State of the art of control schemes for smart systems featuring magneto-rheological materials

This review presents various control strategies for application systems utilizing smart magneto-rheological fluid (MRF) and magneto-rheological elastomers (MRE). It is well known that both MRF and MRE are actively studied and applied to many practical systems such as vehicle dampers. The mandatory requirements for successful applications of MRF and MRE include several factors: advanced material properties, optimal mechanisms, suitable modeling, and appropriate control schemes. Among these requirements, the use of an appropriate control scheme is a crucial factor since it is the final action stage of the application systems to achieve the desired output responses. There are numerous different control strategies which have been applied to many different application systems of MRF and MRE, summarized in this review. In the literature review, advantages and disadvantages of each control scheme are discussed so that potential researchers can develop more effective strategies to achieve higher control performance of many application systems utilizing magneto-rheological materials

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

Neural Network Based Vibration Control of Seismically Excited Civil Structures

This study proposes a neural network based vibration control system designed to attenuate structural vibrations induced by an earthquake. Classical feedback control algorithms are susceptible to parameter changes. For structures with uncertain parameters they can even cause instability problems. The proposed neural network based control system can identify the structural properties of the system and avoids the above mentioned problems. In the present study it is assumed that a full state of the structure is known, which means the at each floor horizontal displacements and rotations about the vertical axis are measured. Additionally, it is assumed the acceleration signal coming from the earthquake is also available. The proposed neural control strategy is compared with the classical linear quadratic regulator (LQR) not only in terms of displacement responses, but also required control forces. Moreover, the influence of different weighting matrices on performance of the proposed control strategy has been presented.The effectiveness of the neuro-controller has been demonstrated on two numerical examples: a simple single degree of freedom (DOF) structure and a multi-DOF structure representing a twelve story building. Both structures under consideration have been excited with El Centro acceleration signal. The results of numerical simulations on the SDOF system indicate that using neuro-controller it would be possible to obtain smaller amplitudes as compared with the LQ regulator, but it would require higher control effort

Adaptive Vibration Control for an Active Mass Damper of a High-rise Building

As a kind of large flexible structure, high-rise buildings need to consider wind-resistant and anti-seismic problems for the safety of occupants and properties, especially in coastal areas. This paper proposes an infinite dimensional model and an adaptive boundary control law for an active mass damper(AMD) on this question. The dynamic model of the high-rise building is a combination of some storeys which have flexible walls and rigid floors under a series of physical conditions. Then the adaptive boundary controller is acted on an AMD which is equipped on the top floor, in order to suppress the vibration of every floor and guarantee the comfort of residents. Moreover, simulations and experiments are carried out on a two-floor flexible building to illustrate the effectiveness of the proposed control strategy

The application of Maxwell elements for modeling, identification and analysis of passive and semi-active vibration systems.

Dynamic analysis and parameter identification of a single mass elastomeric isolation system represented by Maxwell model is examined using both analytical and experimental approaches in this dissertation. Influences that the stiffness and damping values of the Maxwell element have on natural frequency, damping ratio and frequency response are uncovered and three unique categories of Maxwell-type elements are defined. It is revealed through analytical examples that Maxwell models consisting of two Maxwell elements can accurately replicate the dynamic behavior of Maxwell systems having two or more Maxwell elements. Two parameter identification methods are developed for identifying Maxwell models from measured frequency response spectra. To experimentally evaluate the analytic results, three different commercial rubber mounts are considered. For all three rubber isolators, it is shown that Maxwell models with two Maxwell elements can accurately represent the measured static and dynamic characteristics of the real elastomeric isolation systems. Aeroelastic aircraft wings are the structures which have variable natural frequency and damping ratio as flight parameters change. Serious vibration inhibits the flight at high airspeed conditions. In this study, the dynamic analysis of aeroelastic aircraft wings reveals that a DVA (dynamic vibration absorber) with tunable stiffness and damping parameters can effectively suppress vibration over variable airspeeds in the presence of broadband external disturbance. Since tunable stiffness components are not yet well developed, another configuration of a semi-active DVA having only one tunable damping component is designed. Dynamic analysis reveals that the performance of this semiactive DVA is very close to the DVA having both tunable stiffness and damping components. Two control methods are developed for the semi-active DVA. The first control method is based on the measured airspeed. It works well if the air density is constant during the flight. The second method, a neural-network based controller, is formulated directly in terms of ready measured normalized vibration response spectra. It works well with time-varying airspeed and air density. Both methods are based on measured data and do not require prior knowledge of the plant mathematic model