Improved Vibration Suppression Research Articles

Vibration control of FG-pipe conveying fluid using a nonlinear absorber with nonlinear damping in longitudinal direction

This study investigates the use of a nonlinear absorber with nonlinear damping to mitigate the transverse vibrations of a fluid-conveying pipe made of functionally graded materials (FGM). The nonlinear effects arising from the pipe’s curvature and inertia are precisely accounted for in the equation of motion. The governing equations of the FGM pipe-nonlinear absorber system are derived using extended Hamilton’s principle and solved using the method of multiple scales. 1:1 internal resonance condition between the first natural frequency of the pipe and absorber is explored for transferring energy from the pipe to the absorber based on the modal interaction. The frequency-amplitude curves reveal that as the power-law index (n) increases, the nonlinear hardening behavior of the pipe decreases, while that of the absorber increases. Incorporating nonlinear damping in the absorber is found to further improve vibration suppression, leading to a strongly modulated response that reduces the pipe vibrations by over 84.57% and the absorber vibrations by over 94.57%. The impact of the absorber’s nonlinear stiffness on the strongly modulated response is also investigated, indicating that excessively high stiffness can cause the disappearance of this beneficial behavior. The findings of this study provide valuable insights into the optimal design of FGM pipes conveying fluid and the integration of nonlinear absorbers with nonlinear damping for enhanced vibration mitigation.

Vibration control and energy harvesting of offshore wind turbines installed with TMDI under dynamical loading

This study investigates the performance of multiple tuned mass-damper-inerter with multiple electromagnetic motor (TMDI-EM) for the dual objectives of enhancing energy harvesting and dynamic performance in offshore wind turbines (OWTs). OWTs, inherently susceptible to dynamic sensitivity under lateral loads such as wind and waves, necessitate effective solutions for vibration mitigation while harnessing energy from dynamic excitations. The TMDI-EM configuration integrates an electromagnetic motor (EM) as a shunt damper between a secondary mass and an inerter element in series. The scalable inertance of the inerter element allows for adaptability in practical device implementations. Genetic Algorithm (GA) is employed to find optimum parameters for the TMDI-EM system. The research focuses on the dynamic response of OWTs under real-world conditions, where wind and wave forces act as correlated random excitations. Parametric analyses assess the available energy for harvesting at the EM and the displacement variance of the OWT structure as the inertance of the TMDI-EM varies. The study employs methods to optimize the TMDI-EM parameters using Genetic Algorithm, ensuring the system's optimal performance for both enhanced energy harvesting and dynamic response. The findings indicate that lightweight TMDI-EMs, representing only 1.5 % of the OWT structure's mass, demonstrate improved vibration suppression and energy harvesting performance with increasing inertance. This study contributes into the potential integration of TMDI-EMs to enhance the dynamic performance and energy harvesting capabilities of offshore wind turbines under dynamical loading conditions. The use of Genetic Algorithm ensures the identification of optimal parameters for the TMDI-EM system, enhancing its practical applicability.

Adaptive Quasi-Super-Twisting Sliding Mode Control for Flexible Multistate Switch

The mathematical model of a flexible multistate switch (FMSS) exhibits nonlinear and strong coupling characteristics, whereas traditional power decoupling control makes it difficult to completely decouple the output power. The traditional proportional–integral control parameters are difficult to adjust, and their robustness and dynamic performance are poor, which affects the stability of the voltage of the power distribution network and feeder power. To address these problems, this study first converted the original system into a linear system via coordinate transformation using feedback-accurate linearization to decouple active and reactive currents. Thereafter, a super-twisting sliding mode control (ST-SMC) algorithm was introduced, and an adaptive quasi-super-twisting sliding mode control (AQST-SMC) algorithm comprising the quasi-sliding mode function and adaptive proportional term was proposed. An FMSS double closed-loop controller was designed to achieve improved vibration suppression and convergence speed. A three-port FMSS simulation model was developed using MATLAB/Simulink, and the simulation results show that the proposed control strategy enhances the robustness and dynamic performance of the system.

