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Journal ArticleDOI

Model of magnetorheological elastomers

08 Mar 1999-Journal of Applied Physics (American Institute of Physics)-Vol. 85, Iss: 6, pp 3348-3351
TL;DR: In this paper, the authors used finite element analysis to show that the shear modulus of typical elastomers is about 50% of the zero-field modulus at saturation and the optimum particle volume fraction for the largest fractional change in modulus is predicted to be 27%.
Abstract: Magnetorheological elastomers consist of natural or synthetic rubber filled with micron-sized magnetizable particles. During curing of the elastomer, an applied magnetic field aligns the particles into chains. The shear modulus of the resulting cured material is sensitive to magnetic fields of several kOe magnitude. Such sensitivity to magnetic field makes these materials attractive for applications in automotive mounting components. At large fields (magnetic induction B>1 T), the Fe particles are completely magnetized or saturated. Calculations using finite element analysis show that for typical elastomers the increase in shear modulus due to interparticle magnetic forces at saturation is about 50% of the zero-field modulus. The optimum particle volume fraction for the largest fractional change in modulus at saturation is predicted to be 27%. Calculations of the zero-field shear modulus perpendicular to the chain axis indicate that it does not exceed the modulus of a filled elastomer with randomly disper...
Citations
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Journal ArticleDOI
TL;DR: In this paper, a comprehensive assessment of recent developments of nonlinear isolators in the absence of active control means is presented, which highlights resolved and unresolved problems and recommendations for future research directions.

885 citations

Journal ArticleDOI
TL;DR: In this paper, the concept of variable and distributed order fractional operators is introduced and behavior of the operators is studied, including time invariance of the operator, operator initialization, physical realization, linearity, operational transforms, and memory characteristics of the defining kernels.
Abstract: Many physical processes appear to exhibit fractional order behavior that may vary with time or space. The continuum of order in the fractional calculus allows the order of the fractional operator to be considered as a variable. This paper develops the concept of variable and distributed order fractional operators. Definitions based on the Riemann-Liouville definitions are introduced and behavior of the operators is studied. Several time domain definitions that assign different arguments to the order q in the Riemann-Liouville definition are introduced. For each of these definitions various characteristics are determined. These include: time invariance of the operator, operator initialization, physical realization, linearity, operational transforms. and memory characteristics of the defining kernels. A measure (m2) for memory retentiveness of the order history is introduced. A generalized linear argument for the order q allows the concept of "tailored" variable order fractional operators whose a, memory may be chosen for a particular application. Memory retentiveness (m2) and order dynamic behavior are investigated and applications are shown. The concept of distributed order operators where the order of the time based operator depends on an additional independent (spatial) variable is also forwarded. Several definitions and their Laplace transforms are developed, analysis methods with these operators are demonstrated, and examples shown. Finally operators of multivariable and distributed order are defined in their various applications are outlined.

724 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a state-of-the-art review on the recent progress of magnetorheological elastomer technology, with special emphasis on the research and development of MR elastomers and their applications.
Abstract: During the last few decades, magnetorheological (MR) elastomers have attracted a significant amount of attention for their enormous potential in engineering applications. Because they are a solid counterpart to MR fluids, MR elastomers exhibit a unique field-dependent material property when exposed to a magnetic field, and they overcome major issues faced in magnetorheological fluids, e.g. the deposition of iron particles, sealing problems and environmental contamination. Such advantages offer great potential for designing intelligent devices to be used in various engineering fields, especially in fields that involve vibration reduction and isolation. This paper presents a state of the art review on the recent progress of MR elastomer technology, with special emphasis on the research and development of MR elastomer devices and their applications. To keep the integrity of the knowledge, this review includes a brief introduction of MR elastomer materials and follows with a discussion of critical issues involved in designing magnetorheological elastomer devices, i.e. operation modes, coil placements and principle fundamentals. A comprehensive review has been presented on the research and development of MR elastomer devices, including vibration absorbers, vibration isolators, base isolators, sensing devices, and so on. A summary of the research on the modeling mechanical behavior for both the material and the devices is presented. Finally, the challenges and the potential facing magnetorheological elastomer technology are discussed, and suggestions have been made based on the authors’ knowledge and experience.

498 citations


Cites background from "Model of magnetorheological elastom..."

  • ...Since then, research on MR elastomer has progressed to a new level where significant amount activities have been reported, including material empirical modeling [18, 31-40], material development and property testing [2-3, 1012,14-15, 18, 21,41-60], new device design and characterization [61-84], and performance evaluation [85-105] and aimed for applications in aeronautic engineering, mechanical engineering, automobile engineering and civil engineering....

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  • ...Ginder J M, Scholotter W F and Nichols M E 2001 Magnetorheological elastomers in tunable vibration absorbers Smart Structures and Materials 2001: Damping and Isolation, Proceedings of SPIE 4331 10310 [31]....

