Vibration Control Effect Research Articles

Research on active vibration control of flexible wing based on MFC actuator

An active vibration control scheme was proposed based on Macro Fiber Composite (MFC) actuators for the bending and torsional vibration control of large flexible lightweight wing structures. Firstly, a finite element modeling and modal analysis of a flexible wing are carried out. Further, the number, type, and location distribution of the MFC actuators bonded on the supported beam of the wing are designed. Then, the actuated characteristics of the two kinds of MFC actuators required for bending and torsional vibration controls was theoretically analyzed. The simulation model of the overall vibration control system was also finally obtained. Finally, through ANSYS simulation analysis, the vibration control effect of the current control system on the first two-order low-frequency modal response of the wing structure is given. The simulation results show that the proposed active vibration control scheme has specific feasibility and effectiveness.

Study on adaptive-passive multiple tuned mass damper with variable mass for a large-span floor structure

Floor structures, especially large-span floor structures, are sensitive to human-induced vibrations, which might cause a serviceability problem. Multiple tuned mass damper (MTMD) system is often used in the vertical vibration control of large-span floor structures. While it is difficult to determine the design parameters of each TMD in an MTMD system, a passive MTMD system still has the detuning shortcoming. In order to overcome this problem, an adaptive-passive variable mass multiple TMD (APVM-MTMD) system is proposed in this study. Each APVM-TMD in the system has a variable mass configuration and a microcontroller system consisting of an accelerometer, a control circuit board, and a driving device. Under ambient excitation, the control circuit board gathers the signals of the accelerometer on the floor, which can identify the dominant natural frequency of the primary structure where this APVM-TMD is located; this is done through the short time Fourier transformation (STFT)-based frequency identification algorithm. Then, each APVM-TMD can automatically control the driving device to retune itself by varying its mass. After retuning steps of all APVM-TMDs, the previous MTMD system becomes a new MTMD system with a different frequency distribution. A large-span floor structure is proposed as a case study. The original finite element model (FEM) is updated according to the in-situ test. In the updated model, an APVM-MTMD system is designed according to the previous model, then the frequency retuning function is verified. Finally, by applying several kinds of human-induced excitations, the vertical vibration control effect of the retuned MTMD system is compared with the mistuned one. The results show that the APVM-MTMD system can retune itself, and the retuned MTMD system has the best vibration control effect compared to the case without control and the mistuned MTMD system case.

Time delay analysis and constant time-delay compensation control for MRE vibration control system with multiple-frequency excitation

Magnetorheological elastomer (MRE) vibration isolation method has attracted more attention in vibration engineering fields. Time delay in real time control system has an important influence on the control effect, especially for the vibration system with periodic excitations. For the phase difference between the response signal and controlled signal caused by time delay will reduce the vibration control effect or even make the vibration more intense. Therefore, the main purpose in this paper is to improve the vibration attenuation of the MRE vibration control system by analyzing the cause of the time delay and designing the time-delay compensator (TDC) based on the traditional fuzzy controller. The time delay in MRE vibration control system, may be generated by controller, actuator, filter and current driver, was analyzed in theory, and experimental test was carried out to estimate the value. Then a constant TDC was designed for the various vibration amplitude and frequency (single frequency and multiple frequencies). Finally, the real-time control experiments were conducted to verify the effectiveness of the proposed TDC, and the results illustrated that the acceleration RMS with TDC has been attenuated more greatly than that without TDC. Meanwhile, the lower energy consumption is another benefit.

Vibration Control of Hemispherical Shells with Light-Activated Shape Memory Polymers

Light-activated shape memory polymer (LaSMP) is a novel actuator with dynamic Young’s modulus and strain when exposed to ultraviolet lights, which can be used in noncontact vibration control. This study focuses on the vibration control effect of LaSMP patches on hemispherical shells with free boundaries. An LaSMP strain variation model is presented with experimental verifications. Based on the strain model, the control forces of LaSMP patches on hemispherical shells are introduced. The FEM method is used to obtain natural frequencies of the free hemispherical shell by solid modeling in ANSYS and proved by comparing numerical results with analytical and experimental results. Using the modal expansion method, the LaSMP vibration control of hemispheres is investigated, and independent modal responses are presented and evaluated. The results indicate that LaSMP patch can control vibrations of hemispherical shells by reducing vibration amplitudes. And the control effect is better for low modal vibration, as the LaSMP-induced strain is relatively smaller. By establishing the relationship between LaSMP actuator forces and modal amplitude reduction, this study offers an analytical tool and procedure for future LaSMP application to vibration controls of flexible structures.