A novel locally resonance metamaterial cylindrical shell with tower-shaped lattice for broadband vibration suppression

Vibration issues in cylindrical shells are prevalent in engineering applications and can significantly impact the operational performance of systems. To address these challenges, this paper designs a novel local resonance tower structure, and establishes an analytical model to investigate vibration characteristics of the metamaterial cylindrical shell. Based on the model, a gradient design strategy is proposed to improve vibration suppression properties over a wide frequency range. Firstly, the governing equations of the cylindrical shell are derived and the dispersion analysis is conducted to predict the bandgap boundaries using the extended plane wave expansion (EPWE) method. Then, for a finite-period metamaterial cylindrical shell with specific boundary conditions, the frequency response of the structure is obtained by finite element calculations to show the bandgap behavior. The results of these two methods are basically the same. In addition, the effects of frequency spacing, damping and array period on the vibration characteristics are considered comprehensively. The results show that a wider and more stable attenuation range can be obtained by reasonably adjusting these three parameters. Finally, the comparison between experimental and numerical calculations verify that the tower structure is effective, and that the proposed design strategy can broaden the vibration attenuation region.

A novel vari-potential bistable nonlinear energy sink for improved vibration suppression: numerical and experimental study

A novel vari-potential bistable nonlinear energy sink for improved vibration suppression: numerical and experimental study

Enhancement of the vibration attenuation characteristics in local resonance metamaterial beams: Theory and experiment

Enhancing vibration isolation with local resonance metamaterials has attracted widespread attention due to the low-frequency band gap. However, the narrow band gaps limit its application. To improve vibration suppression properties over a wide frequency range under the constraints of space and mass in engineering, this paper presents the modeling techniques and design strategies for a local resonance elastic metamaterial beam with multiple resonators. The local resonance sub-system contains multi-degree-of-freedom resonators and is periodically mounted on the elastic beam. Two special cases, the elastic metamaterial beam with one-degree-of-freedom local resonator sub-system (1-DOF) and two-degree-of-freedom local resonator sub-system (2-DOF) are used to investigate the vibration attenuation characteristics in detail. Results are presented in the form of attenuation constant, which are calculated by the extended plane wave expansion (EPWE) method. The effects of frequency spacing, damping and mass ratio on the vibration attenuation characteristics of elastic metamaterial beams are comprehensively investigated. The results show that a wider and more stable attenuation range can be obtained by reasonably adjusting these three parameters. Finally, the comparison of experimental and simulation results demonstrates that the design strategies proposed in this paper can broaden the vibration attenuation regions. The theoretical approaches and design schemes can provide effective guidance for passive vibration control.

Improved Vibration Suppression Modeling for Reinforcement Clamping by Eco-friendly Magnetorheological Fluid During Milling of Annular Thin-Walled Workpiece

Improved Vibration Suppression Modeling for Reinforcement Clamping by Eco-friendly Magnetorheological Fluid During Milling of Annular Thin-Walled Workpiece

Tuned bistable nonlinear energy sink for simultaneously improved vibration suppression and energy harvesting

Despite the combination of nonlinear vibration suppression (VS) and energy harvesting (EH) has received great attention in recent years, the strategy to simultaneously improve the performance in both purposes and extend the operating amplitude range to low-level excitations is still an open issue. To achieve this goal, this paper proposes a tuned bistable nonlinear energy sink (TBNES) to outperform the typical bistable nonlinear energy sink (BNES). The TBNES replaces the fixed magnet that is opposite to the bistable piezoelectric beam (BPB) in the BNES by a tuning piezoelectric beam (TPB) with a movable tip magnet. On one hand, the TPB with a linear viscous damping and a piezoelectric element can improve both VS and EH performances. On the other hand, the tuning effect can dynamically reduce the elastic potential barrier of the BPB, helping it induce the initial snap-through motion and produce the strong targeted energy transfer at low-level excitations, therefore leading to the extension of its operating amplitude range. The electromechanical model and the magnetic force model are derived for both TBNES and BNES based on Hamilton’s principle and the geometrical dipole–dipole method. Parametric studies are conducted to investigate the influences of key system parameters on their VS and EH performances with three defined figure of merits. With the system parameters optimized by the presented dynamic optimization algorithm, the simulation results show that the performance of the TBNES is better than that of the BNES in VS and EH, and its operating range of excitation amplitudes can be successfully extended. The deep mechanisms for these phenomena are discussed from the aspects of 1:1 resonance, induction of nonlinearity, elastic potential energy, etc.

