model ◽  
Noise Control ◽  
Active Noise Control ◽  
Effective Control ◽  
Elastic Cylindrical Shell ◽  
Noise Sources ◽  
Active Noise ◽  
Fixed Array ◽  
Forced Responses

This paper examines the physical mechanisms governing the use of active noise control in an extended volume of a cylindrical shell. Measured data were compared with computed results from a previously derived analytical model based on infinite shell theory. For both the analytical model and experiment, the radiation of external monopoles is coupled to the internal acoustic field through the radial displacement of the thin, elastic, cylindrical shell. An active noise control system was implemented inside the cylinder using a fixed array of discrete monopole sources, all of which lie in the plane of the exterior noise sources. Good agreement between measurement and prediction was obtained for both internal pressure response and overall noise reduction. Attenuations in the source plane greater than 15 dB were recorded along with a uniformly quieted noise environment over an indicative length inside the experimental model. Results indicate that for forced responses with extended axial distributions, axial arrays of control sources may be required. Finally, the Nyquist criteria for the number of azimuthal control sources is shown to provide for effective control over the full cylinder cross section.

scholarly journals Elastic Response of Acoustic Coating on Fluid-Loaded Rib-Stiffened Cylindrical Shells

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Christopher Gilles Doherty ◽  
Steve C. Southward ◽  
Andrew J. Hull
Keyword(s):  
Cylindrical Shell ◽  
Cylindrical Shells ◽  
Coupled System ◽  
Elastic Response ◽  
System Response ◽  
Elastic Cylindrical Shell ◽  
Fluid Environment ◽  
Reinforcing Ribs ◽  
Double Index ◽  
Stress Boundary Conditions

Reinforced cylindrical shells are used in numerous industries; common examples include undersea vehicles, aircraft, and industrial piping. Current models typically incorporate approximation theories to determine shell behavior, which are limited by both thickness and frequency. In addition, many applications feature coatings on the shell interior or exterior that normally have thicknesses which must also be considered. To increase the fidelity of such systems, this work develops an analytic model of an elastic cylindrical shell featuring periodically spaced ring stiffeners with a coating applied to the outer surface. There is an external fluid environment. Beginning with the equations of elasticity for a solid, spatial-domain displacement field solutions are developed incorporating unknown wave propagation coefficients. These fields are used to determine stresses at the boundaries of the shell and coating, which are then coupled with stresses from the stiffeners and fluid. The stress boundary conditions contain double-index infinite summations, which are decoupled, truncated, and recombined into a global matrix equation. The solution to this global equation results in the displacement responses of the system as well as the exterior scattered pressure field. An incident acoustic wave excitation is considered. Thin-shell reference models are used for validation, and the predicted system response to an example simulation is examined. It is shown that the reinforcing ribs and coating add significant complexity to the overall cylindrical shell model; however, the proposed approach enables the study of structural and acoustic responses of the coupled system.

Dynamic Stability of a Nonlinear Cylindrical Shell

1984 ◽  
Vol 51 (4) ◽  
pp. 852-856 ◽  
Author(s):  
A. Tylikowski
Keyword(s):  
Cylindrical Shell ◽  
Sufficient Conditions ◽  
Middle Surface ◽  
Elastic Cylindrical Shell ◽  
Time Varying ◽  
Liapunov Method ◽  
Linearized Problem ◽  
Nonlinear Shell ◽  
The Stability ◽  
Radial Loading

The stability of the undeflected middle surface of a uniform elastic cylindrical shell governed by Ka´rma´n’s equations is studied. The shell is being subjected to a time-varying axial compression as well as a uniformly distributed time-varying radial loading. Using the direct Liapunov method sufficient conditions for deterministic asymptotic as well as stochastic stability are obtained. A relation between stability conditions of a linearized problem and that of Ka´rma´n’s equations is found. Contrary to the stability theory of nonlinear plates it is established that the linearized problem should be modified to ensure the stability of the nonlinear shell. The case when the shell is governed by the Itoˆ stochastic nonlinear equations is also discussed.

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