Vibrational Power Flow Analysis of Stiffened Plate and Shell Structures

2011 ◽  
Vol 66-68 ◽  
pp. 1897-1901 ◽  
Author(s):  
Xiang Zhu ◽  
Gong Yu Xiao ◽  
Tian Yun Li ◽  
Xiao Fang Hu
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Input Power ◽  
Shell Structures ◽  
Stiffened Plate ◽  
Simply Supported ◽  
Plate And Shell ◽  
Flow Vectors

In this paper, the vibration and power flow characteristics of stiffened plate and cylindrical shell structures are investigated by using finite element method. The power flow formulas of basic shell structural elements are given at first. Then a simply supported plate and stiffened plate’s input power flow characteristics and power flow vectors are investigated. The effects of stiffeners in plates are discussed. For a simply supported cylindrical shell, the influence of the structural damping, viscous damper and stiffeners on the cylindrical shell’s input power flow characteristics and propagated power flow characteristics are discussed in detail. The power flow vectors are visualized to reveal the distribution of energy in the shell structures. Some useful conclusions are drown and helpful for the vibration control of plate and shell structures.

scholarly journals Analysis of the input power flow characteristics of cylindrical shells with combination boundaries

2018 ◽  
Vol 38 (1) ◽  
pp. 93-109
Author(s):  
Luyun Chen ◽  
Yong Liu
Keyword(s):  
Cylindrical Shell ◽  
Power Flow ◽  
Flow Characteristics ◽  
Rigid Wall ◽  
Input Power ◽  
Mirror Image ◽  
Image Method ◽  
Acoustic Space ◽  
Boundary Characteristics ◽  
Power Flow Problem

In this study, the input power flow problem of the cylindrical shell with complex acoustic boundaries was investigated. According to the acoustic characteristic of control domain which combination free interface and rigid wall interface at the same time for the cylindrical shell, the double reflection method and mirror image method were applied, and the analytical function of the input power flow for the cylindrical shell was derived. Finally, a cylindrical shell in the quarter-infinite acoustic space for example, the numerical calculation of input power flow of cylindrical shell was carried out. The influences of acoustic boundary characteristics, location, and frequency on the input power flow were compared. In addition, the effectiveness and convergence of the proposed method was verified using finite element method.

Wave Propagation and Power Flow Analysis of Sandwich Structures With Internal Absorbers

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
J. S. Chen ◽  
R. T. Wang
Keyword(s):  
Wave Propagation ◽  
Power Flow ◽  
Wave Attenuation ◽  
Sandwich Structures ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Continuum Models ◽  
Sandwich Beams ◽  
The Core ◽  
In Series

This study examines wave attenuation and power flow characteristics of sandwich beams with internal absorbers. Two types of absorbing systems embedded in the core are considered, namely, a conventional spring-mass-dashpot system having a mass with a spring and a dashpot in parallel, and a relaxation system containing an additional relaxation spring added in series with the dashpot. Analytical continuum models used for interpreting the attenuation behavior of sandwich structures are presented. Through the analysis of the power flowing into the structure, the correlation of wave attenuation and energy blockage is revealed. The reduction in the power flow indicates that some amount of energy produced by the external force can be effectively obstructed by internal absorbers. The effects of parameters on peak attenuation, bandwidth, and power flow are also studied.

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.

The Vibro-Acoustic Characteristics of the Cylindrical Shell Partially Submerged in the Fluid

2012 ◽  
Vol 170-173 ◽  
pp. 2303-2311 ◽  
Author(s):  
Wen Bing Ye ◽  
Tian Yun Li ◽  
Xiang Zhu
Keyword(s):  
Cylindrical Shell ◽  
Free Surface ◽  
Power Flow ◽  
Sound Pressure ◽  
Harmonic Excitation ◽  
Input Power ◽  
Far Field ◽  
Fluid Coupling ◽  
Vibrational Power Flow ◽  
Field Sound

The characteristics of the sound radiation and vibrational power flow of the partially submerged cylindrical shell under a harmonic excitation are studied. The approximate acoustic boundary of the free surface is used to solve the fluid domain. The structure-fluid coupling equation is established based on the Flügge and Helmholtz theories. The far-field sound pressure is calculated and compared with that in infinite field. It is found that the far-field sound pressure presents large gap in different immersion status in the presence of the free surface while the results of the input power flow in these cases have less differences.

Nonlinear Input Power Flow Analysis of a Plate with a Breathing Crack

2014 ◽  
Vol 638-640 ◽  
pp. 163-167
Author(s):  
Zhong Hao Pang ◽  
Xiang Zhu ◽  
Tian Yun Li ◽  
Ling Zhang
Keyword(s):  
Nonlinear Dynamic ◽  
Power Flow ◽  
Damage Identification ◽  
Flow Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Nonlinear Behavior ◽  
Input Power ◽  
Breathing Crack ◽  
Engineering Structures ◽  
Power Characteristics

Plates are commonly used in engineering structures. However crack is the most common form of damages in the plate structures. The crack in the plate will open and close during vibrational cycle, making the cracked structure with nonlinear dynamic characteristics. Based on vibrational power flow theory, the nonlinear dynamic analysis of a plate structure is carried out. The contact elements are used to simulate the nonlinear behavior of the breathing crack. Aiming to study the input power characteristics and the super harmonic resonance of a breathing cracked plate which is under the resonant excitation. By the finite element calculation, the structural input power curve is analyzed, which provides a theoretical basis for the damage identification of cracked structures.

Power Flow Analysis for Complicated System

2003 ◽  
Author(s):  
Lingling Sun ◽  
Kongjie Song
Keyword(s):  
Structural Analysis ◽  
Power Flow ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Theoretical Models ◽  
Rigid Foundation ◽  
Analysis Method ◽  
Power Flow Control ◽  
Reasonable Choice ◽  
Isolation Systems

The generalized theoretical models for vibrating machines isolated by multiple elastic mounts or by a mount-raft-mount system from non-rigid foundation were proposed. The structural analysis method was developed based on the power flow control perspectives. The dynamic transmission equations were derived to predict the power flow characteristics between subsystems. Numerical calculations of power flow for practical isolation systems were carried out to explore the interaction between the mounting frequency and the flexibility of supporting structure. The effects of mounting frequency on the power transmitted to the foundation were discussed. It is shown that the power flow can be reduced effectively by reasonable choice of mounting frequency.

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