Vibration Control Characteristics Research Articles

Effect of two-parameter partial foundation and viscoelastic supports on free vibration of Terfenol-D layered functionally graded fluid conveying pipe using domain decomposition technique

The purpose of the current research work is to investigate the free vibration control characteristics of a Terfenol-D layered functionally graded fluid-conveying pipe when subjected to partial two-parameter foundation, viscoelastic supports, and multi-span length. The integration of differential quadrature method with domain decomposition and the δ point approach, as well as Terfenol-D layer actuation with viscoelastic supports, distinguishes the current study effort. The equivalent spring stiffness for the two-parameter partial foundation is determined methodically for various elastic soil materials. The effect of varied spans with viscoelastic supports on the stability of fluid conveying pipes is also explored.

Theoretical analysis of the energy conversion and vibration control characteristics of a slanted beam termination

Theoretical analysis of the energy conversion and vibration control characteristics of a slanted beam termination

Designs, analysis, and applications of nonlinear energy sinks

Nonlinear energy sink (NES) is an appropriately designed nonlinear oscillator without positive linear stiffness. NES can suppress vibrations over a wide frequency range due to its targeted energy transfer characteristics. Thus, investigations on NES have attracted a lot of attention since a NES was proposed. Designs, analysis, and applications of NESs are still active since different configurations are needed in various practical circumstances. The present work provides a comprehensive review of state-of-the-art researches on NESs. The work begins with a survey of the generation of a NES and its important vibration control characteristics. The work highlights possible complex dynamics resulting in a NES coupled to a structure. The work also summarizes some significant design on the implements of optimal damping effects and the offsets of NES shortcomings. Then, the work details the applications of NESs in all engineering fields. The concluding remarks suggest further promising directions, such as NESs for multidirectional vibration reduction, NESs with nonlinearities beyond the cubic, potential deterioration caused by a NES, low-cost NESs, NESs for extremely low frequency range, and NESs integrated into active vibration controls. There are 383 references in the review, including some publications of the authors.

Active vibration control of smart composite laminates with partial debonding of actuator

The effect of actuator debonding on the performance of active vibration control is analytically investigated through an optimal control strategy. An improved layerwise theory with Heaviside step functions, which addresses discontinuous displacement fields, is used for modeling the actuator debonding. General finite element procedures are developed to derive the governing equation taking into consideration the electro-mechanical coupling effect. A reduced-order model based on the state-space model is adopted for the design of the active controller. Generally, debonding in actuators reduces their load carrying capability, dynamic properties and vibration control characteristics. The effect of debonding on the vibration control is investigated by the proposed analytical modeling. Numerical results using a 16-layer cross-ply laminate with healthy actuator and partially debonded actuator are given for the investigation of the vibration suppression efficiency and control effort. It is observed that the control authority of the composite laminates with partially debonded piezoelectric actuator is dramatically reduced by increasing the size of the actuator debonding. Since debonding failure may occur during the service life of smart composite laminates, the results showed that actuator debonding must be considered as an uncertainty parameter in the design of active controllers.

Analysis of Damping Performance for Cabin Deck Covered with Floating Floor Coverings

Floating floor coverings are widely applied in ship structures. With regard to the laminated composite shells made up of floating floor coverings and cabin deck and based on ANSYS system, a dynamics analysis on structures of three different kinds of floating floors is performed using FEM built upon laminated shell elements. The influence of rockwool board in terms of thickness, density and elastic modulus on structure dynamic characteristics is discussed. The performances of vibration control of three different floating floor structures are compared. The FEM performs well in analyzing and calculating the vibration control characteristics of structures, the results of which offer certain reference to the design and research on cabin deck covered with floating floor coverings.

106 超小型スマート構造の振動制御と非接触レーザー加振による制振特性評価

Smart structures technology that uses piezoelectric element etc. is effective for the vibration control of small devices. However, for micro devices, it is difficult experimentally to measure and evaluate the vibration control characteristics of the system with control. Namely, it is not realistic to install an external exciter or to apply the excitation force with an impulse hammer. Therefore, in this study, the vibration property is measured and evaluated by using the noncontact excitation technology using laser ablation and the noncontact measurement with Laser Doppler Velocimeter. Since both input excitation and output measurement are made without contact of apparatus and the excitation force has a high reproducibility in the present system, the efficiency and the reliability of the measurement can be improved.

