Design of Vibration Absorbers for Step Motions and Step Disturbances

2001 ◽  
Author(s):  
Joel Fortgang ◽  
William Singhose
Keyword(s):  
Mechanical Systems ◽  
Oscillatory System ◽  
Settling Time ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
External Disturbances

Abstract Mechanical systems with flexible dynamics often suffer from vibration induced by changes in the reference command or from external disturbances. The technique of adding a secondary oscillatory system, called a vibration absorber, has proven useful at eliminating vibrations from external disturbances and rotational imbalances. Traditionally, vibration absorbers have been designed for systems subject to sinusoidal or random excitations. Here the applicability of vibration absorbers to systems with step changes in the reference command or similar disturbances is studied. The absorber can be designed with a weighting on peak overshoot and settling time, with the possibility of a nearly 90% improvement in settling time. The performance of this new absorber is compared with previously proposed vibration absorbers.

Design of Vibration Absorbers for Step Motions and Step Disturbances

2005 ◽  
Vol 127 (1) ◽  
pp. 160-163 ◽  
Author(s):  
Joel Fortgang ◽  
William Singhose
Keyword(s):  
Time Constant ◽  
Mechanical Systems ◽  
Settling Time ◽  
Experimental Results ◽  
Performance Criteria ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Design Strategies ◽  
External Disturbances ◽  
Robotic Applications

Mechanical systems with flexible dynamics often suffer from vibration induced by changes in the reference command or from external disturbances. The technique of adding a vibration absorber has proven useful at eliminating vibrations from external disturbances and rotational imbalances. Traditionally, vibration absorbers have been designed for systems subject to sinusoidal or random excitations. Here the applicability of vibration absorbers to systems with steplike changes in the reference command or similar disturbances is studied. This type of motion is more common in robotic applications. Here absorbers are designed using two methods; the first technique uses a weighting on peak overshoot and settling time to allow tradeoffs between the two performance criteria. The second simpler method utilizes an eigenvalue technique to predict the time constant. Both of these techniques provide the possibility of significant improvement in settling time. The performance of this absorber design strategies is compared with previously proposed vibration absorbers and experimental results verify its utility.

Dynamic Vibration Absorber Optimal Design With Emphasis on Complete Machine Dynamics Modelling

2008 ◽  
Author(s):  
Bohdan M. Diveyev ◽  
Zinovij A. Stotsko
Keyword(s):  
Optimal Design ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Rotating Machines ◽  
Dynamic Vibration Absorber ◽  
New Methods ◽  
Dynamic Vibration ◽  
Methods Development ◽  
Dynamic Vibration Absorbers ◽  
Dynamics Modelling

The main aim of this paper is improved dynamic vibration absorbers design with taking into account complex rotating machines dynamic The is considered for the complex vibroexitated constructions. Methods of decomposition and the numerical schemes synthesis are considered on the basis of new methods of modal methods. Development of of complicated machines and buildings in view of their interaction with system of dynamic vibration absorbers is under discussion.

Design of a turning cutting tool with large length–diameter ratio based on three-element type vibration absorber

2020 ◽  
Vol 234 (6-7) ◽  
pp. 1032-1043
Author(s):  
Yiqing Yang ◽  
Haoyang Gao ◽  
Wenshuo Ma ◽  
Qiang Liu
Keyword(s):  
Frequency Response ◽  
Cutting Tool ◽  
Vibration Suppression ◽  
Diameter Ratio ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Target Mode ◽  
Large Length ◽  
Element Type ◽  
Structural Parts

The vibration absorber has been effective in vibration control. From the demand of manufacturing structural parts with a deep hole, the design of a turning cutting tool with large length–diameter ratio is presented. An analytical approach of acquiring frequency response of primary structure equipped with typical single-degree-of-freedom vibration absorbers is formulated, and background modes are incorporated with the purpose of achieving an accurate tuning of vibration absorber. Specifically, the three-element type is investigated as the damping element of the vibration absorber embedded in the cutting tool contributes to the stiffness, although it demonstrates medium performance of vibration suppression according to non-dimensional analysis. The experimentally tuned frequency response function of the turning cutting tool with three-element vibration absorber achieves 87.1% reduction on the amplitude of the target mode. Finally, several configurations of internal turning operations are carried out to validate the design of the vibration absorber.

