Damped Vibration Absorber Research Articles

Nonlinear interactions of an n-layer X-shape low-frequency vibration isolator equipped with a nonlinear vibration absorber at 1:1 internal resonance: analytical and numerical investigations

This work addresses, for the first time, the nonlinear dynamics of an n− layers bioinspired X− shape low-frequency vibration isolation system equipped with a nonlinear vibration absorber. The comprehensive mathematical model governing the two-degree-of-freedom system has been derived using Lagrangian mechanics. The method of averaging was applied to obtain an accurate analytical solution for the derived mathematical model. Utilizing the established analytical solution, the dynamical characteristics of the X− shape vibration isolator have been explored both as a single-degree-of-freedom system and after coupling with the proposed vibration absorber, as a two-degree-of-freedom system. The influence of different system parameters, including the number of structure layers, the initial inclination angle, the X− shape rod length, and the absorber stiffness and damping coefficients, on the vibration isolation performance has been investigated. The main findings indicate that while the single-degree-of-freedom X− shape low-frequency vibration isolator performs well in eliminating low-frequency vibration excitations, it exhibits strong vibration levels when the base excitation frequency exceeds the structure's natural frequency. Additionally, it was found that coupling a highly damped linear vibration absorber to the X− shape isolator not only eliminates the strong oscillations of the structure when subjected to high-frequency base excitations but also enhances the structure's low-frequency vibration isolation performance. Moreover, it was reported that integrating a nonlinear vibration absorber with either soft or hard spring characteristics instead of a linear one may degrade the vibration isolation performance of the structure rather than enhance it. Finally, numerical validation of all the analytical results was performed, which showed excellent correspondence with the analytical findings.

Research on vibration damping model of flat-head tower crane system based on particle damping vibration absorber

Research on vibration damping model of flat-head tower crane system based on particle damping vibration absorber

Particle Damping Vibration Absorber and Its Application in Underwater Ship

Particle Damping Vibration Absorber and Its Application in Underwater Ship

The Structural Design and Analysis of a Symmetrical Twin-tower Conjoined Building with Vibration Absorber

Throughout the ages, earthquakes have caused numerous instability and destruction of buildings. With the increasing of the height and volume of modern buildings, the seismic force on the buildings gradually increases. To avoid serious damage and ensure the safety, seismic design has become a crucial element in the analysis and design of the structure. In traditional seismic design, increasing stiffness of the building is usually adopted to reduce the structural response during an earthquake. This approach is usually costly, and the effect of practical application is not obvious, which could not fundamentally enhance the bearing capacity of the structure. Basing on existing researches, both theoretical and physical model of symmetrical, conjoined twin tower is made, meanwhile, the reasonable design using damping vibration absorber with the function of energy dissipation, utilizes the movement of additional weight to reduce vibration amplitude of main body structure. The use of shaking table test on the analysis and verification of bearing capacity of the model of symmetrical, conjoined twin tower with vibration absorber, improves the seismic performance of the building. It helps propel innovative and practical design ideas in structural seismic design of symmetrical conjoined twin tower.

Design of a damped vibration absorber to control the resonant vibration of roll

Strip rolling is currently the main steel production process. The vertical vibration of the rolling mill caused by the large reduction ratio and high rolling speed reduces the qualification rate of strip products, and even damages the rolling equipment. In this paper, a new particle damping absorber (PDA) is designed to suppress the vertical vibration of the mill. The adaptive genetic algorithm (AGA) is used to optimize the basic parameters of PDA. Considering the nonlinear stiffness between the roll and the rolling stock, a four-degree-of-freedom vertical vibration model of the roll system with the PDA is established. The amplitude-frequency characteristic equations of the primary resonance and the internal resonance are solved by using the multi-scale method. The static bifurcation of the primary resonance of the system is investigated based on the singularity theory. The effects of parameters on vibration are analyzed. The control effect of the vibration absorber is investigated experimentally, and it is found that the experimental results are basically consistent with the theoretical analysis, which verifies the reliability of the established vibration model. The results show that the PDA can effectively suppress the vertical vibration of the roll. It provides some theoretical guidance for the research on vibration suppression of rolling mills.

