Showing papers on "Damper published in 2009"
TL;DR: In this paper, the structural responses of offshore wind turbines are simulated with an attached damper (Tuned Liquid Column Damper) for controlling the vibrations induced within the structure, and a fatigue analysis is carried out and the implementation of TLCDs is seen to enhance the fatigue life of the structure.
303 citations
TL;DR: In this article, an innovative structural system with slit dampers was developed, which could not only provide good seismic performance but could also be easily repaired after a heavy earthquake by using a mechanical joint that is equipped with a metallic damper as the beam-to-column connection.
248 citations
TL;DR: A novel evolutionary algorithm of particle swarm optimization (PSO) is used for optimization of the required parameters of a TMD system attached to a viscously damped single degree-of-freedom main system.
186 citations
Patent•
30 Dec 2009
TL;DR: In this paper, an intelligent register controller automatically determines when and to what extent to operate its respective controllable damper, based on information collected by the register controller, such as: current temperature of the region; desired temperature of a region; calculated amount of conditioned air required to change the region's temperature to the desired temperature; temperature of air begin supplied by a duct to the register; current time, day of week, vacation or other schedule data; temperatures of other regions and their respective desired temperatures; calculated amounts of supplied or withdrawn by the other controlled registers to change their
Abstract: Distributed nodes, such as intelligent register controllers, of a heating, ventilating and/or air conditioning (HVAC) system wirelessly communicate with each other on a peer-to-peer basis, forming a network, and collectively control the HVAC system, without a central controller. The intelligent register controllers collectively control the amount of conditioned air introduced into each region. Each node may base its operation at least in part on information about one or more (ideally all) of the other nodes. Each intelligent register controller automatically determines how much conditioned air to allow into its region, or how much return air to allow to be withdrawn from its region, based on information collected by the register controller, such as: current temperature of the region; desired temperature of the region; calculated amount of conditioned air required to change the region's temperature to the desired temperature; temperature of conditioned air begin supplied by a duct to the register; current time, day of week, vacation or other schedule data; temperatures of other regions and their respective desired temperatures; calculated amounts of air required to be supplied or withdrawn by the other controlled registers to change their respective regions' temperatures to their desired temperatures; or combinations thereof. Each register controller automatically determines when and to what extent to operate its respective controllable damper.
181 citations
TL;DR: In this paper, the authors developed models for predicting particle dampers (PDs) behavior using the Discrete Element Method (DEM), where individual particles are typically represented as elements with mass and rotational inertia.
162 citations
TL;DR: In this article, shape memory alloys (SMAs) are used for cable-stayed bridges to control the deck displacement and limiting the bending moment demands on the bridge towers, and a study is conducted to determine the sensitivity of the bridge response to the hysteretic properties of the SMA dampers.
143 citations
TL;DR: In this paper, a linear matrix inequality (LMI)-based systematic design methodology for nonlinear control of building structures equipped with a magnetorheological (MR) damper is proposed.
141 citations
TL;DR: In this paper, the authors used Artificial Neural Fuzzy Interface System (ANFIS) method to predict damper gap rate of HVAC system quite accurately and achieved a mean 99.98% recognition success.
135 citations
TL;DR: Dampers and Vehicle Modelling, Human Body Analysis, Semi-active Control Algorithms, and Magnetorheological Dampers are studied.
Abstract: Dampers and Vehicle Modelling.- Human Body Analysis.- Semi-active Control Algorithms.- Friction Dampers.- Magnetorheological Dampers.- Case Studies.
135 citations
Book•
13 Oct 2009
TL;DR: This set of proceedings is based on the International Conference on Advances in Building Technology in Hong Kong on 4-6 December 2002 and contains 9 invited keynote papers, 72 papers delivered by 11 teams, and 133 contributed papers from over 20 countries around the world.