Vibration Control of an Unbalanced Single-Side Cantilevered Rotor System with a Novel Integral Squeeze Film Bearing Damper

In this paper, vibration control of an unbalanced single-side cantilevered rotor system using a novel integral squeeze film bearing damper in terms of stability, energy distribution, and vibration control is analyzed. A finite element model of such a system with an integral squeeze film bearing damper (ISFBD) is developed. The stability, energy distribution, and vibration control of the unbalanced single-side cantilevered rotor system are calculated and analyzed based on the finite element model. The stiffness of the integral squeeze film bearing damper is designed using theoretical calculation and finite element model (FEM) simulation. The influence of installation position and quantity of integral squeeze film bearing dampers on the vibration control of the unbalanced cantilevered rotor system is discussed. An experimental platform is developed to validate the vibration control effect. The results show that the installation position and quantity of the integral squeeze film bearing dampers have different effects on the stability, energy distribution, and vibration control of the unbalanced cantilevered rotor system. When ISFBDs are installed at both bearing housings, the vibration control is best, and the vibration components of the time and frequency domains have good vibration control effects in four working conditions.

Study on wind-induced response of a simplified model of transmission tower based on finite particle method

A reduced model of a transmission tower was established based on the principle of equivalent stiffness. The finite particle method was used to analyse the wind-induced response of the reduced model. The analysis of the dynamic characteristics of the reduced model shows that the accuracy of the equivalent formula proposed in this paper was very high. Compared with the first five order natural frequencies of the complete model, the maximum calculation error of the reduced model was only 0.87%. Since the first order shear deformation beam theory was used in the reduced model, the interpolation-independent element shape functions were developed to avoid the shear locking phenomenon. Moreover, the formula for calculating the internal force of Timoshenko beam for finite particle method was derived. By using two successive Euler angles, a new method for separating the rigid motion and pure deformation of the element was proposed. The computational efficiency of this method is significantly improved, and the computational time is less than half of that of the traditional finite particle method. The results of wind-induced response analysis of the transmission tower show that the simplified model proposed in this paper can obtain highly accurate displacement response of the structure, and the maximum error of the RMS of the displacements at the top of the tower is less than 3.2%. This model is suitable for studying the dynamic response of transmission tower line system and evaluating the effect of the wind-induced vibration control of damping device.

Active vibration control unit with a flywheel inertial actuator

This paper presents simulation and experimental results on the implementation of a velocity feedback control unit with a new flywheel inertial actuator, which can be used to reduce flexural vibration of distributed structures. The actuator incorporates a classical coil–magnet linear transducer and a flywheel element such that both linear and rotational inertia effects are generated by the moving components of the actuator. The additional rotational inertia effect shifts to lower values the fundamental resonance frequency of the actuator without increasing the static deflection of the suspended masses. Therefore, this actuator can be conveniently used to implement feedback control units, which are robust to shocks, have enhanced stability properties and, thus, improved vibration control effects. To illustrate the key features of the proposed actuator, the characteristic electro-mechanical response functions of a classical actuator and of the flywheel actuator are first presented. Then, the stability and flexural vibration control performance of velocity feedback loops with a classical and the flywheel inertial actuators are contrasted considering a thin rectangular plate hosting structure.

A tuned liquid inerter system for vibration control

This study proposes a novel tuned liquid inerter system (TLIS) that employs a tuned liquid element and an inerter-based subsystem, including damping, stiffness, and inerter elements, to completely utilize their synergy benefits. The stochastic analyses for both damped and undamped structure-TLIS systems are conducted, and the analytical solution to the displacement response is derived for an undamped structure. Using the stochastic response results, the vibration control effect of the proposed TLIS is characterized through an extensive analysis in comparison with classic tuned liquid dampers. A parametric analysis is then performed to investigate the response variation pattern of the structure-TLIS with respect to the changes in TLIS parameters. Inspired by the parametric analysis, an optimal design framework for the most economical condition is developed for the TLIS by simultaneously considering the structural performance and control force. In particular, for a TLIS in the presence of an existing tuned liquid element, the optimal damping and stiffness ratios of the inerter subsystem in the TLIS are derived in an analytical form as the functions of tuned liquid mass and inertance to ensure structural responses are minimized. Moreover, the corresponding design procedure and examples are provided to validate the effectiveness of the proposed TLIS and design methods. It is concluded that the employment of the inerter-based subsystem in the TLIS can substantially improve the structural performance and reduce the displacement response of the tuned liquid in comparison with the classic tuned liquid damper for a given liquid mass. The optimal design of the TLIS can satisfy the target structural performance demands despite optimizing control cost. Simultaneously, the function of the tuned liquid element is partly substituted by the added inerter element, which implicitly facilitates the minimization of the physical mass of the TLIS to achieve lightweight-based control.

