Performance tests and mathematical model considering magnetic saturation for magnetorheological damper

2012 ◽  
Vol 23 (12) ◽  
pp. 1331-1349 ◽  
Author(s):  
Zhao-Dong Xu ◽  
Da-Huan Jia ◽  
Xiang-Cheng Zhang
Keyword(s):  
Mathematical Model ◽  
Excitation Frequency ◽  
Experimental Results ◽  
Displacement Amplitude ◽  
Magnetorheological Damper ◽  
Input Current ◽  
Magnetic Flux Density ◽  
Magnetic Saturation ◽  
Loading Frequency ◽  
Magnetorheological Dampers

As a semiactive control device, magnetorheological dampers have been paid more attention due to their high controllability, fast response, and low power demand. One of the important characteristics for magnetorheological dampers is magnetic saturation, that is, the maximum damping force will reach some value and no longer vary with the increasing input current, especially in the presence of large magnetic flux density. In order to take this problem into account fully, tests on a shear-valve mode magnetorheological damper are carried out to consider the effects of input current, displacement amplitude, and loading frequency on the properties of the magnetorheological damper during magnetic saturation situation first. Then, the magnetic saturation phenomenon of the magnetorheological damper is simulated using the finite element method, and the numerical simulation results are compared with the experimental results. Finally, a magnetic saturation mathematical model is proposed to describe the properties of the magnetorheological damper, and the numerical hysteresis curves of the proposed magnetic saturation mathematical model, the Bingham model, and the Bouc–Wen model are compared with the experimental results. It can be concluded that the magnetic saturation mathematical model can describe the influence of input current, displacement amplitude, and excitation frequency on the properties and the magnetic saturation property of the magnetorheological damper.

Parameter identification of modified Bouc–Wen model and analysis of size effect of magnetorheological dampers

2017 ◽  
Vol 29 (7) ◽  
pp. 1464-1480 ◽  
Author(s):  
Yongbo Peng ◽  
Jinggui Yang ◽  
Jie Li
Keyword(s):  
Size Effect ◽  
Performance Test ◽  
Functional Relationship ◽  
Excitation Frequency ◽  
Magnetorheological Damper ◽  
Input Current ◽  
Smart Devices ◽  
Model Parameters ◽  
Magnetorheological Dampers ◽  
Large Size

Magnetorheological damper is one of the most promising smart devices for vibration mitigation of structures subjected to dynamic loads. In order to fulfill the value of magnetorheological damping control, a feasible mechanical model of magnetorheological dampers with simplicity and sufficient accuracy is usually required in practice. It comes up, however, with a challenging issue for the modeling of large-size magnetorheological dampers due to physical constraints on the performance test. The large-size magnetorheological damper is typically modeled in up-scaling parameters associated with models of the small-size magnetorheological damper. This treatment remains open since a size effect hinges upon the intrinsic non-linearity inherent in the device. In this article, a dynamic test of a small-size magnetorheological damper is performed first. The relevance of damper force with the input current and excitation frequency is well revealed. The modified Bouc–Wen model is employed to logically represent the dynamic behaviors of magnetorheological dampers. Identification of model parameters in typical loading cases is then proceeded, of which the functional relationship against input current is established. The size effect of magnetorheological dampers is further addressed through investigating the functional relationship relevant to maximum outputs of 200, 10, and 5 kN. It is indicated that the small-size magnetorheological damper needs more number of control parameters than the large-size magnetorheological damper. Moreover, a linear current relevance of model parameters appears in the small-size magnetorheological damper, while a quadratic current relevance of model parameters appears in the large-size magnetorheological damper. Size effect of magnetorheological dampers arises to be well-marked in the range of low current and becomes unapparent in the range of high current. Besides, the validation of modified Bouc–Wen model is carried out that reveals the applicability of the model with case-optimized parameters.