Using a Vibration Absorber to Suppress Chatter Vibration in Turning Process With a Worn Tool

2009 ◽  
Author(s):  
Hamed Moradi ◽  
Firooz Bakhtiari-Nejad ◽  
Mohammad R. Movahhedi
Keyword(s):  
Transmission Lines ◽  
Gas Turbines ◽  
Block Diagram ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Turning Process ◽  
Electrical Transmission ◽  
Chatter Suppression ◽  
Orthogonal Turning ◽  
Dynamic Vibration Absorbers

Dynamic vibration absorbers are used as semi-active controllers to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges and etc. One type of these absorbers is tunable vibration absorber (TVA). In this paper, regenerative chatter in an orthogonal turning process is suppressed using a (TVA). It is shown that TVA can modify the frequency response function of the cutting tool so as to improve cutting stability in turning process. In addition, tool wear is an important factor which works as a positive damping and helps the chatter suppression beside exertion of the TVA. Finally, using the SIMULINK Toolbox of MATLAB, the analog simulated block diagram of the problem is developed. The advantage of this simulation is that, one can analyze the effect of other types of excitations such as step, ramp, etc on the absorbed system.

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.

Analysis of Parallel Damped Dynamic Vibration Absorbers

1969 ◽  
Vol 91 (1) ◽  
pp. 282-287 ◽  
Author(s):  
A. V. Srinivasan
Keyword(s):  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Dynamic Vibration Absorber ◽  
Main Mass ◽  
Dynamic Vibration ◽  
Frequency Comparison ◽  
Dynamic Vibration Absorbers ◽  
Tuning Frequency ◽  
Comparison Of The Results ◽  
Operational Range

The analysis of parallel damped dynamic vibration absorbers is presented. The system considered is essentially a modification of the conventional damped vibration absorber and consists of adding, in parallel, a subsidiary undamped absorber mass in addition to the damped absorber mass. The analysis clearly shows that it is possible to obtain an undamped antiresonance in a dynamic absorber system which exhibits a well-damped resonance. While the bandwidth of frequencies between the damped peaks is not significantly increased, the amplitudes of the main mass are considerably smaller within the operational range of the absorber. The damped absorber mass and the main mass attain null simultaneously so that the vibratory force is transmitted directly to the undamped absorber. Numerical results are presented for the special case when the absorber masses have the same magnitude. Two cases of tuning have been considered: (a) when the absorber masses are tuned to the frequency of the main mass, and (b) when the absorber masses are tuned to the so-called favorable tuning frequency. Comparison of the results with those of the conventional absorber indicates that the parallel damped dynamic vibration absorber has definite advantages over the conventional damped vibration absorber.

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.

Extending Den Hartog’s Vibration Absorber Technique to Multi-Degree-of-Freedom Systems

2004 ◽  
Vol 127 (4) ◽  
pp. 341-350 ◽  
Author(s):  
Mehmet Bulent Ozer ◽  
Thomas J. Royston
Keyword(s):  
Matrix Inversion ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Single Degree Of Freedom ◽  
Inversion Theorem ◽  
Single Degree ◽  
Main System ◽  
Dynamic Vibration Absorbers ◽  
Invariant Points

The most common method to design tuned dynamic vibration absorbers is still that of Den Hartog, based on the principle of invariant points. However, this method is optimal only when attaching the absorber to a single-degree-of-freedom undamped main system. In the present paper, an extension of the classical Den Hartog approach to a multi-degree-of-freedom undamped main system is presented. The Sherman-Morrison matrix inversion theorem is used to obtain an expression that leads to invariant points for a multi-degree-of-freedom undamped main system. Using this expression, an analytical solution for the optimal damper value of the absorber is derived. Also, the effect of location of the absorber in the multi-degree-of-freedom system and the effect of the absorber on neighboring modes are discussed.

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