Magnetorheological Damper With Micro-Grooves: Design and Experiment

Author(s):  
Gaoyu Liu ◽  
Fei Gao ◽  
Wei-Hsin Liao

Abstract Due to low power consumption and fast response, magnetorheological (MR) dampers are widely used in various engineering applications. To enhance the performances, efforts have been made to increase the field dependent force with the same power consumption. However, the fluid viscous force is also increased significantly, which is undesirable in practical use. To tackle this problem, the focus of this paper is to design and test a new MR damper with micro-grooves for performance enhancement. First, the detailed design of the proposed MR damper is provided. A prototype of the new MR damper is fabricated. Silicon steel circular rings with thickness of 0.25 mm are installed around the damper piston to form two-layer micro-grooves. Experimental results of the two MR dampers without and with micro-grooves are then compared. The advantages of MR damper with micro-grooves over the one without micro-grooves are validated. The damping force and controllable force range of MR damper with micro-grooves are larger than the one without micro-grooves. When designing MR damper, making micro-grooves can also decrease the increment of fluid viscous force while keeping the same increase of field dependent force. With micro-grooves, the field dependent force is increased by 92.7% with the same power consumption, while the fluid viscous force is increased by 43%.

Author(s):  
Gaoyu Liu ◽  
Fei GAO ◽  
Wei-Hsin Liao

Abstract Making full use of the magnetically controllable rheological properties of magnetorheological (MR) fluid, MR actuators have been applied in many engineering fields. To adapt to different application scenarios, parameters of MR actuators often need to be optimized. Previous MR actuator optimization was focused on finding optimal combinations of geometric dimensions and physical parameters that meet certain requirements. The parts with optimized dimensions were still in regular shape, which might not bring optimal damping performance. Therefore, in this paper, shape optimization of MR damper piston based on parametric curve is performed for the first time. First, the regional magnetic saturation problem in the previous prototype is stated. Then, the MR damper with normal piston is simulated as a reference. Later, Bezier curve, one of the typical parametric curves, is used to form the piston with optimized parameters, and the MR damper with optimized piston is also simulated. Finally, prototypes of the MR dampers with normal and optimized pistons are fabricated and tested. Compared with the MR damper with normal piston, the one with optimized piston has larger field dependent force and total damping force under relatively large current, with about 52% and 24% maximum increasing percentage, respectively. The controllable force range of the MR damper with optimized piston is also larger than that with normal piston.


2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Zhizhen Dong ◽  
Zhimin Feng ◽  
Yuehua Chen ◽  
Kefan Yu ◽  
Gang Zhang

The consistency of magnetic flux density of damping gap (CMDG) represents the balancing magnetic flux density in each damping gap of magnetorheological (MR) dampers. It can make influences on the performances of MR dampers and the accuracy of relevant objective functions. In order to improve the mechanical performances of the MR damper with a two-stage coil, the function for calculating CMDG needs to be found. By establishing an equivalent magnetic circuit model of the MR damper, the CMDG function is derived. Then, the multiobjective optimization function and the working flow of optimal design are presented by combining the parallel-plate model of the MR damper with the function posed before. Taking the damping force, the dynamic range, the response time, and the CMDG as the optimization objective, and the external geometric dimensions of the SG-MRD60 damper as the bound variable, this paper optimizes the internal geometric dimensions of MR damper by using a NSGA-III algorithm on the PlatEMO platform. The results show that the obtained scheme in Pareto-optimal solutions has existed with better performance than that of SG-MRD60 scheme. According to the results of the finite element analysis, the multiobjective optimization design including the CMDG function can improve the uniformity of magnetic flux density of the MR damper in damping gap, which meets the requirements of manufacture and application.


