An Active Dynamic Vibration Absorber for a Hand-Held Vibro-Elastography Probe

2006 ◽  
Vol 129 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Hassan Rivaz ◽  
Robert Rohling
Keyword(s):  
Single Frequency ◽  
Vibration Absorber ◽  
Imaging Method ◽  
Vibration Source ◽  
Dynamic Vibration Absorber ◽  
Tissue Properties ◽  
Vibration Absorption ◽  
Dynamic Vibration ◽  
High Level ◽  
Tissue Motion

Vibro-elastography is a new medical imaging method that identifies the mechanical properties of tissue by measuring tissue motion in response to a multi-frequency external vibration source. Previous research on vibro-elastography used ultrasound to measure the tissue motion and system identification techniques to identify the tissue properties. This paper describes a hand-held probe with a combined vibration source and ultrasound transducer to implement the new method as a practical device. The device uses a proportional integral active dynamic vibration absorber with an electromagnetic actuator to counterbalance the reaction forces from contact with the tissue. Experiments show an operational frequency range of 5-20Hz, with at least 15dB vibration absorption in 0.4s for single frequency excitation. Experiments with variable frequency and amplitude excitation also show a high level of vibration absorption.

scholarly journals Attenuation of Motorcycle Handle Vibration Using Dynamic Vibration Absorber

2018 ◽  
Vol 217 ◽  
pp. 01006
Author(s):  
Muhammad Iyad Al-Maliki Saifudin ◽  
Nabil Mohamad Usamah ◽  
Zaidi Mohd Ripin
Keyword(s):  
Vibration Absorber ◽  
Primary System ◽  
Additional Source ◽  
Dynamic Vibration Absorber ◽  
Vibration Absorption ◽  
The Road ◽  
Dynamic Vibration ◽  
Attenuation Level ◽  
Road Surface Roughness ◽  
Extended Exposure

Motorcycle riders are exposed to hand-transmitted vibration of the hand-arm system due to the vibration of the handle and extended exposure can result in numbness and trembling. One feasible solution to attenuate the handle vibration is by using a dynamic vibration absorber (DVA). In this work a DVA is designed and mounted on the motorcycle handle in order to reduce the vibration at the handle by transferring the vibration from the primary system handle to the secondary mass. Removal of elastomeric material at the DVA mounting locations, symmetry of secondary mass and the direction of DVA attachment influence the vibration absorption. A series of tests conducted show that the vibration on the handle is mainly induced by the engine and there is additional source of vibration from the road surface roughness. Installation of DVA at different locations on the handle resulted in various attenuation levels at different speed in the x and z directions. the attenuation level is between 59-68 % in the biodynamic x-directions for speed at 30-50 kmh-1.

Damping of vibration of the car suspension at resonance

2021 ◽  
pp. 3-8
Author(s):  
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
Vibration Absorber ◽  
Optimal Parameters ◽  
Dynamic Vibration Absorber ◽  
Vibration Absorption ◽  
Dynamic Vibration ◽  
Car Suspension ◽  
Dynamic Damping ◽  
Dynamic Absorber

A block diagram of the device has been developed, which is based on the principle of dynamic vibration absorption. The design of a dynamic absorber of car suspension vibrations is considered. A mathematical model of a car suspension with a dynamic vibration absorber and the results of its numerical simulation are presented. The analysis of the results obtained makes it possible to determine the optimal parameters of the device for a dynamic vibration absorber. Keywords: suspension, car, dynamic, damping, vibration, mathematical, model, analysis, parameters

Principle, modeling, and control of a magnetorheological elastomer dynamic vibration absorber for powertrain mount systems of automobiles

2016 ◽  
Vol 28 (16) ◽  
pp. 2239-2254 ◽  
Author(s):  
Fu-Long Xin ◽  
Xian-Xu Bai ◽  
Li-Jun Qian
Keyword(s):  
Frequency Shift ◽  
Vibration Isolation ◽  
Vibration Absorber ◽  
Magnetorheological Elastomer ◽  
Dynamic Vibration Absorber ◽  
Vibration Absorption ◽  
Dynamic Vibration ◽  
Passive Vibration Isolation ◽  
Vibration Attenuation ◽  
Vibration Attenuation Performance

