scholarly journals Optimum Tuning of a Gyroscopic Vibration Absorber Using Coupled Gyroscopes for Vibration Control of a Vertical Cantilever Beam

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
F. Ünker ◽  
O. Çuvalcı
Keyword(s):  
Vibration Absorber ◽  
Primary System ◽  
Compound System ◽  
Dynamic Motion ◽  
Beam System ◽  
Angular Velocities ◽  
Dynamic Absorber ◽  
Vertical Vibrations ◽  
Stiffness And Damping ◽  
Gyroscopic Systems

This paper deals with the investigation of optimum values of the stiffness and damping which connect two gyroscopic systems formed by two rotors mounted in gimbal assuming negligible masses for the spring, damper, and gimbal support. These coupled gyroscopes use two gyroscopic flywheels, spinning in opposing directions to have reverse precessions to eliminate the forces due to the torque existing in the torsional spring and the damper between gyroscopes. The system is mounted on a vertical cantilever with the purpose of studying the horizontal and vertical vibrations. The equation of motion of the compound system (gyro-beam system) is introduced and solved to find the response measured on the primary system. This is fundamental to design, in some way, the dynamic absorber or neutralizer. On the other hand, the effect of the angular velocities of the gyroscopes are studied, and it is shown that the angular velocity (spin velocity) of a gyroscope has a significant effect on the behavior of the dynamic motion. Correctness of the analytical results is verified by numerical simulations. The comparison with the results from the derivation of the corresponding frequency equations shows that the optimized stiffness and damping values are very accurate.

Passive/Active Autoparametric Cantilever Beam Absorber With Piezoelectric Actuator for a Two-Story Building-Like Structure

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Gerardo Silva-Navarro ◽  
Hugo F. Abundis-Fong
Keyword(s):  
Cantilever Beam ◽  
Active Vibration Control ◽  
Parametric Uncertainty ◽  
Vibration Absorber ◽  
Primary System ◽  
Internal Resonances ◽  
Piezoelectric Patch ◽  
Active Vibration ◽  
Stiffness And Damping ◽  
Story Building

This work deals with the design and experimental evaluation of a passive/active cantilever beam autoparametric vibration absorber mounted on a two-story building-like structure (primary system), with two rigid floors connected by flexible columns. The autoparametric vibration absorber consists of a cantilever beam with a piezoelectric patch actuator, cemented to its base, mounted on the top of the structure and actively controlled through an acquisition system. The overall system is then a coupled nonlinear oscillator subjected to sinusoidal excitation in the neighborhood of its external and internal resonances. The addition of the piezoelectric patch actuator to the cantilever beam absorber makes active the passive vibration absorber, thus enabling the possibility to control its equivalent stiffness and damping and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies and parametric uncertainty.

scholarly journals Optimum Tuning of a Gyroscopic Vibration Absorber for Vibration Control of a Vertical Cantilever Beam with Tip Mass

2019 ◽  
Vol 24 (2) ◽  
pp. 210-216
Author(s):  
Faruk Ünker ◽  
Olkan Çuvalcı
Keyword(s):  
Angular Momentum ◽  
Numerical Simulations ◽  
Vibration Control ◽  
Motion Control ◽  
Effective Means ◽  
Vibration Absorber ◽  
Beam System ◽  
Vibration Responses ◽  
Stiffness And Damping ◽  
Tip Mass

In this paper, a symmetric gyro with coupling to the tip mass of a beam mounted on a vibrating base is considered. Taking advantage of the angular momentum of the rotating gyroscope, gyrostabilizer systems are expected to become more widely actualized as they provide an effective means of motion control with several significant advantages for various structures. This paper mainly focused on finding optimized stiffness and damping values that minimize the vibration responses with the derivation of the frequency equations of a special combined gyro-beam system. Correctness of the analytical results is verified by numerical simulations. The comparison with the results from the derivation of the corresponding frequency equations shows that the optimized stiffness and damping values are very accurate.

