Vibration Control Capabilities Research Articles

A systematic review of hybrid passive energy dissipating devices

Once earthquakes occur, they release a considerable amount of elastic strain energy, which is measured by Peak Ground Acceleration (PGA). To reduce the impact of this energy, buildings can be fitted with dampers. These include passive energy dissipation devices, which are effective in mitigating the effects of both high and low PGA. Hybrid dampers, which combine multiple devices, enhance strengths and minimize weaknesses, significantly improving a building’s seismic resilience by reducing roof displacement, drift, inter-story, floor acceleration, and base shear. These dampers are the focus of extensive research, emphasizing their role in seismic performance enhancement. Despite numerous studies, their application in concrete structures remains underexplored, presenting a vast scope for advancement in the design, development, and implementation of hybrid damping devices. These devices are particularly valued for their superior vibration control capabilities, offering a promising avenue for bolstering structural stability.

Vibration Control for Laminated Composite Spherical-Cylindrical-Combined Shells: Theory and Experiment

Considering the structural damage and instability due to extensive vibrations, the present investigation focuses on the dynamic characteristics analysis and vibration control for aerospace structures such as rocket stages and aircraft cowling, modeled as laminated composite spherical-cylindrical-combined shells (SCCSs). The theoretical model of the SCCSs is established by a series of artificial connection and boundary springs. The proposed method’s validity is confirmed through finite element analysis and experimental validation. Nickel-titanium-steel wire ropes (NiTi-STs) are then introduced as a passive vibration control method for the SCCSs. Both circumferential and axial NiTi-ST laying schemes demonstrate good vibration control capabilities on the SCCSs. For similar lengths of NiTi-STs, the vibration control effect of circumferential laying schemes is superior to that of the axial one. Furthermore, the vibration control effect of the circumferential schemes is found to be dependent on the number and positioning of NiTi-STs. The influence of the NiTi-ST structural parameters on the vibration control performance is also analyzed; adjusting the structural parameters appropriately is helpful to improve the vibration reduction effect.

Dynamic characteristics and vibration control of composite laminate wall panels in electric aircraft using NiTi shape memory alloys

This paper investigates the dynamic characteristics and vibration control of a new-energy electric aircraft cockpit wall panel. An innovative boundary-splitting Rayleigh-Ritz method is introduced for modal analyses of wall panel structures in thermal environments, verified with the hammering and finite element methods, showing a maximum error of 5.42 %. NiTi shape memory alloy (SMA) wires are embedded in composite structures for vibration control, with the first theoretical-experimental validation performed. A parametric fitting-computational model for NiTi-SMA is developed to extract mechanical parameters from hysteresis data. Theoretical models are decoupled into dynamical equations using the Galerkin truncation method. The damping capability of NiTi-SMA is demonstrated by solving the amplitude using the harmonic balance and Runge-Kutta methods. Room-temperature and variable-temperature vibration tests show over 30 % vibration control capability with optimized embedding methods. These experimental results confirm the theoretical findings, providing support for the analysis and vibration control of new-energy aircraft.

Experimental investigation and multi-hazard evaluation of viscous outriggers with amplification devices

This study proposes a novel amplified viscous damping outrigger (AVDO) to enhance the energy dissipation efficiency of a viscous damping outrigger (VDO) system. The AVDO combines the VDO with a lever amplification device, significantly enhancing energy dissipation by amplifying damper displacement. A mechanical model of the AVDO was established, and its performance was compared to that of the VDO using model tests. The experimental results demonstrated that the lever device effectively amplified damper deformation. Additionally, the damping force and energy consumption of the AVDO increased by 4.93 and 4.85 times, respectively. The deviation between the experimental and theoretical results was under 10 %, indicating that the mechanical model successfully assessed the AVDO's properties. Finally, a simulation analysis was conducted on a super high-rise structure subjected to seismic and wind loads to verify the vibration control capabilities of AVDO. The vibration-damping efficiency of AVDO was evaluated by comparing the responses of AVDO and VDO. AVDO was found to reduce top acceleration and displacement by 46.5 % and 36.8 %, respectively, under seismic loading. Additionally, AVDO reduced the peak acceleration of the top floor by 39.5 % under wind loading. AVDO effectively enhances the seismic capacity of the structure and improves the comfort of the super high-rise building. It also achieves economic savings of 79.6 % compared to the VDO at the same level of performance.

