On the Efficacy of Magnetorheological Dampers for Seismic Response Reduction

1997 ◽  
Author(s):  
S. J. Dyke ◽  
B. F. Spencer ◽  
M. K. Sain ◽  
J. D. Carlson
Keyword(s):  
Control Systems ◽  
Structural Response ◽  
Mr Damper ◽  
Seismic Protection ◽  
Seismic Excitations ◽  
One Dimensional ◽  
Mr Dampers ◽  
Earthquake Motion ◽  
Intrinsic Nonlinearity ◽  
Series Of Experiments

Abstract In this paper, the efficacy of magnetorheological (MR) dampers for seismic protection of structures is investigated through a series of experiments in which an MR damper is used to control a three story test structure subjected to a one-dimensional earthquake motion. Because of the intrinsic nonlinearity of the MR damper, several earthquake amplitudes are considered to investigate the performance, in terms of both peak and rms responses, of this control systems over a range of loading conditions. The results indicate that the MR damper is quite effective for structural response reduction over a wide class of seismic excitations.

Semi-active MR dampers for seismic control of structures

2009 ◽  
Vol 42 (3) ◽  
pp. 157-166 ◽  
Author(s):  
Jagadish G. Kori ◽  
R.S. Jangid
Keyword(s):  
Structural Response ◽  
Mr Damper ◽  
Control Algorithms ◽  
Shear Mode ◽  
Control Force ◽  
Base Shear ◽  
Seismic Control ◽  
Mr Dampers ◽  
Wide Range ◽  
Input Command

Magnotorheological (MR) dampers have been demonstrated to be more effective in reducing the structural response due to earthquakes using only a small amount of external power. The performance of MR damper depends upon type of control law used and the damper force is directly depends on the input command voltage. The purpose of this study is to evaluate the effectiveness of input command voltage on MR damper system against recently proposed control laws under different earthquakes. The magnitude of control force increases with the increase in the input command voltage of MR damper, however for the different damper locations and configurations maximum command voltage to the current driver may not always effective in reducing the structural responses. To investigate the effective performance of the MR dampers, different control algorithms with multiple MR damper locations are considered in this study. A phenomenological model of a shear- mode MR damper, based on a Bouc–Wen element, is employed in the analysis of the controlled building. The control algorithms are tested on a five-story framed building and parametric study on variation in the input command voltage is conducted for different real earthquake ground motions. The numerically evaluated optimum parametric values are considered for the analysis of the different damper locations in the building in order to reduce the displacement, acceleration and the base shear of the building. It is shown numerically that the performance of the MR damper has a great potential in suppressing structural vibrations over a wide range of seismic inputs by selecting appropriate optimum input command voltages.

scholarly journals Two-Dimensional CFD Modeling of Hysteresis Behavior of MR Dampers

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Pengfei Guo ◽  
Jing Xie
Keyword(s):  
Mr Damper ◽  
Cfd Modeling ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
One Dimensional ◽  
Hysteresis Behavior ◽  
Mr Dampers ◽  
Nonlinear Hysteresis ◽  
Mr Fluids ◽  
Dimensional Modeling

So far, most previous studies on the nonlinear hysteresis analysis of ER/MR dampers have been limited to one-dimensional modeling techniques. A two-dimensional (2D) axisymmetric CFD model of MR dampers is developed in this work. The main advantage of the proposed 2D model of MR dampers lies in that it can be used to predict dynamic behavior of MR devices of arbitrary geometries. The compressibility of MR fluids is the main factor responsible for the hysteresis behavior of MR dampers, and it has been rarely investigated in previous multidimensional modeling of MR damper. In our model, the compressibility of MR fluids is taken into account by the two-dimensional constitutive model which is extended from a previous one-dimensional physical model. The model is solved by using the finite element method, and the movement of the piston is described by the moving mesh technique. The MR damper in a reference is simulated, and the model predictions show good agreement with the experimental data in the reference.

scholarly journals Smart semi-active MR damper to control the structural response