Investigations on damping characteristics of a honge oil-based magnetorheological fluid damper

Magnetorheological (MR) fluid damper is a kind of intelligent control device that can be used to reduce response of a vibrating member instantaneously with very few moving parts, which is essential in most of the mechanical systems, but challenging. In the present work, a prototype of smart damper using MR fluid (MR damper) is designed based on Bingham plastic model and fabricated to conduct vibration related tests. A sudden damping is obtained as a result of quick change in viscosity and shear stress of the MR fluid in response to the change in magnetic field. Biodegradable oil namely honge oil is proposed as carrier liquid of the MR fluid. The relation between yield stress and magnetic field of the proposed honge oil-based MR fluid is used while designing the MR damper. Then an experimental setup is designed to investigate the damping and vibration control characteristics of the fluid. Damping force at various frequencies, amplitudes and currents are obtained and their inter-relations are studied. Furth...

Vibration Control Evaluation of Micro Smart Structures with Non-Contact Laser Excitation

Smart structures technology that uses piezoelectric element etc. is effective for the vibration control of small devices. However, for micro devices, it is difficult to experimentally measure and evaluate the vibration control characteristics of the system due to its microscopic scale. Namely, it is not realistic to install an external exciter or to apply the excitation force with an impulse hammer. Therefore, in this study, the vibration property is measured and evaluated by using the non-contact excitation/measurement technology using laser ablation for the excitation and laser Doppler vibrometer for the measurement. Since both input excitation and output measurement are made without contact of apparatus and the excitation force has a high reproducibility in the present system, the efficiency and the reliability of the measurement can be improved.

Distributed actuation characteristics of clamped-free conical shells using diagonalpiezoelectric actuators

In spacecraft, severe vibrations induced by the launch vehicle may cause damage to theprecision payload. Therefore active adapters with vibration suspending characteristics areneeded. This paper presents theoretical studies of the active vibration controlcharacteristics of conical shells with laminated piezoelectric actuators. A diagonalpiezoelectric actuator is proposed to control the axial, lateral and transverse vibrations ofthe conical shell. Modal functions are designed to represent the free vibrations of theconical shell with clamped-free boundary conditions. General formulae of the modal controlforce and corresponding components are derived based on the converse piezoelectriceffects and then specified for the diagonal actuators. By using an open-loop controlmethod, the modal control characteristics of diagonal actuator segments at differentlocations are investigated and compared, and the axial, lateral and transversevibrations of two conical shell models are evaluated. The optimal locations ofactuator segments for the control of different natural modes are also investigated.

Active vibration control characteristics of flexible manipulator with laminated piezoelectric actuator

Active vibration control characteristics of flexible manipulator with laminated piezoelectric actuator

Active vibration control of smart plates with partially debonded multilayered PZTactuators

The influence of actuator damage on the performance of closed loop vibration control isnumerically evaluated. Debonding is considered a damage mode and finite elementprocedures are subsequently developed to introduce its effect on system matrices, namelyelastic and electro-elastic stiffness. A simple modelling scheme for multiple debonding isproposed, which can also idealize multiple delamination in the host laminate.Debonding in actuators in general has reduced their load carrying appreciably aswell as vibration control characteristics. Therefore, incorporating such a damagemode in the control design as an uncertainty parameter would help to realize adamage-tolerant active vibration control system. It is interesting to note thatdebonding in actuators has influenced both active damping and active stiffeningeffects.

Design and testing of a hybrid polymeric electrostrictive/piezoelectric beam with bang–bang control

Electrostrictive materials, hard ceramics and soft polymers, have been used as precision actuators in many engineering applications. This study is to examine bang–bang control performance of a hybrid Plexiglas beam laminated with polymeric electrostrictive (RTV 270) actuator and piezoelectric polyvinylidene fluoride (PVDF) sensor layers using both analytical and experimental techniques. Material characteristics are calibrated via static testing first; a hybrid beam model is then fabricated and an experiment set-up, consisting of a bang–bang controller, high-voltage amplifier, data acquisition system and the hybrid beam system, is designed to evaluate vibration control characteristics (i.e., damping ratio estimation) of the hybrid beam subjected to various control conditions. Due to the quadratic behaviour of electrostrictive materials, the controller activates the electrostrictive actuator only in upward motion of the beam, with reference to signals generated from the piezoelectric sensor. Base on constitutive equations and dynamic/control characteristics, a mathematic hybrid beam model is also derived from the electrostrictive thin shell theory and its dynamic responses, based on the finite difference discretization, are simulated to predict damping ratios resulting from control forces induced by the electrostrictive actuators. Dynamic responses (with and without control) of the physical beam model are measured and compared with simulation results. Favourable comparison suggests that the mathematical model describes the experimental model very well and its application to other advanced structures can be proceeded.