Optimization of dual-function suspension structures using particle swarm optimization approaches

The suspension system integrating both vibration control and energy harvesting capabilities is denoted as Dual-function Suspension (DFS). The principal objectives for DFS encompass lightweight structure, high output force, extensive adjustability in damping, and minimized energy consumption. In pursuit of optimizing the linear motor and magnetorheological damper (MRD) amalgamated into the DFS, a multi-objective Particle Swarm Optimization (PSO) algorithm is conceived, emphasizing primary and secondary objectives to enhance the holistic performance of the DFS. A comprehensive mathematical model of the DFS is established, and subsequent to this modeling, the structural parameters of DFS are meticulously analyzed. Drawing upon the insights from this analysis, primary and supplementary optimization objectives are delineated, employing PSO for the refinement of the DFS structure. Following this, the Pareto solution set, derived from the optimization process, is judiciously selected utilizing fuzzy theorem principles. The outcomes reveal that, under the constraints of unaltered suspension packaging dimensions and overall energy consumption, the optimized suspension system manifests a 50% augmentation in output force, a 30% expansion in adjustable damping range, and a 39% reduction in thrust ripple compared to its pre-optimized state.

Nonlinear vibration control of interconnected functionally graded fluid-conveying pipeline

In this study, an exploratory vibration experiment is established and an interconnected functionally graded material (FGM) pipeline system is installed. This experiment represents the first time that NiTiNOL-steel wire ropes (NiTi-ST) are applied to FGM pipeline system. And the experimental results demonstrate that the NiTi-ST has a practical vibration damping effect. Based on the experiment, a further theoretical pipeline system model is created. The effects of fluid velocity, temperature difference, and clamp stiffness on the modal and response of the pipeline system are added. The modal analysis part is solved through the implementation of the Rayleigh-Ritz approach using a set of modified orthogonal polynomials. In order to verify the accuracy of the Raylei-Ritz calculations, the finite element method (FEM) is also used. The response analysis part is solved through the Galerkin truncation method (GTM) and harmonic balance method (HBM). To match the harmonic balance solutions, the Runge-Kutta method (RK) are adopted. The results of the response analysis reveal that NiTi-ST demonstrates significant nonlinear vibration control capabilities to the interconnected FGM pipeline system under various conditions.

Sound transmission loss analysis of double-walled sandwich functionally graded carbon nanotube-reinforced composite magneto-electro-elastic plates under thermal environment

Sandwich structures with functionally graded (FG) cores have gained interest in vibroacoustic applications. This article considers the vibroacoustic properties of double-walled sandwich magneto-electro-elastic (MEE) plates with a functionally graded carbon nanotube-reinforced composite (FG-CNTRC) core layer in a thermal environment. A coupled multiphysics model is developed based on third-order shear deformation theory (TSDT) and acoustic-structure interaction. Special attention is paid to the transmission loss of this arrangement for simply supported and clamped boundaries for four different kinds of CNT distributions, namely, UD, FG-V, FG-O, and FG-X. Sound velocity potential, normal velocity continuity conditions, and Hamilton's principle are used to generate the coupled vibroacoustic equations, which are then solved using the Galerkin method. The effects of boundary conditions, CNT distributions, cavity depth, multiphysics coupling fields, and temperature on the STL are comprehensively studied. The results provide guidelines for tailoring the dynamic response of these materials to achieve enhanced acoustic insulation performance. It enhances fundamental understanding and enables the engineering design of multilayered composite panels with optimized vibration and noise control capabilities.

Experimental investigation on amplified multilayer viscoelastic damper and vibration mitigation evaluation subjected to wind loads

Methods to improve the damping efficiency of dampers have been extensively studied. This study proposes a multilayer viscoelastic damper with an amplified deformation device (MAVE), which combines a traditional viscoelastic damper (VE) with a lever amplification device. The proposed device utilizes multiple viscoelastic damping layers and a lever system to amplify the inter-story displacement, thereby increasing the damping force and enhancing energy dissipation capability. A mechanical model of MAVE was established, and model tests were performed to compare MAVE and VE. The test results demonstrate that MAVE can effectively amplify the deformation of the damper. The damping force of MAVE increased by 5.23 times, while the stiffness increased by 5.59 times, resulting in a 3.11 times increase in energy dissipation capacity. Furthermore, the deviations in the amplification factor and the comparisons between experimental and theoretical results were discussed. The experimental and theoretical deviations were within 10%. Finally, a numerical simulation was performed on a super-tall structure to demonstrate the vibration control capabilities of the MAVE system. By comparing the response of the structure and the energy consumption of the dampers, the vibration reduction efficiency of MAVE under wind loads was confirmed. The peak acceleration at the top floor was reduced by 51%, and the standard deviation (STD) acceleration was reduced by 37%. The peak displacement at the top floor was reduced by 80%, and the STD displacement of the same floor was reduced by 76%. MAVE effectively enhanced the comfort level of super-tall structures.

