scholarly journals Intensity vector and power flow in an infinite cylindrical shell excited by a point force

1990 ◽  
Vol 88 (S1) ◽  
pp. S53-S53
Author(s):  
Giorgio V. Borgiotti ◽  
Eric Rosen
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Point Force ◽  
Intensity Vector ◽  
Infinite Cylindrical Shell

Power Flow and Sound Radiation of a Submerged Cylindrical Shell with Internal Structural

2011 ◽  
Vol 105-107 ◽  
pp. 321-325 ◽  
Author(s):  
Jin Yan ◽  
Juan Zhang
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Coupled System ◽  
Engineering Practice ◽  
Coupling Condition ◽  
Space Harmonics ◽  
In Series ◽  
Infinite Cylindrical Shell ◽  
Radiated Sound ◽  
Vibrational Power Flow

The vibrational power flow in a submerged infinite cylindrical shell with internal rings and bulkheads are studied analytically. The harmonic motion of the shell and the pressure field in the fluid is described by Flügge shell theory and Helmholtz equation, respectively. The coupling condition on the outer surface of the shell wall is introduced to obtain the vibrational equation of this coupled system. Both four kinds of forces (moments) between rings and shell and between bulkheads and shell are considered. The solution is obtained in series form by expanding the system responses in terms of the space harmonics of the spacing of both ring stiffeners and bulkheads. The vibrational power flow and radiated sound power are obtained and the influences of various complicating effects such as the ring, bulkhead and fluid loading on the results are analyzed. The analytic model is close to engineering practice, which will be valuable to the application on noise and vibration control of submarines and underwater pipes.

Active Control of Input Power Flow to the Cylindrical Shells Based on Piezoelectric Actuator

2013 ◽  
Vol 321-324 ◽  
pp. 1730-1743
Author(s):  
Tian Yun Li ◽  
Xu Wang ◽  
Xiang Zhu ◽  
Quan Zhou Jin
Keyword(s):  
Cylindrical Shell ◽  
Piezoelectric Actuator ◽  
Power Flow ◽  
Dynamic Models ◽  
Input Power ◽  
Control Effect ◽  
Total Input ◽  
Optimal Theory ◽  
Hermitian Quadratic Form ◽  
Infinite Cylindrical Shell

The dynamic models of the infinite cylindrical shell with integrated piezoelectric actuator are derived firstly in this paper, then, the total input power flow is calculated and expressed as the Hermitian quadratic form to act as the objective function to implement the control. The optimum set of secondary force is obtained by using feed-forward quadratic optimal theory, and the total input power flow with control was calculated for different locations of the actuator. The results show that different axial and circumferential locations will induce different influences on the control effect, and the results are greatly related to the vibration type and the circumferential mode.

Vibration Power Flow Analysis of a Submerged Constrained Layer Damping Cylindrical Shell

2012 ◽  
Author(s):  
Yun Wang ◽  
Gangtie Zheng
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Axial Direction ◽  
Input Power ◽  
Exciting Force ◽  
Dynamic Equations ◽  
Constrained Layer Damping ◽  
Vibration Power Flow ◽  
Constrained Damping ◽  
Mode Order

The vibration power flow in a submerged infinite constrained layer damping (CLD) cylindrical shell is studied in the present paper using the wave propagation approach. Dynamic equations of the shell are derived with the Hamilton principle in conjunction with the Donnell shell assumptions. Besides, the pressure field in the fluid is described by the Helmholtz equation and the damping characteristics are considered with the complex modulus method. Then, the shell-fluid coupling dynamic equations are obtained by using the coupling between the shell and the fluid. Vibration power flows inputted to the coupled system and transmitted along the shell axial direction are both studied. Results show that input power flow varies with driving frequency and circumferential mode order, and the constrained damping layer will restrict the exciting force inputting power flow into the shell, especially for a thicker viscoelastic layer, a thicker or stiffer constraining layer (CL), and a higher circumferential mode order. Cut-off frequencies do not exist in the CLD cylindrical shell so that the exciting force can input power flow into the shell at any frequency and for any circumferential mode order. The power flow transmitted in the CLD cylindrical shell exhibits an exponential decay form along its axial direction, which indicates that the constrained damping layer has a good damping effect especially at middle or high frequencies.

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