An Inerter-Based Dynamic Vibration Absorber With Concurrently Enhanced Energy Harvesting and Motion Control Performances Under Broadband Stochastic Excitation Via Inertance Amplification

Abstract This paper examines the performance of a regenerative dynamic vibration absorber, dubbed energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI), for simultaneous vibration suppression and energy harvesting in white-noise-excited damped linear primary structures. Both single-degree-of-freedom (SDOF) structures under force and base excitations and multi-degrees-of-freedom (MDOF) structures under correlated random forces are studied. The EH-TMDI includes an electromagnetic motor (EM), assumed to behave as a shunt damper, sandwiched between a secondary mass and an inerter element connected in series. The latter element resists relative acceleration at its ends through a constant termed inertance known to be readily scalable in actual inerter device implementations. In this regard, attention is herein focused on gauging the available energy for harvesting at the EM and the displacement variance of the primary structure as the inertance increases through comprehensive parametric investigations. This is supported by adopting simplified inertance-dependent tuning formulae for the EH-TMDI stiffness and damping properties and deriving in closed-form the response of white-noise-excited EH-TMDI-equipped SDOF and MDOF systems through linear random vibration analyses. It is found that lightweight EH-TMDIs, having 1% the mass of the primary structure, achieve improved vibration suppression and energy harvesting performance as inertance amplifies. For SDOF structures with grounded inerter, the rate of improvement is higher as the inherent structural damping reduces and the EM shunt damping increases. For MDOF structures with nongrounded inerter, improvement rate is higher as the primary structure flexibility between the two EH-TMDI attachment points increases.

Experimental study and numerical modeling of nonlinear dynamic response of SDOF system equipped with tuned mass damper inerter (TMDI) tested on shaking table under harmonic excitation

This paper considers a novel shaking table testing campaign to assess the tuned mass-damper-inerter (TMDI) vibrations suppression attributes in harmonically excited structures under the combined effect of nonlinear structural response and nonlinear inerter device behavior deviating from the ideal linear inerter element developing acceleration-dependent force proportional to the inertance constant. Physical specimens of TMDI-equipped single-degree-of-freedom (SDOF) structure are considered featuring a custom-built rack-and-pinion flywheel inerter device with nonlinear behavior due to friction and backlash effects to connect the TMDI secondary mass to the ground. Damping and elastic properties are endowed to the SDOF structure and to the TMDI via high damping rubber bearings (HDRBs) exhibiting softening nonlinear elastic behaviour. Comprehensive experimental data in time and frequency domains are presented for 9 specimens with different sets of secondary mass and inertance subject to sine-sweep excitations for three different amplitudes. The data demonstrate that the main practical advantage of the TMDI established in the literature for linear structures and ideal inerter elements (i.e., improved vibration suppression through increasing inertance without increasing secondary mass leading to lightweight vibration absorbers) is maintained for nonlinear structures and inerter devices. Moreover, a comparison of experimental data with data derived from two different nonlinear parametric numerical models capturing faithfully the HDRBs response, one using a nonlinear mechanical model to represent the inerter device and the other using an ideal linear inerter element instead, demonstrate that displacement, acceleration and base shear response of the SDOF structure is insignificantly influenced by the nonlinear attributes of the inerter device. This outcome paves the way for developing simplified, thus practically meritorious, optimal TMDI tuning approaches adopting the ideal inerter element assumption to model physical inerter devices.

Self-Sensing Vibration Suppression of Piezoelectric Cantilever Beam Based on Improved Mirror Circuit

The self-sensing technique allows a single piece of piezoelectric element to function simultaneously as an actuator and a sensor in a closed-loop system. This study proposes an improved vibration suppression system using the piezoelectric self-sensing technique whose usefulness is experimentally verified in a cantilever beam. A single piezoelectric element is bonded to the root of the beam and functions as an actuator and a sensor simultaneously. A mirror circuit constructed with two charge driver circuits is used to pick up the sensing signal from the driving voltage signal. Then, a closed-loop control strategy based on the proportion integration differentiation (PID) algorithm can adjust the sensing signal precisely to suppress the vibration of the cantilever beam quickly. The first mode of vibration is suppressed, and the amplitude of the vibration is actively dampened by a factor exceeding 96.4%. Moreover, the frequency sweep experiments demonstrate that with the PID feedback control circuit connected to the piezoelectric cantilever beam, the Q value of the system is greatly reduced, and the loss factor is increased from 0.053 to 0.288. The improved mirror circuit with PID control has a good suppression effect in the frequency range near the first order mode of the cantilever beam.

