Dynamic Vibration Absorber Research Articles

Shaking Table Test Studies on Adaptive-Passive Variable Frequency Gas-Spring DVA for Structural Seismic Response Mitigation

The control performance of a passive dynamic vibration absorber (DVA) is known to be sensitive to its frequency deviation. This study upgrades the conventional device and proposes an adaptive-passive variable frequency gas-spring DVA (APVF-GSDVA) for controlling the structural seismic response, while an adaptive control algorithm is developed that requires only a single input signal. The DVA’s vibration frequency is precisely modulated by adjusting the gas pressure in the gas-spring, aligning it with the inherent frequency of the multi-degree-of-freedom (MDOF) structure. The working principle and control algorithm of the APVF system is introduced and derived in detail, the corresponding gas-spring DVA and implementation are designed, and the configuration of the entire control system is realized. An adaptive variable frequency test scheme is designed and the frequency retuning function of the prototype APVF-GSDVA device installed on an MDOF structure is experimentally validated. The seismic response control effectiveness of the retuned DVA is demonstrated by comparing the detuned DVA, highlighting the necessity of implementing adaptive frequency adjustment of the gas-spring DVA. Experimental findings demonstrate that APVF-GSDVA accurately identifies the inherent frequency of the MDOF structure in ambient excitation, it then adjusts the pressure of the gas-spring according to the frequency-pressure relationship, optimally retuning the DVA. A retuned GSDVA can effectively suppress the structural seismic responses, compared to a detuned DVA, its control effectiveness on peak and RMS responses can be improved by a maximum of nearly 13.5% and 53.3% at a frequency deviation of 10%. Furthermore, results from two “detuning-retuning” test paths with distinct seismic excitations indicate that the retuned DVA exhibits superior control effectiveness, underscoring the significance of the adaptive frequency adjustment function in passive DVAs.

Research on dynamic vibration absorption technology for power equipment based on energy degradation

Research on dynamic vibration absorption technology for power equipment based on energy degradation

A viscoelastic harvester-absorber for energy generation and vibration control

Abstract A vibration energy harvester harnesses the oscillatory movement and
converts it into electrical energy. On the other hand, a (dynamic) vibration absorber
dissipates the mechanical energy of a host structure (primary system). The proposal for
a harvester-absorber device (HAD), comprinsing a piezoelectric element (conventional
harvester) bonded with a viscoelastic layer and a steel constrained layer, is based on the
dual purpose of generating energy and at the same time reducing the vibratory response
of the primary system. Introducing a viscoelastic dissipative layer in a conventional
harvester, also offers the advantage of simultaneously reducing wear on the piezoelectric
element, thereby extending its lifespan and preventing fatigue-related breakage. The
paper presents a model of a harvester-absorber built from a bimorph piezoelectric
beam, a layer of viscoelastic material (E-A-R C1002-01PSA) and a beam of steel, which
acts as a constrained layer. A lumped parameter model is proposed for the theoretical
description of the HAD which is successfully used to experimentally determine its
parameters. After that, and using the equivalent stiffness concept, the HAD was
coupled to a free-free beam with two masses at its ends to study its perfomance over a
real host structure. The inertance of the composite system and voltage/force frequency
response function of the HAD were obtained and compared with experimental results.
The accuracy of the results justifies and validate the model which has the advantage
of simplicity and can contribute to reducing wear and increasing the lifespan of brittle
piezoelectric structures.