A Sensitivity Study on Optimum Delayed Feedback Vibration Absorber

1998 ◽  
Vol 122 (2) ◽  
pp. 314-321 ◽  
Author(s):  
Nader Jalili ◽  
Nejat Olgac
Keyword(s):  
Sensitivity Analysis ◽  
Wide Band ◽  
Sensitivity Study ◽  
Optimal Operation ◽  
Delayed Feedback ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorption ◽  
The Stability ◽  
Stiffness And Damping

A sensitivity analysis is presented for a novel tuned vibration absorber. The active tuning of the absorber is achieved using partial state feedback with a controlled time delay. The final structure, which is named Delayed Feedback Vibration Absorber (DFVA), is optimized to yield minimum Mpeak of the primary system involved for a given wide band of excitation frequencies. The optimization is performed over the absorber’s structural properties and the feedback control parameters. An optimal tuning over optimally designed passive absorber is conducted first, and separately a collective optimization over both the absorber structure and the control is studied. The assurance of the stability of the time-delayed system, which forms a critical constraint on the optimization, is also discussed. Regardless of the nature of the optimal operation, the parametric variations in the structure can influence the vibration absorption performance significantly. This concern is addressed via a sensitivity analysis. Primarily, the variations on the absorber stiffness and damping properties are studied. The findings of this effort provide tools for determining the acceptable tolerance limits of the absorber properties. [S0022-0434(00)02202-4]

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.

Effects of nonlinear interactions of flexural modes on the performance of a beam autoparametric vibration absorber

2019 ◽  
Vol 26 (7-8) ◽  
pp. 459-474
Author(s):  
Saeed Mahmoudkhani ◽  
Hodjat Soleymani Meymand
Keyword(s):  
Frequency Response ◽  
Internal Resonance ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Vibration Absorber ◽  
Primary System ◽  
Lumped Mass ◽  
Response Curves ◽  
Internal Resonances ◽  
The One

The performance of the cantilever beam autoparametric vibration absorber with a lumped mass attached at an arbitrary point on the beam span is investigated. The absorber would have a distinct feature that in addition to the two-to-one internal resonance, the one-to-three and one-to-five internal resonances would also occur between flexural modes of the beam by tuning the mass and position of the lumped mass. Special attention is paid on studying the effect of these resonances on increasing the effectiveness and extending the range of excitation amplitudes at which the autoparametric vibration absorber remains effective. The problem is formulated based on the third-order nonlinear Euler–Bernoulli beam theory, where the assumed-mode method is used for deriving the discretized equations of motion. The numerical continuation method is then applied to obtain the frequency response curves and detect the bifurcation points. The harmonic balance method is also employed for detecting the type of internal resonances between flexural modes by inspecting the frequency response curves corresponding to different harmonics of the response. Parametric studies on the performance of the absorber are conducted by varying the position and mass of the lumped mass, while the frequency ratio of the primary system to the first mode of the beam is kept equal to two. Results indicated that the one-to-five internal resonance is especially responsible for the considerable enhancement of the performance.

The Influence Region Analysis for the Delayed Resonator Vibration Absorber

2001 ◽  
Author(s):  
Giulio Grillo ◽  
Nejat Olgac
Keyword(s):  
Vibration Suppression ◽  
Vibration Absorber ◽  
Primary System ◽  
Frequency Interval ◽  
Vibration Absorption ◽  
Region Analysis ◽  
The Common ◽  
Resonator Vibration ◽  
Three Degree Of Freedom ◽  
Tuned Vibration Absorber

Abstract This paper presents an influence region analysis for an actively tuned vibration absorber, the Delayed Resonator (DR). DR is shown to respond to tonal excitations with time varying frequencies [1–3]. The vibration suppression is most effective at the point of attachment of the absorber to the primary structure. In this study we show that proper feedback control on the absorber can yield successful vibration suppression at points away from this point of attachment. The form and the size of such “influence region” strongly depend on the structural properties of the absorber and the primary system. There are a number of questions addressed in this paper: a) Stability of vibration absorption, considering that a single absorber is used to suppress oscillations at different locations. b) Possible common operating frequency intervals in which the suppression can be switched from one point on the structure to the others. A three-degree-of-freedom system is taken for as example case. One single DR absorber is demonstrated to suppress the oscillations at one of the three masses at a given time. Instead of an “influence region” a set of “influence points” is introduced. An analysis method is presented to find the common frequency interval in which the DR absorber operates at all three influence points.

scholarly journals Energy Harvesting in a Nonlinear Cantilever Piezoelastic Beam System Excited by Random Vertical Vibrations

2014 ◽  
Vol 14 (08) ◽  
pp. 1440018 ◽  
Author(s):  
Marek Borowiec ◽  
Grzegorz Litak ◽  
Michael I. Friswell ◽  
Sondipon Adhikari
Keyword(s):  
Power Generation ◽  
Energy Harvester ◽  
Elastic Beam ◽  
Stochastic Force ◽  
Beam System ◽  
Voltage Output ◽  
Single Well ◽  
Vertical Vibrations ◽  
Ambient Excitation ◽  
Tip Mass

The vertical elastic beam with vertical ambient excitation is proposed as an energy harvester. The beam has a tip mass and piezoelectric patches which transduce the bending strains induced by the stochastic force caused by vertical kinematic forcing into electrical charge. We focus on the region with a fairly large amplitude of voltage output where the beam overcomes the potential barrier. Increasing the noise level allows the transition from single well oscillations to inter-well stochastic jumps with more power generation.

