scholarly journals Design of a rotational type vibration absorber

2020 ◽  
pp. 16-22
Author(s):  
Benjamín Vázquez-González ◽  
Homero Jiménez-Rabiela ◽  
José Luis Ramírez-Cruz
Keyword(s):  
Center Of Mass ◽  
Mechanical Vibration ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Secondary System ◽  
Lagrange Equations ◽  
Oscillatory Movement ◽  
Type Coupling ◽  
The Mathematical Model

Mechanical vibration absorbers are mechanical subsystems capable of developing an oscillatory movement, which dynamically compensates for the vibratory motion developed by a mechanical system of interest, which is affected by an action that can produce a movement that directly affects it in a non-desirable way. The system of interest is called the primary system and the absorber is called the secondary system. The way in which both systems interact establishes the conditions in which absorption will take place. Traditional absorbers are made up of systems coupled by means of an elastic element, they can also have viscous type coupling and very complex couplings can be presented by elastic and viscous type combinations. The objective of the present work is to design a rotational type vibration absorber, in which the interaction between both mechanical systems is developed by contact by rotation without sliding and elastic coupling. Euler-Lagrange equations are used to obtain the mathematical model of the system. One of the main characteristics of the rotary absorber is that the absorber can be designed to achieve small amplitudes of the displacement of its center of mass, but large displacements. Results are presented in numerical simulation.

Parameters optimization of dynamic vibration absorber based on grounded stiffness, inerter, and amplifying mechanism

2021 ◽  
pp. 107754632110382
Author(s):  
Peng Sui ◽  
Yongjun Shen ◽  
Shaopu Yang ◽  
Junfeng Wang
Keyword(s):  
Analytical Solution ◽  
Vibration Isolation ◽  
Damping Ratio ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Stiffness Ratio ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Dynamic Vibration Absorbers

In the field of dynamics and control, some typical vibration devices, including grounded stiffness, inerter and amplifying mechanism, have good vibration isolation and reduction effects, especially in dynamic vibration absorber (DVA). However, most of the current research studies only focus on the performance of a single device on the system, and those DVAs are gradually becoming difficult to meet the growth of performance demand for vibration control. On the basis of Voigt dynamic vibration absorber, a novel dynamic vibration absorber model based on the combined structure of grounded stiffness, inerter, and amplifying mechanism is presented, and the analytical solution of the optimal design formula is derived. First, the motion differential equation of the system is established, and the normalized amplitude amplification factor of the displacement is calculated. It is found that the system has three fixed points unrelated to the damping ratio. The optimal frequency ratio is obtained based on the fixed-point theory. In order to ensure the stability of the system, it is found that inappropriate inerter coefficient will cause the system instable when screening optimal grounded stiffness ratio. Accordingly, the best working range of inerter is determined. Finally, optimal grounded stiffness ratio and approximate optimal damping ratio are also obtained. The influence of inerter coefficient and magnification ratio on the response of the primary system is analyzed. The correctness of the derived analytical solution is verified by numerical simulation. Compared with other dynamic vibration absorbers, it is verified that presented model has superior vibration absorption performance and provides a theoretical basis for the design of a new type of dynamic vibration absorbers.

scholarly journals Attenuation of sound radiation in concrete structure through the reduction of mechanical vibration

2018 ◽  
Vol 11 (1) ◽  
pp. 95-114
Author(s):  
R. V. DE HOLANDA ◽  
M. A. V. DUARTE ◽  
M. A. B. C. BADAN ◽  
J. L. DE O. PENA ◽  
R. C. ROSA
Keyword(s):  
Frequency Band ◽  
Concrete Beam ◽  
Low Cost ◽  
Mechanical Vibration ◽  
System Structure ◽  
Primary System ◽  
Vibration Absorbers ◽  
Viable Option ◽  
Secondary Systems ◽  
Dynamic Vibration Absorbers

Abstract The efficiency of sound irradiance in structure has direct relation with its vibratory movement. Dynamic vibration absorbers (DVAs) are a low cost viable option for reducing vibrations in passive structures. Secondary systems attached to the primary system (structure) in order to reduce vibration. In this work it was used an experimental modal analysis procedure (EMA) for vibratory responses through impulsive excitations to determine the natural frequencies and the location of points suitable for attachment of DVAs in a concrete beam. Later it was designed and built DVAs to reduce vibration in a frequency band where the response of the human auditory system is more sensitive. The best project configuration for DVAs was evaluated for sensitivity thereof with respect to the change of the loss factor of the viscoelastic material used. Obtained reduction of more than 36% over the considered frequency band and over 70% in the region of the resonance frequency in which the DVAs were tuned.

