scholarly journals Modeling of Magnetorheological Dampers under Various Impact Loads

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
K. Sarp Arsava ◽  
Yeesock Kim
Keyword(s):  
Structural Control ◽  
Experimental Studies ◽  
Mr Damper ◽  
Impact Behavior ◽  
Impact Loads ◽  
Mr Dampers ◽  
Fuzzy Models ◽  
Control Signals ◽  
And Control ◽  
The Impact

Magnetorheological (MR) damper has received great attention from structural control engineering because it provides the best features of both passive and active control systems. However, many studies on the application of MR dampers to large civil structures have tended to center on the modeling of MR dampers under seismic excitations, while, to date, there has been minimal research regarding the MR damper model under impact loads. Hence, this paper investigates nonlinear models of MR dampers under a variety of impact loads and control signals. Two fuzzy models are proposed for modeling the nonlinear impact behavior of MR dampers. They are compared with mechanical models, the Bingham and Bouc-Wen models. Experimental studies are performed to generate sets of input and output data for training, validating, and testing the models: the deflection, acceleration, velocity, and current signals. It is demonstrated that the proposed fuzzy models are effective in predicting the complex nonlinear behavior of the MR damper subjected to a variety of impact loads and control signals. The proposed fuzzy model resulted in an accuracy of 99% to predict the impact forces of the MR damper.

Design and Analysis of Magneto-Rheological Dampers under Impact Loads

2013 ◽  
Vol 295-298 ◽  
pp. 2045-2048
Author(s):  
Xiao Ming Han ◽  
Yu Cheng Bo ◽  
Qiang Li ◽  
Ji Huang
Keyword(s):  
Control Strategy ◽  
Test Bench ◽  
Mr Damper ◽  
Second Law ◽  
Impact Loads ◽  
Structure Parameter ◽  
Mr Dampers ◽  
Recoil Force ◽  
Magneto Rheological ◽  
And Control

In order to improve recoil mechanism’s buffering function of automatic weapon, using Newton’s second law, its recoil movement is analyzed and design model of magneto-rheological (MR) damper under impact loads is built. Structure parameter and control strategy are defined. Dampers’ characteristic curves at different magnetizing currents and different recoil speeds are tested on a damper indicator test bench. Some weapon’s recoil forces are artificially computed. The research results indicate that MR dampers have a perfect damping plateau effect. Recoil force of automatic weapon will be reduced by a big margin using the property that MR fluid can change at applied magnetic to control damping rules.

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.

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.

Experimental and Numerical Study of Basalt FRP Strip Strengthened RC Slabs under Impact Loads

2020 ◽  
Vol 20 (06) ◽  
pp. 2040001 ◽  
Author(s):  
Wensu Chen ◽  
Thong M. Pham ◽  
Mohamed Elchalakani ◽  
Huawei Li ◽  
Hong Hao ◽  
...  
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Numerical Study ◽  
Impact Resistance ◽  
Basalt Fiber ◽  
Impact Behavior ◽  
Impact Loads ◽  
Quantitative Measurements ◽  
Rc Slabs ◽  
The Impact

Basalt fiber-reinforced polymer (BFRP) has been applied for strengthening concrete structures. However, studies on reinforced concrete (RC) slabs strengthened by BFRP strips under impact loads are limited in open literature. This study investigates the efficiency of using BFRP strips with various strengthening layouts and anchoring schemes on the impact resistance of RC slabs. A total of 11 two-way square slabs were prepared and tested, including one reference specimen without strengthening and ten slabs strengthened with BFRP strips and/or anchors. The RC slabs were impacted by a drop weight with increasing height until slab failure. The observed failure modes include punching shear failure, BFRP sheet debonding and reinforcement fracture. The failure modes and the effects of using various strengthening schemes on the impact resistant capacity of RC slabs were examined. The quantitative measurements, such as impact velocity, indentation depth and diameter, were compared and discussed. In addition, numerical studies were carried out by using LS-DYNA to simulate the impact tests of RC slabs with and without BFRP strengthening. With the calibrated numerical model, the impact behavior of slabs with various dimensions and strengthening layouts under different impact intensities can be predicted with good accuracy.

