VIBRATION POWER FLOW IN A FLUID-FILLED CYLINDRICAL SHELL

1998 ◽  
Vol 218 (4) ◽  
pp. 587-598 ◽  
Author(s):  
M.B. Xu ◽  
X.M. Zhang
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Vibration Power Flow

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.

Effects of Joint Discontinuity on the Vibration Power Flow Propagation in a Submerged Cylindrical Shell

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Yun Wang ◽  
Gangtie Zheng
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Shell Theory ◽  
Pressure Field ◽  
Mean Value ◽  
Propagation Characteristics ◽  
Vibration Power Flow ◽  
The Mean ◽  
Flow Propagation ◽  
Transmission And Reflection

The propagation characteristics of the vibration power flow in a submerged cylindrical shell with joint discontinuity are investigated by the wave propagation approach. The motion of the cylindrical shell and the pressure field in fluid are described by the Flügge shell theory and the Helmholtz equation, respectively. And the dynamic equations of the system are obtained by the coupling between the shell and the fluid. Then, an analysis of the vibration power flow transmission and reflection at the joint discontinuity is presented and the power flow transmission ratio Tr through the joint discontinuity is studied. Results show that the joint discontinuity can reduce the mean value of the Tr and thus, reduce the energy level of the transmitted vibration, as it has the effect of partially reflecting some of the incident wave with relations to its physical and geometric parameters. The influences of the fluid and the material damping of the joint discontinuity are also studied.

scholarly journals Vibration Power Flow of an Infinite Cylindrical Shell Submerged in Viscous Fluids

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Haosen Chen ◽  
Peng Yang ◽  
Yijun Shen
Keyword(s):  
Cylindrical Shell ◽  
Flow Field ◽  
Integral Method ◽  
Power Flow ◽  
Coupled System ◽  
Input Power ◽  
Wave Number ◽  
Acoustic Medium ◽  
Fluid Viscosity ◽  
Vibration Power Flow

In the previous investigations of the vibroacoustic characteristics of a submerged cylindrical shell in a flow field, the fluid viscosity was usually ignored. In this paper, the effect of fluid viscosity on the characteristics of vibration power flow in an infinite circular cylindrical shell immersed in a viscous acoustic medium is studied. Flügge’s thin shell theory for an isotropic, elastic, and thin cylindrical shell is employed to obtain the motion equations of the structure under circumferential-distributed line force. Together with the wave equations for the viscous flow field as well as continuity conditions at the interface, the vibroacoustic equation of motion in the coupled system is derived. Numerical analysis based on the additional-damping numerical integral method and ten-point Gaussian integral method is conducted to solve the vibroacoustic coupling equation with varying levels of viscosity. Then, the variation of the input power flow against the nondimensional axial wave number in the coupled system with different circumferential mode numbers is discussed in detail. It is found that the influence of fluid viscosity on the vibroacoustic coupled system is mainly concentrated in the low-frequency band, which is shown as the increase of the crest number and amplitude of the input power flow curves.

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

2013 ◽  
Vol 136 (1) ◽  
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.

Structure-Borne Power Transmission in Thin Naturally Orthotropic Plates: General Case

2003 ◽  
Vol 9 (10) ◽  
pp. 1189-1199 ◽  
Author(s):  
Nirmal Kumar Mandal ◽  
Roslan Abd. Rahman ◽  
M. Salman Leong
Keyword(s):  
Fourier Transform ◽  
Power Flow ◽  
Power Transmission ◽  
Far Field ◽  
Orthotropic Plates ◽  
Flow Estimation ◽  
Structural Intensity ◽  
Vibration Power Flow ◽  
Conventional Idea ◽  
Bending Wave

The structural intensity technique is usually used to estimate vibration power flow in structures. This method is used to determine vibration power flow in thin naturally orthotropic plates. The bending wave is considered to find general vibration power transmission in the frequency domain that is not approximated by far field conditions. This intensity formulation defines power flow per unit width of the plates (W m−1) similar to that of the conventional idea. Power flow estimation is formulated using cross-spectra of field signals, facilitating the use of a fast Fourier transform analyzer.

Research on Vibration Isolation Parameters of Double-Deck Isolation System of Heat Water Pump

2013 ◽  
Vol 694-697 ◽  
pp. 316-320
Author(s):  
Xiang Jun Kong ◽  
Er Ming Song ◽  
Chang Zheng Chen
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Mass Effect ◽  
Transmitted Power ◽  
Intermediate Mass ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Upper Deck ◽  
Vibration Power Flow

Isolation system of the heat water pumps can be simplified as a double sources exciting and double output double-deck vibration isolation system model, expressions of transmitted power flow and vibration speed to the basement are deduced based on the double sources exciting and double output double-deck vibration isolation system electric-force(E-F) analog picture, the curves of power flow and vibration speed transmitted to basement how the upper deck vibration isolation and intermediate mass effect are drawn by using mat lab program. The results show that the adjusting the upper deck vibration isolation stiffness parameters has little effect on the amplitude of vibration power flow, increasing intermediate mass can move first peak to the low frequency, increasing intermediate mass can obviously reduce t transmitted power flow and transmitted vibration speed amplitude to the basement.

Structure Vibration Shape Optimization Based on Power Flow Response Analysis

2014 ◽  
Vol 490-491 ◽  
pp. 712-718
Author(s):  
Xue Bao Xia ◽  
Yang Xiang ◽  
Shao Wei Wu
Keyword(s):  
Shape Optimization ◽  
Mode Shape ◽  
Power Flow ◽  
Flow Analysis ◽  
Optimization Method ◽  
Weight Coefficient ◽  
Surface Shape ◽  
Response Analysis ◽  
Flow Response ◽  
Vibration Power Flow

Power flow analysis is a method to describe the dynamic behavior of structures by taking not only the amplitude of exciting force and velocity response into account, but also the phase between the two qualities. Shape optimization is an effective method to reduce vibration level. By choosing the vibration power flow as design objective, a shape optimization method of structure is presented. The structure surface is restructured with a series of mode shape superposition. By using genetic algorithm, the weight coefficient of each mode shape is optimized to get the best surface shape with minimum power flow response. Some examples are demonstrated to verify the efficiency and accuracy of the method.

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