Investigation of the mechanism of noise radiation reduction from an ABH-cavity under interior acoustic excitation considering multistage coupling

The acoustic black hole (ABH) structure exhibits superior vibration and sound radiation control capability compared to its flat counterpart. However, for a coupled plate-cavity system under interior acoustic excitation, the underlying suppression mechanism of noise radiation has not been explored, especially below the critical frequency of the structure. In this paper, the noise suppression mechanism of an ABH-cavity system under interior acoustic excitation is investigated both theoretically and numerically. Based on the theoretical analysis, the noise radiation depends on both the structural modes and the cavity modes, which can be suppressed in two ways. One is to lower the magnitude of structural transfer functions. The other is to change the mapping matrix which maps the structural modal amplitude to the amplitude of radiation modes. For the former, numerical analysis based on FEM demonstrates that a lower structural transfer function is obtained in the ABH-cavity system compared to its flat counterpart because of the damping enhancement characteristic of the ABH structure. Therefore, attenuated flexural vibrations and reduced sound radiation are achieved at corresponding modal frequencies. For the latter, ABH-cavity systems with varying numbers of ABHs are constructed to demonstrate a simple solution of manipulating the mapping matrix to achieve the reduced radiation efficiency of structural panels and the enhanced suppressing effect of noise radiation. The study in this paper indicates a feasible direction for the further optimization analysis of noise radiation suppression of the ABH-cavity system.

Compromised Vibration Isolator of Electric Power Generator Considering Self-Excitation and Basement Input

A previous study proposed an optimal vibration isolator for self-excitation, but the solution results showed a critical drawback for the basement input. Because the plant system is exposed to self-excitation and basement input, the vibration isolator characteristics must meet all the requirements of both excitation cases. Two performance indices of the vibration isolator were introduced to evaluate the vibration control capability over two excitation cases, self-excitation and basement input, using the theoretical linear model of the electric power generator. The compromise strategy was devoted to enhancing the vibration control capability over the basement input, owing to the acceptable margin for self-excitation. The modification of the mechanical properties of the vibration isolator focused on the isolator between the mass block and the surrounding building. Simulation results revealed that an increase in the spring coefficient and a decrease in the damping coefficient of the vibration isolator beneath the mass block could enhance the vibration reduction capability over the basement input.

Research on Vibration Control of Power Transmission Lines-TMDI Based on Colliding Bodies Optimization

To investigate the vibration control capability of a tuned mass damper inerter (TMDI) on a transmission line, the motion equations of the transmission line with TMDI under harmonic excitation were derived. Thus, the closed-form solutions of the displacement response spectrum were obtained by Fourier transform. Based on the colliding bodies optimization (CBO), one of the metaheuristic algorithms, the TMDI parameters, was optimized to minimize the displacement of the transmission line-TMDI system. The research results show that the response of the transmission line was reduced by at least half for different mass ratio and frequency ratio conditions, which indicates that the TMDI can effectively control the displacement response of the transmission line. In addition, the TMDI parameters were optimized by CBO, and the vibration control efficiency was significantly improved. The results of the study show that the data converge quickly with fewer iterations in collision body optimization. On the one hand, CBO avoids getting into local optimization compared to other metaheuristic algorithms. On the other hand, it is cheaper in terms of the cost of its calculations compared to the methods of mathematical derivation. It plays an active role in the optimization of complex structures. The vibration suppression performance of the TMDI after optimization reaches 56–96%.

Magnetic and vibrational amplitude dependences of MRE grid composite sandwich plates

In this work, both magnetic and vibration amplitude dependent properties of magnetorheological elastomer (MRE) grid composite sandwich plates (MREGCSPs) are investigated. Initially, to prove such a nonlinearly dependent phenomenon, a series of characterization tests are performed on the MREGCSP specimens with different magnetic field intensities and base vibrational amplitudes. Then, using the Jones-Nelson nonlinear material theory, the strain energy density function method, the complex modulus approach, and the Biot-Savart law, the nonlinear material assumption of MRE is defined. A theoretical model consisting of an MRE grid core and two fiber-reinforced polymer (FRP) skins is also proposed to obtain the solutions for the nonlinear frequency, damping, and vibration response parameters, which is based on the modified first-order shear deformation theory, the energy principle, the eigenvalue increment method, the Newmark- beta approach, etc. Finally, a detailed comparison of magnetic and vibrational amplitude dependent natural frequencies, loss factors, and vibration responses is performed to confirm the effectiveness and superiority of the current model over a linear model. This provides a solid basis to reveal the nonlinear dynamic mechanism of the studied smart structure subjected to complex excitation loads. Also, some practical suggestions are summarized for improving its active vibration control capability.