Consistent Modal Calibration of a Pendulum-Type Vibration Absorber

2022 ◽  
Author(s):  
J. Høgsberg
Keyword(s):  
Wind Turbines ◽  
Offshore Wind ◽  
Vibration Absorber ◽  
Wave Loading ◽  
Offshore Wind Turbines ◽  
Stiffness And Damping

Abstract. Pendulum absorbers are installation in offshore wind turbines to mitigate excessive vibration amplitudes from wind and wave loading. The pendulum damper is placed inside the tower and attached to the structure at two distinct points: The tower top, where the pendulum arm is fixated, and at the position of the pendulum mass, which is connected to the tower wall by the damper. The present paper derives a modal calibration principle, which consistently accounts for different points of attachment for the absorber stiffness and damping.

Dynamic Vibration Absorber for a Ropeway Carrier

1997 ◽  
Author(s):  
Hiroshi Matsuhisa ◽  
Osamu Nishihara
Keyword(s):  
Natural Frequency ◽  
Damping Ratio ◽  
Vibration Absorber ◽  
Moving Mass ◽  
Dynamic Vibration Absorber ◽  
Damping Effect ◽  
The World ◽  
Dynamic Absorber ◽  
First Time ◽  
Suspended Bridge

Abstract Ropeways such as gondola lifts have attracted increasing interest as a means of transportation in cities. However, swing of ropeway carriers is easily caused by wind, and usually a ropeway cannot operate if the wind velocity exceeds about 15m/s. The study of how to reduce the wind-induced swing of ropeway carriers has attracted many researchers. It had been said that it was impossible to reduce the vibration of pendulum type structures such as ropeway carriers by a dynamic absorber. But in 1993, Matsuhisa showed that the swing of carrier can be reduced by a dynamic absorber if it is located far above or below from the center of oscillation. Based on this finding, a dynamic absorber composed of a moving mass on an arc-shaped track was designed for practical use, and it was installed in chairlift-type carriers and gondola type carriers in snow skiing sites in Japan in 1995 for the first time in the world. It has been shown that a dynamic absorber with the weight of one tenth of the carrier can reduce the swing to half. The liquid dynamic absorber was also investigated. It has the same damping effect as the conventional solid absorber. It is easy to adjust the natural frequency and the damping ratio, and the structure is simple. Therefore, it will be applied for not only ropeway carriers but also ships and rope suspended bridge and others.

scholarly journals Suspension parameter design of underframe equipment considering series stiffness of shock absorber

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092264
Author(s):  
Jie Chen ◽  
Yangjun Wu ◽  
Xiaolong He ◽  
Limin Zhang ◽  
Shijie Dong
Keyword(s):  
Simulation Software ◽  
Dynamics Simulation ◽  
Ride Quality ◽  
Railway Vehicle ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Suspension Parameters ◽  
Dynamic Vibration ◽  
Beam System ◽  
Element Type

In this article, a vertical rigid–flexible coupling model between the vehicle and the equipment is established. Considering the series stiffness of hydraulic shock absorbers, the underframe equipment is like a three-element-type Maxwell model dynamic vibration absorber. The carbody is approximated by an elastic beam and the three-element-type dynamic vibration absorber for general beam system was studied by fixed-point theory. The analytical solution of the optimal suspension parameters for the beam system subjected to harmonic excitation is obtained. The dynamic vibration absorber theory is applied to reduce the resonance of the carbody and to design the suspension parameters of the underframe equipment accordingly. Then, the railway vehicle model was established by multi-body dynamics simulation software, and the vibration levels of the vehicle at different speeds were calculated. A comparative analysis was made between the vehicles whose underframe equipment was suspended by the three-element-type dynamic vibration absorber model and the Kelvin–Voigt-type dynamic vibration absorber model, respectively. The results show that, compared with the vehicle whose underframe equipment is suspended by the Kelvin–Voigt-type dynamic vibration absorber model, the vehicle whose underframe equipment is suspended by the three-element-type dynamic vibration absorber model can achieve a much better ride quality and root mean square value of the vibration acceleration of the carbody. The carbody elastic vibration can be reduced and the vehicle ride quality can be improved effectively using the designed absorber.

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