Enhancing the Design of Dynamic Vibration Absorbers through Harmonic Analysis and Lumped Parallel Configuration

Enhancing the Design of Dynamic Vibration Absorbers through Harmonic Analysis and Lumped Parallel Configuration

Basic study of structural health monitoring for layered structures subjected to vibration from a semi-active dynamic vibration absorbers

Vibration suppression of structures and structural health monitoring (SHM) are important technologies for realizing a sustainable society, and as stated in SDGs No. 11 "Sustainable cities and communities,"their importance is widely known. Semi-active dynamic vibration absorbers (SADVA) are used in vibration suppression technology, in addition to passive and active dynamic vibration absorbers. Basically, the physical properties of SADVA, which are passive elements such as the spring constant and viscous damping coefficient, can be changed externally. These dynamic vibration absorbers generally operate only when an earthquake occurs. Here, to achieve SDG No. 12 "Responsible consumption, production," we verify whether it is possible to use some of the SADVA mentioned above for SHM. The vibration data of structures is sometimes used in SHM technology. Specifically, an abnormality is diagnosed by measuring the frequency response with a sensor installed in a structure and focusing on the change in the frequency response between normal and abnormal conditions. In this study, we propose a method to identify the location and level of abnormalities in layered structures using a part of SADVA as a shaker.

Vibration attenuation of dual periodic pipelines using interconnected vibration absorbers

Pipelines are crucial elements in various engineering applications. However, unexpected vibrations from different sources can jeopardize the operational performance and potentially damage the piping structures and other connected units. This study explores flexural wave propagation and attenuation characteristics of the pipes supported periodically on a rack. Also, a specific case of a rack with infinite stiffness (simple support) is investigated. The dispersion relations pertinent to pipe rack scenario is obtained through transfer matrix method (TMM) in conjunction with Floquet-Bloch’s theorem, and the accuracy of ensuing band gaps (BGs) are confirmed through finite element (FE) models. Following this, the modal analysis is performed to ascertain the minimum number of unit-cells necessary for the FE model to accurately mimic the attenuation and propagation characteristics of the corresponding infinite structure. The findings indicate that a pipe supported on rack displays resonance and Bragg-type BGs, arising from local resonance and spatial periodicity, respectively, while the pipe on simple support exhibits only Bragg-type BGs. To control low-frequency vibrations in dual pipelines placed on the rack, a novel configuration using interconnected dynamic vibration absorbers (DVAs) is proposed. The DVA consisting of two spring-damper units along with a mass is connected across the center of each span of the two pipelines. The proposed DVA is designed via genetic algorithm-based optimization. It was found that the designed DVA significantly reduces the vibration of the two pipelines. The performance of DVAs improves with an increase in the mass ratio. Additionally, the performance of pipes connected with conventional tuned mass damper (TMD) is evaluated and compared with the proposed DVA. The effectiveness of DVAs is also verified by employing a white Gaussian noise as input. The proposed DVAs are efficient in scenarios involving multiple pipes within a rack, leveraging other pipe’s mass, stiffness, and damping properties to mitigate vibrations in the considered pipes.

An Investigation of the Effects of a Dynamic Vibration Absorber (DVA) to the Comfort of a Bus's Driver Seat

The frequency weighted acceleration, relative displacement, and Seat Effective Amplitude Transmissibility (SEAT) of a bus driver's seat are investigated by a 4 degrees of freedom (4DOF) vertical dynamic model, including a dynamic vibration absorber (DVA). The Root Mean Squared (RMS) values of the gain responses in the frequency domain are analyzed in the DVA damping ratio domain to help determine the optimal value of the DVA' s suspension. The obtained results show that the comfort evaluation index, in the case of a bus driver's seat with DVA, can be improved by more than 15% and nearly 10%, respectively, with the seat suspension natural frequency of 1~Hz and 4~Hz respectively. The comfort is better with the lower seat suspension natural frequency and vice versa. Especially in the case of both the seat and the DVA suspensions with low natural frequencies, all the three mean of evaluation indexes in the whole damping ratio domain of the DVA, have improved by more than 12%. This is the case with all three evaluation indexes which are the best when the damping ratio of the DVA is greater than 0.6.

