Optimization of Dynamic Vibration Absorbers for Suppressing Sound Radiation of Plate Structures

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Guanghe Huo ◽  
Zhaobo Chen ◽  
Yinghou Jiao ◽  
Xuezhi Zhu
Keyword(s):  
Fixed Points ◽  
Frequency Ratio ◽  
Vibration Suppression ◽  
Damping Ratio ◽  
Sound Radiation ◽  
Thin Plates ◽  
Optimal Frequency ◽  
Radiation Control ◽  
Dynamic Vibration ◽  
Analytical Expressions

Abstract Dynamic vibration absorber (DVA) is a practical tool used for sound and vibration suppression in the specific frequency band. The parameters of DVAs should be optimally tuned to obtain the best sound and vibration suppression application effects. When the DVAs are used for structural vibration reduction, DVAs’ two parameters which are the optimal frequency ratio and damping ratio have simple analytical expressions. However, the concise analytical expressions of the DVAs that are used for suppressing the structural sound radiations have not been reported. First, this paper investigates the characteristics of DVAs in suppressing sound radiation from thin plates. Second, the fixed points’ phenomenon of the sound radiations of the plate carrying DVAs is revealed. In addition, the classical fixed points’ theory is extended into the optimization process of the DVAs that are used for sound radiation control of the plate. The analytical expression of the optimal frequency ratio, as well as the damping ratio optimization method of the DVA, is simultaneously proposed. Third, the installation position of DVAs is also presented to obtain a better acoustic radiation effect. Finally, the numerical simulations are performed to verify the availability of the method. It is showed that the best sound radiation control effect could be obtained by adopting the optimization means proposed in this paper.

scholarly journals Optimal parameters of dynamic vibration absorber for linear damped rotary systems subjected to harmonic excitation

2020 ◽  
Author(s):  
Vu Duc Phuc ◽  
Tong Van Canh ◽  
Pham Van Lieu
Keyword(s):  
Vibration Suppression ◽  
Fixed Point Theory ◽  
Damping Ratio ◽  
Harmonic Excitation ◽  
Tuning Parameter ◽  
Vibration Absorber ◽  
Optimal Parameters ◽  
Dynamic Vibration Absorber ◽  
Practical Applications ◽  
Dynamic Vibration

Dynamic vibration absorber (DVA) is a simple and effective device for vibration absorption used in many practical applications. Determination of suitable parameters for DVA is of significant importance to achieve high vibration reduction effectiveness. This paper presents a   method to find the optimal parameters of a DVA attached to a linear damped rotary system excited by harmonic torque. To this end, a closed-form formula for the optimum tuning parameter is derived using the fixed-point theory based on an assumption that the damped rotary systems are lightly or moderately damped. The optimal damping ratio of DVA is found by solving a set of non-linear equations established by the Chebyshev's min-max criterion. The performance of the proposed optimal DVA is compared with that obtained by existing optimal solution in literature. It is shown that the proposed optimal parameters are possible to obtain superior vibration suppression compared to existing optimal formula. Extended simulations are carried out to examine the performance of the optimally designed DVA and the sensitivity of the optimum parameters. The simulation results show that the improvement of the vibration performance on damped rotary system can be as much as 90% by using DVA.

scholarly journals Mechanism Analysis and Parameter Optimization of Mega-Sub-Isolation System

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Xiangxiu Li ◽  
Ping Tan ◽  
Xiaojun Li ◽  
Aiwen Liu
Keyword(s):  
Frequency Ratio ◽  
Seismic Isolation ◽  
Structural Parameters ◽  
Damping Ratio ◽  
Great Influence ◽  
Mechanism Analysis ◽  
Control Performance ◽  
Optimal Frequency ◽  
Working Mechanism ◽  
Isolation System