Wavelength-limited optical accordion.

We demonstrate a method to create dynamic optical lattices with lattice constant tunable down to the optical wavelength limit. The periodicity of 1D lattice is to be adjusted by rotating the incoming direction of one of the two interfering laser beams with its fiber port. The relative phase between the stationary and rotating lasers are stabilized with a heterodyne phase-lock loop (Ma et al, Opt. Lett. 19, 1777, 1994), by reflecting part of the rotating laser beam back from a cylindrical mirror near the experiment. Our preliminary demonstration shows tuning of lattice constant λ2sinθ/2, limited by our imaging resolution, between θ = 3° and 20°, with stable and tunable phase. The results can be extended to achieve lattice constant tuning range from ∼ 10λ down to λ/2. We discuss extension of the demonstrated scheme for improved vibration suppression, and for lattice utilizing broadband lasers. Finally we propose a 2D accordion lattice design for quantum gas experiments.

Improving the vibration suppression capabilities of a magneto-rheological damper using hybrid active and semi-active control

This paper presents a new hybrid active and semi-active control method for vibration suppression in flexible structures. The method uses a combination of a semi-active device and an active control actuator situated elsewhere in the structure to suppress vibrations. The key novelty is to use the hybrid controller to enable the magneto-rheological damper to achieve a performance as close to a fully active device as possible. This is achieved by ensuring that the active actuator can assist the magneto-rheological damper in the regions where energy is required. In addition, the hybrid active and semi-active controller is designed to minimize the switching of the semi-active controller. The control framework used is the immersion and invariance control technique in combination with sliding mode control. A two degree-of-freedom system with lightly damped resonances is used as an example system. Both numerical and experimental results are generated for this system, and then compared as part of a validation study. The experimental system uses hardware-in-the-loop to simulate the effect of both the degrees-of-freedom. The results show that the concept is viable both numerically and experimentally, and improved vibration suppression results can be obtained for the magneto-rheological damper that approach the performance of an active device.

Improving Active Preview Control System of Structures Using Online Prediction of Seismic Waves

AbstractThis paper presents a study on the applicability of the preview control method for improving the performance of active seismic control systems. The active preview control method is examined as described for its ability to improve vibration suppression as follows: (1) the relation between the number of preview steps and the degree of improvement in control performance is clarified by analysis using predicted earthquake waves, and (2) to evaluate the applicability to an actual structure, predicted surface seismic waves are calculated by an autoregressive model from observed KiK-net data on 100–200-m-deep underground seismic waves and the applicability of the method is confirmed.

Experimental evaluation of discrete sliding mode controller for piezo actuated structure with multisensor data fusion

This paper evaluates the closed loop performance of the reaching law based discrete sliding mode controller with multisensor data fusion (MSDF) in real time, by controlling the first two vibrating modes of a piezo actuated structure. The vibration is measured using two homogeneous piezo sensors. The states estimated from sensors output are fused. Four fusion algorithms are considered, whose output is used to control the structural vibration. The controller is designed using a model identified through linear Recursive Least Square (RLS) method, based on ARX model. Improved vibration suppression is achieved with fused data as compared to single sensor. The experimental evaluation of the closed loop performance of sliding mode controller with data fusion applied to piezo actuated structure is the contribution in this work.

