Investigation on Vibro-Acoustic Characteristics from Submerged Cylindrical Shell with Double Damping Layers

The vibration and sound radiation from submerged cylindrical shell with double damping layers are presented. The cylindrical shell motion was described with classical thin shell theory. The double damping layers motion was described with the Navier viscoelasticity theory. For different Youngs modulus parameters of double damping layers, the sound radiated power and the radial quadratic velocity of cylindrical shell models were calculated and analyzed. The results show that the sound radiated power and radial quadratic velocity are reduced to varying degrees due to double damping layers in a large frequency domain except low frequency. The double damping layer with soft inner layer and hard outer layer can make the sound radiated peaks move to high frequency, can help to reduce the radial quadratic velocity on outer surface of damping layer, and can help to reduce the vibration of model at antiresonance frequency.

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Sound Radiation From a Finite Cylindrical Shell Covered With a Compliant Layer

Journal of Vibration and Acoustics ◽

10.1115/1.2930180 ◽

1991 ◽

Vol 113 (2) ◽

pp. 267-272 ◽

Cited By ~ 15

Author(s):

B. Laulagnet ◽

J. L. Guyader

Keyword(s):

Cylindrical Shell ◽

Frequency Domain ◽

Mathematical Analysis ◽

Strong Influence ◽

Sound Radiation ◽

Radiated Power ◽

Shell Motion ◽

Compliant Layer ◽

Finite Cylindrical Shell ◽

Large Frequency

The aim of this work is to present the mathematical analysis and numerical results about sound radiation from a finite cylindrical shell covered with a compliant layer, immersed in water. The shell motion is obtained using Flu¨gge’s operator whereas the layer is described by a locally reacting material. The results are presented both in shell radial quadratic velocity and radiated power. Two major conclusions can be drawn when looking at results: (1) a reasonable stiffness layer allows one to reduce the radiated power in a large frequency domain; (2) the layer has a strong influence on the shell velocity which exhibits an antiresonance phenomenon when covered.

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Research on Metal-Rubber Composite Damping Steel Plate Application in Acoustic Bridge for Double Cylindrical Shell

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.490-495.3505 ◽

2012 ◽

Vol 490-495 ◽

pp. 3505-3510

Author(s):

Qi Qiang Xia ◽

Zhi Jian Chen ◽

Jie Gong ◽

Li Jun Zhang

Keyword(s):

Cylindrical Shell ◽

Steel Plate ◽

Low Frequency ◽

Sound Radiation ◽

Composite Plates ◽

Vibration Energy ◽

Acoustic Characteristics ◽

Rubber Composite ◽

Vibration Attenuation ◽

Metal Rubber

In order to reduce the low-frequency line spectrum of double cylindrical shell, the research was done to apply composite damping steel plate in acoustic bridge between two shells. By suppressing vibration energy transmission along acoustic bridge, two types of composite damping rib-plate were designed with the resistance increasing technology based on the principle of damping vibration attenuation. Then the vibro-acoustic characteristics of double cylindrical shell were analyzed through numerical calculations, considering original and improved acoustic bridge. The results shows that: composite damping steel plate applying in acoustic bridge can reduce sound radiation of double cylindrical shell effectively, properly increasing damping between composite plates is beneficial for vibration and noise reduction. These research results could be a reference for submarine acoustic stealth design.

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Low-frequency vibrations of a cylindrical shell rotating on rollers

10.1063/1.5034686 ◽

2018 ◽

Author(s):

S. B. Filippov

Keyword(s):

Cylindrical Shell ◽

Low Frequency

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Effects of non-axisymmetric internal structures on vibro-acoustic characteristics of a submerged cylindrical shell using wavenumber analysis

Thin-Walled Structures ◽

10.1016/j.tws.2021.108758 ◽

2022 ◽

Vol 171 ◽

pp. 108758

Author(s):

Wenchao Jia ◽

Meixia Chen ◽

Zhiwei Zhou ◽

Kun Xie

Keyword(s):

Cylindrical Shell ◽

Acoustic Characteristics ◽

Internal Structures

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Study on Vibro-acoustic Characteristics of Laminated Composite Cylindrical Shell

10.1109/coa50123.2021.9519977 ◽

2021 ◽

Author(s):

Wu Jiang-Hai ◽

Hou Xi-Chen ◽

Guo Hong-Ci ◽

Duan Yong ◽

Zhu Hong-Zhen

Keyword(s):

Cylindrical Shell ◽

Laminated Composite ◽

Composite Cylindrical Shell ◽

Acoustic Characteristics

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Vibrational and acoustic radiation from a submerged periodic cylindrical shell with axial stiffening

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes1187 ◽

2009 ◽

Vol 223 (5) ◽

pp. 1083-1089 ◽

Cited By ~ 2

Author(s):

C-J Liao ◽

W-K Jiang ◽

H Duan ◽

Y Wang

Keyword(s):

Cylindrical Shell ◽

Analytical Study ◽

Acoustic Radiation ◽

Sound Radiation ◽

Mechanical Impedance ◽

Stiffened Cylindrical Shell ◽

Reaction Forces ◽

Radial Forces ◽

Vibration And Sound Radiation ◽

Finite Cylindrical Shell

An analytical study on the vibration and acoustic radiation from an axially stiffened cylindrical shell in water is presented. Supposing that the axial stiffeners interact with the cylindrical shell only through radial forces, the reaction forces on the shell from stiffeners can be expressed by additional impedance. The coupled vibration equation of the finite cylindrical shell with axial stiffening is derived; in this equation additional impedance caused by the axial stiffeners is added. As a result, the vibration and sound radiation of the shell are dependent on the mechanical impedance of the shell, the radiation sound impedance, and the additional impedance of the axial stiffeners. Based on the numerical simulation, it is found that the existence of axial stiffeners decreases the sound radiation and surface average velocity, whereas it increases the radiation factor. The characteristics of the acoustic radiation can be understood from the simulation with good results, which show that the presented methodology can be used to study the mechanism of the acoustic radiation of the complicated cylindrical shell and to optimize its design.