Internal model-based optimal vibration control for linear vehicle suspension systems with actuator delay

The problem of optimal vibration control for active vehicle suspension systems with actuator delay is considered. Based on the model transformation, the quarter-car suspension system with actuator delay is transformed into a delay-free one. The existence and uniqueness of the optimal control law are proved. The vibration control law is obtained by solving an optimal regulation problem. A dynamic compensator is designed, which is combined by an internal model and an optimal control. The actuator delay is compensated by a control memory term. Numerical simulations are used to illustrate the effectiveness of the optimal vibration control.

Research on the Vibration Control Effect of High-Rise isolation system combined with damping device under Strong ground motions

Considering large deformation of the upper structure for base isolation structure and easily overturned whole structure under strong ground motion, the characteristics of earthquake control and seismic response of a high-rise base isolation structure with viscous dampers are studied in this paper. At first, the motion equation of high-rise base isolation structure and high-rise combined control system is established based on the calculation model of multi-degree of freedom system with lumped masses of isolation structure; Then, the state space method and variable order numerical differential algorithm are used to calculate the seismic response of the structure; Finally, the ordinary ground motion records and near-source pulse-like ground motion records are selected as input, and the seismic response of high-rise base isolation structure and high-rise combined control system are calculated, furthermore, its characteristics of seismic response and control effect are compared. The results show that the high-rise base isolation structure with viscous dampers can reduce the structural displacement response significantly, and the displacement demand of isolation bearing can be reduced dramatically too. it is an effective way to develop the new type bearing with low yield stiffness, large deformation and a high tensile strength to solve these questions of base isolation technology in high-rise structure applications.

Panel with self-tuning shunted piezoelectric patches for broadband flexural vibration control

Abstract A practical approach based on maximisation of vibration power dissipation is proposed for the self-tuning of single- and multi-resonant shunts connected to piezoelectric patches, which are bonded on thin rectangular panels to reduce the broadband flexural vibrations produced by stochastic disturbances at low audio-frequencies. The single- and multi-resonant shunts are formed either by one or by multiple resistance-inductance-capacitance (RLC) branches connected in parallel. The proposed self-tuning approach sequentially adapts the RL elements in the branches of each shunt in such a way as to maximise the vibration power dissipation from the resonant response of the flexural modes of the hosting structure that resonate in a target frequency band. The vibration power dissipated is estimated from the measured electric power dissipated by each shunt so that self-tuning can be implemented locally and independently in each shunt without the need of system identification or on-line measurement of the vibration response of the hosting structure. Therefore, on-line tuning can be implemented to control the vibrations of distributed structures, also in those cases where they are characterised by time-varying dynamics, generated, for example, by tensioning effects, mass variations, moving loads, uneven constraints, etc. To start with, the paper presents a parametric study on a thin rectangular panel with two piezoelectric patches connected to multi-resonant shunts, which shows that, the time-averaged total flexural kinetic energy of the smart panel and the time-averaged electric power dissipated by each shunt are characterised by matching local minima and maxima, which identify the optimal RL parameters in the branches of each shunt necessary to control the resonant responses of the panel low order flexural modes. A practical iterative approach, based on the maximisation of the time-averaged electric power dissipated by each shunt, is then introduced to find on-line these optimal RL parameters. Finally, a brief survey is presented to show the flexural vibration control effects produced in the panel by increasingly larger arrays of piezoelectric patches connected to the proposed self-tuning multi-resonant shunts.