This article proposes and validates the principle of a new magnetorheological elastomer (MRE) dynamic vibration absorber (DVA) for powertrain mount systems of automobiles. The MRE DVA consists of a vibration absorption unit and a passive vibration isolation unit. The vibration absorption unit composed of a magnetic conductor, a shearing sleeve, a bobbin core, an electromagnetic coil, and a circular cylindrical MRE is utilized to absorb the vibration energy, and the passive vibration isolation unit is used to support the powertrain. The finite element method is employed to validate the electromagnetic circuit of the MRE DVA and obtain the electromagnetic characteristics. The theoretical frequency-shift principle is analyzed via the established constitutive equations of the circular cylindrical MRE In order to demonstrate how the parameters of the MRE influence the vibration attenuation performance, the MRE DVA is applied to a powertrain mount system to replace the conventional passive mount. The frequency-shift property of the vibration absorption unit and the vibration attenuation performance of the MRE DVA on the powertrain mount system are experimentally tested. To validate and improve the vibration attenuation performance for the semi-active powertrain mount systems, an optimal variable step algorithm is proposed for the MRE DVA and numerical experiments are carried out.

scholarly journals Dynamic vibration absorption design and parameter analysis of oil tank wall of transformer

2021 ◽  
Vol 248 ◽  
pp. 01069
Author(s):  
Hong Zhang ◽  
Meigen Cao
Keyword(s):  
Vibration Reduction ◽  
Parameter Analysis ◽  
Mode Analysis ◽  
Vibration Absorber ◽  
Vibration Source ◽  
Tank Wall ◽  
Mass Ratio ◽  
Vibration Absorption ◽  
Dynamic Vibration ◽  
Oil Tank

Taking a 10kV test transformer as the research object, based on the analysis of transformer vibration and noise vibration sources, the oil tank model of the test transformer is established firstly, and the vibration mode analysis of the oil tank is carried out, and the typical vibration modes of transformer oil tanks with different thicknesses are obtained Then, according to the characteristics of vibration and vibration source of distribution transformer tank wall, the design method and parameter optimization analysis of transformer tank wall vibration absorption are carried out. The analysis shows that the principle of dynamic vibration absorption is clear, and the vibration of the box wall can be effectively controlled with 76% vibration reduction efficiency under the condition of reasonable arrangement of vibration absorption devices and parameter selection. The vibration control effect of vibration absorber increases with the increase of mass ratio between vibration absorber and transformer tank wall. When the mass ratio is determined, the closer the stiffness of vibration absorber is to the optimal stiffness, the better the vibration reduction effect will be.

Research of Two-Series-Mass Dynamic Vibration Absorber and it’s Application on Building Vibration Control

2011 ◽  
Vol 368-373 ◽  
pp. 146-149
Author(s):  
Gong Yu Pan ◽  
Ying Zhang
Keyword(s):  
Vibration Control ◽  
Total Mass ◽  
Absorption Efficiency ◽  
Vibration Absorber ◽  
Mass Ratio ◽  
Dynamic Vibration Absorber ◽  
Vibration Absorption ◽  
Dynamic Vibration ◽  
Simulation And Experiment ◽  
Single Mass

Multiplexing the dynamic vibration absorber (DVA) has tried for improving the vibration absorption efficiency of the dynamic vibration absorber, and because there are several tuning vibration frequencies in the multi-mass dynamic vibration absorber system, the vibration absorption efficiency is more excellent than a conventional single-mass dynamic vibration absorber when they are in the same total mass ratio. In this paper, a two-series-mass dynamic vibration absorber was proposed, optimal parameters of the two-series-mass dynamic vibration absorber have been calculated and vibration absorption is analyzed with the simulation and experiment. The results show that the two-series-mss dynamic vibration absorber can improve vibration absorption, in the same total mass ratio, by about 20% above that of a conventional single-mass dynamic vibration absorber. Based on the above optimal results, the two-series-mass dynamic vibration was used for vibration control on high building, and the practical measure result shows its effectiveness.