The equation of motion of mega-sub-isolation system is established. The working mechanism of the mega-sub-isolation system is obtained by systematically investigating its dynamic characteristics corresponding to various structural parameters. Considering the number and location of the isolated substructures, a procedure to optimally design the isolator parameters of the mega-sub-isolation system is put forward based on the genetic algorithm with base shear as the optimization objective. The influence of the number and locations of isolated substructures on the control performance of mega-sub-isolation system has also been investigated from the perspective of energy. Results show that, with increase in substructure mass, the working mechanism of the mega-sub-isolation system is changed from tuned vibration absorber and energy dissipation to seismic isolation. The locations of the isolated substructures have little influence on the optimal frequency ratio but have great influence on the optimal damping ratio, while the number of isolated substructures shows great impact on both the optimal frequency ratio and damping ratio. When the number of the isolated substructures is determined, the higher the isolated substructures, the more the energy that will be consumed by the isolation devices, and with the increase of the number of isolated substructures, the better control performance can be achieved.

scholarly journals Longitudinal vibration compensation model of stepped-pipe strings in deep-sea mining

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241650
Author(s):  
QingHui Song ◽  
HaiYan Jiang ◽  
QingJun Song ◽  
Linjing Xiao ◽  
Qiang Liu
Keyword(s):  
Dynamic Model ◽  
Deep Sea ◽  
Vibration Suppression ◽  
Longitudinal Vibration ◽  
Damping Ratio ◽  
Sea Breeze ◽  
Analysis Method ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Spring Coefficient

In this paper, the dynamic model of the rigid space stepped-pipe strings system is derived with Lagrangian method to represent the system dynamic behaviors which enriches the analysis method of longitudinal vibration of stepped-pipe strings. The stepped-pipe strings is constructed of pipes with different diameters and lengths, the physical properties of which mainly depends on the axial force and the depth of deep-sea mining. Based on lumped element method, the heave compensation system with dynamic vibration absorber is designed for longitudinal vibration suppression of the stepped-pipe strings. The analytical solution is obtained by modal analysis method when the mining ship is subjected to sea breeze excitation. The proposed method is easily implementable for rigid space stepped-pipe strings system with complex multi-degree-of-free deep-sea mining dynamic model. Furthermore, the optimal combination of mass ratio, spring coefficient and damping ratio is shown to have a better vibration suppression performance. Finally, numerical simulations on the stepped-pipe strings system with or without dynamic vibration absorbers are provided to demonstrate the effectiveness of the proposed method.

Artificial Intelligence-Based Prediction Models for Optimal Design of Tuned Mass Dampers in Damped Structures Subjected to Different Excitations

2021 ◽  
pp. 2150120
Author(s):  
Sadegh Etedali ◽  
Zohreh Khosravi Bijaem ◽  
Nader Mollayi ◽  
Vahide Babaiyan
Keyword(s):  
Neural Network ◽  
Artificial Intelligence ◽  
White Noise ◽  
Frequency Ratio ◽  
Damping Ratio ◽  
Mass Ratio ◽  
Optimal Frequency ◽  
Inference System ◽  
Main Structure ◽  
Optimal Damping

Tuned mass damper (TMD) is a type of energy absorbers that can mitigate the vibrations of the main system if its frequency and damping ratios are well adjusted. By adopting simple assumptions on the structure and loadings, many analytical and empirical relationships have been presented for the estimation of the parameters for TMDs. In this research, methods based on the artificial intelligence (AI) techniques are proposed for optimal tuning of the TMD parameters of the main damped-structure for three kinds of loadings: white-noise base acceleration, external white-noise force, and harmonic base acceleration. For this purpose, a dataset using the cuckoo search (CS) optimization algorithm is created. The performance of the proposed methods based on the radial basis function (RBF) neural network, feed-forward neural network (FFNN), adaptive neuro-fuzzy inference system (ANFIS), and random forest (RF) techniques are evaluated by some statistical indicators. The results show the proper performance of these methods for the optimal estimation of the TMD parameters. Overall, the ANFIS method results in best matching with the observed dataset. Moreover, the simulation results indicate that the TMD’s optimal frequency ratio is reduced, while its optimal damping ratio is increased, against the increase in the TMD mass ratio of the main structure subjected to harmonic base acceleration. This trend with a less slope is observed for the optimal frequency ratio of the TMD in the main structure subjected to external white-noise force; however, the optimal damping ratio of the TMD is independent of its mass ratio in this case. Similar results are obtained for the main structure subjected to white-noise base acceleration.

