A comprehensive optimal design method for magnetorheological dampers utilized in DMU power package

Author(s):  
Fanghui Xu ◽  
Dawei Dong ◽  
Yan Huang ◽  
Rui Zhang ◽  
Shizhe Song ◽  
...  

The diesel multiple unit (DMU) has been widely used in high-speed railway service due to its flexibility and economy. Considering the broadband and complex vibration generated by DMU power package, the advanced semi-active suspension with magnetorheological (MR) dampers is introduced to promote anti-vibration performance. In this work, a comprehensive optimal design approach for MR damper used in DMU power package is proposed. Quasi-static modeling process is conducted to obtain MR damper's low-frequency outputs, while its high-frequency damping forces are calculated by physical modeling considering the fluid compressibility and piston assembly inertia. Then the objective functions and optimization variables are determined. Based on response surface and linear correlation analysis, the influence of the optimal variables on the objective functions is discussed. Using reference-point based nondominated sorting approach (NSGA-III), the evolutionary many-objective optimization is conducted. In addition, magnetic design is incorporated into the optimal process to ensure the magnetic flux density in the effective working area. Finally, an optimized MR damper prototype is manufactured and tested. By comparing the experimental damping force with calculated results in both low-frequency and high-frequency ranges, the effectiveness of the presented optimal method for MR dampers is validated.

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.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Pengfei Guo ◽  
Jing Xie ◽  
Xinchun Guan

As a key to understand dynamic performances of MR dampers, a comprehensive dynamic magnetic circuit model is proposed in this work on the basis of Ampere’s and Gauss’s laws. It takes into account not only the magnetic saturation, which many existing studies have focused on, but also the magnetic hysteresis and eddy currents in a MR damper. The hysteresis of steel parts of MR dampers is described by Jiles-Atherton (J-A) models, and the eddy current is included based on the field separation. Compared with the FEM results, the proposed model is validated in low- and high-frequency studies for the predictions of the magnetic saturation, the hysteresis, and the effect of eddy currents. A simple multiphysics model is developed to demonstrate how to combine the proposed magnetic circuit model with the commonly used Bingham fluid model. The damping force in the high-frequency case obviously lags behind the coil current, which exhibits a hysteresis loop in the current-force plane. The lag of damping force even exists in a low-frequency varying magnetic field and becomes more severe in the presence of eddy currents.


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).


Author(s):  
R.B. Soujanya ◽  
D.D. Jebaseelan ◽  
S. Kannan

Passenger’s comfort in moving vehicles depends on the quality of the ride. The major cause of discomfort is the vibration transmitted to passengers due to the road irregularities. For a comfortable ride on a vehicle, vibration must stay within prescribed standards. In the present work, an attempt was made to show that, the vibrations can be limited with the use of Magneto-rheological (MR) dampers for varying road profiles than the passive damping methods. MR dampers are semi-active control devices that use MR fluids to produce controllable damping force as they are known to exhibit nonlinear behaviour. Multi body dynamic studies were done to study the response of the system using a quarter car model. In this paper, passive damping (viscous damping) was considered at natural frequency of 1.012Hz, the response of damping was observed after 10s and the acceleration was found to be 6m/s2. When MR damper is employed as the magnetic force increases, the response of the damping was better than the passive damping, at 1.2A it comes down to 0.55m/s2, and the vibration gets dampened after 1.75s. Hence, from this study it is concluded that the MR damper can be employed in automobile for better ride comfort.


Author(s):  
Kai Hsiang Chang ◽  
Jing Long Tong ◽  
Chou Min Chia ◽  
Kuang Yuh Huang

In this article, a novel design of MR damper, concentric spiral flow MR damper, is proposed. It could improve the heat dissipation problem which is usually found in traditional MR damper. The proposed MR damper has a concentric spiral flow channel around the cylinder which not only separates coils from MR fluid, but also increases the length of flow channel in a fixed space. Experimental studies has been conducted to demonstrate the performance of the proposed MR damper, the result shows the MR damper generates the maximum damping force of 188 N without applying magnetic field and 1251 N when inputting 1.5 A at low frequency, which means the damper has high range of adjustable damping force. The CSF-damper can be used to systems or structures with low dynamic response.