Influence of inerters on the vibration control effect of series double tuned mass dampers: Two layouts and analytical study

In this paper, two configurations of series double tuned mass damper with inerters (SDTMDI) are investigated: grounded type (G-SDTMDI) and inserted type (I-SDTMDI). For the former layout, two inerters relate each tuned mass to the ground, while they are inserted between any two adjacent masses in the latter layout. Implementing on a harmonically forced primary system of single degree of freedom, their optimal design is conducted by using an extended version of fixed points theory. The present study suggests that for a given total tuned mass, the vibration control effect of G-SDTMDI is solely controlled by the total inertance, because of which one of the two grounded inerters can be removed, and the vibration control performance will not be influenced under the condition that the amount of inertance remains unchanged. Meanwhile, the control effect delivered by I-SDTMDI is dictated by the inerter relating the primary system and its adjacent tuned mass. Finally, it is analytically and numerically proven that grounded inerters can render the vibration control effect more pronounced, featured by a decreased peak amplitude and an enlarged frequency bandwidth of vibration reduction. The only potential detrimental effect observed is by incorporating an inerter between the host structure and its adjacent tuned mass. In this case, the vibration amplitude of host structure is amplified, and the effective plateau of vibration reduction is narrowed.

Multiflexoelectric Actuation and Control of Beams

Flexoelectric materials subject to inhomogeneous electric field can actuate and control flexible structures based on the converse flexoelectric effect. An atomic force microscope (AFM) probe placed on top of a flexoelectric patch can generate a nonuniform electric field with an excitation control voltage, and consequently, an internal actuation stress is generated in the flexoelectric material. The induced flexoelectric membrane force and bending moment, in turn, influence the vibration of the structure. Because of high stress concentration of the flexoelectric actuation, multiple AFM probes/patches are necessary to alleviate potential fracture. In this study, the vibration control effectiveness of an elastic cantilever beam with multiple AFM probes/patches placed at optimal locations is evaluated. The beam is excited initially with an external mechanical force. In case studies, both open-loop and closed-loop control methods are imposed, and optimal combinations of three actuator positions are chosen to minimize the tip displacement. For the open-loop responses, amplified tip displacements are also observed due to overactuation. Displacement feedback control is proposed. Free vibration, and open-loop and closed loop vibration control are compared for the first three beam modes. The results prove that multiple flexoelectric actuators can effectively accelerate the beam damp process with closed-loop control.

Studies on vibration control effects of a semi-active impact damper for seismically excited nonlinear building

The semi-active impact damper (SAID) is proposed to improve the damping efficiency of traditional passive impact dampers. In order to investigate its damping mechanism and vibration control effects on realistic engineering structures, a 20-story nonlinear benchmark building is used as the main structure. The studies on system parameters, including the mass ratio, damping ratio, rigid coefficient, and the intensity of excitation are carried out, and their effects both on linear and nonlinear indexes are evaluated. The damping mechanism is herein further investigated and some suggestions for the design in high-rise buildings are also proposed. To validate the superiority of SAID, an optimal passive particle impact damper (PIDopt) is also investigated as a control group, in which the parameters of the SAID remain the same, and the optimal parameters of the PIDopt are designed by differential evolution algorithm based on a reduced-order model. The numerical simulation shows that the SAID has better control effects than that of the optimized passive particle impact damper, not only for linear indexes (e.g., root mean square response), but also for nonlinear indexes (e.g., component energy consumption and hinge joint curvature).

Optimal Design and Application of a Multiple Tuned Mass Damper System for an In-Service Footbridge

Slender steel footbridges suffer excessive human-induced vibrations due to their low damping nature and their frequency being located in the range of human-induced excitations. Tuned mass dampers (TMDs) are usually used to solve the serviceability problem of footbridges. A multiple TMD (MTMD) system, which consists of several TMDs with different frequencies, has a wide application in the vibration control of footbridges. An MTMD system with well-designed parameters will have a satisfactory effect for vibration control. This study firstly discusses the relationship between the acceleration dynamic amplification factor and important parameters of an MTMD system, i.e., the frequency bandwidth, TMD damping ratio, central frequency ratio, mass ratio and the number of TMDs. Then, the frequency bandwidth and damping ratio optimal formulas are proposed according to the parametric study. At last, an in-service slender footbridge is proposed as a case study. The footbridge is analyzed through a finite element model and an in situ test, and then, an MTMD system is designed based on the proposed optimal design formulas. The vibration control effect of the MTMD system is verified through a series of in situ comparison tests. Results show that under walking, running and jumping excitations with different frequency, the MTMD system always has an excellent vibration control effect. Under a crowd-induced excitation with the resonance frequency, the footbridge with an MTMD system can meet the acceleration limit requirement. It is also found that the analysis result agrees well with the in situ test.