AI-driven optimization of dynamic vibration absorbers with hydraulic amplifier and mechanical inerter integration

Dynamic vibration absorbers (DVAs) have been widely employed in vibration suppression applications for decades. While DVAs offer an effective solution, they are limited by the need for a high mass ratio between the DVA and the primary system to achieve significant vibration attenuation. To overcome this, researchers have introduced lever mechanisms, allowing for enhanced vibration suppression without increasing the mass ratio. However, levers, commonly used as amplification mechanisms, suffer from high inertia and limited amplification, particularly in larger applications. Another limitation is when DVAs are employed for energy harvesting as a secondary objective, they exhibit high sensitivity to system parameter variations, requiring extensive optimization. Various optimization techniques have been applied to DVAs for multi-objective optimization, including fixed-point theory, which is complex and requires intensive mathematical derivation, and simple metaheuristic techniques such as genetic algorithms (GA). This study proposes four novel DVAs using a hydraulic amplifier (HA) to address the limitations of traditional lever mechanisms and a mechanical inerter to improve the vibration damping. Also, multi-objective optimization was performed using particle swarm optimization (PSO) which is considered innovative in this application and compared with commonly used genetic algorithms (GA). The governing equations were derived using Newton’s second law and solved numerically with the Runge-Kutta method. An AI-based approach was utilized for HA design. The results show that integrating HA and mechanical inerters significantly enhances vibration attenuation and broadens the frequency response. Additionally, the location of the mechanical inerter is critical in reducing vibration amplitude. Also, the multi-objective PSO outperforms GA in solution diversity and quality. The proposed integration of HA in DVAs offers potential applications across various engineering fields.

Transmission and Dissipation of Vibration in a Dynamic Vibration Absorber-Roller System Based on Particle Damping Technology

The research of rolling mill vibration theory has always been a scientific problem in the field of rolling forming, which is very important to the quality of sheet metal and the stable operation of equipment. The essence of rolling mill vibration is the transfer of energy, which is generated from inside and outside. Based on particle damping technology, a dynamic vibration absorber (DVA) is proposed to control the vertical vibration of roll in the rolling process from the point of energy transfer and dissipation. A nonlinear vibration equation for the DVA-roller system is solved by the incremental harmonic balance method. Based on the obtained solutions, the effects of the basic parameters of the DVA on the properties of vibration transmission are investigated by using the power flow method, which provides theoretical guidance for the selection of the basic parameters of the DVA. Furthermore, the influence of the parameters of the particles on the overall dissipation of energy of the particle group is analyzed in a more systematic way, which provides a reference for the selection of the material and diameter and other parameters of the particles in the practical application of the DVA. The effect of particle parameters on roll amplitude inhibition is studied by experiments. The experimental results agree with the theoretical analysis, which proves the correctness of the theoretical analysis and the feasibility of the particle damping absorber. This research proposes a particle damping absorber to absorb and dissipate the energy transfer in rolling process, which provides a new idea for nonlinear dynamic analysis and stability control of rolling mills, and has important guiding significance for practical production.

Virtual Dynamic Vibration Absorber Trap Fusion Active Vibration Suppression Algorithm Based on Inertial Actuators for Large Flexible Space Trusses

This paper presents a virtual dynamic vibration absorber (DVA) trap fusion active vibration suppression algorithm based on inertial actuators as a solution to the harmonic vibration control problem of large flexible space trusses. Firstly, the mechanism of the inertial actuator is analyzed, and the relationship between the bandwidth of the algorithm and the intrinsic frequency of the inertial actuator is derived. Secondly, a dynamic model of the space truss is constructed. Subsequently, an analysis is conducted to determine the manner in which the virtual DVA exerts influence on the system’s dynamic characteristics. Based on this analysis, a virtual DVA trap fusion active vibration suppression algorithm is designed. Finally, the efficacy of the proposed algorithm in suppressing vibration is demonstrated through experimentation. The algorithm was demonstrated to be effective in suppressing both single-frequency harmonic vibration and multi-frequency harmonic vibration under the working conditions of single-degree-of-freedom and multi-degree-of-freedom of a flexible truss. The vibration suppression efficiency was found to be greater than 60%. It is therefore evident that the proposed algorithm has the potential to be applied to the vibration suppression of telescopes assembled in orbit in the future.