Abstract: Eight different sets of equations proposed for tuning the parameters of tuned mass dampers (TMDs) are compared using a 5-story building with plan and elevation irregularity, and a 15-story and a 20-story building with plan irregularity subjected to seismic loading. Next, the performance of bidirectional tuned mass damper (BTMD) is compared with that of the pendulum tuned mass damper (PTMD) using three different structures with plan and vertical irregularities ranging in height from 5 to 20 stories and dominant fundamental periods ranging from 0.55 sec to 4.25 sec subjected to Loma Prieta earthquake. It is concluded that BTMD performs consistently better than PTMD for reduction of maximum displacement, acceleration and base shear. BTMD is advantageous over PTMD because it can be tuned for two modes of vibrations and therefore can be used as an alternative to using two TMDs. Then, the effectiveness of BTMD is investigated using a 20-story building structure with plan irregularity subjected to six seismic accelerograms. Finally, the optimal placement of the BTMD is investigated using five different multi-story building structures with plan and elevation irregularities ranging in height from 5 to 20 stories and fundamental periods ranging from 0.55 sec to 4.25 sec subjected to Loma Prieta earthquake. This set of proceedings is based on the International Conference on Advances in Building Technology in Hong Kong on 4-6 December 2002. The two volumes of proceedings contain 9 invited keynote papers, 72 papers delivered by 11 teams , and 133 contributed papers from over 20 countries around the world. The papers cover a wide spectrum of topics across the three technology sub-themes of structures and construction, environment, and information technology. The variety within these categories spans a width of topics, and these proceedings provide readers with a good general overview of recent advances in building research. This book is an up-to-date source for computation applications of optimization, prediction via artificial intelligence methods, and evaluation of metaheuristic algorithm with different structural applications. As the current interest of researcher, metaheuristic algorithms are a high interest
128 citations
TL;DR: In this paper, a semi-active magnetorheological (MR) damper located on the suspension that links the drum to the cabinet is used for vibration and noise reduction in a washing machine.
TL;DR: In this article, an optimal design of a passenger vehicle magnetorheological (MR) damper based on finite element analysis is presented, which is constrained in a specific volume and the optimization problem identifies the geometric dimensions of the damper that minimize an objective function.
Abstract: This paper presents an optimal design of a passenger vehicle magnetorheological (MR) damper based on finite element analysis. The MR damper is constrained in a specific volume and the optimization problem identifies the geometric dimensions of the damper that minimize an objective function. The objective function consists of the damping force, the dynamic range, and the inductive time constant of the damper. After describing the configuration of the MR damper, the damping force and dynamic range are obtained on the basis of the Bingham model of an MR fluid. Then, the control energy (power consumption of the damper coil) and the inductive time constant are derived. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initial damper. Subsequently, the optimization procedure, using a golden-section algorithm and a local quadratic fitting technique, is constructed via commercial finite element method parametric design language. Using the developed optimization tool, optimal solutions of the MR damper, which are constrained in a specific cylindrical volume defined by its radius and height, are determined and a comparative work on damping force and inductive time constant between the initial and optimal design is undertaken.
TL;DR: Pseudo-negative-stiffness dampers (PNS dampers) as mentioned in this paper are controlled variable dampers that produce negative stiffness hysteretic loops, which are advantageous since dampers are usually set parallel to structure's members.
Abstract: Pseudo-negative-stiffness dampers or PNS dampers are controlled variable dampers that produce negative-stiffness hysteretic loops. Negative-stiffness hysteretic loops are advantageous since dampers are usually set parallel to structure's members, which have stiffness. By adding negative-stiffness hysteretic loops, artificial nonlinearity is obtained but the total force would not be larger than the member's stiffness force. Common passive dampers set parallel to structure's members will have the total force larger than the member's stiffness force. Moreover, applications of the PNS damping to the benchmark control problems for seismic response reduction are also reported. The benchmark structures, consisting of cable-stayed bridges, buildings, and highway bridges, are excited by various types of recorded ground motions. The application of PNS dampers to those benchmark structures shows that this strategy is effective in reducing seismic responses. Recently, the new negative-stiffness damper was innovated and its effectiveness was experimentally proven. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: In this paper, a human simulated intelligent control (HSIC) scheme is developed to attenuate unwanted vibrations such as pitch angle acceleration in a half-car magnetorheological suspension system.
