Simulation of Vibration and Acoustic Radiation of Finite Underwater Cylindrical Shells

2000 ◽  
Author(s):  
X. M. Zhang ◽  
G. R. Liu ◽  
K. Y. Lam
Keyword(s):  
Acoustic Analysis ◽  
Acoustic Radiation ◽  
Cylindrical Shells ◽  
Sound Radiation ◽  
Coupled Vibration ◽  
Response Curves ◽  
Vibration And Sound Radiation ◽  
Acoustic Domain ◽  
High Sound ◽  
Element Method

Abstract A coupled structural-acoustic analysis of vibration and sound radiation of underwater finite cylindrical shells is investigated in this paper. The coupled vibration and radiation problem is formulated using Finite Element Method (FEM) for the structure and Boundary Element Method (BEM) for the acoustic domain. Vibration and sound radiation under symmetrical and unsymmetrical point force excitations are examined. It is shown that the coupled modals are the causes of large vibration of the shell and high sound pressure radiation of the acoustic fields. The shapes of frequency response curves of pressure are quite similar in the far fields but change greatly in the near fields.

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

2009 ◽  
Vol 223 (5) ◽  
pp. 1083-1089 ◽  
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.

Acoustic and Vibration Characteristics of Stiffened Finite Cylindrical Shells in Water under Multiple Axial-Excitations

2013 ◽  
Vol 662 ◽  
pp. 721-725
Author(s):  
Qi Zheng Zhou ◽  
De Shi Wang ◽  
Sheng Yao Gao
Keyword(s):  
Analytical Solution ◽  
Shell Theory ◽  
Acoustic Pressure ◽  
Acoustic Radiation ◽  
Cylindrical Shells ◽  
High Frequencies ◽  
Acoustic Coupling ◽  
Coupling Equations ◽  
Vibration And Sound Radiation ◽  
Thin Shell Theory

A research on the vibration and acoustic radiation of stiffened finite cylindrical shells in water under a multiple axial-excitations driven was presented. The vibro-acoustic coupling equations of shell under multiple axial-excitations based on Flügge thin shell theory were established. The displacements, surface acoustic pressure and stiffener impedances were expressed in terms of the numbers of normal modals and modes, and considering multiple excitations, the forces were expressed in terms of the numbers of normal modals and modes. Then analytical solution was derived for the vibration and sound radiation from the stiffened shell under multiple excitations. Based on the analytical solution, the influences of excitations’ positions to the vibration and acoustic radiation were investigated. The results show that for double excitations, at high frequencies, the distance between excitations was more large, the average velocity was more low. The results could be used to control the underwater vehicle’s vibration and acoustic radiation.

Research on Vibration and Sound Radiation from Submarine Functionally Graded Material Nonpressure Cylindrical Shell

2013 ◽  
Vol 690-693 ◽  
pp. 3046-3049
Author(s):  
Yan Bing Zhang ◽  
Chun Yu Ren ◽  
Xi Zhu
Keyword(s):  
Cylindrical Shell ◽  
Acoustic Radiation ◽  
Radiation Power ◽  
Sound Radiation ◽  
Functionally Graded ◽  
Underwater Sound ◽  
Graded Materials ◽  
Graded Material ◽  
Vibration And Sound Radiation ◽  
Sound Radiation Power

In this paper, we establish the finite element (FEM) and boundary element (BEM) models of a submarine section, and study the underwater sound radiation field of three different non-pressure shells made of steel, steel with anechoic tile, and the functionally graded materials (FGM) separately using a method combining of FEM and BEM . Research shows that the combination of FEM and BEM can address the acoustic radiation calculation problem of FGM, and in comparison with steel and anechoic tile laying submarine section, the weight of FGM non-pressure shell reduces 1600kg, and the sound radiation power decreases 4db and 2.5db respectively, thus having better performance in vibration and noise reduction.

Vibration and Sound Radiation of Sandwich Beams With Honeycomb Truss Core

2003 ◽  
Author(s):  
M. Ruzzene
Keyword(s):  
Acoustic Radiation ◽  
Sound Radiation ◽  
Structural Response ◽  
Element Model ◽  
Frame Structure ◽  
Sandwich Beams ◽  
The Core ◽  
Truss Core ◽  
Vibration And Sound Radiation ◽  
Spectral Finite Element

The vibrations of and the sound radiation from sandwich beams with truss core are here analyzed. The structure of the core is composed of a sequence of identical unit cells repeating along the beam length and across the core thickness. Each cell is composed of beam elements assembled to form a frame structure. Layouts with honeycomb patterns arranged through the thickness of the core are considered. This design represents an alternative with respect to the traditional application of honeycombs in sandwich construction. The proposed configuration provides sandwich beams with interesting structural as well as acoustic characteristics. A spectral finite element model is developed to evaluate the structural and the acoustic behavior of the considered class of sandwich beams. The spectral model can be easily coupled with a Fourier Transform based analysis of the sound radiated by the fluidloaded structure. The model predicts the performance of beams with various core configurations. The comparison is carried out in terms of vibration and sound radiation in an unbounded acoustic half-plane. Hexagonal and re-entrant honeycomb configurations are considered to study the effects of core geometry on structural response and acoustic radiation.

Coupled vibration and sound radiation from a fluid‐filled and submerged or embedded vascular tube with internal turbulent flow due to a constriction

2005 ◽  
Vol 117 (4) ◽  
pp. 2587-2588
Author(s):  
Yigit Yazicioglu ◽  
Thomas J. Royston ◽  
Todd Spohnholtz ◽  
Bryn Martin ◽  
Francis Loth ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Sound Radiation ◽  
Coupled Vibration ◽  
Vibration And Sound Radiation

Application of the Boundary Element Method and Modal Analysis to Tire Acoustics Problems

1993 ◽  
Vol 21 (2) ◽  
pp. 66-90 ◽  
Author(s):  
Y. Nakajima ◽  
Y. Inoue ◽  
H. Ogawa
Keyword(s):  
Finite Element ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Radiation ◽  
Traffic Noise ◽  
Noise Prediction ◽  
Prediction System ◽  
Tire Noise ◽  
Acoustic Contribution ◽  
Element Method

Abstract Road traffic noise needs to be reduced, because traffic volume is increasing every year. The noise generated from a tire is becoming one of the dominant sources in the total traffic noise because the engine noise is constantly being reduced by the vehicle manufacturers. Although the acoustic intensity measurement technology has been enhanced by the recent developments in digital measurement techniques, repetitive measurements are necessary to find effective ways for noise control. Hence, a simulation method to predict generated noise is required to replace the time-consuming experiments. The boundary element method (BEM) is applied to predict the acoustic radiation caused by the vibration of a tire sidewall and a tire noise prediction system is developed. The BEM requires the geometry and the modal characteristics of a tire which are provided by an experiment or the finite element method (FEM). Since the finite element procedure is applied to the prediction of modal characteristics in a tire noise prediction system, the acoustic pressure can be predicted without any measurements. Furthermore, the acoustic contribution analysis obtained from the post-processing of the predicted results is very helpful to know where and how the design change affects the acoustic radiation. The predictability of this system is verified by measurements and the acoustic contribution analysis is applied to tire noise control.

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