scholarly journals A New Design of Vibration Absorber for Periodic Excitation

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Shyh-Chin Huang ◽  
Kao-An Lin
Keyword(s):  
Mechanical Systems ◽  
Harmonic Excitation ◽  
Design Parameters ◽  
Vibration Absorber ◽  
Periodic Excitation ◽  
Dynamic Vibration Absorber ◽  
Dual Beam ◽  
Design Variables ◽  
Resonance Frequencies ◽  
Engineering Significance

The authors designed a novel type of dynamic vibration absorber, called periodic vibration absorber (PVA), for mechanical systems subjected to periodic excitation. Since the periodic rather than single harmonic excitation is themost occurring case in mechanical systems, the design of PVA is hence of engineering significance. The PVA designed in this paper is composed of a dual-beam interconnected with a discrete spring in between. By appropriately choosing the design parameters, the PVA can be of resonance frequencies in integer multiples of the base frequency such that the PVA can absorb significant amount of higher harmonics in addition to the base harmonic. The designed PVA was first experimentally verified for its resonance frequencies. The PVA implemented onto a mechanical system was then tested for its absorption ability. From both tests, satisfying agreement between experiments and numerical calculations has been obtained. The sensitivities of the design variables, such as the discrete spring’s stiffness and location, were discussed as well. The parameters’ sensitivities provided us with the PVA’s adjustable room for excitation frequency’s mismatch. Numerical results showed that within 3% of frequency mismatch, the PVA still performed better than a single DVA via adjusting the spring’s constant and location. All the results proved that the novel type of PVA could be a very effective device for vibration reduction of mechanical systems subjected to periodic excitation.

Numerical and Experimental Studies of Pendulum Dynamic Vibration Absorber for Structural Vibration

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Seon Il Ha ◽  
Gil Ho Yoon
Keyword(s):  
Experimental Studies ◽  
Point Of View ◽  
Structural Vibration ◽  
Vibration Absorber ◽  
Square Root ◽  
Vibration Absorbers ◽  
Structural Vibrations ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Resonance Frequencies

Abstract This research presents a pendulum dynamic vibration absorber (PDVA) consisting of a spring and a mass in order to attenuate structural vibrations at two frequencies of hosting structure. It is a convention to attach several dynamic absorbers to hosting structure for the sake of the attenuations of structural vibrations at multiple frequencies with enlarged bandwidth and often it increases the total mass and the installation cost. Therefore, the reduction of the number of vibration absorbers for multiple excitation frequencies is an important issue from an engineering point of view. To resolve these difficulties, this study proposes to adopt the vibration absorber framework of the spring-mass vibration as well as the pendulum vibration simultaneously with the present PDVA system. It is composed of a spring and a mass but being allowed to swing circumferentially, the structural vibrations at the two resonance frequencies, i.e., the square root of stiffness over mass and the square root of a length over gravidity, can be simultaneously attenuated. As the length of the spring of the present PDVA is varied, the effective ranges for the pendulum dynamic vibration absorber become widen. To prove the concept of the present PDVA, this research conducts several numerical simulations and experiments.

Controlling the vibration and noise of a ballasted track using a dynamic vibration absorber with negative stiffness

2019 ◽  
Vol 234 (10) ◽  
pp. 1265-1274
Author(s):  
Haiping Liu ◽  
Dongmei Zhu
Keyword(s):  
Decay Rate ◽  
Negative Stiffness ◽  
Design Parameters ◽  
Vibration Energy ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Radiated Noise ◽  
Dynamic Vibration ◽  
Track System ◽  
Ballasted Track

In this study, a rail dynamic vibration absorber with negative stiffness is developed to reduce the vibration transmission and radiated noise from the rail components of a ballasted track. The compound models of the ballasted track system with and without the proposed dynamic vibration absorber and a traditional dynamic vibration absorber are constructed. A parametric study is performed to evaluate the effects of the design parameters of the proposed dynamic vibration absorber on the vibration and noise reduction of the track system in terms of the point receptance, the decay rate of rail vibration along the track, and the vibration energy level of the rail. Compared with the traditional dynamic vibration absorber, the proposed counterpart can work effectively over a broad frequency range around resonance. The efficiency of the dynamic vibration absorber can be improved by adjusting the design values of the active mass and damping coefficient. A comparison with the traditional dynamic vibration absorber shows that the vibration and noise suppression capability of the proposed one can be enhanced by increasing the value of the stiffness ratio. However, different from the traditional dynamic vibration absorber, the design parameters of the proposed one can also affect the decay rate and vibration energy at low-frequency regions. A discrete track with the proposed dynamic vibration absorber, which is arranged in continuous or discrete distribution along the rail, is illustrated to study the influences of the rail components on the decay rate and vibration energy level of rails. These calculated results could provide a theoretical basis for the design of the proposed dynamic vibration absorber in controlling the vibration and radiated noise from rails.

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.