High-frequency disturbance force suppression mechanism of a flywheel equipped with a flexible dynamic vibration absorber

Flywheels generate speed-related disturbances and induce micro-vibrations that influence the performance of high-sensitivity instruments on board. This study addresses dynamic modeling and disturbance force suppression of the flywheels due to its inherent characteristic structural modes. The disturbance force transmission of a rotating flywheel due to a unit radial force applied at the rim of the wheel body is reported using the three-dimensional finite element method and frequency response function–based substructuring method. The characteristic structural modes for the radial and axial disturbance forces are identified. The axial deformation–dominated flapping mode and the radial deformation–dominated transverse mode will contribute most to the axial and radial disturbance forces, respectively. A flexible ring structure, which is rested on the arms of the wheel body through independent viscoelastic pads and simultaneously in contact with the inner rim of the wheel body by independent resilient cushion members, is proposed to function as a damped dynamic vibration absorber. The modes of the dynamic vibration absorber and the modes of the flywheel equipped with the dynamic vibration absorber are analyzed. It is shown that the dynamic vibration absorber is effective to suppress both the radial and axial disturbance forces at the characteristic structural modes under different rotational speeds, provided that the loss factor of the complex elastic modulus for the viscoelastic pads is larger than 0.2 and the proportional damping constant for the stiffness matrix is larger than 6 Ns/m. Experimental analyses are conducted on a flywheel with a well-designed dynamic vibration absorber to validate the theoretical findings. Modal tests and disturbance force measurements are carried out for the flywheel with/without the dynamic vibration absorber. It is shown that the identified characteristic structural modes will contribute remarkable peaks for the radial and axial disturbance forces. The proposed dynamic vibration absorber is capable to suppress the high-frequency disturbance forces efficiently under different rotational speeds.

Coupled and Multimode Tailboom Vibration Control Using Fluidic Flexible Matrix Composite Tubes

This paper covers the modeling and testing of a helicopter tailboom integrated with a fluidic flexible matrix composite (F2MC) damped vibration absorber. In an advance over previous work, the F2MC absorber presented in this paper treats a combination of tailboom lateral, torsional, and vertical vibrations. A finite element structural model of a laboratory-scale tailboom is combined with a model of attached F2MC tubes and a tuned fluidic circuit. Vibration reductions of over 75% in a coupled 26.8-Hz lateral bending/torsion tailboom mode are predicted by the model and measured experimentally. These results demonstrate that F2MC vibration control is viable at higher frequencies and for more complex vibration modes than previous research had explored. A new absorber with a fluidic circuit that targets two tailboom vibration modes is designed and experimentally tested. On the lab-scale tailboom testbed, the absorber with this circuit is shown to provide vibration reductions of over 60% in both a 12.2-Hz vertical mode and a 26.8-Hz lateral bending/torsion mode. Using this new absorber, vertical and lateral/torsion mode damping are achieved with almost no added weight relative to a purely vertical absorber.

Control of Beam Vibrations using Viscoelastically Damped Absorber System

The aim of this paper is to study the use of viscoelasically damped vibration absorber systems to optimally control the vibrations of a fixed-fixed beam. In this paper, a main beam with fixed-fixed boundary condition with viscoelstically damped cantilever beam as absorber is taken for the analysis. The paper includes optimum design & analysis of vibration absorber with viscoelastic damping. The equations of motion of the system have been derived to find the vibration response with absorber and used for optimization of parameters. The classical and Den Hartong optimization methods are used to optimize the design parameters and optimum values of design are found out. Theoretical calculations have been done for a fixed-fixed beam with three types of absorber beams (undamped, unconstrained treated damped absorber beam and constrained treated absorber beam). To validate the theoretical calculations, experiments have performed and deviation from theoretical data is discussed.

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

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.

Optimal parameters of viscoelastic tuned-mass dampers

A vibration absorber, also known as a tuned mass damper (TMD), is a passive vibration control device. This is achieved by attaching a secondary oscillator to a primary oscillator. In general, the aim is to reduce the vibration of the primary oscillator by suitably choosing the parameters of the secondary oscillator. The effectiveness of a TMD depends on (a) optimised the value of the tuned parameters, and (b) the nature of ambient damping of the absorber. They theory of TMD when the secondary and the primary oscillators are undamped or viscously damped is well developed. This paper presents an analytical approach to obtain optimal parameters of a TMD when the vibration absorber is viscoelastically damped. Classical results on viscously damped vibration absorbers can be obtained as a special case of the general results reduced in the paper. It is shown that by using a viscoelastically damped TMD, it is possible to obtain superior vibration absorption compared to an equivalent viscously damped TMD.