Testing and Modeling of MR Damper and Its Application to SDOF Systems Using Integral Backstepping Technique

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Sk. Faruque Ali ◽  
Ananth Ramaswamy
Keyword(s):  
Active Control ◽  
Testing Machine ◽  
Mr Damper ◽  
Control Device ◽  
Magnetorheological Damper ◽  
Input Current ◽  
Magnetorheological Dampers ◽  
Damper Control ◽  
Nonlinear Devices ◽  
Current Monitoring

Magnetorheological dampers are intrinsically nonlinear devices, which make the modeling and design of a suitable control algorithm an interesting and challenging task. To evaluate the potential of magnetorheological (MR) dampers in control applications and to take full advantages of its unique features, a mathematical model to accurately reproduce its dynamic behavior has to be developed and then a proper control strategy has to be taken that is implementable and can fully utilize their capabilities as a semi-active control device. The present paper focuses on both the aspects. First, the paper reports the testing of a magnetorheological damper with an universal testing machine, for a set of frequency, amplitude, and current. A modified Bouc–Wen model considering the amplitude and input current dependence of the damper parameters has been proposed. It has been shown that the damper response can be satisfactorily predicted with this model. Second, a backstepping based nonlinear current monitoring of magnetorheological dampers for semi-active control of structures under earthquakes has been developed. It provides a stable nonlinear magnetorheological damper current monitoring directly based on system feedback such that current change in magnetorheological damper is gradual. Unlike other MR damper control techniques available in literature, the main advantage of the proposed technique lies in its current input prediction directly based on system feedback and smooth update of input current. Furthermore, while developing the proposed semi-active algorithm, the dynamics of the supplied and commanded current to the damper has been considered. The efficiency of the proposed technique has been shown taking a base isolated three story building under a set of seismic excitation. Comparison with widely used clipped-optimal strategy has also been shown.

A Capacitive Microcantilever: Modelling, Validation, and Estimation Using Current Measurements

2004 ◽  
Vol 126 (2) ◽  
pp. 319-326 ◽  
Author(s):  
Mariateresa Napoli ◽  
Bassam Bamieh ◽  
Kimberly Turner
Keyword(s):  
Mathematical Model ◽  
Resonant Frequency ◽  
Parametric Resonance ◽  
Periodic System ◽  
Excitation Frequency ◽  
Mathieu Equation ◽  
Experimental Results ◽  
Electrostatically Actuated ◽  
The Common ◽  
Micro Cantilever

We present a mathematical model for the dynamics of an electrostatically actuated micro-cantilever. For the common case of cantilevers excited by a periodic voltage, we show that the underlying linearized dynamics are those of a periodic system described by a Mathieu equation. We present experimental results that confirm the validity of the model, and in particular, illustrate that parametric resonance phenomena occur in capacitively actuated micro-cantilevers. We propose a system where the current measured is used as the sensing signal of the cantilever state and position through a dynamical observer. By investigating how the best achievable performance of an optimal observer depends on the excitation frequency, we show that the best such frequency is not necessarily the resonant frequency of the cantilever.

scholarly journals Full-Scale Simulations of Magnetorheological Damper for Implementation of Semi-Actively Structural Control

2018 ◽  
Vol 35 (4) ◽  
pp. 549-562 ◽  
Author(s):  
Y. B. Peng ◽  
Z. K. Zhang ◽  
J. G. Yang ◽  
L. H. Wang
Keyword(s):  
Structural Control ◽  
Low Cost ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Mr Damper ◽  
Excitation Amplitude ◽  
Full Scale ◽  
Magnetorheological Damper ◽  
Input Current ◽  
Two Dimensional

ABSTRACTFull-scale simulations of a (Magnetorheological) MR damper are carried out for revealing its hysteretic behaviors associated with implementation of semi-active control using the routine of computational fluid dynamics. By virtue of the structural symmetry of the MR damper, a two-dimensional configuration for finite element simulation is built up. Herschel-Bulkley model is employed to represent the property of the MR fluid, of which the control parameters and their relevances to the input current are addressed. Typical cases involving sinusoidal and irregular displacements, steady and transient currents loaded upon the MR damper are investigated. Numerical investigations reveal that the damper force has a positive correlation with input current, excitation amplitude and excitation frequency. The full-scale simulation is proved to exhibit a sound accuracy through the validation of experimental data. It provides a logical manner revealing the true performance of MR dampers under desirable operating modes in practice, and can be readily integrated with the gain design of the associated semi-actively controlled structure. This progress bypasses the technical challenge inherent in the traditional tests with low-frequency cyclic loadings due to the limitation of experimental setup. Besides, comparative study between two-dimensional and three-dimensional configuration simulations of the MR damper shows that former has a better applicability, which can be carried out on a low-cost platform.