Author(s):  
Anria Strydom ◽  
Werner Scholtz ◽  
Schalk Els

Magnetorheological (MR) dampers are controllable semi-active dampers capable of providing a range of continuous damping settings. MR dampers are often incorporated in suspension systems of vehicles where conflicting damping characteristics are required for favorable ride comfort and handling behavior. For control applications the damper controller determines the required damper current in order to track the desired damping force, often by using a suitable MR damper model. In order to utilise the fast switching time capability of MR dampers, a model that can be used to directly calculate damper current is desired. Unfortunately few such models exist and other methods, which often negatively affect the computational efficiency of the model, need to be used when implementing these models. In this paper a selection of MR damper models are developed and evaluated for both accuracy and computational efficiency while tracking a desired damping force. The Kwok model is identified as a suitable candidate for the intended suspension control application.


2014 ◽  
Vol 6 ◽  
pp. 931683 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley

This paper analyzes flow mode magnetorheological (MR) dampers with an eccentric annular gap (i.e., a nonuniform annular gap). To this end, an MR damper analysis for an eccentric annular gap is constructed based on approximating the eccentric annular gap using a rectangular duct with a variable gap, as well as a Bingham-plastic constitutive model of the MR fluid. Performance of flow mode MR dampers with an eccentric gap was assessed analytically using both field-dependent damping force and damping coefficient, which is the ratio of equivalent viscous field-on damping to field-off damping. In addition, damper capabilities of flow mode MR dampers with an eccentric gap were compared to a concentric gap (i.e., uniform annular gap).


2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Zekeriya Parlak ◽  
Tahsin Engin ◽  
İsmail Şahin

Magnetorheological (MR) dampers have attracted the interest of suspension designers and researchers because of their variable damping feature, mechanical simplicity, robustness, low power consumption and fast response. This study deals with the optimal configuration of an MR damper using the Taguchi experimental design approach. The optimal solutions of the MR damper are evaluated for the maximum dynamic range and the maximum damper force separately. The MR dampers are constrained in a cylindrical container defined by radius and height. The optimal damper configurations obtained from this study are fabricated and tested for verification. The verification tests show that the dampers provide the specified damper force and dynamic range.


2019 ◽  
Vol 4 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Jong-Seok Oh ◽  
Seung-Bok Choi

It is generally known that MR fluid is a kind of designed materials whose rheological properties are controllable with the application of an external magnetic field. Based on these features, MR dampers have gained much attention of researchers owing to their salient properties such as controllable damping force and relatively fast response time. This article offers a recent review on the MR damper technology, particularly focusing on the application to various fields. Conceivable limitations, challenges, and comparative advantages of MR damper are critically analyzed. In order to promote the practical use of MR damper in application from the automobile to the military sector, this review summarizes different MR dampers and their significant contribution.


Author(s):  
Ehsan Asadi ◽  
Siamak Arzanpour

This paper introduces a methodology for generating digital resistance-map that can be utilized in an MR-Damper based robotic rehabilitation. Typically, in rehabilitation procedures, patients are getting involved in the recovery process of gradually training weak and damaged muscles by constraining motion in repetitive exercises. The whole purpose of robotic rehabilitation is to restrict body organ motion to the one prescribed by the therapist at the initial steps of treatment to avoid further damages to other weak muscles while focusing on recovering a particular muscle. MR-Dampers are semi-active actuators that can potentially be employed for this application. These dampers can be activated to produce high resistance to motion, and a platform that contains sufficient number of them can be manipulated to create regions of different resistance against motion. To apply this to the robotic rehabilitation, the motion recommended by the therapist should be converted to the resistance-maps that can be used by MR-Damper for implementation. To accomplish that, procedure of generating the digital resistance map is introduced and several digital resistance-maps are created. An MR-damper control methodology is also developed to activate the dampers. This controller relies on the accurate modeling of the MR-Damper. Bouc-Wen model is used for MR-Damper modeling. A 3-D platform containing three linear MR-Dampers is modeled using SimMechanics. 1-D and 2-D models are used to develop the idea and build up 3-D model. Several simulations are carried out to investigate the performance of the systems in generating the prescribed digital resistance-maps. The promising results of the simulations indicate that the method can be adopted for robotic rehabilitation purposes.