508 二振子動吸振器による傾斜振動系の制振特性

508 二振子動吸振器による傾斜振動系の制振特性

Interaction of active and passive vibration control of laminated composite beams with piezoceramic sensors/actuators

The interaction between active and passive vibration control characteristics was investigated numerically and verified experimentally for carbon/epoxy laminated composite beams with a collocated piezoceramic sensor and actuator. The finite element method was used for the analysis of dynamic characteristics of the laminated composite beams. Damping and stiffness of adhesive and piezoceramic layers were taken into account in the finite element modeling. The optimal control theory was applied for the analysis of control characteristics of the beam. Experiments on the active vibration control of the laminated composite beams were carried out using velocity feedback control. The effect of varying the stacking sequence of the laminated composite beam on the active and passive damping properties was studied. The finite element analysis was verified by comparing the experimental results in terms of active and passive damping ratios (ζ) and modal dampings (2ζω) as well as fundamental frequency. When the gain in velocity feedback control is small, the active control follows the trend of the passive control, but provides additional effects due to the active control. For a large feedback gain, the active control is dominant over the passive control. Active control is more effective in the structure with higher bending stiffness than in the structure with lower bending stiffness when the feedback gain is large.

Vibration control characteristics of a hybrid mass damper system installed in tall buildings

Vibration control characteristics of a hybrid mass damper system installed in tall buildings

Vibration control characteristics of a hybrid mass damper system installed in tall buildings

AbstractA large‐scale hybrid mass damper (HMD) system was developed to reduce building response during strong winds and earthquakes of up to medium strength. The HMD consists of an auxiliary mass supported by multi‐stage rubber bearings and actuators driven by AC servomotors.Two HMDs were installed on the top floor of a target building to suppress both translational and torsional vibration. The system was installed in two high‐rise buildings. One was a 50‐storey, 200‐m high, steel‐frame building. The dynamic characteristics of both the building and the HMDs were identified through forced vibration tests using the HMD system. The effectiveness of the HMD system was confirmed by these tests and both wind and earthquake observation data.The other building was a triangular‐plan, 43‐storey, steel‐frame building. The dynamic characteristics of the building were estimated using two different methods. One method comprised a series of vibration tests using the HMDs to excite the building. The other method was an analysis of the earthquake response records of the building, which showed the additional damping effect of the HMD system. The performance of the HMD system during a strong typhoon was also analysed. Copyright © 2001 John Wiley & Sons, Ltd.

Effect of modal filter errors on vibration control characteristics

When designing a control system for vibration suppression of flexible structures using modal control strategy, one must know the modal displacements and velocities of the controlled modes. If the vibration control forces are designed based on inaccurate modal states, the closed-loop performance of the vibration control system will be degraded depending on the extent of the modal filter errors. In this study, the effect of modal filter errors on the vibration control characteristics of flexible structures is analyzed for IMSC (Independent Modal Space Control). A Lyapunov asymptotic stability condition that depends on the magnitude of the modal filter errors is derived. The extent of the response deviation of the closed-loop system is also derived and evaluated using operator techniques. The extent of the response deviation is found to be proportional to the magnitude of the modal filter errors.

Robustness of Independent Modal Space Control for Parameter and Modal Filter Errors

In this study, the effect of parameter and modal filter errors on the vibration control characteristics of flexible structures is analyzed for IMSC ( Independent Modal Space Control). If the control force is designed on the basis of the mathematical model with the parameter and modal filter errors, the closed-loop performance of the vibration control system will be degraded depending on the magnitude of the errors. An asymptotic stability condition of the system with parameter and modal filter errors has more significant effect on the stability condition of the system with parameter and modal filter errors has been drived using Lyapunov approach. It has been found that modal filter error has more significant effect on the stability of closed-loop system than parameter error does. The extent of the response deviation of the closed-loop system is also derived and evaluated using operator thchniques.