An efficient method to quench excess vibration for a harmonically excited damped plate

In this paper, a simple and efficient method to suppress excess vibration on an arbitrarily supported rectangular damped plate subjected to steady-state harmonic excitations is developed. This vibration suppression is achieved by enforcing points of zero displacement, or otherwise referred to as nodes, at desired locations on the plate using properly tuned damped vibration absorbers. A systematic design procedure that consists of two steps is introduced to enforce the specified nodes. In the first step, sets of feasible attachment locations for the absorbers are identified, and in the second step, the required absorber parameters that are physically realizable are obtained, under the constraints of a tolerable vibration amplitude for the absorber masses. Numerical experiments show that by inducing nodes at the appropriate locations, points of nearly zero vibration amplitudes can be enforced, effectively quenching vibration in that region of the plate.

Damped Vibration Absorbers for Multi-mode Longitudinal Vibration Control of a Hollow Shaft

The present work adopted damped vibration absorbers (DVAs) to attenuate multi-mode longitudinal vibration of the hollow shaft. The dynamic behavior of a shaft is analyzed for the guidance to the initial parameter design of DVAs and the parameters of DVAs are optimized. Subsequently, specific structures of DVAs are designed taking into account the hollow characteristic of the shaft. Furthermore, finite element stimulation of solid modeling has been performed. In this work, with the aid of the transfer matrix method (TMM) in conjunction with the substructure synthesis method (SSM), a dynamic model of the shaft incorporating multiple DVAs is established. The proposed method is developed for the calculation of dynamics character of the coupled system and estimation of absorption effectiveness of DVAs. To demonstrate the validity of theoretical result obtained from the TMM proposed in this paper, a simulation of the shaft vibration by means of the finite element method (FEM) is also carried out. Theoretical and stimulation results both demonstrate that the resonance peaks of the shaft longitudinal vibration are suppressed obviously with the application of those DVAs, which verify the effectiveness of the absorption performance of DVAs.

Optimum Design of Damped Vibration Absorber for Rotationally Periodic Structures

AbstractIn this study, a damped centrifugally driven order-tuned vibration absorber designed for vibration reduction in rotating flexible structures, bladed disk assemblies and blisk such as turbine blades, compressor and fan blades, pump and helicopter rotor bladesetc. during steady operation with constant speed and under engine order excitation (e.o excitation). Effect of mistuning is disregarded. System is assumed with fully cyclic symmetry. The disk is imposed as being rigid. Elastic behavior for blades is supposed. A model with two degree of freedom is extracted for the blades. Each blade is fitted with nominally identical damped order-tuned vibration absorber that is moved in a circular path. Aerodynamic damping and coupling effects between the blades are considered. Optimal values of parameters of the absorber, to suppress blade vibration especially in resonance condition, are derived by Genetic Algorithm (GA) and MATLAB software. H2optimization criterion is used. It is observed that with the deviation of each parameter from the optimal condition, the system response is moved away from the ideal design situation and all of the absorbers’ design parameters have definite effects on the system frequency response and on the dissipated energy during vibration. Therefore, ignorance of the effect of one of those parameters (which was happened in literature) affected the system response completely. Literature is reviewed and validity of the results is confirmed.

Optimum Design of Damped Vibration Absorber for Viscoelastic Bladed Disk Assemblies

The main goal of this study is to examine the effectiveness of viscoelastic blades which are equipped with order tuned vibration absorber for vibration suppression of rationally periodic bladed disk assemblies. Kelvin-Voigt model is chosen to represent the linear viscoelastic behavior of the blade. A model with one degree of freedom is extracted for blades. Simple pendulum, as a damped order-tuned vibration absorber, is attached to the each blade. Aerodynamic damping and coupling effects between the blades are considered. A numerical method with H2 optimization criterion is used to optimize the parameters of the absorber to attenuate vibrations during steady operation. Results are compared with the behavior of the elastic blades. Finally, the literature is reviewed and validity of the results is confirmed. DOI: http://dx.doi.org/10.5755/j01.mech.21.6.13243

Optimal Damped Vibration Absorber: Including Multiple Modes and Excitation Due to Rotating Unbalance

Optimal vibration absorbers are designed using the definition of H-infinity norm and numerical optimization. The cases of both constant amplitude excitation and rotating unbalance excitation are considered. The design procedure is quite general, and can easily handle multiple modes of vibration. A general procedure to construct a root loci plot is also developed. Using a cantilever beam, numerical results are presented.