Dynamic analysis and vibration reduction of articulated silicone gel column with varying geometry

2021 ◽  
pp. 1-13
Author(s):  
Ji-Hou Yang ◽  
Xiao-Dong Yang ◽  
Qing-Kai Han ◽  
Jinguo Liu
Keyword(s):  
Frequency Band ◽  
Vibration Reduction ◽  
Low Frequency ◽  
Vibration Absorber ◽  
Frequency Range ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Silicone Gel ◽  
Resonance Frequencies ◽  
Reduction Effect

Abstract To improve vibration reduction effect in low-frequency band of dynamic vibration absorber (DVA), a novel type of articulated silicone gel column (SGC) is introduced in the design of the tuned dynamic vibration absorber. The nonlinear variation of frequency of SGC with varying geometry is obtained by both finite element simulation and experiments. The most sensitive mode is located, which has wider frequency range by varying the geometry. The polynomial fitting is used to describe nonlinear relation between frequency and geometry. By tuning the geometry, the equivalent stiffness and then resonance frequencies can be manipulated to behave as an active vibration absorber. The vibration reduction experiment of SGC vibration absorbers is investigated. It is found that SGC has better vibration reduction effect in low-frequency band. The experimental results in the current design demonstrate that the vibration reduction effect can reach 94.03% when tuning SCG to the first order main resonance. The dimensions and material parameters of SGC should be altered for specific frequency range and vibration strength.

scholarly journals Optimal In-Operation Redesign of Mechanical Systems Considering Vibrations—A New Methodology Based on Frequency-Band Constraint Formulation and Efficient Sensitivity Analysis

Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 11
Author(s):  
Erich Wehrle ◽  
Veit Gufler ◽  
Renato Vidoni
Keyword(s):  
Sensitivity Analysis ◽  
Mechanical Systems ◽  
Acoustic Emissions ◽  
Test Case ◽  
Analytical Sensitivity ◽  
Design Variables ◽  
Resonance Frequencies ◽  
Analytical Sensitivity Analysis ◽  
System Properties ◽  
New Formulation

The vibrational behavior of components in mechanical systems like drives and robots can become critical under changes in the system properties or loading in operation. Such undesired vibration can lead to detrimental conditions including excess wear, fatigue, discomfort, and acoustic emissions. Systems are designed to avoid certain frequencies to avoid such problems, but system parameters can change during operation due damage, wear, or change in loading. An example is the change in system properties or operation state that then activates resonance frequencies in our system. Therefore, this work has the goal of modifying the modal behavior of a system to avoid vibrational problems. Methods of design optimization are applied to find a new optimum design for this altered condition. Here, this is limited to the addition of mass in order to move the resonance frequency out of critical ranges. This though requires a new formulation of the optimization problem. We propose a new constraint formulation to avoid frequency ranges. To increase efficiency, a reduced analytical sensitivity analysis is introduced. This methodology is demonstrated on two test cases: a two-mass oscillator followed by a test case of higher complexity which is a gear housing considering over 15,000 design variables. The results show that the optimization solution gives the position and amount of mass added, which is a discrete solution that is practically implementable.

scholarly journals Vibration Control of Time-Varying Delay under Complex Excitation

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1081
Author(s):  
Kaiwei Wu ◽  
Chuanbo Ren ◽  
Yuanchang Chen ◽  
Sujuan Shao ◽  
Jilei Zhou ◽  
...  
Keyword(s):  
Time Delay ◽  
Harmonic Excitation ◽  
Vibration Absorber ◽  
Time Interval ◽  
Control Effect ◽  
Dynamic Vibration Absorber ◽  
Time Varying Delay ◽  
Dynamic Vibration ◽  
Vibration Attenuation ◽  
Varying Delay

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.

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

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.

Theoretical Upper and Lower Bounds of the Performance of an On-Off Damping Dynamic Vibration Absorber Attached to a Multi-Degree-of-Freedom System

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
La Duc Viet ◽  
Phan Thi Tra My
Keyword(s):  
Lower Bounds ◽  
Harmonic Excitation ◽  
Upper And Lower Bounds ◽  
Vibration Absorber ◽  
Amplitude Curve ◽  
Dynamic Vibration Absorber ◽  
Mass System ◽  
Variable Function ◽  
Frequency Curves ◽  
Damping Controller

This paper reveals the theoretical (upper and lower) bounds of the performance of an on-off damping vibration absorber attached to an undamped multi-degrees-of-freedom (MDOF) system under harmonic excitation. The solution reduces to the maximization or minimization problem of a simple single-variable function. Among the class of on-off damping controller, which switches the damping level from high to low and back at fixed times every half period, the revealed solutions produce the highest and lowest amplitude–frequency curves. These curves are the good theoretical benchmarks to measure how good or bad an on-off damping controller is. To demonstrate the usefulness of the theoretical bound solutions, two versions of power flow-driven controller are introduced to produce the amplitude–frequency curves tracing the lowest-amplitude curve. A case study of a four-mass system is discussed.

Parametric Uncertainty and Random Excitation in Energy Harvesting Dynamic Vibration Absorber

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.

Vibration Control of Plates by Plate-Type Dynamic Vibration Absorbers

1995 ◽  
Vol 117 (3A) ◽  
pp. 332-338 ◽  
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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