scholarly journals Study of Magnetic Vibration Absorber with Permanent Magnets along Vibrating Beam Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
F. B. Sayyad ◽  
N. D. Gadhave
Keyword(s):  
Cantilever Beam ◽  
Gas Turbines ◽  
Permanent Magnets ◽  
Excitation Frequency ◽  
Harmonic Excitation ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Vibratory System ◽  
Electrical Generator

The vibration absorbers are frequently used to control and minimize excess vibration in structural system. Dynamic vibration absorbers are used to reduce the undesirable vibration in many applications such as pumps, gas turbines, engine, bridge, and electrical generator. To reduce the vibration of the system, the frequency of absorber should be equal to the excitation frequency. The aim of this study is to investigate the effect of magnetic vibration absorber along vibrating cantilever beam. This study will aim to develop a position of magnetic vibration absorber along the cantilever beam to adopt the change in vibratory system. The absorber system is mounted on a cantilever beam acting as the primary system. The objective is to suppress the vibration of the primary system subjected to a harmonic excitation whose frequencies are varying. It can be achieved by varying the position of magnetic vibration absorber along the length of beam. The advantage of magnetic vibration absorber is that it can be easily tuned to the excitation frequency, so it can be used to reduce the vibration of system subjected to variable excitation frequency.

Implementation of a Nonlinear Torsional Vibration Absorber for Suppression of Vibrations in Rotating Machinery

2013 ◽  
Author(s):  
Ammaar Bin Tahir ◽  
Oleg Shiryayev ◽  
Nader Vahdati ◽  
Hamad Karki
Keyword(s):  
Nonlinear Vibration ◽  
Torsional Vibration ◽  
Vibration Suppression ◽  
Nonlinear Energy Sink ◽  
Modal Parameters ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Modal Model ◽  
Linear Spring

Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is tuned for a specific resonant frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies. Vibrations dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. Experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, we carry out the design optimization of the nonlinear torsional vibration absorber using an equivalent 2-DOF modal model. A linear vibration absorber is developed in parallel. Subsequently, both absorbers will be manufactured, assembled and mounted on the system to evaluate their vibration suppression capabilities.

scholarly journals A Principle of Similarity for Nonlinear Vibration Absorbers

2015 ◽  
Author(s):  
Giuseppe Habib ◽  
Gaetan Kerschen
Keyword(s):  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Engineering Systems ◽  
Restoring Force ◽  
Optimal Value ◽  
Real World Applications ◽  
Nonlinear Components ◽  
Principle Of Similarity ◽  
Tuned Vibration Absorber

With continual interest in expanding the performance envelope of engineering systems, nonlinear components are increasingly utilized in real-world applications. This causes the failure of well-established techniques to mitigate resonant vibrations. In particular, this holds for the linear tuned vibration absorber (LTVA), which requires an accurate tuning of its natural frequency to the resonant vibration frequency of interest. This is why the nonlinear tuned vibration absorber (NLTVA), the nonlinear counterpart of the LTVA, has been recently developed. An unconventional aspect of this absorber is that its restoring force is tailored according to the nonlinear restoring force of the primary system. This allows the NLTVA to extend the so-called Den Hartog’s equal-peak rule to the nonlinear range. In this work, a fully analytical procedure, exploiting harmonic balance and perturbation techniques, is developed to define the optimal value of the nonlinear terms of the NLTVA. The developments are such that they can deal with any polynomial nonlinearity in the host structure. Another interesting feature of the NLTVA, discussed in the paper, is that nonlinear terms of different orders do not interact with each other in first approximation, thus they can be treated separately. Numerical results obtained through the shooting method coupled with pseudo-arclength continuation validate the analytical developments.

An Electromechanical Vibration Absorber

1995 ◽  
Author(s):  
Raymond J. Nagem ◽  
Sameer Madanshetty ◽  
Gunajit Medhi
Keyword(s):  
Dynamic Response ◽  
Large Amplitude ◽  
Theoretical Basis ◽  
Electric Circuit ◽  
Vibration Absorber ◽  
Primary System ◽  
Secondary System ◽  
Mechanical Oscillator ◽  
Vibratory System ◽  
Mechanical Oscillations

Abstract A conventional vibration absorber consists of a secondary mechanical oscillator whose properties are chosen to improve the dynamic response of a primary vibratory system. The improvement in the primary system is obtained at the expense of large amplitude mechanical oscillations of the secondary system. We propose an electromechanical absorber in which the secondary system consists of a resonant electric circuit capable of withstanding large amplitude electrical oscillations. The theoretical basis for the design of the electromechanical absorber is presented, and initial experiments to test the technique are described.

scholarly journals Dynamical Behavior of a Pseudoelastic Vibration Absorber Using Shape Memory Alloys

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Hugo De S. Oliveira ◽  
Aline S. De Paula ◽  
Marcelo A. Savi
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Dynamical Behavior ◽  
Vibration Reduction ◽  
Hysteretic Behavior ◽  
System Response ◽  
Vibration Absorber ◽  
Primary System ◽  
Secondary System ◽  
Tuned Vibration Absorber

