Characterization of Magneto-Rheological Elastomer and Modelling of MRE Based Isolators (original) (raw)
Related papers
A Feasibility Study of Magnetorheological Elastomer Base Isolator
Magnetorheological elastomer (MRE) is a controllable smart material that demonstrates changes in rheological properties depending on the magnetic field strength. This paper presents the development of a new concept of MRE isolator in terms of design and magnetic simulation. All features of geometry parameters were considered and altered expeditiously in order to provide ample and uniform magnetic field. Finite Element Method Magnetics (FEMM) was used to design the electromagnetic circuit to generate magnetic fluxes penetrate through the MRE. The study, eventually, leads to the conclusion of different design parameters approach; selection of materials, diameter of the shaft, shape of MRE, length of shaft and thickness of housing. when designing your figures and tables etc
Modeling of a new semi-active/passive magnetorheological elastomer isolator
Smart Materials and Structures, 2014
This paper presents theoretical modeling of a new magnetorheological elastomer (MRE) base isolator and its performance for vibration control. The elastomeric element of the traditional steel-rubber base isolator is modified to a composite layer of passive elastomer and MRE which makes the isolator controllable with respect to its stiffness and damping. The proposed variable stiffness and damping isolator (VSDI) is designed based on an optimized magnetic field passing through MRE layers to achieve maximum changes in mechanical properties. The controllability of the VSDI is investigated experimentally under double lap shear tests. A model employing the Bouc-Wen hysteresis element is proposed to characterize the force-displacement relationship of the VSDI. An integrated system which consists of four VSDIs is designed, built and tested. Dynamic testing on the integrated system is performed to investigate the effectiveness of the VSDIs for vibration control. Experimental results show significant shift in natural frequency, when VSDIs are activated and the possibility of using the VSDIs as a controllable base isolator.
Dynamic Properties of Magnetorheologic Elastomer
Rakenteiden Mekaniikka, 2007
SUMMARY Machinery and buildings often have to be protected from vibrations. The needed reduction of dynamic response can be achieved efficiently with semi-active isolation. One way to use semi-active isolation is to install vibration isolators between the base and the object to be protected and control the dynamic properties of these isolators. The advantage of semiactive isolation compared to passive isolation is the adjustability of the system. With adaptive semi-active isolators it is possible to react simultaneously to the changes of the loads and dynamics of the system. This paper describes the laboratory tests and the measurement results of an improved vibration isolator material and an improved adaptive vibration isolator developed by the Technical Research Centre of Finland (VTT). On the basis of the results the presented adaptive material and isolator system is applicable for typical industrial and transportation environments.
Development and Dynamic Characterization of a Mixed Mode Magnetorheological Elastomer Isolator
IEEE Transactions on Magnetics, 2017
Magnetorheological elastomers (MREs) are a kind of smart material, whose mechanical properties are controllable with applied magnetic field. Moreover, there is a greater magnetorheological effect for MREs at small strain amplitude, which has attracted more attention in the field of microvibration control. In this paper, an MRE isolator with shear-compression mixed mode was developed to suppress the high-frequency and microamplitude vibration of a precision-fabrication platform. To evaluate and characterize the dynamic behavior of the MRE isolator, experiments were conducted under harmonic load and different magnetic fields, respectively. Experiments showed that the resonance frequency of the MRE isolation system shifted from 45.82 (0 A) to 82.55 Hz (1.5 A). Meanwhile, the relative change in equivalent stiffness and damping was 175% and 216%, respectively, and the relative change in isolator force was 190% from 0 to 1.5 A. The proposed mixed mode MRE isolator effectively isolated vibration at high frequency for microamplitude.