Improving convergence of the Matrix Power Control Algorithm for random vibration testing

This paper describes modifications to the Matrix Power Control Algorithm (MPCA) to improve convergence for Random Vibration Control (RVC) testing. In particular, this paper presents Multiple-Input Multiple-Output (MIMO) implementations of MPCA in simulation and experiment. An Euler–Bernoulli beam model was simulated with applied base excitations and the Box Assembly with Removable Component (BARC) was used in experiment to validate results. The Bayesian optimization package Dragonfly was used to optimize control parameters. Additionally, a moving-average was employed and optimized to improve the measured response feedback for MPCA, reduce the number of averages needed to be taken between control updates, and further improve convergence. The key results of this paper show that the performance of MPCA can be improved by tuning the control parameters and by applying an optimized moving-average. Furthermore, it is demonstrated that convergence can be achieved within 12 drive-frames, which greatly enhances vibration control capability.

Fluid inerter for optimal vibration control of floating offshore wind turbine towers

This paper proposes the use of a tuned mass damper fluid-inerter (TMDFI) for vibration control of spar-type floating offshore wind turbine towers. The use of an inerter in parallel with the spring and damper of a tuned mass damper (TMD) is a relatively new concept. The ideal inerter has a mass amplification effect on the classical TMD leading to greater vibration control capabilities. Previous work by the authors has shown that inerter based TMDs have great potential in vibration control of floating offshore wind turbines where enhanced vibration mitigation can be achieved using a relatively lighter device than classical TMDs. However, this previous work was based on the assumption of an ideal inerter that assumes the use of a mechanical flywheel type inerter. Mechanical inerters have some inherent disadvantages due to their complexity in design and high cost of maintenance. The use of a fluid inerter can alleviate these disadvantages as its design is rather simple and it comes with very low maintenance. Such devices have been proposed and investigated in the literature, however, their applicability in vibration control of floating wind turbines has not been investigated by researchers. The optimal design of a TMDFI is presented in this paper. It has been shown that optimization of a TMDFI is a six-dimensional non-linear optimization problem whose solution hyperplane contains multiple local minima. A systematic way has been developed in this paper, avoiding the use of metaheuristic search techniques, to optimize the damper while providing greater insight into the damper properties that offers a set of guidance to the designer. Numerical results demonstrate impressive vibration control capabilities of this new device under various stochastic wind-wave loads. It has been shown that the fluid-inerter performs as well as the ideal mechanical inerter. The considerable advantages of a TMDFI over the classical TMD demonstrated in this paper makes it an exciting candidate for vibration control.

Characterization of Liquid Oscillation and Sloshing Properties of Toroidal TLCDs for Multidirectional Vibration Control

The toroidal tuned liquid column damper (TTLCD) has been known so far only for its multidirectional vibration control capabilities. The details of its liquid motion characteristics and energy dissipation capacity have been missing. To cover this gap, in this paper, experimental studies are carried out by shaking table tests and an effective three-dimensional computational fluid dynamics model of the TTLCD is developed. All parametric effects and the characteristics of the liquid motion in the TTLCD are addressed. The findings of the paper now clearly reveal that the TTLCD encompasses both an oscillatory liquid deflection as the first mode and a sloshing motion as the second mode vibration response. Accordingly, the results prove that the TTLCD operates not only multidirectionally but also as a unique multimodal device, which unites the properties of tuned liquid dampers (TLDs)/tuned sloshing dampers (TSDs) with tuned liquid column dampers (TLCDs).

Suppression of the sutural interface on vibration behaviors of sandwich beam with shear stiffening gel

Sutural composites have been widely adopted as structural components in various engineering applications. In this work, a series of sutural sandwich beam were prepared by integrating the magneto-rheological shear stiffening gel (SSG) and 3D-printed face sheet material. The structural stiffness of beam samples with different sutural interface was tested. It could be found that the sutural interface geometry showed significant influence on the structural stiffness. Due to the specific viscoelastic property of SSG material, the damping ratio of the beam could be improved with the sutural interface. Meanwhile, benefitted from the rate-dependent stiffening and magneto-rheological properties of the SSG core, the sandwich beams exhibited passive and active vibrations suppression capacities. A theory model about the transmission of the beam with SSG core under external vibration excitation was carried out to explain the experimental results. This work proved that the sutural interface could be adopted as a promising strategy to improve the structural stiffness and vibration control capability of the sandwich beam, which was every important in the application of many industry fields.