scholarly journals Influence of M-EMS on Fluid Flow and Initial Solidification in Slab Continuous Casting

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3681
Author(s):  
Guoliang Liu ◽  
Haibiao Lu ◽  
Bin Li ◽  
Chenxi Ji ◽  
Jiangshan Zhang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Field ◽  
Continuous Casting ◽  
Casting Speed ◽  
Liquid Pool ◽  
Industrial Test ◽  
Magnetic Flux Density ◽  
Continuous Casting Mold ◽  
Slab Continuous Casting ◽  
Initial Solidification

A mathematical model coupled with electromagnetic field has been developed to simulate the transient turbulence flow and initial solidification in a slab continuous casting mold under different electromagnetic stirring (EMS) currents and casting speeds. Through comparing the magnetic flux density, flow field with measured results, the reliability of the mathematical model is proved. The uniform index of solidified shell thickness has been introduced to judge the uniformity of the solidified shell. The results show that a horizonal recirculation flow has been generated when EMS is applied, and either accelerated or decelerated regions of flow field are formed in the liquid pool. Large EMS current and low casting speed may cause the plug flow near the mold narrow face and a suitable EMS current can benefit to the uniform growth of solidified shell. Meanwhile, an industrial test exhibits that EMS can weaken the level fluctuation and number density of inclusion. Overall, a rational EMS current range is gained, when the casting speed is 1.2 m/min, the rational EMS current is 500–600 A.

Lumped Parameter Modeling of a Magnetorheological Fluid Clutch

2006 ◽  
Author(s):  
John C. Ulicny ◽  
Daniel J. Klingenberg ◽  
Anthony L. Smith ◽  
Zongxuan Sun
Keyword(s):  
Mathematical Model ◽  
Physical Properties ◽  
Magnetorheological Fluid ◽  
Input Current ◽  
Fluid Composition ◽  
Fluid Temperature ◽  
Temperature Range ◽  
Lumped Parameter ◽  
Lumped Parameter Modeling ◽  
Fan Speed

A lumped-parameter mathematical model of an automotive magnetorheological (MR) fluid fan clutch was developed. This model is able to describe the average fluid temperature, average clutch temperature, and output fan speed as a function of time, input current, and fluid composition. The model also reproduces numerous features of fan operation observed experimentally and revealed a mechanism for some observed cases of hysteresis. However, it fails to capture certain other features which lead us to conclude that phenomena which are not included in the model, e.g., sedimentation and re-suspension, are important to the clutch behavior. In addition, the results indicate that certain physical properties need to be measured over a larger temperature range in order for the model to better predict the clutch behavior.

Friction and Tribological Considerations for Nanometer Range Machining

2001 ◽  
Author(s):  
Som Chattopadhyay
Keyword(s):  
Mathematical Model ◽  
High Precision ◽  
Local Deformation ◽  
Experimental Results ◽  
Precision Machining ◽  
Complex Motion ◽  
Positioning Accuracy ◽  
Nanometer Range ◽  
Motion Characteristic ◽  
Low Speeds

Abstract Positioning accuracy within the range of nanometers is required for high precision machining applications. The implementation of such a range is difficult through the slides because of (a) irregular nature of friction at the slider-guideway interface, and (b) complex motion characteristic at very low speeds. The complexity arises due to the local deformation at the interface prior to breakaway, which is known as microdynamics. In this work prior experimental results exhibiting microdynamics have been appraised, and mathematical model developed to understand this behavior.

Design and Experimental Analysis of Novel Refractometer Based on Photoelectric Sensor Technology

2011 ◽  
Vol 383-390 ◽  
pp. 5211-5215
Author(s):  
Yin Lin Li ◽  
Zhong Hua Huang ◽  
Kai Bo Hu
Keyword(s):  
Mathematical Model ◽  
Experimental Analysis ◽  
Differential Method ◽  
Theoretical Solution ◽  
Experimental Results ◽  
Sensor Technology ◽  
Photoelectric Sensor ◽  
Better Than

A novel refractometer based on photoelectric sensor technology and differential method is proposed. Sensing principle and mathematical model are introduced; structure and key parameters of sensing probe are designed through detail calculation. Theoretical solution shows resolution reaches order of 10-5. Preliminary experiments verify the feasibility of the design, experimental results show stability error better than ±1.02×10-4, error caused by temperature is 6.65×10-6/°C.

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