Acoustic radiation efficiency of a submerged periodic ring-stiffened cylindrical shell with finite vibration loading

2021 ◽  
Vol 171 ◽  
pp. 107664
Author(s):  
Haesang Yang ◽  
Woojae Seong
Keyword(s):  
Cylindrical Shell ◽  
Acoustic Radiation ◽  
Radiation Efficiency ◽  
Stiffened Cylindrical Shell ◽  
Vibration Loading ◽  
Periodic Ring

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 Radiation From Stiffened Cylindrical Shells With Constrained Layer Damping

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Xiongtao Cao ◽  
Hongxing Hua ◽  
Zhenguo Zhang
Keyword(s):  
Cylindrical Shell ◽  
Sound Pressure ◽  
Acoustic Radiation ◽  
Equations Of Motion ◽  
Cylindrical Shells ◽  
Phase Method ◽  
Stationary Phase Method ◽  
Constrained Layer Damping ◽  
Acoustic Characteristics ◽  
Stiffened Cylindrical Shell

Acoustic radiation from cylindrical shells stiffened by two sets of rings, with constrained layer damping (CLD), is investigated theoretically. The governing equations of motion for the cylindrical shell with CLD are described on the basis of Sanders thin shell theory. Two sets of rings interact with the host cylindrical shell only through the normal line forces. The solutions are derived in the wavenumber domain and the stationary phase method is used to find an analytical expression of the far-field sound pressure. The effects of the viscoelastic material core, constrained layer and multiple loadings on sound pressure are illustrated. The helical wave spectra of sound pressure and the radial displacement clearly show the vibrational and acoustic characteristics of the stiffened cylindrical shell with CLD. It is shown that CLD can effectively suppress the radial vibration and reduce acoustic radiation.

Experimental Determination of SEA Parameters of Stiffened Cylindrical Shell Structure

2006 ◽  
Vol 3-4 ◽  
pp. 315-324
Author(s):  
P. Ramachandran ◽  
S. Narayanan
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Prediction Method ◽  
Radiation Efficiency ◽  
Laser Vibrometer ◽  
Correction Procedure ◽  
Discrete Elements ◽  
Stiffened Cylindrical Shell ◽  
Modal Density

A method to predict the modal density and radiation efficiency of orthogonally stiffened cylindrical shell is presented in this paper. The modal density is derived using energy method from the undamped natural frequencies of stiffened shell by treating the stiffeners as discrete elements. The band averaged radiation efficiency is estimated by categorizing the structural modes into acoustically fast and acoustically slow modes. The predicted parameters are compared with experimental results using laser vibrometer measurements. Phase-roll off has been observed in laser vibrometer measurements for which a correction procedure is applied. This prediction method can be easily extended to shells with stiffeners having different size, orientation etc.

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