Passive Vibration Control System Research Articles

Soil-dependent optimum design of a new passive vibration control system combining seismic base isolation with tuned inerter damper

The papers addresses a novel passive vibration control system combining seismic base isolation with a tuned inerter damper (TID) system. The latter, by analogy with the tuned mass damper (TMD), is a dynamic vibration absorber in which the physical mass of the TMD is partly or entirely replaced by an apparent mass, also called inertance, created by a particular arrangement of mechanical gearings—the inerter. By attaching a TID to the isolation floor, not only the displacement demand of base-isolated structures can be significantly reduced, but also the superstructure response (e.g. interstory drift, base shear) is effectively controlled. Optimum parameters of this system are found based on a simplified three degree-of-freedom model that reflects the dynamic properties of both the isolation system and the TID while accounting for the flexibility of the base-isolated superstructure. Within a probabilistic framework, the influence of soil conditions is investigated by modeling the seismic ground motion as a filtered Gaussian random process. Different filter parameters are considered that may be associated with firm, medium or soft soil conditions depending on the frequency content of the power spectral density function. A wide parametric study is performed in order to detect the optimal TID parameters depending on the soil conditions for a variety of isolation ratios, mass ratios and damping ratios of both the superstructure and the isolation system. Finally, a multi-story building equipped with the proposed passive vibration control system is examined. Effectiveness of the proposed system is assessed via the evaluation of the structural response in the time domain. Detuning effects are investigated via a sensitivity analysis. Comparison with alternative passive vibration control systems proposed in the literature and based on different arrangements of TMD and inerter-based device is discussed.

Invited Review: Recent developments in vibration control of building and bridge structures

This paper presents a state-of-the-art review of recent articles published on active, passive, semi-active and hybrid vibration control systems for structures under dynamic loadings primarily since 2013. Active control systems include active mass dampers, active tuned mass dampers, distributed mass dampers, and active tendon control. Passive systems include tuned mass dampers (TMD), particle TMD, tuned liquid particle damper, tuned liquid column damper (TLCD), eddy-current TMD, tuned mass generator, tuned-inerter dampers, magnetic negative stiffness device, resetting passive stiffness damper, re-entering shape memory alloy damper, viscous wall dampers, viscoelastic dampers, and friction dampers. Semi-active systems include tuned liquid damper with floating roof, resettable variable stiffness TMD, variable friction dampers, semi-active TMD, magnetorheological dampers, leverage-type stiffness controllable mass damper, semi-active friction tendon. Hybrid systems include shape memory alloys-liquid column damper, shape memory alloy-based damper, and TMD-high damping rubber.

Integrated Design of Hybrid Interstory-Interbuilding Multi-Actuation Schemes for Vibration Control of Adjacent Buildings under Seismic Excitations

The design of vibration control systems for the seismic protection of closely adjacent buildings is a complex and challenging problem. In this paper, we consider distributed multi-actuation schemes that combine interbuilding linking elements and interstory actuation devices. Using an advanced static output-feedback H ∞ approach, active and passive vibration control systems are designed for a multi-story two-building structure equipped with a selected set of linked and unlinked actuation schemes. To validate the effectiveness of the obtained controllers, the corresponding frequency responses are investigated and a proper set of numerical simulations is conducted using the full scale North–South El Centro 1940 seismic record as ground acceleration disturbance. The observed results indicate that using combined interstory-interbuilding multi-actuation schemes is an effective means of mitigating the vibrational response of the individual buildings and, simultaneously, reducing the risk of interbuilding pounding. These results also point out that passive control systems with high-performance characteristics can be designed using damping elements.

The identification of the vibration control system parameters designed for continuous miner machines

The Continuous Miner machines are exposed to time dependent loads during normal operation of the rock cutting process. These loads cause vibrations, which have a negative influence on the whole structure of the machine. This phenomenon can be eliminated by applying passive or active vibration control systems (VCS). Generally these systems are coupled with additional elements, which provide dispersion or transfer energy. The energy thus acquired can also reinforce the intended function such as rock cutting operation in the case of mining machines. The objective of this paper is to present the method of numerical identification of VCS parameters for Continuous Miner machines. The main function of the presented system is to reduce displacement of cutting drum by using elastic element joined to machine chassis and applying appropriate algorithm of control of the angular velocity of cutting drum. The method described improves efficiency of mining and increases durability of machine. In order to determine mechanical and control parameters of VCS the genetic algorithm optimisation method conjugated with numerical modal analysis was used. Finally the transient dynamic analysis was performed for the full-scale model of Continuous Miner in order to verify VCS in normal working condition.