2020 ◽  
Vol 10 (12) ◽  
pp. 4099
Author(s):  
Quoc-Duy Bui ◽  
Quoc Hung Nguyen ◽  
Tan Tien Nguyen ◽  
Duc-Dai Mai

Magnetorheological (MR) dampers have been widely investigated and proposed for vibration mitigation systems because they possess continuous variability of damping coefficient in response to different operating conditions. In the conventional design of MR dampers, a separate controller and power supply are required, causing an increment of complexity and cost, which are not suitable for home appliances like washing machines. To solve these issues and to reuse wasted energy from vibration of washing machines, in this study, a self-powered shear-mode MR damper, which integrates MR damping and energy-harvesting technologies into a single device, is proposed. The MR damper is composed of an inner housing, on which magnetic coils are wound directly, and an outer housing for covering and creating a closed magnetic circuit of the damper. The gap between the inner housing and the moving shaft is filled with MR fluid to produce the damping force. The energy-harvesting part consists of permanent magnets fastened together on the shaft and induction coils wound directly on slots of the housing. The induced power from the induction coils is directly applied to the excitation coils of the damping part to generate a corresponding damping force against the vibration. In order to achieve optimal geometry of the self-powered MR damper, an optimization for both the damping part and the energy harvesting part of the proposed dampers are conducted based on ANSYS finite element analysis. From optimal solutions, a prototype of the proposed damper is designed in detail, manufactured, and experimentally validated.


2005 ◽  
Vol 19 (07n09) ◽  
pp. 1549-1555 ◽  
Author(s):  
WILLIAM B. FACEY ◽  
NICHOLAS C. ROSENFELD ◽  
YOUNG-TAI CHOI ◽  
NORMAN M. WERELEY ◽  
SEUNG BOK CHOI ◽  
...  

Magnetorheological (MR) based semi-active dampers for the protection of sensitive devices against high shock and impact is examined from design considerations to characterization testing. Shock and impact dampers should be able to produce a high damping force at high velocities. However, a specification requiring high damping force generally causes an increase in the size of shock and impact dampers, which motivates the study of MR dampers to retrofit existing or conventional passive shock and impact dampers. A novel MR damper design was developed in this study for achieving both design goals: high force and compactness. The novel MR damper design increases the number of magnetically active volumes through which fluid to passes while minimizing damper length. Through FEM (Finite Element Method) analysis, the magnetic properties of the proposed design are investigated prior to actual fabrication. In addition to the unique magnetic circuit, other considerations stemming from the high pressures and velocities expected in this device are addressed. Characterization testing was performed up to 12 Hz with 1 inch sinusoidal stroke on a servo-hydraulic testing machine. These tests demonstrate that the MR damper is able to provide a high damping force at high velocity.


2005 ◽  
Vol 19 (07n09) ◽  
pp. 1556-1562 ◽  
Author(s):  
KUM-GIL SUNG ◽  
SEUNG-BOK CHOI ◽  
HO-GUEN LEE ◽  
KYUNG-WON MIN ◽  
SANG-HYUN LEE

In this work, three different magneto-rheological(MR) dampers, which are applicable for vibration control of a multi-story structure, are devised and their performance characteristics are compared. As a first step, the schematic configurations of the shear, flow, and mixed mode MR dampers are described with design constraints. The analytical models to predict the field-dependent damping forces are derived for each type and their damping forces are evaluated. The field-dependent damping forces are compared in terms of the damping force magnitude and the mixed-mode type of MR damper is chosen as an optimal candidate for the vibration control of the multi-story structure. An appropriate size of the mixed mode MR damper is manufactured and its field-dependent damping characteristics are evaluated in time domain. In addition, the displacement vs. damping force cycles of the piston are observed at various field intensities.


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