Choosing Damping Parameters for the Inertial Orientation System

2021 ◽  
pp. 113-128
Author(s):  
V.P. Podchezertsev ◽  
S.V. Topilskaya
Keyword(s):  
Natural Frequency ◽  
Vibration Suppression ◽  
Outer Space ◽  
Protection System ◽  
Dynamic Vibration ◽  
Shock Absorbers ◽  
Vibration Protection ◽  
Orientation System ◽  
Vibration Impact ◽  
Vibration Dampers

The article discusses criteria for selecting the vibration protection for the spacecraft inertial orientation system. The considered vibration protection system allows providing acceptable amplitude acceleration for the gyroscopic device sensitive elements under vibration impact on the device body during the spacecraft launching and high angular stability of the position of the sensitive elements relative to the inertial coordinate system during a long period of operation (15 years) in orbit. The proposed vibration protection system consists of shock absorbers (springs) with stable high elastic characteristics under all factors of operation in the outer space and dynamic vibration dampers. The article presents a method for determining the parameters of dynamic vibration dampers taking into account the characteristics of the shock absorber, critical for the damping system of an inertial device. The proposed method for adjusting dynamic vibration dampers consists in suppressing vibrations at the natural frequency f1 of the shock absorption system and providing acceptable values of the gain coefficients of the structure resonant vibration amplitudes near the natural frequency f1. Certain characteristics of the damping system allow realizing the permissible vibration amplification coefficients at resonance, without significantly affecting the level of vibration suppression in the natural frequency zone of the vibration protection object

scholarly journals Fluid-Induced Vibration Elimination of a Rotor/Seal System with the Dynamic Vibration Absorber

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Qi Xu ◽  
Junkai Niu ◽  
Hongliang Yao ◽  
Lichao Zhao ◽  
Bangchun Wen
Keyword(s):  
Natural Frequency ◽  
Nonlinear Differential Equations ◽  
Damping Ratio ◽  
Force Model ◽  
Vibration Absorbers ◽  
Dynamic Vibration Absorber ◽  
Major Purpose ◽  
Rotating Speed ◽  
Dynamic Vibration ◽  
Nonlinear Responses

The dynamic vibration absorbers have been applied to attenuate the rotor unbalance and torsional vibrations. The major purpose of this paper is to research the elimination of the fluid-induced vibration in the rotor/seal system using the absorber. The simplified rotor model with the absorber is established, and the Muszynska fluid force model is employed for the nonlinear seal force. The numerical method is used for the solutions of the nonlinear differential equations. The nonlinear responses of the rotor/seal system without and with the absorber are obtained, and then the rotating speed ranges by which the fluid-induced instability can be eliminated completely and partially are presented, respectively. The absorber parameters ranges by which the instability vibration can be eliminated completely and partially are obtained. The results show that the natural frequency vibration due to the fluid-induced instability in the rotor/seal system can be eliminated efficiently using the absorber. The appropriate natural frequency and damping ratio of the absorber can extend the complete elimination region of the instability vibration and postpone the occurrence of the instability vibration.

Dynamic Vibration Absorber Design to Suppress Boring Chatter: Absorber Parameters Identification Based on Modal Correlation

2013 ◽  
Vol 753-755 ◽  
pp. 1816-1820 ◽  
Author(s):  
Zhen Kun Hu ◽  
Ming Wang ◽  
Tao Zan
Keyword(s):  
Damping Ratio ◽  
Correlation Method ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Element Analysis ◽  
Simple Method ◽  
Dynamic Vibration ◽  
The Finite Element Analysis ◽  
Chatter Control ◽  
Modal Method

The dynamic vibration absorber (DVA) is generally used to suppress the machining vibration in boring processes. The DVA consists of an additional massspringdamper sub-system, and needs accurately tuning of its natural frequency and damping ratio to match the main structure for vibration control. For obtaining the optimal performance of the DVA, the parameters of the DVA used in a boring bar is identified using modal correlation method, which combines the finite element analysis method with test modal method to validate the FEMs results. The analysis results show that the modal correlation method is an effective and simple method to accurately identify the dynamic parameters of DVA and guarantee the optimal design of the DVA for boring chatter control.

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