Author(s):  
Toshihiko Shiraishi ◽  
Tomoya Sakuma ◽  
Shin Morishita

Two typical types of MR damper were proposed, where the orifice for MR fluid was designed to place between the piston and the cylinder in one type, and to place on the piston in the other type. In the former design, MR fluid was expected to be subjected to shear flow in the orifice, and subjected to Poiseuille flow in the latter design. The damping force of MR dampers was experimentally measured under various conditions of piston speed, piston amplitude and applied electric current to the magnetic coil. The experimental results showed that the maximum damping force were almost the same in both types of damper under the same conditions, except for case under very little amplitude. It was also shown that typical characteristics of MR damper depended on the clearance of orifice and air volume in MR dampers, and the optimal design for the dynamic range of damping force existed in relation to the clearance of orifice. The experimental result of the damping force of these dampers showed good agreement with the analytical result.


2019 ◽  
Vol 20 (1-2) ◽  
pp. 57-61
Author(s):  
Wiesław Grzesikiewicz ◽  
Michał Makowski

We considered of a vehicle model equipped with controlled magneto-rheological (MR) dampers and controlled aerodynamic elements. The vibrations of the vehicle moving at high speed during acceleration and braking are analysed. The purpose of this analysis is to determine the effect of forces generated on aerodynamic elements on vehicle vibrations and changes in wheel pressure on the road surface during acceleration and braking. The presented work presents the results of numerical investigations obtained on the basis of the developed vehicle model.


2010 ◽  
Vol 103 (4) ◽  
pp. 2195-2207 ◽  
Author(s):  
Robert A. Jenks ◽  
Ashkan Vaziri ◽  
Ali-Reza Boloori ◽  
Garrett B. Stanley

Sensory systems must form stable representations of the external environment in the presence of self-induced variations in sensory signals. It is also possible that the variations themselves may provide useful information about self-motion relative to the external environment. Rats have been shown to be capable of fine texture discrimination and object localization based on palpation by facial vibrissae, or whiskers, alone. During behavior, the facial vibrissae brush against objects and undergo deflection patterns that are influenced both by the surface features of the objects and by the animal's own motion. The extent to which behavioral variability shapes the sensory inputs to this pathway is unknown. Using high-resolution, high-speed videography of unconstrained rats running on a linear track, we measured several behavioral variables including running speed, distance to the track wall, and head angle, as well as the proximal vibrissa deflections while the distal portions of the vibrissae were in contact with periodic gratings. The measured deflections, which serve as the sensory input to this pathway, were strongly modulated both by the properties of the gratings and the trial-to-trial variations in head-motion and locomotion. Using presumed internal knowledge of locomotion and head-rotation, gratings were classified using short-duration trials (<150 ms) from high-frequency vibrissa motion, and the continuous trajectory of the animal's own motion through the track was decoded from the low frequency content. Together, these results suggest that rats have simultaneous access to low- and high-frequency information about their environment, which has been shown to be parsed into different processing streams that are likely important for accurate object localization and texture coding.


1999 ◽  
Author(s):  
Mehdi Ahmadian

Abstract The design and fabrication of a magneto rheological (MR) damper for bicycle suspension applications is addressed. Two 1998 Judy® Dampers are retrofitted with MR valves, to achieve the damping force adjustability that the MR fluid offers. One design attempts to use as many of the Judy® Damper components as possible. The second design significantly modifies the Judy® Damper, to better accommodate the MR valve and ease of fabrication and assembly, although fitting into the same envelope as the Judy® damper for a direct retrofit. The two MR dampers are fabricated and assembled for force-velocity characterization testing. The test results show that properly-designed MR dampers can provide significant dynamic performance improvements, as compared to conventional passive bicycle dampers.


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