Radar-based impact load prediction for damage mitigation of infrastructure

2015 ◽  
Vol 23 (12) ◽  
pp. 1908-1924 ◽  
Author(s):  
Jake Edmond Hughes ◽  
Yeesock Kim ◽  
Tahar El-Korchi ◽  
David Cyganski
Keyword(s):  
Control System ◽  
Structural Control ◽  
Impact Load ◽  
Impact Loads ◽  
Control Technology ◽  
Velocity Measurements ◽  
Engineering Structures ◽  
Mr Dampers ◽  
Controller Performance ◽  
Smart Control

The application of smart control technology to both aging and new infrastructure is essential to extending service life, increasing life safety, and decreasing repair and replacement costs. One area of control technology research for civil engineering structures that has received little attention historically is that of high-impact loads, such as collision events. The dissipation of impact energy using smart control devices, such as magnetorheological (MR) dampers, leads to less plastic deformation and damage, and a lower likelihood of collapse in civil engineering structures. Due to the short duration and high variability in magnitude of potential impact loads, the issue of sub-optimal controller performance arises. In order to boost controller performance and improve the effectiveness of the control system, a radar-based impact load identifier is proposed. This radar-based impact load identifier will be used to estimate impact loads from imminent impacting objects, for example vessels and trucks, thus providing input information to the control system before the impact actually occurs. This paper presents the characterization and validation, through laboratory tests, of one part of the radar-based impact load identifier, the range and velocity estimation of the incoming moving objects. The range and velocity information are then used to direct structural control based on laboratory impact tests. An ultrawideband monostatic pulsed radar is used for range and velocity measurements of a laboratory-scale impacting vehicle. The range and velocity measurements obtained from the radar scans are verified using physical measurements and control testing. The tests showed great accuracy for both range and velocity with less than 3% error for each measurement and demonstrated structural control based on these measurements. It is shown from control system testing that the proposed approach is effective in reducing the structural impact responses by 11–30%, depending on the performance index, for pre-impact structural stiffening with passive control of MR dampers.

scholarly journals Thin-Ideal Images and Affect: An Investigation Using Magazines and Minimizing Demand

2019 ◽  
Author(s):  
Zahra Vahedi ◽  
Stephen Charles Want
Keyword(s):  
Experimental Studies ◽  
Thin Ideal ◽  
Demand Characteristics ◽  
Fashion Magazines ◽  
Undergraduate Female ◽  
Women And Girls ◽  
Everyday Context ◽  
And Control ◽  
The Impact ◽  
Break Period

Women and girls generally experience slightly reduced satisfaction with their appearance following exposure to thin-ideal media images. Inconsistent findings have been obtained regarding the impact of such images on positive and negative affect. However, in experimental studies, researchers have typically exposed participants to a concentrated dose of such images, isolated from context, instead of showing them in an everyday context such as within a fashion magazine. This has implications for external validity because the context in which thin-ideal images are viewed may change their effects. Concentrated exposure also increases demand characteristics. The present study investigated the effect of thin-ideal images presented in magazines on viewers’ affect, while manipulating the level of demand characteristics. Undergraduate female students (N = 172) were assigned to three groups (Implied Demand, Minimized Demand, and Control), two of which were exposed to fashion magazines; the third group was exposed to control magazines containing no thin-ideal images. Demand characteristics were manipulated when the experimenter provided the magazines during a putative break period, and participants’ affect was assessed both pre- and post-exposure. Our results indicated that exposure to fashion magazines was no different from exposure to control magazines in the effects on participants’ affect.

scholarly journals The impact of thin ideal images on mood: what role do demand characteristics play?