A multifunctional lattice sandwich structure with energy harvesting and nonlinear vibration control

A new multifunctional lattice sandwich structure consisting of a lattice sandwich beam, a nonlinear energy sink (NES) and a giant magnetostrictive material (GMM) is proposed in this research. This structure exhibits excellent self-vibration suppression and aeroelastic energy harvesting performance. The dynamic equations of the whole structure are established using Hamilton principle and Newton’s second law, and the Runge-Kutta algorithm is used to obtain the amplitude response of the beam coupled with NES and without NES, which can indicate the vibration control effect of NES. Moreover, the energy harvest effect of the structure with GMM is also analyzed through numerical simulation. And a comparative analysis of relevant parameters such as NES mass, spring stiffness and damping coefficient is also implemented. The results show that this new multifunctional lattice sandwich structure can achieve the desired effect of vibration suppression and energy harvesting, and proper adjustment of parameters will improve the effect. This study provides a new idea for related research on vibration control and energy harvesting.

Comparative studies of vibration control effects between structures with particle dampers and tuned liquid dampers using substructure shake table testing methods

This paper compares the vibration control performance of particle dampers (PDs) and tuned liquid dampers (TLDs) by using the up-to-date substructure shake table testing (SSTT) method. In implementing the SSTT, three representative model-based integration algorithms, whose algorithmic parameters are functions of the complete model of the structure system to enable unconditional stability to be achieved within the framework of an explicit formulation, are adopted. The experimental procedures of the SSTT methods using the three integration algorithms are presented. The SSTT system of the single-degree-of-freedom (SDOF) structures with PDs/TLDs is constructed and verified by comparing the experimental results of the SSTTs and the corresponding complete structure shake table tests. The vibration reduction effects of PDs and TLDs with the same mass ratio are investigated and compared by conducting a series of SSTTs of the SDOF systems with such devices under the excitation of ground motion. The influences of mass ratio, damping ratio and structural frequency on control efficiency of PDs and TLDs are studied. The results from the parametric analyses demonstrate that all the aforementioned factors have significant impacts on the vibration control performance of both dampers. Most experimental results indicate that the PDs have better vibration control performance than the counterpart TLDs.

Tuning of vibration absorbers and Helmholtz resonators based on modal density/overlap parameters of distributed mechanical and acoustic systems

This paper presents a study on the tuning of vibration absorbers and Helmholtz resonators used to control at target resonance frequencies respectively the flexural response of lightly damped distributed structures and the acoustic response of lightly damped cavities subject to broadband stochastic excitations. The vibration and acoustic control effects of these two devices are assessed considering the broadband flexural response and acoustic response of typical structures and enclosures encountered in practical applications, that is: beam, thin plate and thin walled cylinder structures and one-dimensional duct, two-dimensional slender volume, three-dimensional volume enclosures. The herein proposed multi-mode tuning approaches are based on the H2 cost functions of the total flexural kinetic energy of the three structures and of the total acoustic potential energy of the three enclosures. The H2 cost functions are defined within finite frequency bands centred at the target structural or acoustic resonance frequencies respectively. A comprehensive overview of the modal density and modal overlap functions for the flexural response of the three structures and for the acoustic response of the three enclosures is also presented to provide physical interpretations and practical guidelines on the performance and applicability of classical single-mode and the proposed multi-mode tuning approaches. The study shows that classical tuning laws can be straightforwardly employed to control the response at low resonance frequencies such that the modal overlap is not greater than one, whereas to control the response at higher resonance frequencies, where the modal overlap is significantly greater than one, the proposed multi-mode tuning approach should be adopted.

Effect of vibration control on heat transfer in spatially developing pipe flow

Effect of vibration control on heat transfer in spatially developing pipe flow

Vibration control method for a crawler-type combine harvester

The traditional vibration control method for the crawler-type combine harvester based on experience is only a small piece of weight iron added to the main drive shaft of the cutter,and the mass of the weight iron is determined by the technician with experience, so the vibration control effect is not obvious. Therefore, a vibration control method for the new crawler-type combined harvester is put forward in this paper. The engine and cutting structure are the main sources of the crawler-type combine. According to the force analysis results of the cutting structure and the results of structural dynamics analysis, each acting force and moment of force are obtained, and the optimal combination scheme for calculating the position and mass of weight distribution is calculated to solve the cutting structure’s vibration of the crawler-type combine harvester. According to the vibration theory and modern design method, the vibration control of the crawler-type combine harvester engine is realized through the model analysis and the finite element calculation to establish the vibration damping model and design the parameters of the damping cushion. The experimental results show that the proposed method can effectively improve the vibration status of crawler-type combine harvesters, and the vibration level of harvesters is reduced by 50% to 80% in field operation.