Vibration analysis of the civic tower in Rieti

In the last decades the definition of a suitable monitoring system for identifying the dynamic behavior of structures has had a central position in the civil engineering research area. The vibration analysis leads to the recognition of the reference state of structures which is essential to determine the integrity level when extreme events occur, such as earthquakes. The latest seismic events occurred in the world have shown the essential role of the new passive seismic techniques which aim to protect structures and the importance of supervising the building construction operations and the adopted improvement measures.In this work the structural monitoring of the civic tower located in Rieti is presented. In the tower a non-conventional TMD has been installed via an inter-story isolation system at the top floor by means of High Damping Rubber Bearings (HDRB).The general goal is to define a monitoring system suitable with this experimental case through the vibration analysis. Several aspects will be taken into account: the choice of sensors setup, the measured quantities and the extraction of structural information. Firstly this will allow to define the structure’s reference state featured by frequencies, damping ratios and mode shapes. Moreover the effective design of the monitoring system would lead to the characterization of the dynamic behavior of the structure equipped with a passive vibration control system. Different tests have been carried forward: ambient vibration test (AVT), forced vibration test (FVT) with vibrodyne and seismic test (ST). The AVT and the FVT enable to define the monitoring system and check the reliability of the adopted identification tools, among which an Output Only algorithm stands out: the Observer Kalman Filter System Id. On the other hand the ST will point out some preliminary information about the dynamic behaviour of the structure equipped with a non conventional Tuned Mass Damper referring it to higher levels of vibrations.

Cyclic behavior of seesaw energy dissipation system with steel slit dampers

This paper presents an investigation into the cyclic behavior of a passive vibration control system in which steel slit dampers are applied to a seesaw energy dissipation system. The fundamental concept of the seesaw system is the quasi-linear motion mechanism, which enables the bracing members to remain in tension during vibration. The lateral stiffness and strength formulae of the frame with this system are derived first. Six cyclic loading tests were conducted to reveal that the proposed system has a stable hysteretic property and a large energy dissipation capacity. For all specimens, the slit dampers yielded at early stages of the tests around a story rotation angle of 0.001rad. This property is preferred for energy dissipation properties to reduce story drift in building structures under seismic loads. The important seesaw system characteristic of the bracing members remaining tensile was also observed. The tri-linear hysteretic model is introduced to model the cyclic behavior of the proposed damping system. A comparison of the hysteretic loops and the energy dissipation amount between the model and test results reveals the adaptability of the tri-linear model to the hysteretic behavior of the proposed system. The validity of the stiffness and strength prediction is also shown from the test results.

Using an inerter‐based device for structural vibration suppression

SUMMARYThis paper proposes the use of a novel type of passive vibration control system to reduce vibrations in civil engineering structures subject to base excitation. The new system is based on the inerter, a device that was initially developed for high‐performance suspensions in Formula 1 racing cars. The principal advantage of the inerter is that a high level of vibration isolation can be achieved with low amounts of added mass. This feature makes it an attractive potential alternative to traditional tuned mass dampers (TMDs). In this paper, the inerter system is modelled inside a multi‐storey building and is located on braces between adjacent storeys. Numerical results show that an excellent level of vibration reduction is achieved, potentially offering improvement over TMDs. The inerter‐based system is compared to a TMD system by using a range of base excitation inputs, including an earthquake signal, to demonstrate how the performance could potentially be improved by using an inerter instead of a TMD. Copyright © 2013 John Wiley & Sons, Ltd.