Integrated design method for protection against vibration of offshore platform plate structure

The paper integrates the modal avoidance method, pedestal design method, and dynamic vibration absorber theory to investigate vibration control technology for offshore platform plate structures. We develop an integrated design method for vibration suppression by controlling the vibration excitation load, vibration transmission, and vibration energy dissipation. Firstly, a modal avoidance design is implemented to suppress vibration transmission along the propagation path of the plate structure. Subsequently, pedestal optimization is conducted for pedestal structure to attenuate vibration excitation at the input end. Finally, dynamic vibration absorber theory is employed to control dominant vibration frequency responses further and achieve multi-target vibration control. Case simulation results demonstrate that the integrated design method reduces the acceleration vibrations level at 113.75, 145.61, and 153 Hz, and this method could guide multi-objective vibration control in offshore platform plate structures.

Nonlinear optimal frequency control for dynamic vibration absorber and its application

A principal limitation of passive dynamic vibration absorber (DVA) lies in its intrinsic design constraint, as it is tuned to a specific resonant frequency, rendering it less effective at mitigating vibrations over a variable frequency range. To ensure that the DVA retains its vibration reduction capability under loads with time-varying frequencies, this paper proposes a method for designing the optimal suspension frequency based on the external load frequency. The approach involves altering the stiffness of the DVA through semi-active or active control to achieve the optimal suspension frequency and the best vibration reduction performance. In this study, the ratio R between the optimal suspension frequency and the load frequency is defined, and the nonlinear characteristic of R, based on the lowest vibration transmission rate, is studied using a two degree-of-freedom DVA model. Furthermore, an optimal suspension frequency variation control strategy based on load frequency identification is presented. Combined with the typical load with time-varying frequency encountered in metro vehicles, a multi-body dynamics theoretical model and a rigid–flexible coupling dynamics model are established to verify the effectiveness of the nonlinear optimal frequency control. Finally, the full-size railway vehicle roller rig is used to verify the correctness of the principle of optimal frequency curve. The research results show that when the mass ratio is 0.1, compared with rigid suspension, the nonlinear optimal frequency control can reduce the root mean square (RMS) value of the carbody’s entire time period acceleration during variable speed operation by 62.2%, and the maximum RMS value is reduced by 83.6%. In nonlinear control, unlike passive DVA, the vibration is never higher than that of rigid suspension within a specific velocity range. Compared with linear control strategy, nonlinearity can further reduce the elastic vibration. The test results from roller rig indicate that the semi-active DVA can effectively reduce the elastic vibrations of the carbody, while also validating the correctness of the nonlinear optimal suspension frequency principle. Therefore, the nonlinear frequency control in this study can provide reference for structural vibration control under loads with time-varying frequencies.

Design and experiment of a crawling-inchworm-type self-tuned dynamic vibration absorber based on silicone gel materials

Based on the different body configurations caused by varying head-to-tail distances exhibited by crawling inchworms during locomotion, this paper proposes a crawling-inchworm-type self-tuned dynamic vibration absorber (DVA) based on silicone gel materials for reducing low-frequency vibration. The proposed DVA was designed and developed by employing a magnetic hanging design with movable features, a span adjustment design with an embedded stepper motor, and a real-time control design using a microcontroller. First, a finite element simulation model was established to analyze the main structure of the self-tuned DVA using the finite element method. The frequency-shifting characteristics of the absorber were obtained by identifying the actuating modes that are sensitive to the hanging span. Second, based on the frequency-shifting characteristics of the self-tuned DVA, an absorber control system was designed by introducing a short-time Fourier transform and PID algorithm to achieve autonomous frequency adjustment of the DVA. Finally, the self-tuned absorption effects of the prototype self-tuned DVA were tested through a series of experiments, which confirmed its excellent self-tuned vibration absorption capability within the low-frequency range.