2021 ◽  
Author(s):  
Zahra Vahedi
Keyword(s):  
Experimental Studies ◽  
Media Images ◽  
Future Directions ◽  
Demand Characteristics ◽  
Fashion Magazines ◽  
True Purpose ◽  
Undergraduate Female ◽  
And Control ◽  
The Impact

Previous research has shown that female viewers generally experience detrimental effects following exposure to idealized media images. However, in experimental studies, demand characteristics – or cues that help the participant deduce the true purpose of the study – might influence the responses participants provide, particularly in studies involving idealized images. The present study investigated the potential role of demand characteristics following exposure to media images. Undergraduate female students (N = 172) were assigned to three groups (Implied Demand, Minimized Demand and Control), two of which were exposed to idealized media images in fashion magazines. Demand characteristics were manipulated when the experimenter provided the magazines during a break period, and participants’ mood was assessed both pre and post-exposure. Contrary to previous research, our results indicated that exposure to magazine images did not have consistently detrimental effects on the measures of participants’ mood. Potential explanations for these results and future directions of research are discussed.

scholarly journals The impact of thin ideal images on mood: what role do demand characteristics play?

2021 ◽  
Author(s):  
Zahra Vahedi
Keyword(s):  
Experimental Studies ◽  
Media Images ◽  
Future Directions ◽  
Demand Characteristics ◽  
Fashion Magazines ◽  
True Purpose ◽  
Undergraduate Female ◽  
And Control ◽  
The Impact

Previous research has shown that female viewers generally experience detrimental effects following exposure to idealized media images. However, in experimental studies, demand characteristics – or cues that help the participant deduce the true purpose of the study – might influence the responses participants provide, particularly in studies involving idealized images. The present study investigated the potential role of demand characteristics following exposure to media images. Undergraduate female students (N = 172) were assigned to three groups (Implied Demand, Minimized Demand and Control), two of which were exposed to idealized media images in fashion magazines. Demand characteristics were manipulated when the experimenter provided the magazines during a break period, and participants’ mood was assessed both pre and post-exposure. Contrary to previous research, our results indicated that exposure to magazine images did not have consistently detrimental effects on the measures of participants’ mood. Potential explanations for these results and future directions of research are discussed.

How Do Values Affect Behavior? Let Me Count the Ways

2021 ◽  
pp. 108886832110159
Author(s):  
Lilach Sagiv ◽  
Sonia Roccas
Keyword(s):  
Conceptual Model ◽  
Personal Values ◽  
Past Research ◽  
Impact Behavior ◽  
Future Research ◽  
And Behavior ◽  
And Control ◽  
The Impact ◽  
Structural Aspects ◽  
Organizing Principles

The impact of personal values on preferences, choices, and behaviors has evoked much interest. Relatively little is known, however, about the processes through which values impact behavior. In this conceptual article, we consider both the content and the structural aspects of the relationships between values and behavior. We point to unique features of values that have implications to their relationships with behavior and build on these features to review past research. We then propose a conceptual model that presents three organizing principles: accessibility, interpretation, and control. For each principle, we identify mechanisms through which values and behavior are connected. Some of these mechanisms have been exemplified in past research and are reviewed; others call for future research. Integrating the knowledge on the multiple ways in which values impact behavior deepens our understanding of the complex ways through which cognition is translated into action.

Design and Control of Semi-Active Railway Vehicle Suspension Featuring MR Damper

2014 ◽  
Author(s):  
Jong-Seok Oh ◽  
Hwan-Choong Kim ◽  
Seung-bok Choi
Keyword(s):  
Mr Damper ◽  
Design Parameters ◽  
Vehicle Suspension ◽  
Railway Vehicle ◽  
Damping Force ◽  
Bogie Frame ◽  
Car Body ◽  
Mr Dampers ◽  
Vehicle Suspension System ◽  
And Control

In this work, control performance of a semi-active railway vehicle suspension system featuring MR damper is evaluated. Firstly, a mathematical model for railway vehicle which contains car body, bogie frame and wheel-set is derived to represent lateral, yaw and roll motions. From this model, design parameters of MR damper are optimally determined. And then, MR dampers which can generate proper damping force to control the unwanted vibration of the railway vehicle are manufactured and evaluated experimentally. In order to attenuate the vibration of railway vehicle, in this work, skyhook controller is designed and implemented. Control performances of MR damper for railway vehicle including car body lateral motion and acceleration of MR damper are evaluated using test rig composed of a car body and two bogies.

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