scholarly journals An Empirical Method for Particle Damping Design

2004 ◽  
Vol 11 (5-6) ◽  
pp. 647-664 ◽  
Author(s):  
Zhi Wei Xu ◽  
K.W. Chan ◽  
W.H. Liao
Keyword(s):  
Vibration Suppression ◽  
Empirical Method ◽  
Steel Beam ◽  
Structural Systems ◽  
Practical Applications ◽  
Particle Damping ◽  
Suppression Method

Particle damping is an effective vibration suppression method. The purpose of this paper is to develop an empirical method for particle damping design based on extensive experiments on three structural objects – steel beam, bond arm and bond head stand. The relationships among several key parameters of structure/particles are obtained. Then the procedures with the use of particle damping are proposed to provide guidelines for practical applications. It is believed that the results presented in this paper would be helpful to effectively implement the particle damping for various structural systems for the purpose of vibration suppression.

Vibration suppression method of humanoid flexible arm based on model-free predictive control

2021 ◽  
pp. 1-9
Author(s):  
Qinjun Du ◽  
Chuanming Song ◽  
Wei Ding ◽  
Long Zhao ◽  
Yonggang Luo
Keyword(s):  
Predictive Control ◽  
Vibration Suppression ◽  
Model Free ◽  
Flexible Arm ◽  
Suppression Method

Vibration suppression of wind turbine nacelle with active electromagnetic mass damper systems using adaptive backstepping control

2021 ◽  
pp. 107754632199887
Author(s):  
Sinan Basaran ◽  
Fevzi Cakmak Bolat ◽  
Selim Sivrioglu
Keyword(s):  
Vibration Suppression ◽  
Controller Design ◽  
Wind Load ◽  
Backstepping Control ◽  
Structural Systems ◽  
Adaptive Backstepping ◽  
Electromagnetic Mass ◽  
Flow Induced Vibration ◽  
Adaptive Backstepping Control ◽  
Mass Damper

Many structural systems, such as wind turbines, are exposed to high levels of stress during operation. This is mainly because of the flow-induced vibrations caused by the wind load encountered in every tall structure. Preventing the flow-induced vibration has been an important research area. In this study, an active electromagnetic mass damper system was used to eliminate the vibrations. The position of the stabilizer mass in the active electromagnetic mass damper system was determined according to the displacement information read on the system without using any spring element, unlike any conventional system. The proposed system in this study has a structure that can be implemented as a vibration suppressor in many intelligent structural systems. Two opposing electromagnets were used to determine the instant displacement of the stabilizer mass. The control currents to be given to these electromagnets are determined by using an adaptive backstepping control design. The adaptive controller algorithm can predict the wind load used in the controller design without prior knowledge of the actual wind load. It was observed that the designed active electromagnetic mass damper structure is successful in suppressing system vibrations. As a result, the proposed active electromagnetic mass damper system has been shown to be suitable for structural systems in flow-induced vibration damping.

An Active Vibration Suppression Method for Macro-Mini Manipulator

2021 ◽  
Author(s):  
Junjie Dai ◽  
Chin-Yin Chen ◽  
Renfeng Zhu ◽  
Guilin Yang ◽  
Chongchong Wang ◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Active Vibration Suppression ◽  
Active Vibration ◽  
Suppression Method

scholarly journals MR Damper-Based Vibration Suppression Method for Control Moment Gyroscope

2018 ◽  
Vol 36 (5) ◽  
pp. 884-889
Author(s):  
Wendong Wang ◽  
Xing Ming ◽  
Yang Chu ◽  
Minghui Liu ◽  
Yikai Shi
Keyword(s):  
Active Control ◽  
Control Algorithm ◽  
Vibration Suppression ◽  
Control Method ◽  
Magnetorheological Damper ◽  
Magnetic Flux Density ◽  
Damping Force ◽  
Control Moment Gyroscope ◽  
Control Moment ◽  
Suppression Method

To restrain the interference of micro-vibration caused by Control Moment Gyroscope, a new control method based on Magnetorheological damper was proposed in this paper. A mechanical model based on the structure of the presented design was built, and the semi-active control algorithm of damping force was proposed for the designed Magnetorheological damper. The magnetic flux density and other magnetic field parameters were considered and analyzed in Maxwell, and also the related hardware circuit which implements the control algorithm was prepared to test the presented design and algorithm. The results of simulation and experiments show that the presented Magnetorheological damper model and semi-active control algorithm can complete the requirements, and the vibration suppression method is efficient for Control Moment Gyroscope.

Coupling Simulation Algorithm of Dynamic Feature of a Plate With Particle Dampers Under Centrifugal Loads

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Zhaowang Xia ◽  
Xiandong Liu ◽  
Yingchun Shan
Keyword(s):  
Vibration Suppression ◽  
Extreme Temperature ◽  
Extreme Environment ◽  
Dynamic Feature ◽  
Simulation Algorithm ◽  
Centrifugal Forces ◽  
Granular Particle ◽  
Particle Damping ◽  
Particle Dampers ◽  
Element Method

