Low-force magneto-rheological damper design for small-scale structural control

The present research work is a part of a project was a semi-active structural control technique using magneto-rheological damper has to be performed. Magneto-rheological dampers are an innovative class of semi-active devices that mesh well with the demands and constraints of seismic applications; this includes having very low power requirements and adaptability. A small stroke magneto-rheological damper was mathematically simulated and experimentally tested. The damper was subjected to periodic excitations of different amplitudes and frequencies at varying voltage. The damper was mathematically modeled using parametric Modified Bouc-Wen model of magneto-rheological damper in MATLAB/SIMULINK and the parameters of the model were set as per the prototype available. The variation of mechanical properties of magneto-rheological damper like damping coefficient and damping force with a change in amplitude, frequency and voltage were experimentally verified on INSTRON 8800 testing machine. It was observed that damping force produced by the damper depended on the frequency as well, in addition to the input voltage and amplitude of the excitation. While the damping coefficient (c) is independent of the frequency of excitation it varies with the amplitude of excitation and input voltage. The variation of the damping coefficient with amplitude and input voltage is linear and quadratic respectively. More ever the mathematical model simulated in MATLAB was in agreement with the experimental results obtained.

Download Full-text

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

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.56.218 ◽

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.

Download Full-text

Magneto-Rheological (MR) Damper Design for High-Flowrate Suspensions

Volume 4B: Dynamics, Vibration and Control ◽

10.1115/imece2013-62930 ◽

2013 ◽

Author(s):

Riaan F. Meeser ◽

P. Schalk Els ◽

Sudhir Kaul

Keyword(s):

Mr Damper ◽

Damping Force ◽

Mr Fluid ◽

Bingham Plastic ◽

Damping Characteristics ◽

Final Design ◽

Variable Damping ◽

Input Variables ◽

Damper Design ◽

Magneto Rheological

This paper presents the design of a magneto-rheological (MR) damper for an off-road vehicle where large suspension travel and high flow rates, as compared to typical passenger car suspensions, are required. The MR damper is expected to enhance the capability of the suspension system by allowing variable damping due to inherent properties of the MR fluid. MR fluids exhibit a reversible behavior that can be controlled with the intensity of a magnetic field, allowing a change in the effective viscosity and thereby in the damping characteristics of the fluid. A mathematical model of the proposed damper has been developed using the Bingham plastic model so as to determine the necessary geometry for the damper designed in this study, using the fluid flow rate and current to the electromagnet as the input variables. The model is used to compute the damping force, and the analytical results show that the designed MR damper provides the required range of damping force for the specific vehicle setup that is being used for this study. A valve-mode MR fluid channel has been designed such that the required minimum damping is reached in the off-state, and the desired maximum damping is reached in the on-state. For manufacturing and size considerations, the final design incorporates a triple pass layout with the MR fluid flowing through the three passages that are arranged in an S-shape so as to minimize the cross section of the electromagnet core.

Download Full-text

Optimum Method of Magneto-rheological Damper Design

2011 Second International Conference on Digital Manufacturing & Automation ◽

10.1109/icdma.2011.204 ◽

2011 ◽

Cited By ~ 1

Author(s):

Wei Wang ◽

Xiangcai Yu

Keyword(s):

Damper Design ◽

Magneto Rheological

Download Full-text

An Experimental Study on a Magneto-Rheological Fluid Damper for Structural Control Subject to Base Excitation

Transactions of the Korean Society for Noise and Vibration Engineering ◽

10.5050/ksnvn.2004.14.8.767 ◽

2004 ◽

Vol 14 (8) ◽

pp. 767-773 ◽

Cited By ~ 2

Keyword(s):

Experimental Study ◽

Control Subject ◽

Structural Control ◽

Base Excitation ◽

Fluid Damper ◽

Magneto Rheological

Download Full-text

Methodologies for risk mapping of radon gas at various scales in Tondela and Oliveira do Hospital region (center of Portugal)

10.5194/egusphere-egu21-7503 ◽

2021 ◽

Author(s):

Gustavo Santiago ◽

Alcides Pereira

Keyword(s):

Roc Curve ◽

Structural Control ◽

Roc Analysis ◽

Regional Scale ◽

Curve Analysis ◽

Exceedance Probability ◽

Small Scale ◽

Roc Curve Analysis ◽

Risk Area ◽

Radon Gas

Inhalation of radon gas exposes the lungs to ionizing radiation which significantly contributes to the equivalent dose received by a human body. European Union advises Member States to identify radon prone areas (RPA), characterized by a significant percentage of dwellings above the national reference level (RL).The presented work aims to evaluate the use of Receiver Operating Characteristic (ROC) curve analysis to map RPAs at a small-scale (from 1:25 000 to 1:1&#160;000, henceforward called &#8220;regional&#8221; and &#8220;local&#8221; scale respectably), using interpolated surfaces of total gamma radiation (TGR) as proxy and point data of radon concentration in dwellings as the observed variable.The case-study areas are in the center of Portugal (Tondela and Oliveira do Hospital) where outcrops different coarse-grained biotite granites (Beira&#8217;s Granite) and metasediments of Beiras&#8217; Group, frequently as small enclaves hosted in the granites. An intense network of faults is also characteristic of these regions.At Tondela area the geospatial analysis and ordinary kriging interpolation of TGR, on a regional scale, evidenced: a) a geological control on this variable; b) a structural control on anomalies by N35&#186;W orientated faults and by the intersection of these structures with others, namely N75&#186;E and N55&#186;E; c) and an anisotropic covariance of equally spaced points with N35oE oriented major axis. At Oliveira do Hospital, where at a regional scale just data of anomalies was available, the log-normal distribution of background values was simulated based on high-definition data obtained at a local scale. The results are consistent with the structural control pattern identified at Tondela. The best classifiers identified by the ROC analysis were 175 cps and 450 cps, respectably for Tondela and Oliveira do Hospital regions.Establishing a 10% probability of dwellings with concentrations of radon above RL ( ) to define an RPA, all the areas were classified as RPAs. At Tondela region, the lowest risk area represents 25% probability of exceeding the RL and the highest risk area 52%. At Oliveira do Hospital almost the entire region represents 56% exceedance probability. The highest risk area is spatially related to intense anomalies and represent 78% exceedance probability.For the geological context studied, the use of TGR proved to be suitable for radon gas risk mapping. The ROC curve analysis enabled to significantly classify higher and lower risk areas within high-risk regions, considering the small-scale variability. The ROC analysis did not produce a classifier properly calibrated to the RL but one that improves the cost-benefit of the classification relatively to the natural prevalence of the studied areas.

Download Full-text