A high-static-low-dynamic-stiffness delayed resonator vibration absorber

Delayed resonator (DR), which enables complete vibration suppression through loop delay tuning, has been extensively investigated as a linear active dynamic vibration absorber since its invention. Besides, the nonlinear high-static-low-dynamic stiffness (HSLDS) has been widely used in vibration isolators for broadband (yet incomplete) vibration reduction. This work combines the benefits of DR and the nonlinear HSLDS characteristics, thus creating a nonlinear DR (NDR). Three unexplored topics are considered: (1). To address the nonlinear dynamics that are made complicated by the introduction of delay and the nonlinearity coupled between the NDR and the primary structure; (2). To tune the control parameters to seek possible complete vibration suppression in the nonlinear case, and accordingly, to determine the operable frequency band; (3). To evaluate how the HSLDS characteristics can enhance the performance of the linear DR (LDR) and how to design an NDR to maximize its benefits. Without loss of generality, a classic nonlinear HSLDS structure with three springs and two links is considered, and mathematical tools and computational algorithms are introduced or proposed to efficiently address theoretical analysis. Using the parameters of an experimental setup, we show that a properly tuned NDR suppresses the vibrations on the primary structure to a sufficiently low level. Besides, the HSLDS characteristics extend the operable frequency band compared with the LDR, while strong nonlinearity limits such extension. The proposed analysis procedures for delay-coupled nonlinear dynamics, alongside the control parameter tuning, determination of operable frequency bands, and structural design rules, establish a basic theoretical framework for the NDR design.

Vibration suppression of a platform by a fractional type electromagnetic damper and inerter-based nonlinear energy sink

The theory of linear and nonlinear dynamic vibration absorbers is a well-established topic for many years. However, many recent contributions paid attention to the nonlinear vibration absorbers and different practical realizations of corresponding devices. Here, we propose a mechanical system constituted of the inerter-based nonlinear energy sink attached to the main body that is resting on an elastic foundation and is grounded through the fractional type electromagnetic damper. The two-degree-of-freedom system is described via two coupled differential equations with one of them having a fractional-order derivative term and the other one containing cubic stiffness nonlinearity. The incremental harmonic balance (IHB) method is employed to solve the equations and studies the strongly nonlinear periodic responses of the system. Applied approximated solution methodology is validated by the numerical Newmark method adapted to deal with the system of nonlinear fractional-order differential equations. The appropriate and necessary number of harmonics used in the IHB solution is commented and validated. This study can be a first step in understanding the dynamics and giving directions for the future design of vibration-isolating platforms based on inerter-based nonlinear vibration absorbers and electromagnetic dampers.

Quenching Vibration on a Symmetric Laminated Composite Plate Excited by Multiple Harmonics Using Inerter-based Dynamic Vibration Absorbers

Abstract In this paper a simple and efficient method is developed to quench the steady state vibration of a symmetric laminated composite rectangular plate subjected to multiple harmonics with distinct excitation frequencies. The introduction of the inerter into the traditional dynamic vibration absorber enlarges the solution space for both the feasible attachment locations and the absorber parameters. For a given set of attachment locations, when the traditional vibration absorbers yield physically unrealizable absorber parameters, i.e., negative absorber parameters, an inerter-based vibration absorber can be used such that the absorber parameters become strictly positive. Using the assumed modes method, the governing equations of the laminated composite plate carrying the inerter-based dynamic vibration absorbers are first formulated. A set of constraint equations is established by enforcing nodes at user-specified locations on the plate. Harmonic excitations consisting of a single or multiple distinct excitations are considered. In addition, two attachment scenarios are analyzed: when the attachment and node locations coincide, and when they are distinct. Numerical experiments show that the absorbers parameters can be readily determined for both cases, and validate the proposed method of enforcing the desired node locations when the plate is subjected to either a single or multiple harmonic excitations.