TL;DR: In this paper, a half car model with magnetorheological dampers is modelled by the modified Bouc-Wen model and the MR damper performance is sought to be improved by suitable choice of input currents to the levels of performance of an active suspension based on H ∞ control without and with preview.
TL;DR: In this article, a semi-active controller for a class of vehicle suspension system that employs a magnetorheological (MR) damper as the actuator is designed following the standard backstepping technique.
TL;DR: In this paper, a 17-degree-of-freedom (DOF) model of a full-scale railway vehicle integrated with the semi-active controlled magnetorheological (MR) fluid dampers in its secondary suspension system is proposed to cope with the lateral, yaw, and roll motions of the car body, trucks, and wheelsets.
Abstract: In this paper, it is aimed to investigate semi-active suspension systems using magnetorheological (MR) fluid dampers for improving the ride quality of railway vehicles. A 17-degree-of-freedom (DOF) model of a full-scale railway vehicle integrated with the semi-active controlled MR fluid dampers in its secondary suspension system is proposed to cope with the lateral, yaw, and roll motions of the car body, trucks, and wheelsets. The governing equations combining the dynamics of the railway vehicle integrated with MR dampers in the suspension system and the dynamics of the rail track irregularities are developed and a linear quadratic Gaussian (LQG) control law using the acceleration feedback is adopted, in which the state variables are estimated from the measurable accelerations with a Kalman estimator. In order to evaluate the performances of the semi-active suspension systems based on MR dampers for railway vehicles, the random and periodical track irregularities are modelled with a uniform state-space formulation according to the testing data and incorporated into the governing equation of the railway vehicle integrated with the semi-active suspension system. Utilising the governing equations and the semi-active controller developed in this paper, the simulation and analysis are presented in Part II of this paper.
TL;DR: In this article, an experimental and analytical study on pounding reduction of highway bridges subjected to earthquake ground motions by using magnetorheological (MR) dampers is presented, in which an analytical model, which incorporates structural pounding and MR dampers, is developed.
Abstract: Pounding between adjacent superstructures has been a major cause of highway bridge damage in the past several earthquakes. This paper presents an experimental and analytical study on pounding reduction of highway bridges subjected to earthquake ground motions by using magnetorheological (MR) dampers. An analytical model, which incorporates structural pounding and MR dampers, is developed. A series of shaking table tests on a 1:20 scaled base-isolated bridge model are performed to investigate the effects of pounding between adjacent superstructures on the dynamics of the structures. Based on the test results, the parameters of the linear and the nonlinear viscoelastic impact models are identified. Performance of the semiactive system for reducing structural pounding is also investigated experimentally, in which the MR dampers are used in conjunction with the proposed control strategy, to verify the effectiveness of the MR dampers. Structural responses are also simulated by using the established analytical model and compared with the shaking table test results. The results show that pounding between adjacent superstructures of the highway bridge significantly increases the structural acceleration responses. For the base-isolated bridge model considered here, the semiactive control system with MR dampers effectively precludes pounding. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: In this paper, the effects of a large number of system parameters (such as number, size and particle material, mass ratio, excitation frequency and amplitude level, coefficient of restitution, damping ratio of the primary system, and the coefficient of friction) were evaluated using high-fidelity simulations based on the discrete-element method.
