Analysis of the coupling characteristics of a tapered three-guide coupled system

1990 ◽  
Vol 8 (10) ◽  
pp. 1621-1629 ◽  
Author(s):  
Y. Cai ◽  
T. Mizumoto ◽  
Y. Naito
Keyword(s):  
Coupled System ◽  
Coupling Characteristics

Structural-Acoustic Coupling Analysis of Two Cavities Connected by Boundary Structures and Small Holes

2005 ◽  
Vol 127 (6) ◽  
pp. 566-574 ◽  
Author(s):  
Chang-Gi Ahn ◽  
Hyoung Gil Choi ◽  
Jang Moo Lee
Keyword(s):  
Low Frequency ◽  
Coupled System ◽  
Expansion Method ◽  
Mode Shapes ◽  
Coupling Analysis ◽  
Theoretical Formulation ◽  
Modal Expansion ◽  
Acoustic Coupling ◽  
Coupling Characteristics ◽  
Small Holes

In some passenger vehicles, unexpected acoustic modes in the low-frequency range may be observed that cannot be explained by the conventional vibro-acoustic coupling analysis. It is because these methods only use the dynamic characteristics of a vehicle structure and its compartment cavity. However, some small holes or gaps existing at the boundaries between the compartment cavity and the trunk cavity of the vehicles change the modal characteristics of a coupled system. In this paper, a new analytical method is presented to investigate the structural-acoustic coupling characteristics of two cavities connected by small holes and in-between boundary structures. Small holes are modeled as an equivalent mass-spring-damper system in the analysis. A theoretical formulation for vibro-acoustic characteristics of this system is made, and the modal expansion method is used to obtain eigenvalues and their mode shapes. The validity of the proposed method is successfully examined by comparing the results of the analytical predictions with those of experiments.

scholarly journals Modelling and Analysis of Global Vibroacoustic Coupling Characteristics of a Rectangular Enclosure Bounded by a Flexible Panel

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Fei Xue ◽  
Beibei Sun
Keyword(s):  
Boundary Conditions ◽  
Structural Parameters ◽  
Sound Field ◽  
Coupled System ◽  
Structure Design ◽  
Transfer Factors ◽  
Coupling Property ◽  
Flexible Panel ◽  
Global Coupling ◽  
Coupling Characteristics

The interaction between the sound field in an enclosure and its flexible panel is a critical problem; the influence of structural parameters on global vibroacoustic coupling characteristics of the panel-enclosure system is very important. In this paper, a novel index of the global coupling level was first proposed to describe the global vibroacoustic coupling extent between multiple panel vibration modes and enclosure acoustical modes of the coupled system. Then, the influence of structural parameters on global coupling levels of the coupled system with different panel boundary conditions was obtained based on the numerical results of transfer factors. Moreover, according to the comprehensive influence of the structural parameters on global coupling levels, design methods of the coupled system with low global coupling levels were then discussed. Finally, the influence mechanism of panel boundary conditions on the coupling characteristics of the coupled system was analyzed. The results show that the structural parameters have similar effect on the coupling property of the system with different panel boundary conditions. Furthermore, the influence of the structural parameters on the coupling property of the system with a clamped panel is more sensitive than that of the system with a simply supported one. Furthermore, the structural parameters, especially the enclosure depth and panel thickness, are not completely negative correlated to the global coupling levels of the system. In conclusion, this study could provide a theoretical basis for acoustical design of the panel-enclosure system (e.g., rectangular vehicle cabins) with low global coupling level, as well as the lightweight structure design of the system.

Analysis of Structure–Acoustic Coupling Characteristics Between Adjacent Flexible Panels and Enclosed Cavity

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Jie Zhang ◽  
Jian Pang ◽  
Yuping Wan ◽  
Liang Yang ◽  
Wenyu Jia ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Structural Characteristics ◽  
Coupled System ◽  
Coupling Mechanism ◽  
Coupling Coefficients ◽  
Mathematical Methods ◽  
Modal Expansion ◽  
Acoustic Coupling ◽  
Coupling Characteristics ◽  
Flexible Panels

Abstract This article studies the structure–acoustic coupling mechanism between two adjacent flexible panels and an enclosed cavity by analytical and mathematical methods based on modal expansion methods and impedance mobility techniques. The results show that the coupling relations among subsystem modes of the coupled system have selectivity characteristics. The coupling strength depends on the normalized mode–shape coupling coefficients. The coupling relationship between two flexible panels is established through the enclosed cavity. The structural–acoustic coupling effect mainly affects the low-order modes of the coupled system, especially the first-order modes of the panels and cavity. When one panel is weakly coupled with the cavity, the two flexible panels are decoupled. The vibration of the panel only depends on its structural characteristics and external excitation, and the panel radiates sound into the cavity. The vibration of another panel depends not only on its structural characteristics but also on its coupling effect with the cavity.