A Magneto-Electric Device for Fluid Pipelines with Vibration Damping and Vibration Energy Harvesting.

This study introduces an innovative energy harvesting system designed for industrial applications such as fluid pipelines, air conditioning ducts, sewer systems, and subsea oil pipelines. The system integrates magneto-electric flow coupling and utilizes a dynamic vibration absorber (DVA) to mitigate the vibrations induced by fluid flow while simultaneously harvesting energy through magnetic dipole-dipole interactions in a vibration energy harvester (VEH). The theoretical models, based on Hamilton's Principle and the Biot-Savart Law, were validated through comprehensive experiments. The results indicate the superior performance of the small-magnet system over the large-magnet system in both damping and power generation. The study analyzed the frequency response and energy conversion efficiency across different parameters, including the DVA mass, spring constant, and placement location. The experimental findings demonstrated significant vibration reduction and increased voltage output, validating the theoretical model. This research offers new avenues for energy harvesting systems in pipeline infrastructures, potentially enhancing energy efficiency and structural integrity.

Study of Resonance between Bogie Hunting and Carbody Mode via Field Measurements and Dynamic Simulation.

By addressing the phenomenon of carbody abnormal vibrations in the field, the acceleration of the carbody and bogie was measured using accelerometers, and the diamond mode of the carbody was identified. The equivalent conicity of the wheelset and the acceleration at the frame end indicated that the shaking of the carbody was caused by bogie hunting. In the SIMPACK simulation, the acceleration frequency and amplitude at the frame end and midsection of the side beam were calculated. The lateral deformation amplitude of the side beam in the finite element model was extracted, and a modal shape function for the diamond-shaped mode was established. By utilizing the modal vibration equation, the modal generalized forces of the carbody were computed, revealing that, during carbody shaking, the yaw damper force contributed significantly among the forces of the secondary suspension, with the phase difference between the front and rear bogies approaching 180°. This insight offers a novel perspective for subsequent active control strategies. Subsequently, these modal generalized forces were applied as external excitation to a coupled vibration model encompassing both the carbody and transformer. Aiming to reduce the acceleration amplitude at the side beam, the transformer was treated as a dynamic vibration absorber, allowing for the optimization of its lateral suspension parameters. As a result, the lateral and vertical acceleration amplitudes at the side beam were concurrently reduced, with the maximum decrease reaching 58.5%, significantly enhancing the ride comfort.

Analytical H2 optimization for the design parameters of lever-type stiffness-based grounded damping dynamic vibration absorber with grounded stiffness

Analytical H2 optimization for the design parameters of lever-type stiffness-based grounded damping dynamic vibration absorber with grounded stiffness

Embedded periodically ABHs and distributed DVAs for passive low-frequency broadband vibration attenuation in thin-walled structures

The acoustic black hole (ABH) structure exhibits remarkable energy focalization above a given cut-on frequency, offering potential for broadband vibration suppression in structures. However, its energy focusing properties diminish significantly below this cut-on frequency. Therefore, it is crucial to enhance the vibration attenuation capabilities of ABH structures within the low frequency range. This study presents a numerical investigation into the impact of thin-walled structures with embedded ABHs and distributed dynamic vibration absorbers (DVAs) on low frequency broadband vibration reduction. Initially, the focusing characteristics of the ABH thin-walled structure is analyzed, aiding in the attached position of DVAs. Furthermore, the influence of the design parameters and attached position of DVA on the broadband damping effect of the structure is explored. The findings indicate that DVAs designed for low frequencies can achieve significant vibration attenuation across the entire frequency spectrum, including low frequencies, when installed at specific focusing positions. When compared to the position with the maximum vibration response, while the attenuation of the low frequency common amplitude value is slightly reduced, greater vibration attenuation across the entire frequency band is achieved. This research offers valuable insights into optimizing the integration of DVAs with ABHs in thin-walled structures for enhanced broadband vibration attenuation.