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Study on Static Assembly Interference Pressure between a Thin-Wall Flexible Cup and a Hollow Flexible Shaft

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.179-180.212 ◽

2011 ◽

Vol 179-180 ◽

pp. 212-219

Author(s):

Guo Ping Wang ◽

Hua Ling Chen ◽

She Miao Qi ◽

Jiu Hui Wu ◽

Lie Yu

Keyword(s):

Cylindrical Shell ◽

Pressure Distribution ◽

Superposition Principle ◽

Special Solution ◽

Thin Wall ◽

Thin Cylindrical Shell ◽

Bending Deformation ◽

Flexible Shaft ◽

First Time ◽

Thin Shell Theory

Distribution of static interference pressure between a thin-wall flexible cup and a flexible shaft fluctuates heavily along the axis of the cup and is quite different from pressure distribution of common interference styles. In this article, aiming at solving distribution of static interference pressure between a thin-wall flexible cup with much thicker bottom and a hollow flexible shaft, mechanical model and mathematical model of solving the problem were built based on classic thin shell theory. Special difference is that precise special solution of bending equation of thin cylindrical shell was used to substitute the special solution which is original from bending deformation of thin cylindrical shell in no moment status. And a brand new general solution, the relational expression between bending deformation of thin wall of the cup and distribution of the static interference pressure, was obtained. Then, a method used to solve the pressure distribution was presented by solving integral equation and applying superposition principle for the first time. Through using the method to solve an example and comparing calculated results with FEM results, it was proved that the method is correct and effective.

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Simulation and analysis on low-frequency scattering characteristics of the finite cylindrical shell in shallow water

MATEC Web of Conferences ◽

10.1051/matecconf/201928303007 ◽

2019 ◽

Vol 283 ◽

pp. 03007

Author(s):

Jinyu Li ◽

Dejiang Shang ◽

Yan Xiao

Keyword(s):

Cylindrical Shell ◽

Free Space ◽

Acoustic Scattering ◽

Low Frequency ◽

Target Strength ◽

Wave Direction ◽

Scattering Field ◽

Simulation Results ◽

Finite Cylindrical Shell ◽

Target Locations

Low-frequency acoustic scatterings from a finite cylindrical shell are numerically analyzed by FEM. The simulation results show that the acoustic-scattering field in waveguide has lots of frequency-related sidelobes, while no sidelobes exist in free space at low frequencies. The simulation also indicates that the module value in waveguide can be almost 20 dB larger than that in free space at low frequency, which is caused by the ocean boundaries. We also demonstrate that when the incident wave direction is normal to the target at low frequency, the target strength will be maximum and the distribution of the acoustic-scattering field is axisymmetric about the incident waving direction. Meanwhile, the acoustic-scattering field is also related to the impedance of the seabed, and the change of the impedance makes just a little contribution to the scattering field. Finally, the influence of different target locations is analyzed, including the targets near the sea surface, seabed and the middle region of the ocean waveguide, respectively. From simulation results, it is evident that the distribution of the acoustic-scattering field at low frequency has a little difference, which is smaller than 0.5 dB with various target locations, and the change is frequency and boundary-related.

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Early Life Maternal Separation and Maternal Behaviour Modulate Acoustic Characteristics of Rat Pup Ultrasonic Vocalizations

Scientific Reports ◽

10.1038/s41598-019-54800-z ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Jasmine H. Kaidbey ◽

Manon Ranger ◽

Michael M. Myers ◽

Muhammad Anwar ◽

Robert J. Ludwig ◽

...

Keyword(s):

Maternal Separation ◽

Low Frequency ◽

Ultrasonic Vocalizations ◽

Maternal Behaviour ◽

Long Term Effects ◽

Acoustic Characteristics ◽

Rat Pups ◽

Before And After ◽

And Control

AbstractEarly separation of preterm infants from their mothers has adverse, long-term neurodevelopmental consequences. We investigated the effects of daily maternal separation (MS) of rat pups from postnatal days 2–10 (PND2–10) on neurobehavioural responses to brief isolation at PND12 compared with pups receiving controlled handling without MS. Ultrasonic vocalizations (USV) were measured at PND12 during two, 3-minute isolations occurring immediately before and after a 3-minute maternal reunion. There were no significant differences in acoustic characteristics between MS and control animals in the first isolation. However, in the second isolation, MS pups produced a greater proportion of high (~60 kHz) vs low (~40 kHz) frequency calls. During this isolation, control pups made longer and louder low frequency calls compared to the first isolation, whereas MS pups did the opposite. Maternal behaviour of control and MS mothers modulated pup acoustic characteristics in opposite directions; higher maternal care was associated with more low frequency calls in control pups but more high frequency calls in MS pups. We hypothesize that MS results in USV emission patterns reflective of a greater stress response to isolation. This translational model can be used to identify mechanisms and interventions that may be exploited to overcome the negative, long-term effects of MS.

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