Dynamic characterization of complex bridge structures with passive control systems

The article focuses on dynamic identification strategies for complex bridge structures equipped with passive vibration control systems. In detail, a recently built curved twin-deck cable-stayed footbridge was analysed, whose structural complexity required wind tunnel tests and a specific design for vibration reduction. A passive control system was deemed necessary in order to: (i) meet wind safety requirements owing to premature aeroelastic instability, and (ii) mitigate pedestrian vibrations. Uncertainties in numerical modelling and changes during its construction suggested a modal testing campaign in order to check the effectiveness of the vibration absorption system. Different excitation sources related to output-only techniques were exploited, including ambient noise and free-decay oscillations through released masses. Several sensor set-ups were deemed necessary in the view of the structure complexity that exhibits numerous close modes and modal couplings between the two decks. The effect of the dampers was analysed by performing the testing campaign for two distinct configurations: (i) disconnected dampers, and (ii) connected dampers. The dynamic properties of the cables were also investigated in order to complete the whole dynamic characterization of the structure. Two time-domain techniques were applied and compared under different excitations. The dynamic identification procedure provided consistent results and highlighted that full functionality of the damping system was realized only for high vibration levels. Finally, time–frequency instantaneous estimators were applied in order to analyse both the modal frequency and the damping time-variation. These results revealed amplitude dependent behaviours as well as dynamic deck-cable interactions. Copyright © 2011 John Wiley & Sons, Ltd.

Active control of electro-rheological fluid embedded pneumatic vibration isolator

Vibration isolation is crucial to better product quality in precision machinery, and can be achieved through either passive or active vibration control systems. Although passive pneumatic vibration...

Optimum Parametric Studies on Tuned Rotary-Mass Damper

We suggest a new passive type vibration control system, tuned rotary-mass damper (TRMD), which consists of the rolling mass (rotary-mass) and the container (outer shell) allowing the free movement of the mass along its inner arc. This TRMD has a simple construction and is applicable to the structure. The tuning of TRMD can be made by adjusting the diameter of the rotary-mass and the curvature of inside the outer shell. To determine the optimum tuning and damping ratio for a linear system of TRMD, a design technique of tuned mass damper is applied. The frequency response analysis is also performed to the nonlinear system of TRMD. It was found that the response magnification factor of the structure-TRMD system showed a strong dependency on the external strength ratio, and can be reduced by designing TRMD against the targeted external strength ratio.

Active control of electro-rheological fluid embedded pneumatic vibration isolator

Vibration isolation is crucial to better product quality in precision machinery, and can be achieved through either passive or active vibration control systems. Although passive pneumatic vibration isolators have excellent isolation characteristics a

Numerical simulation of superelastic shape memory alloys subjected to dynamicloads

Superelasticity, a unique property of shape memory alloys (SMAs), allows the material torecover after withstanding large deformations. This recovery takes place without anyresidual strains, while dissipating a considerable amount of energy. This property makesSMAs particularly suitable for applications in vibration control devices. Numerical models,calibrated with experimental laboratory tests from the literature, are used to investigatethe dynamic response of three vibration control devices, built up of austenitic superelasticwires. The energy dissipation and re-centering capabilities, important featuresof these devices, are clearly illustrated by the numerical tests. Their sensitivityto ambient temperature and strain rate is also addressed. Finally, one of thesedevices is tested as a seismic passive vibration control system in a simplifiednumerical model of a railway viaduct, subjected to different ground accelerations.

439 GKYP補題に基づくパッシブ型制振装置の設計

In this paper, we propose a new method of designing a passive vibration control system. The standpoint is that the structure of the passive vibration control system is similar to that of a PD controller. Variable parameters of one-degree-of-freedom passive isolation device, i.e. spring and damper, are considered as the feedback gain of the PD controller. After that, frequency characteristics of the open-loop transfer function of the transformed system with PD controller are optimized in the suitable restriction by GKYP lemma.

Control algorithms for active vibration isolation systems subject to random disturbances

Isolation from disturbances, particularly from foundations of high precision instruments, is achieved through either passive or active vibration control systems. Although a passive isolation system offers a simple and reliable means of protecting precision equipment from a vibration environment, it has performance limitations since its controllable frequency range is limited. An effective method for reducing an oscillation is by using an active vibration isolation system, which allows control of the dynamic rigidity of shock absorbers. In this paper, by considering the characteristics of the disturbing influences acting upon vibro-isolated objects, the dynamic characteristics of the AVIS device and control restriction, new optimal and quasi-optimal control algorithms are proposed. The characteristics of the new quasi-optimal active vibration isolation system proposed in the paper are investigated via experiments. It is shown that the adopted quasi-optimal active vibration isolation system can improve performance using in situ measurements.