Particle damper comprises granular particle enclosed in a container within a vibrating structure. The performance of particle damper is strongly nonlinear whose energy dissipation is derived from a combination of mechanisms including plastic collisions and friction between particles or particles and cavity walls. Particle damper containing suitable materials may be effective in a wider temperature range than most other types of passive damping devices. Therefore, it may be applied in extreme temperature environments where most conventional dampers would fail. It may also attenuate vibrations over a broad range of frequencies and cost less. Researches have indicated that particle damper could be a viable option for extreme environment applications. However, to date, no effort has come forward the can prove analytically or numerically that the particle damping is a viable solution for vibration suppression under centrifugal forces. In this paper, a coupling simulation algorithm based on the discrete element method and finite element method and the results of simulative studies aimed at understanding the effects of parameters of particle damper under centrifugal forces are presented. And the results show that the presented coupling simulation algorithm is effective and the analyses of dynamic feature of a plate with particle dampers under centrifugal loads are reasonable.

scholarly journals Practical Fire Safety Assessment of Steel-beam Floors Made According to the Old Technologies – an Exemplary Case Study. Influence of the Initial Assumptions on the Final Results of Analyses

2017 ◽  
Author(s):  
Pawel Artur Krol
Keyword(s):  
Fire Resistance ◽  
Structural Design ◽  
Safety Assessment ◽  
Steel Beam ◽  
Practical Applications ◽  
Standard Fire ◽  
The Subject ◽  
Technical Features ◽  
The Eu

The purpose of this article is to present procedures and methodsfor assessing fire resistance of steel-beam floors with thejoists hidden within the thickness of the slab. These technologiesare currently experiencing their renaissance, both in contemporarilydesigned buildings and the existing ones, subjectedto comprehensive redevelopment, refurbishment or modernization.Due to their simplicity and ease of execution, these floorsare just perfect as technology ideal for repairs or alterations ofbuildings under use or in the case of need of complete replacementof existing floors with new ones. These arguments justifythe need to raise the subject of proper safety assessment of thesefloors in relation to the regulations and requirements of lawsapplicable in the EU and pursuant to provisions of the latestcodes for structural design. A significant part of the study consistsof a suggestive computational example, which is a sort ofguide, in which the author, by making detailed step-by-step calculationsproduces a finished pattern of procedure, intended formultiple use. The suggested method of procedure can be successfullyused in the assessment of the fire resistance of floorstructures with similar technical features. The computationalexample presented in the study shows that contrary to a popularbelief, the use of standard fire model does not always leadto conservative estimates. In the article summary, the authorformulates a number of practical applications and conclusions.

On Vibration Suppression and Energy Dissipation Using Tuned Mass Particle Damper

2016 ◽  
Author(s):  
Shilong Li ◽  
J. Tang
Keyword(s):  
Primary Structure ◽  
Vibration Suppression ◽  
Tuned Mass Damper ◽  
Harsh Environment ◽  
Gravitational Acceleration ◽  
Mass Particle ◽  
Damping Effect ◽  
Numerical Studies ◽  
Mass Damper ◽  
Particle Damping

Particle damping has the promising potential for attenuating the unwanted vibrations in harsh environment. However, the damping performance of the conventional particle damper (PD) may be ineffective, especially when the acceleration of the particle damper is less than gravitational acceleration (1g). In order to improve the damping performance of the traditional PD, the tuned mass particle damper (TMPD) which utilizes the advantages of both the tuned mass damper and particle damper is investigated in this paper. The TMPD can act as the tuned mass damper to not only absorb the vibration of the primary structure but also amplify the motions of the particles in the enclosure, which will significantly enhance the particle damping effect. To analyze the damping effect of the TMPD, a new coupling method to integrate the TMPD into the continuous host structure is first developed. The 3D discrete element method is then adopted to accurately describe and analyze the motion of particles in the enclosure. Furthermore, the analysis is validated by correlating the numerical and experimental results. With the new method as basis, detailed numerical studies are further carried out to verify the damping effectiveness of the TMPD compared with conventional PD under various excitation levels. The results demonstrate that the TMPD can significantly improve the damping effect of the conventional PD on suppressing the vibration of the primary structure under both the low and high excitation levels.

H 2, Mixed H2/H∞ and H2/L1 Optimally Tuned Passive Isolators and Absorbers

1998 ◽  
Vol 120 (2) ◽  
pp. 282-287 ◽  
Author(s):  
Wassim M. Haddad ◽  
Ali Razavi
Keyword(s):  
Frequency Response ◽  
Ad Hoc ◽  
Vibration Suppression ◽  
Peak Frequency ◽  
Optimization Method ◽  
Worst Case ◽  
Practical Applications ◽  
System Vibration ◽  
Response Performance ◽  
Optimization Schemes

In many practical applications, unbalanced rotating machinery cause vibrations that transmit large oscillatory forces to the system foundation. Using ad hoc optimization schemes tuned isolators and absorbers have traditionally been designed to suppress system vibration levels by attempting to minimize the peak frequency response of the force/displacement transmissibility system transfer function. In this paper, we formulate the classical isolator and absorber vibration suppression problems in terms of modern system theoretic criteria involving H2 (shock response), mixed H2/H∞ (worst-case peak frequency response), and mixed H2/L1 (worst-case peak amplitude response) performance measures. In particular, using a quasi-Newton optimization method we design H2, mixed H2/H∞ and mixed H2/L1 optimally tuned isolators and absorbers for multi-degree-of-freedom vibrational systems. Finally, we compare our results to the classical Snowdon and Den Hartog absorbers.

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