Abstract: The performance of particle dampers under dynamic loads is very complicated and highly nonlinear; consequently, no guidelines currently exist for determining the optimum strategies for maximizing their behavior. The underlying interaction mechanics involve energy dissipation and momentum exchange. This paper presents the concept of ‘effective momentum exchange’ to quantify its influence on the performance of particle dampers with low volumetric filling ratio. The paper also evaluates the effects of a large number of system parameters (such as number, size and particle material, mass ratio, excitation frequency and amplitude level, coefficient of restitution, damping ratio of the primary system, and the coefficient of friction), using high-fidelity simulations based on the discrete-element method. It is shown that applying more particles with a high value of the coefficient of restitution can result in a broader range of acceptable response levels. For a given mass ratio, the particle type and size have minor effects on the primary system performance. Increasing the mass ratio can improve the damper's effectiveness but only up to a certain level. Friction is usually detrimental in low volumetric filling ratio particle dampers. It is shown that by using a properly designed particle damper, a lightly damped primary system can achieve a considerable reduction in its response with a small weight penalty. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: In this paper, a novel eddy current damper (ECD) is proposed for vehicle suspension systems, which utilizes permanent magnets (PMs), separated by iron poles that are screwed to an iron rod, and a conductive hollow cylinder to generate damping.
Abstract: This paper presents the modeling, simulation and testing of a novel eddy current damper (ECD) to be used in vehicle suspension systems. The conceived ECD utilizes permanent magnets (PMs), separated by iron poles that are screwed to an iron rod, and a conductive hollow cylinder to generate damping. Eddy currents develop in the conductor due to its relative motion with respect to the magnets. Since the eddy currents produce a repulsive force that is proportional to the velocity of the conductor, the moving magnet and conductor behave as a viscous damper. The structure of the new passive ECD is straightforward and does not require an external power supply or any other electronic devices. An accurate, analytical model of the system is obtained by applying electromagnetic theory to estimate the electromagnetic forces induced in the system. To optimize the design, simulations are conducted and the design parameters are evaluated. After a prototype ECD is fabricated, experiments are carried out to verify the accuracy of the theoretical model. The heat transfer analysis is established to ensure that the damper does not overheat, and the demagnetization effect is studied to confirm the ECD reliability. The eddy current model has 1.4?N RMS error in the damping force estimation, and a damping coefficient as high as 53?N?s?m?1 is achievable with the fabricated, scaled-down prototype. Finally, a full-size ECD is designed and its predicted performance is compared with that of commercial dampers, proving the applicability of the ECD in vehicle suspension systems.
TL;DR: In this paper, the feasibility and effectiveness of a self-powered magnetorheological (MR) damper using in-situ energy harvested from the vibration and shock environment in which it is deployed is addressed.
Abstract: This study addresses the feasibility and effectiveness of a self-powered magnetorheological (MR) damper using in-situ energy harvested from the vibration and shock environment in which it is deployed. To achieve this, an energy-harvesting device is designed and added to a MR damper. This energy-harvesting device consists of a stator, a permanent magnet, and a spring and operates as an energy-harvesting dynamic vibration absorber (DVA). The dynamic equation for the self-powered MR damper is derived. To evaluate the vibration isolation capability of the self-powered MR damper, a single-degree-of-freedom engine mount system using the MR damper is simulated. The governing equation of motion for the engine mount system is derived. A parametric study is conducted to find the optimal stiffness of the energy-harvesting DVA for the engine mount system. The isolation performance of the engine mount system employing the self-powered MR damper is theoretically evaluated in the frequency domain.
TL;DR: In this article, semiactive controllers based on backstepping and quantitative feedback theory techniques are proposed and their performances are compared with each other on the problem of vibration control in a structure with an MR damper.
Abstract: Magnetorheological (MR) dampers have been widely studied and employed to solve the vibration problem in structures such as buildings and bridges. It is known that MR dampers can generate high damping forces with low-energy requirements and low-cost productions. However, the complex dynamics that characterize MR dampers make difficult the control design to achieve the vibration reduction goals in an efficient manner. In this paper, semiactive controllers based on the backstepping and quantitative feedback theory techniques are proposed and their performances are compared with each other on the problem of vibration control in a structure with an MR damper. They are applied to a large-scale three-story building with an MR damper at its first floor subject to seismic motions. The performance of the proposed controllers is experimentally evaluated by means of real-time hybrid testing scheme that accounts for time delays and actuator dynamics, allowing for the test of velocity-dependent devices. Copyright © 2009 John Wiley & Sons, Ltd.