2015 ◽  
Vol 48 (4) ◽  
pp. 235-244 ◽  
Author(s):  
Nikoo K. Hazaveh ◽  
J. Geoffrey Chase ◽  
Geoffrey W. Rodgers ◽  
Stefano Pampanin
Keyword(s):  
Optimal Control ◽  
Control Algorithm ◽  
Structural Response ◽  
Mr Damper ◽  
Discrete Wavelet ◽  
Nonlinear Behaviour ◽  
Control Force ◽  
Research Attention ◽  
Mr Dampers ◽  
The Impact

One advanced means of protecting structures against earthquake ground motions is the use of semi-active devices to customise and limit structural response. Thus, the design, modelling and analysis of different semi-active control devices have received increasing research attention. This study presents a method to determine optimal control forces for magneto-rheological (MR) dampers, using three algorithms: a discrete wavelet transform (DWT), a linear quadratic regulator (LQR), and a clipped-optimal control algorithm. DWT is used to obtain the local energy distribution of the motivation over the frequency bands to modify conventional LQR. The clipped-optimal control algorithm is used to get the MR damper control force to approach the desired optimal force obtained from modified LQR. A Bouc-Wen phenomenological model is utilized to capture the observed nonlinear behaviour of MR dampers. Time history analysis for a single degree of freedom (SDOF) with periods of T= 0.2-5.0 sec is utilized to compare the impact of using classic and modified LQR in controlling the MR damper force under 20 design level earthquakes of the SAC (SEAOC-ATC-CUREE) project. Performance is assessed by comparing the maximum displacement (Sd), total base shear (Fb) and the controller energy. This study shows the proposed modified LQR is more effective at reducing displacement response than conventional LQR. The modified LQR method reduces the median value of uncontrolled Sd by approximately 40% to 88%, over all periods to 5.0 seconds. Moreover, the modified LQR uses about 45% less energy than conventional LQR. Overall, these results indicate the robustness of the proposed method to mitigate structural response and damage using MR devices.

A Reliability Assessment Model for MR Damper Components within a Smart Structural Control Scheme

2008 ◽  
Vol 56 ◽  
pp. 218-224
Author(s):  
Maguid H.M. Hassan
Keyword(s):  
Structural Control ◽  
Inverse Dynamics ◽  
Mr Damper ◽  
Assessment Model ◽  
Resistance Force ◽  
Mr Dampers ◽  
Control Scheme ◽  
Smart Control ◽  
Control Devices ◽  
Magneto Rheological

Smart control devices have gained a wide interest in the seismic research community in recent years. Such interest is triggered by the fact that these devices are capable of adjusting their characteristics and/or properties in order to counter act adverse effects. Magneto-Rheological (MR) dampers have emerged as one of a range of promising smart control devices, being considered for seismic applications. However, the reliability of such devices, as a component within a smart structural control scheme, still pause a viable question. In this paper, the reliability of MR dampers, employed as devices within a smart structural control system, is investigated. An integrated smart control setup is proposed for that purpose. The system comprises a smart controller, which employs a single MR damper to improve the seismic response of a single-degree-of-freedom system. The smart controller, in addition to, a model of the MR damper, is utilized in estimating the damper resistance force available to the system. On the other hand, an inverse dynamics model is utilized in evaluating the required damper resistance force necessary to maintain a predefined displacement pattern. The required and supplied forces are, then, utilized in evaluating the reliability of the MR damper. This is the first in a series of studies that aim to explore the effect of other smart control techniques such as, neural networks and neuro fuzzy controllers, on the reliability of MR dampers.

Application of Magneto Rheological Dampers for Controlling Shock Loading

1999 ◽  
Author(s):  
Mehdi Ahmadian ◽  
James C. Poynor ◽  
Jason M. Gooch
Keyword(s):  
Dynamic System ◽  
Shock Loading ◽  
Closed Loop ◽  
Shock Absorber ◽  
Mr Damper ◽  
Test Results ◽  
Closed Loop System ◽  
Mr Dampers ◽  
Shock Dynamics ◽  
Magneto Rheological

Abstract This study will examine the effectiveness of magneto-rheological (MR) dampers for controlling shock dynamics. Using a system that includes a 50-caliber rifle and a magneto-rheological damper, it is experimentally shown that MR dampers can be quite effective in controlling the compromise that commonly exists between shock forces and strokes across the shock absorber mechanism. A series of tests are conducted to demonstrate that different damping forces by the MR damper can result in different shock-force/stroke profiles. The test results further show that MR dampers can be used in a closed-loop system to adjust the shock loading characteristics in a manner that fits the dynamic system constraints and requirements.