scholarly journals Dynamic Modeling and Coupling Characteristic Analysis of Two-Axis Rate Gyro Seeker

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Shixiang Liu ◽  
Tianyu Lu ◽  
Teng Shang ◽  
Qunli Xia
Keyword(s):  
Block Diagram ◽  
Cross Coupling ◽  
Coupled System ◽  
Open Loop ◽  
Servo Control ◽  
Control Mode ◽  
Characteristic Analysis ◽  
Rate Gyro ◽  
Coupling Characteristics ◽  
Stabilized Platform

A dynamic model of a two-axis rate gyro-stabilized platform-based seeker with cross-coupling, mass imbalance, and disturbance torque is developed on the basis of the working principle of seeker two-loop steady tracking theory; coordinate transformations are used to analyze the effects of seeker servo control mode on missile guidance and control systems. Frequency domain is used to identify the servo motor transfer function. Furthermore, a block diagram of the two-gimbal-coupled system is developed, and the coupling characteristics of gimbal angle are analyzed with different missile body inputs. Simulation results show that the analysis conforms with the actual movement rule of seeker gimbal and optical axis, and cross-coupling exists between the two gimbals. The lag compensation network can increase the open loop gain and increase the capacity for disturbance rate rejection. Simulations validate the theory and technology support for developing the seeker servo control model in engineering.

Shape Optimization of Hydraulic Structures: an Example of an Optimum Design of a Fish Passage

10.29007/2k64 ◽  
2018 ◽  
Author(s):  
Pat Prodanovic ◽  
Cedric Goeury ◽  
Fabrice Zaoui ◽  
Riadh Ata ◽  
Jacques Fontaine ◽  
...  
Keyword(s):  
Numerical Model ◽  
Shape Optimization ◽  
Objective Function ◽  
Optimum Design ◽  
Optimization Problem ◽  
A Priori ◽  
Coupled System ◽  
Fish Passage ◽  
Hydraulic Structures ◽  
Design Variables

This paper presents a practical methodology developed for shape optimization studies of hydraulic structures using environmental numerical modelling codes. The methodology starts by defining the optimization problem and identifying relevant problem constraints. Design variables in shape optimization studies are configuration of structures (such as length or spacing of groins, orientation and layout of breakwaters, etc.) whose optimal orientation is not known a priori. The optimization problem is solved numerically by coupling an optimization algorithm to a numerical model. The coupled system is able to define, test and evaluate a multitude of new shapes, which are internally generated and then simulated using a numerical model. The developed methodology is tested using an example of an optimum design of a fish passage, where the design variables are the length and the position of slots. In this paper an objective function is defined where a target is specified and the numerical optimizer is asked to retrieve the target solution. Such a definition of the objective function is used to validate the developed tool chain. This work uses the numerical model TELEMAC- 2Dfrom the TELEMAC-MASCARET suite of numerical solvers for the solution of shallow water equations, coupled with various numerical optimization algorithms available in the literature.

Nonlinear singular one dimensional thermo-elasticity coupled system and double Laplace decomposition methods

Filomat ◽  
2017 ◽  
Vol 31 (20) ◽  
pp. 6269-6280
Author(s):  
Hassan Gadain
Keyword(s):  
Laplace Transform ◽  
Decomposition Method ◽  
Adomian Decomposition Method ◽  
Coupled System ◽  
Decomposition Methods ◽  
One Dimensional ◽  
Convergence Proof ◽  
Double Laplace Transform ◽  
Adomian Decomposition

In this work, combined double Laplace transform and Adomian decomposition method is presented to solve nonlinear singular one dimensional thermo-elasticity coupled system. Moreover, the convergence proof of the double Laplace transform decomposition method applied to our problem. By using one example, our proposed method is illustrated and the obtained results are confirmed.

scholarly journals Combustion Optimization for Coal Fired Power Plant Boilers Based on Improved Distributed ELM and Distributed PSO

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1036 ◽  
Author(s):  
Xinying Xu ◽  
Qi Chen ◽  
Mifeng Ren ◽  
Lan Cheng ◽  
Jun Xie
Keyword(s):  
Power Plant ◽  
Combustion Process ◽  
Optimization Method ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Nox Emissions ◽  
Coupling Characteristics ◽  
Learning Machine ◽  
Combustion Optimization

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.

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