The tuned vibration absorber (TVA) provides vibration reduction of a primary system subjected to external excitation. The idea is to increase the number of system degrees of freedom connecting a secondary system to the primary system. This procedure promotes vibration reduction at its design forcing frequency but two new resonance peaks appear introducing critical behaviors that must be avoided. The use of shape memory alloys (SMAs) can improve the performance of the classical TVA establishing an adaptive TVA (ATVA). This paper deals with the nonlinear dynamics of a passive pseudoelastic tuned vibration absorber with an SMA element. In this regard, a single degree of freedom elastic oscillator is used to represent the primary system, while an extra oscillator with an SMA element represents the secondary system. Temperature dependent behavior of the system allows one to change the system response avoiding undesirable responses. Nevertheless, hysteretic behavior introduces complex characteristics to the system dynamics. The influence of the hysteretic behavior due to stress-induced phase transformation is investigated. The ATVA performance is evaluated by analyzing primary system maximum vibration amplitudes for different forcing amplitudes and frequencies. Numerical simulations establish comparisons of the ATVA results with those obtained from the classical TVA. A parametric study is developed showing the best performance conditions and this information can be useful for design purposes.

A method for vibration absorber tuning based on baseline frequency response functions

2007 ◽  
Vol 221 (9) ◽  
pp. 1071-1078 ◽  
Author(s):  
C Q Liu ◽  
C C Chang
Keyword(s):  
Frequency Response ◽  
Experimental Methods ◽  
Vibration Absorber ◽  
Physical Parameters ◽  
Primary System ◽  
Vibration Absorbers ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Baseline Frequency ◽  
Stiffness And Damping

This paper presents explicit expressions for new frequency response functions (FRFs) of a primary system when a vibration absorber is attached to it. The new FRF is expressed in terms of the baseline (‘old’) FRFs of the primary system and the physical parameters (the mass, stiffness, and damping) of the vibration absorber. The baseline FRF of the primary system can be obtained by either analytical or experimental methods. This approach allows engineers and designers to evaluate a number of alternative vibration absorbers before these absorbers are physically implemented on the structure. Therefore a considerable amount of time and effort for engineers and designers can be saved. Several examples are provided to illustrate the use of the method.

Optimal Design and Experimental Study of a Multidynamic Vibration Absorber for Multifrequency Excitation

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Xi Wang ◽  
Bintang Yang ◽  
Hu Yu
Keyword(s):  
Vibration Suppression ◽  
Optimization Method ◽  
Equal Mass ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Optimal Damping ◽  
Manufacturing Errors ◽  
Limited Frequency ◽  
Dynamic Vibration Absorbers

The inevitable manufacturing errors of rotational machineries cause vibration of multifrequency. This paper presents a multidynamic vibration absorber (MDVA) to suppress the vibration of multifrequency. The MDVA consists of two parts, and each part includes three dynamic vibration absorbers (DVAs) with equal mass but different stiffness values. In order to improve the robustness of the system, an optimization method to obtain the optimal damping values of each DVA is proposed based on dynamic response. The objective function of optimization aims to flatten the frequency response of the primary system with the changeable excitation and reduce the vibration level in a limited frequency bandwidth. The multifrequency vibration suppression is experimentally verified. To achieve the optimal damping values, the magnetic dampers are applied in the tests. The experimental results indicate that the sensitivity of the system is reduced and the robustness of the system is enhanced, which are coincident with the simulations.

Performance of Bi-Unit Impact Vibration Absorbers With Staggered and Identical Clearances

2009 ◽  
Author(s):  
S. Ekwaro-Osire ◽  
F. M. Alemayehu ◽  
I. Durukan ◽  
J. F. Ca´rdenas-Garci´a
Keyword(s):  
High Speed ◽  
Time Series Data ◽  
Series Data ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Constant Frequency ◽  
Frequency Responses ◽  
The Impact ◽  
Impact Vibration

Impact vibration absorbers have been used extensively to control vibrations of mechanical systems. This paper deals with an experimental study on the performance of bi-unit impact vibration absorbers. The objective of this research was to study the performance of staggered versus identical clearances for two impact balls. This means that in the staggered clearance, the two impact balls had different distances to travel before impacting the limit walls whereas the clearances were identical for the other case. An experimental setup was designed and constructed. A novel digital image system, consisting of high speed camera and image acquisition software, was designed. The primary system was tuned to have a natural frequency of 5 Hz. A time series data of the location of the impact wall and both balls was acquired through constant frequency and constant amplitude excitation. This data was used to obtain motion plots and frequency responses. It was demonstrated that the vibration absorber with staggered clearances was more effective than the vibration absorber with identical clearances.

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