Vibration Control of Time-Varying Delay under Complex Excitation

The existing available research outcomes on vibration attenuation control for time-delay feedback indicate that, for the delay dynamic vibration absorber with fixed time-delay control parameters, under harmonic excitation, a good vibration attenuation control effect occurs on the vibration of the main system. However, the effect is not obvious for complex excitation. Aiming at the above problems, in a short time interval, a harmonic excitation with the same displacement size as the complex excitation was established. Then, by calculating its equivalent amplitude and equivalent frequency, a harmonic equivalent method for complex excitation was proposed in this paper. The time-delay parameters were adjusted according to the equivalent frequency of harmonic equivalent excitation in real time; therefore, a good vibration attenuation control effect was obtained through the delay dynamic vibration absorber in the discrete time interval. In this paper, research on a time-varying delay dynamic vibration absorber was conducted by taking the two-degree-of-freedom vibration system with a delay dynamic vibration absorber as an example. The simulation results show that the proposed control method can reduce the vibration of the main system by about 30% compared with the passive vibration absorber. This can obviously improve the performance of the time-delay dynamic vibration absorber. It provides a new technical idea for the design of vehicle active frame system.

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

Vietnam Journal of Mechanics ◽

10.15625/0866-7136/14897 ◽

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.

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Effect of delayed resonator on the vibration reduction performance of vehicle active seat suspension

Journal of Low Frequency Noise Vibration and Active Control ◽

10.1177/14613484211046458 ◽

2021 ◽

pp. 146134842110464

Author(s):

Yongguo Zhang ◽

Chuanbo Ren ◽

Kehui Ma ◽

Zhen Xu ◽

Pengcheng Zhou ◽

...

Keyword(s):

Time Delay ◽

Vibration Reduction ◽

Suspension System ◽

Vibration Response ◽

Vibration Absorber ◽

Dynamic Vibration Absorber ◽

Precise Integration ◽

Seat Suspension ◽

Dynamic Vibration ◽

Seat Vibration

The combination of dynamic vibration absorber and partial state feedback with time-delay is called delayed resonator. In order to suppress the seat vibration caused by uneven road surface and improve ride comfort, the delayed resonator is applied to the seat suspension to realize active control of the seat suspension system. The dynamic model of the half-vehicle suspension system is established, and the time-delay differential equation of the system under external excitation is solved by the precise integration method. The root mean square of the time-domain vibration response of seat displacement, seat acceleration and vehicle acceleration are selected as the objective function. Then, the optimal time-delay control parameters are obtained by particle swarm optimization algorithm. The frequency sweeping method is used to obtain the critical time-delay value and time-delay stable interval of the system. Finally, an active seat suspension model with delayed resonator is established for numerical simulation. The results show that the delayed resonator can greatly suppress the seat vibration response regardless of the road simple harmonic excitation or random excitation. Compared with dynamic vibration absorber, it has a better vibration absorption effect and a wider vibration reduction frequency band.

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

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x16672731 ◽

2016 ◽

Vol 28 (16) ◽

pp. 2239-2254 ◽

Cited By ~ 14

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.

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Research of a Dynamic Vibration Absorber with Tunable Resonant Frequency and its Vibration Attenuation Characteristics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.511-512.601 ◽

2014 ◽

Vol 511-512 ◽

pp. 601-605

Author(s):

Qiang Ma ◽

Jie Jian Di ◽

Xiao Wu Du ◽

Quan Liang Zhao

Keyword(s):

Resonant Frequency ◽

Frequency Band ◽

Vibration Absorber ◽

Geometrical Parameters ◽

Dynamic Vibration Absorber ◽

Damping Effect ◽

Dynamic Vibration ◽

Vibration Attenuation ◽

Working Frequency ◽

Attenuation Characteristics

In order to improve working frequency band and damping effect of a dynamic vibration absorber, a new kind of dynamic vibration absorber is presented. Its resonant frequency could be real-time adjusted by adapting the stiffness of the spring. The vibration attenuation characteristics are analyzed theoretically and numerically. According to simulation analysis, effects of geometrical parameters are researched and optimum geometric parameters are determined. The damping effect was simulated in a flat structure, the results show that the working frequency band and damping effect of the DVA are both remarkable.