A Study on Optimum Design of Joint Dampers Connecting Two Towers. The Case of Connecting Two Same Height Towers at Multiple Points.

A large number of ancient five-storied pagoda in Japan has survived strong earthquakes over centuries, proving its structural advantage. Typical structure of pagoda, consisted of self-supporting outer tower and inner core post, yields friction and collision between outer and inner structures. Similar mechanism can be applied to modern buildings exited by earthquakes or strong wind to absorb response energy efficiently. This paper presents a passive vibration control system which utilize the above-mentioned mechanism. The system consists of ioint dampers which connected two high rise towers of the same height. The dampers locate every three to four stories between two towers. The method to obtain the optimum distribution of ioint dampers is described. An example is presented through a numerical simulation showing the effectiveness of the presented scheme.

Mechanics and Dynamics of Intelligent Passive Vibration Control System

A new structural vibration control system called the Intelligent Passive Vibration Control (IPVC) System is presented. Such a system theoretically consists of two parts: a passive part (first) and an intelligent part (second). Generally, under small earthquake excitations, only the first part works as a base-isolation device. In the case of intense earthquake shaking, if the response (e.g., the displacement response) of the structure exceeds the determined allowance of the first part, then the intelligent part also works to change the mechanical characteristics of the system. The general constitutive law and the mechanism of the system are presented. Assuming the passive part and the intelligent part to be viscoelastic material with fading memory, the mechanics of such a new system have been studied, and the theoretical solution to the vibration equation is presented. Also a numerical simulation was done for a real twin structure (one is nonisolated and the other is base isolated) built at the campus of Tohoku University together with one more structure having the IPVC system. The result clearly shows that the system is effective, especially for reduction of maximum displacement response.

Satellite active and passive vibration control during liftoff

The feasibility of active and passive vibration control systems for suppressing the transfer pf orbiter vibration energy to its payload during liftoff is studied. A simple five-degree-of-freedom lump parameter model of a satellite is considered, and the performances of active and passive vibration control systems are evaluated and compared. Effectiveness of various vibration control systems for protection of the Space Shuttle payload during liftoff are analyzed. Peak responses of the satellite with active and passive vibration control systems are compared with those in the absence of vibration control systems. The results show that properly designed passive and active vibration control systems are highly effective in reducing the liftoff vibration to its payload.

A HYBRID-TYPE ACTIVE VIBRATION ISOLATION SYSTEM USING NEURAL NETWORKS

Vibration isolation of mechanical systems is achieved through either passive or active vibration control systems. Although a passive vibration isolation system offers simple and reliable means to protect mechanical systems from a vibration environment, it has inherent performance limitations, that is, its controllable frequency range is limited and the shape of its transmissibility does not change. Recently, in some applications, such as active suspensions or precise vibration systems, active vibration isolation systems have been employed to overcome the limitations of the passive systems. In this paper, a hybrid-type active vibration isolation system that uses electromagnetic and pneumatic force is developed, and a new control algorithm adopting neural networks is proposed. The characteristics of the hybrid system proposed in the paper were investigated via computer simulation and experiments. It was shown that the transmissibility of the vibration isolation system could be kept below 0.63 over the entire frequency range, including the resonance frequency.

Quenching of Self-Excited Vibrations

A passive vibration control system for the quenching of undesirable self-excited vibrations in mechanical systems is presented. The system is a Lanchester damper, attached to the main self-excited system; a van der Pol oscillator. A first-order perturbation solution shows that complete quenching of self-excited vibration is possible. The result is verified by numerical integration of the governing differential equations. Furthermore, the damper is shown to be effective in suppressing forced self-excited vibrations.

Vibration Control Using Semi-Active Force Generators

A type of force generator which can respond to general feedback signals from a vibrating system in order to control the vibration but which does not require the power supply of a servomechanism is described. Computer simulation studies show that performance comparable to that of fully active vibration control systems can be achieved with the semi-active type of device. Physical embodiments of the concept are discussed and compared to hardware used in active and passive vibration control systems.