A Non Parametric Model for Magneto Rheological Dampers

1999 ◽  
Author(s):  
Mehdi Ahmadian ◽  
Xubin Song
Keyword(s):  
Test Data ◽  
Mr Damper ◽  
Parametric Model ◽  
Parametric Models ◽  
Magnetic Saturation ◽  
Mr Dampers ◽  
Electro Magnetic ◽  
Magneto Rheological ◽  
Force Characteristics ◽  
Non Parametric

Abstract A non-parametric model for magneto-rheological (MR) dampers is presented. After discussing the merits of parametric and non-parametric models for MR dampers, the test data for a MR damper is used to develop a non-parametric model. The results of the model are compared with the test data to illustrate the accuracy of the model. The comparison shows that the non-parametric model is able to accurately predict the damper force characteristics, including the damper non-linearity and electro-magnetic saturation. It is further shown that the parametric model can be numerically solved more efficiently than the parametric models.

Semi-Active Damping of Ground Resonance in Helicopters Using Magnetorheological Dampers

2000 ◽  
Author(s):  
Norman M. Wereley ◽  
Nicolas Costes
Keyword(s):  
Mr Damper ◽  
Active Damping ◽  
Rotor System ◽  
Magnetorheological Dampers ◽  
Resonance Analysis ◽  
Mr Dampers ◽  
Resonance Behavior ◽  
Ground Resonance ◽  
And Control

Abstract We will assess the capabilities of physically motivated MR dampers to mitigate ground resonance instability and control the damping level of rotor lag modes. The objectives of this research are threefold: (1) develop a methodology for the integration of the MR damper into a classic linear ground resonance analysis assuming an isotropic rotor hub (all dampers and blades similar) and an anisotropic rotor hub (due to lag damper dissimilarity due to damage, for example), (2) assess whether MR dampers can stabilize a rotor system that exhibits unstable ground resonance, (3) assess whether MR dampers can stabilize a rotor which exhibits unstable ground resonance behavior due to lag damper degradation or damage. The analyses developed in this study show that MR dampers are feasible for achieving these goals.

A shuffled frog-leaping algorithm based mixed-sensitivity H∞ control of a seismically excited structural building using MR dampers

2017 ◽  
Vol 24 (13) ◽  
pp. 2832-2852 ◽  
Author(s):  
Xiufang Lin ◽  
Shumei Chen ◽  
Guorong Huang
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Structural Parameters ◽  
Mr Damper ◽  
Inverse Model ◽  
Shuffled Frog Leaping Algorithm ◽  
Weighting Functions ◽  
Inference System ◽  
Mr Dampers ◽  
Shuffled Frog Leaping

An intelligent robust controller, which combines a shuffled frog-leaping algorithm (SFLA) and an H∞ control strategy, is designed for a semi-active control system with magnetorheological (MR) dampers to reduce seismic responses of structures. Generally, the performance of mixed-sensitivity H∞ (MSH) control highly depends on expert experience in selecting the parameters of the weighting functions. In this study, as a recently-developed heuristic approach, a multi-objective SFLA with constraints is adopted to search for the optimal weighting functions. In the proposed semi-active control, firstly, based on the Bouc–Wen model, the forward dynamic characteristics of the MR damper are investigated through a series of tensile and compression experiments. Secondly, the MR damper inverse model is developed with an adaptive-network-based fuzzy inference system (ANFIS) technique. Finally, the SFLA-optimized MSH control approach integrated with the ANFIS inverse model is used to suppress the structural vibration. The simulation results for a three-story building model equipped with an MR damper verify that the proposed semi-active control method outperforms fuzzy control and two passive control methods. Besides, with the proposed strategy, the changes in structural parameters and earthquake excitations can be satisfactorily dealt with.

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