C07 既設TMDの質量を見かけ上増加させることで性能向上をはかるTMDブースターの開発(M-OS6-1:運動制御とシミュレーションの融合I,M-OS6 運動制御とシミュレーションの融合,M-OS16 MBSE(モデルベースシステムズエンジニアリング)と1D-CAEジョイントセッション,「海を越え,国を越え,世代を超えて!」)

Recently, vibration control with tuned mass dampers (TMD) has becoming well known technology, and there are various studies and many practical realizations. For instance, TMDs are effective for vibration problems caused by human walking on long span bridges or office floors, and also building vibration caused by wind. However, sometimes, we can not get sufficient vibration suppression performance by installed TMDs. In such cases, we have to replace the installed TMD for a new large TMD. This process normally requires high cost and long time. In order to avoid this situation, we propose "TMD booster" which can improve vibration suppression performance by just attaching the TMD booster to the existing TMD. Therefore, TMD replacing process is not required. In this paper, first, the concept of the TMD booster is described, then the control method called "Direct Velocity Force Control (DIFC)" is discussed. Finally, effectiveness of the TMD booster is shown in experiments.

Experiments of optimal delay extraction algorithm using adaptive time-delay filter for improved vibration suppression

In the previously introduced direct adaptive command shaping filter (ACSF), the time-delay value is fixed and only the magnitudes of the impulses are learned. The performance of the direct adaptive time-delay command shaping filter, however, depends on the select time-delay. In this paper, the authors introduce a new scheme to extract the optimal time-delay value for the improved vibration suppression in flexible motion system. To develop the optimal time-delay extraction scheme, the authors have analyzed the effect of the time-delay value on the performance of the direct ACSF. Based on the analysis result the authors have established a set of equations to extract the optimal time-delay toward the optimal vibration suppression performance of ACSF. Experimental results using a gantry robot with a single flexible link show the effectiveness of the proposed time-delay adaptation approach for the improved vibration suppression.

유연한 매니퓰레이터 제어를 위한 적응형 명령성형 필터의 최적 시간지연 값 추출

The performance of the direct adaptive time-delay command shaping filter depends on the select time-delay. In the previously introduced direct adaptive command shaping filter, however, the time-delay value is fixed and only the magnitudes of the impulses are learned. In this paper, the authors introduce a new scheme to adapt the time-delay which is to be used in conjunction with the direct adaptive command shaping for the improved vibration suppression in flexible motion system. In order to formulate the time-delay adaptation scheme, the authors have analyzed the effect of the time-delay value on the performance of the direct adaptive command shaping filter. By modifying the direct adaptation formula based on the analysis result the authors have established a set of equations to adapt the time-delay toward the optimal value. Simulation results show the effectiveness of the proposed time-delay adaptation approach for the improved vibration suppression.

A nonlinear double-winged adaptive neutralizer for optimum structural vibration suppression

A distributed, nonlinear dynamic vibration neutralizer is presented to improve vibration suppression characteristics of harmonically excited structures. The absorber subsection consists of a double-ended cantilever beam carrying intermediate lumped masses. The positions of the moving masses are adjustable along the beam in order to comply with the desired optimal performance. The absorber is assumed to be linearly elastic but with the inextensibility along the neutral axis of the beam. Due to the existence of parametric resonance, nonlinearities of the system begin to affect the motion and hence parametric instability occurs. The necessary and sufficient conditions for the existence of periodic oscillatory behavior along with some physical bounds placed on the absorber parameters form a constrained optimization problem for the optimum tuning strategy. Numerical simulations show that adaptive tuning can be achieved by variation of the tuning mass locations such that the first mode natural frequency is modulated on-line. The optimally tuned neutralizer provides considerable vibration suppression improvements over both the passive and de-tuned absorbers.

Adaptive-passive structural vibration attenuation using distributed absorbers

A distributed dynamic vibration absorber with adaptive capability is presented to improve vibration suppression characteristics of harmonically excited structures. A double-ended cantilever beam carrying intermediate lumped masses forms the absorber subsection. The adaptive capability is achieved through concurrent adjustment of the positions of the moving masses, along the beam, to comply with the desired optimal performance. The necessary and sufficient conditions for the existence of periodic oscillatory behaviour, along with some physical bounds placed on the absorber parameters, form a constrained optimization problem for the optimum tuning strategy. Through numerical simulations it is shown that adaptive tuning is achieved by the variation of tuning mass locations such that the first-mode natural frequency is modulated on-line. The optimally tuned absorber provides considerable vibration suppression improvement over the passive and detuned absorbers.