Journal of Central South University, 2015
The preparation of natural rubber based isotropic thick magnetorheological elastomers (MRE) was focused on by varying the percentage volume concentration of carbonyl iron powder and developing a test set up to test the dynamic properties. Effect of magnetic field on the damping ratio was studied on the amplification region of the transmissibility curve. The viscoelastic dynamic damping nature of the elastomer was also studied by analyzing the force-displacement hysteresis graphs. The results show that MR effect increases with the increase in magnetic field as well as carbonyl iron powder particle concentration. It is observed that softer matrix material produces more MR effect. A maximum of 125% improvement in the loss factor is observed for the MRE with 25% carbonyl iron volume concentration. FEMM simulation shows that as carbonyl iron particle distribution becomes denser, MR effect is improved. FEMM analysis also reveals that if the distance between the adjacent iron particles are reduced from 20 μm to 10 μm, a 40% increase in stored energy is observed.
Development and Characterization of Isotropic Magnetorheological Elastomer
Universal Journal of Mechanical Engineering, 2013
Magneto rheological elastomer (MRE) is a new kind of smart materials. Its dynamic mechanical performances can be controlled by controlling an applied magnetic field. MRE is usually used as stiffness-changeable spring in the semi-active vibration absorber. In order to get perfect vibration control effect, low dynamic damping of MRE is needed. This paper presents a new method of fabricating isotropic MREs under normal temperature and pressure conditions. In the absence of a magnetic field, a variety of MR elastomer samples were prepared using Sylard's184 silicone elastomer along with un-annealed electrolytic iron power 500 mesh and 15 micron size. Their dynamic characteristics like fractional change in resonant frequency and fractional change in have been studied. The effects of iron particles and the applied magnetic field were investigated. This study is also expected to provide a good guide for designing and preparing new MR elastomers.
Modeling of a new magnetorheological elastomer-based isolator
Active and Passive Smart Structures and Integrated Systems 2013, 2013
A variable stiffness and damping isolator (VSDI) is designed and developed employing MREs. A double lap shear test has been carried out to characterize two MRE based VSDIs under quasi-static shear loading. A phenomenological model which can capture the behavior of the VSDI is developed and related parameters are identified using experimental data. Both experimental and theoretical modeling results have shown good agreements.
Experimental Analysis of Magneto-Rheological Elastomer
2016
Recently, a very attractive and effective semiactive absorbers featuring magneto-rheological (MR) materials such as MR fluids (MRFs) or MR elastomers (MRE’s) have been proposed by many investigators. These absorbing devices based on MR technique have a number of attractive characteristics for use in vibration control, such as fast response characteristic to magnetic field, wide control bandwidth and compact size. MR materials include MRFs, MR foams and MREs, whose rheological properties can be controlled by the application of an external magnetic field. The most common MR material is MRFs, which is magnetically polarizable particles suspended in viscous fluids. Since their invention in 1948, MRF technique has made significant advancements. The MRFs have been proved to be commercially viable and well suited for many applications, such as the automotive suspension vibration control, the earthquake resistance, clutch. Solid analogs of MRFs and MREs can avoid those disadvantages such as...
Smart Materials and Structures, 2014
Magneto-rheological elastomers (MREs) have attracted notable credits in the development of smart isolators and absorbers due to their controllable stiffness and damping properties. For the purpose of mitigating unwanted structural and/or machinery vibrations, the traditional MRE-based isolators have been generally proven effective because the MR effect can increase the stiffness when the magnetic field is strengthened. This study presents a novel MRE isolator that experienced reduced stiffness when the applied current was increased. This innovative work was accomplished by applying a hybrid magnet (electromagnet and permanent magnets) onto a multilayered MRE structure. To characterise this negative changing stiffness concept, a multilayered MRE isolator with a hybrid magnet was first designed, fabricated and then tested to measure its properties. An obvious reduction of the effective stiffness and natural frequency of the proposed MRE isolator occurred when the current was continuously adjusted. This device could also work as a conventional MRE isolator as its effective stiffness and natural frequency also increased when a negative current was applied. Further testing was carried out on a one-degree-of-freedom system to assess how effectively this device could isolate vibration. In this experiment, two cases were considered; in each case, the vibration of the primary system was obviously attenuated under ON-OFF control logic, thus demonstrating the feasibility of this novel design as an alternative adaptive vibration isolator.