Theoretical Analysis and Experimental Study of a Cantilever Beam-Type Dynamic Vibration Absorber

2013 ◽  
Vol 415 ◽  
pp. 436-441
Author(s):  
Jun Zhao ◽  
Chao Yang Ma
Keyword(s):  
Cantilever Beam ◽  
Vibration Isolation ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Isolation System ◽  
Absorption Frequency ◽  
Vibration Absorption ◽  
Response Characteristics ◽  
Dynamic Vibration ◽  
Beam Type

Aiming at the limitation problem of constant dynamic parameters for classical vibration absorber, a new cantilever beam-type absorber device is designed which is composed of a continuous beam and mass block, a vibration isolation system model with a beam-type absorber is established, the absorption frequency of the mass block at different positions is calculated. And based on the software of ADAMS, the frequency response characteristics of the system are obtained. Finally, the good vibration absorption of the beam absorber is verified. The results show that the feasibility and effectiveness of cantilever beam-type absorber is confirmed, and the dynamic vibration absorber with continuous adjustable parameters is achieved.

Research on Frequency-Tuned Dynamic Vibration Absorber

2011 ◽  
Vol 66-68 ◽  
pp. 1762-1768
Author(s):  
Shi Liang Jiang ◽  
Tie Jun Yang ◽  
Jing Tao Du ◽  
Yin Yin Hu
Keyword(s):  
Vibration Absorber ◽  
Beam Structure ◽  
Dynamic Vibration Absorber ◽  
Bending Vibration ◽  
Element Analysis ◽  
Simply Supported Beam ◽  
Vibration Absorption ◽  
Simply Supported ◽  
Dynamic Vibration ◽  
Resonance Frequencies

A frequency-tuned dynamic vibration absorber by tuning stiffness to reduce vibration at some troubled resonance frequencies of a simply supported beam structure is designed in this paper. Both theoretical and simulation analysis of vibration absorption are conducted. On the basis of analyzing bending vibration of the simply supported beam structure, inherent characteristics and frequency response characteristics of the simply supported beam system before and after being fixed dynamic vibration absorber are obtained by using the energy method with Rayleigh-Ritz procedure of flexible structure. Simulation model of the whole system, which is established by code written, is compared with the model established by finite element analysis software. Results are presented to show the efficiency of the vibration absorber, and then the effect of damping of the dynamic vibration absorber on vibration absorption is studied.

Numerical and experimental studies on the car body flexible vibration reduction due to the effect of car body-mounted equipment

2016 ◽  
Vol 232 (1) ◽  
pp. 103-120 ◽  
Author(s):  
Caihong Huang ◽  
Jing Zeng ◽  
Guangbing Luo ◽  
Huailong Shi
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Numerical Study ◽  
Experimental Studies ◽  
Vibration Absorber ◽  
Response Analysis ◽  
Dynamic Vibration Absorber ◽  
Vibration Absorption ◽  
Car Body ◽  
Dynamic Vibration

To study the effect of car body-mounted equipment on the car body flexible vibration, a vertical rigid-flexible coupling model of a high-speed vehicle is established, which includes a flexible car body, rigid bodies for two bogie frames, four wheelsets, and the car body-mounted equipment. The car body is approximated by an elastic beam, with dimensions selected to give similar mass and vertical bending frequency to an existing car body. Model validation is then carried out by comparing results from numerical simulation and on-track test. Using frequency response analysis and ride comfort analysis, parametric studies are undertaken in order to investigate the respective effect of equipment mounting systems on the car body flexible vibration and ride comfort perceived by the passenger. It is found that the equipment behaves as a dynamic vibration absorber on account of its elastic connections to the car body. The stiffness, damping, mass, and installing position of the equipment have a significant influence on the car body flexible vibration. The optimal parameters of the dynamic vibration absorber are given, which can contribute much to the vibration absorption of the car body flexible vibration. Finally, extensive tests on a high-speed test vehicle are conducted to represent a part of results obtained in the numerical study, including modal tests on the car body, component tests on rubber springs used in the equipment mounting systems, and roller rig tests on the vibration absorption performance of the equipment. It is shown that the car body flexible vibration can be effectively suppressed by reasonably suspending the car body-mounted equipment.

scholarly journals Suppression of Vibration Induced by Reciprocal Motion of Displacer in Cryopump with an Active Dynamic Vibration Absorber

2019 ◽  
Vol 52 (15) ◽  
pp. 531-536
Author(s):  
Takeshi Mizuno ◽  
Takahito Iida ◽  
Yuji Ishino ◽  
Masaya Takasaki ◽  
Daisuke Yamaguchi
Keyword(s):  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration
Sign in / Sign up

Export Citation Format

Share Document