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A Simple Method to Design and Analyze Dynamic Vibration Absorber of Pipeline Structure Using Dimensional Analysis

Shock and Vibration ◽

10.1155/2020/2478371 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Mehrdad Shemshadi ◽

Mahdi Karimi ◽

Farzad Veysi

Keyword(s):

Dimensional Analysis ◽

Experimental Studies ◽

Experimental Tests ◽

Harmonic Excitation ◽

Vibration Absorber ◽

Concentrated Mass ◽

Dynamic Vibration Absorber ◽

Simple Method ◽

Dynamic Vibration ◽

Pipe Vibration

Vibrations due to mechanical excitation and internal and external fluid flow can cause fatigue in pipelines and leaks in fittings. A beam-based dynamic vibration absorber (beam DVA) is a device comprising an L-shaped beam with a concentrated mass at its free end that can be used to absorb and dissipate vibrations in the pipeline. In this paper, a mathematical equation is extracted to design the beam DVA using the dimensional analysis (DA) method and data recorded from 120 experimental tests. In the experimental studies, the pipes are fabricated in 1-inch, 2-inch, and 3-inch sizes. Each pipe is subjected to harmonic excitation at different frequencies, and the amplitude of vibration of the pipe is evaluated by changes in the geometric characteristics of beam DVA and concentrated mass. The proposed methodology is validated using the finite element method and simulation in the SIMULINK/MATLAB. The results showed that, out of the nine effective dimensionless parameters identified in pipe vibration control, mass ratio and stiffness ratio have the highest and lowest impacts on pipe vibration absorption, respectively.

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Parametric Uncertainty and Random Excitation in Energy Harvesting Dynamic Vibration Absorber

ASCE-ASME J Risk and Uncert in Engrg Sys Part B Mech Engrg ◽

10.1115/1.4049211 ◽

2020 ◽

Author(s):

M Rajarathinam ◽

Shaikh Faruque Ali

Keyword(s):

Energy Harvesting ◽

Damping Ratio ◽

Parametric Uncertainty ◽

Electrical Energy ◽

Harmonic Excitation ◽

Random Excitation ◽

Vibration Absorber ◽

Dynamic Vibration Absorber ◽

Dynamic Vibration ◽

Host Structure

Abstract An energy harvesting dynamic vibration absorber is studied to suppress undesirable vibrations in a host structure as well as to harvest electrical energy from vibrations using piezoelectric transduction. The present work studies the feasibility of using vibration absorber for harvesting energy under random excitation and in presence of parametric uncertainties. A two degrees of freedom model is considered in the analytical formulation for the host along with the absorber. A separate equation is used for energy generation from piezoelectric material. Two studies are reported here, (i) with random excitation where the base input is considered to be Gaussian; (ii) parametric uncertainty is considered with harmonic excitation. Under random base excitation the analytical results show that, with the proper selection of parameters, harvested electrical energy can be increased along with the reduction in vibration of the host structure. Graphs are reported showing trade-off between harvested energy and vibration control. Whereas, Monte Carlo simulations are carried out to analyze the system with parametric uncertainty. This showed that the mean harvested power decreases with an increase in uncertainties in the natural frequency as well as damping ratio. In addition, optimal electrical parameters for obtaining maximum power for the case of uncertain parameters are also reported in this study.

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Vibration Control of Plates by Plate-Type Dynamic Vibration Absorbers

Journal of Vibration and Acoustics ◽

10.1115/1.2874455 ◽

1995 ◽

Vol 117 (3A) ◽

pp. 332-338 ◽

Cited By ~ 16

Author(s):

T. Aida ◽

K. Kawazoe ◽

S. Toda

Keyword(s):

Degrees Of Freedom ◽

Large Scale ◽

Equations Of Motion ◽

Harmonic Excitation ◽

Vibration Absorber ◽

Dynamic Vibration Absorber ◽

Two Degrees Of Freedom ◽

Tuning Method ◽

Dynamic Vibration ◽

Plate Type

In this paper, a new plate-type dynamic vibration absorber is presented for controlling the several predominant modes of vibration of plate (mainplate) under harmonic excitation, which consists of a plate (dynamic absorbing plate) under the same boundary condition as the main plate and with uniformly distributed connecting springs and dampers between the main and dynamic absorbing plates. Equations of motion of the system in the modal coordinates of the main plate become equal to those of the two-degrees-of-freedom system with two masses and three springs. Formulas for optimum design of the plate-type dynamic vibration absorber are presented using the optimum tuning method of a dynamic absorber in two-degrees-of-freedom system, obtained by the Den Hartog method. Moreover, for practical problems regarding large-scale plates, an approximate tuning method of the plate-type dynamic absorbers with several sets of concentrated connecting springs and dampers is also presented. The numerical calculations demonstrate the effectiveness of the plate-type dynamic absorbers.

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