Wave propagation of 2D elastic metamaterial with rotating squares and hinges

Auxetic metamaterials have attracted widespread attention because of their untraditional physical properties and practical application values. In this paper, we focus on an elastic auxetic metamaterial composed of hinged rotating rigid squares. Theoretical analysis based on a mass-spring system is adopted to investigate the wave propagation behavior and vibration characteristic of the elastic metamaterial (EM). The motion equations are derived based on a discrete rigid-squares hinged model. The dispersion curves and eigenmodes under two configurations are studied based on Bloch's theorem with linear assumption. Moreover, the evolution process of the bandgap with the change of configuration parameter is revealed systematically and the transmission of the finite periodic hinged squares are explored under harmonic excitation. The results show that with proper parameter configuration, the considered EM structure can exhibit a complete bandgap. The formation mechanism of the bandgap is translational and rotational mode resonance. Moreover, the expressions of bandgap boundary frequencies with parameters are analytically derived, which provides explicit guidance for the adjustment of the bandgap characteristics and the parameter design of the structure. Furthermore, the harmonic transmission analysis validates the wave attenuation predicted by the bandgap. The structure can convert part of the energy into rotational energy, thereby obtaining a better vibration control capability. This work provides significant guidance for the design of elastic metamaterials with potential applications of vibration control.

Uncovering low frequency band gaps in electrically resonant metamaterials through tuned dissipation and negative impedance conversion

A new class of electromechanically coupled metamaterial is presented which relies on magnetic field interactions between the host structure and a local resonator circuit to realize novel vibration control capabilities. The metamaterial chain exhibits a highly tunable vibration band gap which can be easily placed at a desired frequency using the resonant circuit parameters, providing a robust mechanism to independently alter the band gap width, depth, and frequency of maximum attenuation. In its dissipative form, the electromechanical metamaterial is shown to exhibit electrical metadamping as a function of the local resonance circuit resistance. The impact of the damping ratio as a function of the electrical resistance is characterized in frequency and time domains, and related to the infinite system dynamics. A robust experimental realization of the system is constructed which achieves electromechanical coupling through a moving coil and magnet system. The apparatus is used to show that the band gap location and depth can be readily tuned with the circuit elements. The presented metamaterial has potential for meaningful vibroacoustic practical applications in addition to revealing fundamentally new properties of damped electrically-resonant structures.

Ultra-low frequency vibration control of urban rail transit: the general quasi-zero-stiffness vibration isolator

More intensive vibration reduction measures are necessary given increasing demands for urban rail transit vibration control. While the floating slab track system remains the most effective vibration isolation measure, a large vibration reduction blind area can still be observed at low frequencies. In the present study, a general quasi-zero-stiffness vibration isolator (GQZS vibration isolator) was proposed to enhance the ultra-low frequency (< 20 Hz) vibration control capability of floating slab tracks. The dimensionless analysis was utilised to design nonlinear stiffness curves and to determine the proposed GQZS vibration isolator static mechanical performance. Analyses of the dynamic mechanical behaviours of the proposed vibration isolator were conducted based on the force transmissibility rate. Results showed that the designed stiffness curve effectively reduced force transmissibility at low frequencies. A vehicle-floating slab track-substrate coupled dynamic model was proposed considering complicated train loads, and the results were consistent with force transmissibility analyses. When compared with conventional linear steel spring vibration isolators, the proposed GQZS vibration isolator significantly enhanced the floating slab track vibration reduction performance at ultra-low frequencies without affecting the driving stability or safety.

Active Vibration Isolation of a Maglev Inertially Stabilized Platform Based on an Improved Linear Extended State Observer

An inertially stabilized platform is subject to the vibration force and moment from its support base, and low-frequency vibrations cannot be eliminated by mechanical vibration isolation. Combining gimbals with magnetic bearings instead of mechanical bearings, a maglev inertially stabilized platform (MISP) is characterized by no friction or an active vibration control capability. In this paper, an improved linear extended state observer (LESO) replacing displacement error with next-order error is proposed to estimate the low-frequency vibration and improve the estimation accuracy. An active vibration isolation control method is then designed to realize cancellation compensation on the MISP. Finally, a simulation example is presented to validate that the proposed measures can effectively eliminate the low-frequency vibration force transmitted from the base and ensure the stability of the MISP.