Suppressing Chaos in a Nonideal Double-Well Oscillator Using an Based Electromechanical Damped Device

In this paper, we analyzed chaotic dynamics of an electromechanical damped Duffing oscillator coupled to a rotor. The electromechanical damped device or electromechanical vibration absorber consists of an electrical system coupled magnetically to a mechanical structure (represented by the Duffing oscillator), and that works by transferring the vibration energy of the mechanical system to the electrical system. A Duffing oscillator with double-well potential is considered. Numerical simulations results are presented to demonstrate the effectiveness of the electromechanical vibration absorber. Lyapunov exponents are numerically calculated to prove the occurrence of a chaotic vibration in the non-ideal system and the suppressing of chaotic vibration in the system using the electromechanical damped device.

Optimization of damped dynamic vibration absorber to control chatter in metal cutting process

This paper deals with finding the optimum parameters of a damped dynamic vibration absorber (DVA) to control chatter in metal cutting systems. The performance of conventional damped DVA is compared with the proposed skyhook damper in which the damper of the absorber system is connected between the absorber mass and an inertial reference in the sky, referred to as a skyhook damper. The damped DVA is optimized by reducing the magnitude in the positive side and increasing it in the negative side of the real part of the frequency response function of the main system. The optimum frequency ratio and the damping ratio of the damped DVA for the undamped and damped main system are obtained using analytical solutions and a numerical optimisation technique, viz genetic algorithm, respectively. The performance of the proposed skyhook damper is marginally better than the conventional type of damped DVA in controlling the vibration of the main system. This is verified by analyzing both the proposed and conventional models using finite element method-based commercial software ANSYS.

Analysis and Design of Wire Transport System in Microwire-Electronic Discharge Machining

A dynamic model for analyzing the wire transport system of micro w-EDM (wire electronic discharge machining) is proposed. Based on the model, two mechanisms are proposed to stabilize the wire tension. The first mechanism is the active wire feed apparatus where the wire spool is fed by a motor actively, instead of passively pulled by the windup motor. Hence, the inertia loading of the wire spool can be isolated from the system. The second mechanism is mounting a multilayer damped vibration absorber (MDVA) on the system. As the wire tension variation occurs, the MDVA oscillates to attenuate the wire tension variation. The performances of both mechanisms on the wire tension variation are theoretically investigated and experimentally validated through corner cutting on the 1.0 mm thickness tungsten carbide. Results show that the wire tension variation can be reduced from 10.3 gf to 3.3 gf after mounting the active wire feed apparatus and the oscillation frequency is increased from 13 Hz to 21 Hz. The wire tension variation can be further reduced to 1.9 gf after mounting the MDVA on the system and the high frequency perturbation is significantly attenuated. The 30-deg corner cutting shows that the corner error are significantly reduced from 26.0 μm to 12.0 μm; the standard deviation of kerf is reduced from 4.34 μm to 0.96 μm, and the surface roughness Ra is reduced from 1.15 μm to 0.63 μm after employing both developed mechanisms.

The Design of an Electromagnetic Damping Vibration Absorber

In order to improve vehicle performance, an electromagnetic damping vibration absorber was designed. The parameter formula of an electromagnetic damping vibration absorber was derived from the utilization of the electromagnetic induction principle. At the same time, the electromagnetic force which was generated by induction current replaced the damping force. According to the experimental data, the damping parameter was calculated by means of the response surface method. It showed that the application of the vibration absorber was feasible.

Optimal design of vibration absorber using minimax criterion with simplified constraints

In this paper, a minimax design of damped dynamic vibration absorber for a damped primary system is investigated to minimize the vibration magnitude peaks. Moreover, to reduce the sensitivity of the primary system response to variations of the forcing frequency for a two-degree-of-freedom system, the primary system should have two equal resonance magnitude peaks. To meet this requirement, a set of simplified constraint equations including distribution characteristics of the resonant frequencies of the primary system is established for the minimax objective function. The modified constraint equations have less unknown variables than those by other authors, which not only simplifies the computation but also improves the accuracy of the optimal values. The advantage of the proposed method is illustrated through numerical simulations.