TL;DR: The solution uses element extraction of the damper and inerter followed by the derivation of a necessary and sufficient condition for the one-element-kind (transformerless) realization of an associated three-port network to solve the realization problem of restricted complexity.
Abstract: This paper considers a realization problem of restricted complexity arising in an approach to passive control of mechanical systems. This approach is based on synthesizing a positive-real admittance or impedance function using springs, dampers and inerters. This paper solves the following problem: what is the most general class of mechanical admittances which can be realized if the number of dampers and inerters is restricted to one in each case, while allowing an arbitrary number of springs and no transformers (levers)? The solution uses element extraction of the damper and inerter followed by the derivation of a necessary and sufficient condition for the one-element-kind (transformerless) realization of an associated three-port network. This involves the derivation of a necessary and sufficient condition for a third-order non-negative definite matrix to be reducible to a paramount matrix using a diagonal transformation. It is shown that the relevant class of mechanical admittances can be parametrized in terms of five circuit arrangements each containing four springs.
TL;DR: In this article, a detailed literature review of passive devices is provided which includes the historical development of the devices, their dynamic behavior, testing of these devices incorporated in the structural models and their analytical formulations.
Abstract: Research and development of seismic response control devices has gained prime importance recently, due to an increased number of devastating earthquakes. Passive control systems are now accepted all over the world and hence research in this area is continuing to develop reliable, efficient and cost effective devices along with constitutive modeling. This paper begins with qualitative description and comparison of passive, active and semiactive control systems. Further, it mentions advantages of passive control systems over the others. A detailed literature review of passive devices is then provided which includes the historical development of the devices, their dynamic behavior, testing of these devices incorporated in the structural models and their analytical formulations. The pros and cons of these devices in retrofitting of structures and their first and recent applications in a wide variety of structures are also discussed. The passive response control systems that are discussed include viscoelastic dampers, yielding dampers, viscous dampers, friction dampers, tuned mass dampers, tuned liquid dampers, tuned liquid column dampers, superelastic dampers, like shape memory alloy dampers and base isolators.
TL;DR: The performance of friction dampers to mitigate the wave-induced vibrations in jacket-type offshore platforms has been investigated in this article, where a full stochastic analysis method has been used to evaluate the response of the structures equipped with these devices.
TL;DR: In this article, the performance of nonlinear dampers in comparison with the classical linear damper was evaluated using the Euler-Bernoulli theory, and the partial differential equation governing the beam dynamics was reduced to an ordinary differential equation set by means of the Galerkin-Bubnov method.
TL;DR: In this paper, the sky-hook damper control strategy is realized through a feedback control scheme, which is optimized by equating the control force of the feedback system to that obtained by linear quadratic regulator (LQR) control in a mean square equivalence sense.
TL;DR: In this paper, the authors investigated the effectiveness of cross-tie and damper-cross-tie systems for stay cable vibration mitigation on cable-stayed bridges, based on both analytical formulation and full-scale measurement.
TL;DR: In this paper, the semi-active suspension system for railway vehicles based on the controlled fluid dampers is investigated, and compared with the passive on and passive off suspension systems, while the car body accelerations of the railway vehicle integrated with four MR dampers in the secondary suspension systems are simulated under the random and periodical track irregularities using the established governing equations of a railway vehicle and the modelled track irregularities.
Abstract: In this paper, the semi-active suspension system for railway vehicles based on the controlled (MR) fluid dampers is investigated, and compared with the passive on and passive off suspension systems. The lateral, yaw, and roll accelerations of the car body, trucks, and wheelsets of a full-scale railway vehicle integrated with four MR dampers in the secondary suspension systems, which are in the closed and open loops respectively, are simulated under the random and periodical track irregularities using the established governing equations of the railway vehicle and the modelled track irregularities in Part I of this paper. The simulation results indicate that (1) the semi-active controlled MR damper-based suspension system for railway vehicles is effective and beneficial as compared with the passive on and passive off modes, and (2) while the car body accelerations of the railway vehicle integrated with semi-active controlled MR dampers can be significantly reduced relative to the passive on and passive off ...