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Journal ArticleDOI
TL;DR: In this paper, an adaptive tuned vibration absorber (ATVA) based on the unique characteristics of magnetorheological elastomers (MREs), whose modulus can be controlled by an applied magnetic field.
Abstract: In this technical note we develop an adaptive tuned vibration absorber (ATVA) based on the unique characteristics of magnetorheological elastomers (MREs), whose modulus can be controlled by an applied magnetic field. The MRE used in the developed ATVA was prepared by curing a mixture of 704 silicon rubber, carbonyl iron particles and a small amount of silicone oil under a magnetic field. The ATVA works in shear mode and consists of an oscillator, smart spring elements with MREs, a magnet conductor and two coils. Natural frequencies of the ATVA under different magnetic fields were both theoretically analyzed and experimentally evaluated by employing a beam structure with two ends supported. The experimental results demonstrated that the natural frequency of the ATVA can be tuned from 55 to 82 Hz. The relative frequency change is as high as 147%. Furthermore, the absorption capacity of the developed ATVA can achieve as high as 60 dB, which was also experimentally justified.

346 citations


Cites methods from "Model of magnetorheological elastom..."

  • ...Using this model, the shear modulus increment under the magnetic field is given by [22]...

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Journal ArticleDOI
TL;DR: In this article, it was shown that MR rubber materials with large irregular particles have a large MR effect although the particles are not aligned within the material, which is explained by the low critical particle volume concentration of such particles.

311 citations


Cites background from "Model of magnetorheological elastom..."

  • ...Furthermore, alignment of the particles decreases the zero-field shear modulus [27]....

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References
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Journal ArticleDOI
TL;DR: In this article, the authors generalized the model for ellipsoidal (including plate-and rod-like) filler particles and extended it to the computation of various properties in terms of the properties of the matrix and of the fillers.
Abstract: For small loadings (up to about 10 percent volume parts) the colloidal carbon black spheres may be considered as suspended in a continuous rubber matrix. In the present paper this model is generalized for ellipsoidal (including plate‐ and rod‐like) filler particles and it is extended to the computation of various properties of the suspension in terms of the properties of the matrix and of the fillers. Viscosity, Young's modulus, stress‐strain curve below crystallization, and dielectric constant of the suspension are derived as linear functions of the volume concentration for small, and as quadratic functions for higher loadings. The stress‐strain curves for varying amounts of fillers are similar. For small loadings the tensile strength first decreases because of the stress concentrations occurring around the carbon black spheres when the samples are stretched. The increase of the tensile strength observed for greater loadings is caused by the tendency of the carbon black spheres to form chains and finally...

1,075 citations

Journal ArticleDOI
TL;DR: In this paper, a quasi-static, one-dimensional model is developed that examines the mechanical and magnetic properties of magnetorheological materials, and the model attempts to account for magnetic nonlinearities and saturation by establishing a mechanism by which magnetic flux density is distributed within the composite material.
Abstract: Magnetorheological materials are a class of smart materials whose rheological properties may be rapidly varied by application of a magnetic field These materials typically consist of micron-sized ferrous particles dispersed in a fluid or an elastomer A quasi-static, one-dimensional model is developed that examines the mechanical and magnetic properties of magnetorheological materials This model attempts to account for magnetic non-linearities and saturation by establishing a mechanism by which magnetic flux density is distributed within the composite material Experimental evidence of the viscoelastic behaviour and magnetic properties of magnetorheological fluids and elastomers suggests that the assumptions made in the model development are reasonable It is shown that the model is semi-empirical in that it must be fit to the experimental data by adjusting a parameter that accounts for unmodelled magnetic interactions

779 citations

Journal ArticleDOI
TL;DR: The 23-volume "Encyclopedia of Applied Physics" seeks to demonstrate the synergy between physics and technological applications as discussed by the authors, and provides a broad overview of the main aspects of physics and their applications.
Abstract: The 23-volume "Encyclopedia of Applied Physics" seeks to demonstrate the synergy between physics and technological applications. Information is presented according to the following subject areas: general aspects; mathematical and information techniques; measurement sciences, general devices and/or methods; nuclear and elementary particle physics; atomic and molecular physics; electricity and magnetism; optics (classical and quantum); acoustics; thermodynamics and properties of gases; fluids and plasma physics; condensed matter - structure and mechanical properties; thermal, acoustic, and quantum properties; electronic properties; magnetic properties; dielectrical and optical properties; surfaces and interfaces; materials science; physical chemistry; energy research and environmental physics; biophysics and medical physics; geophysics, meteorology, space physics and aeronautics.

613 citations

Journal ArticleDOI
TL;DR: Controllable magnetorheological (MR) fluid devices have reached the stage where they are in commercial production as discussed by the authors, and such devices are finding application in a variety of real world situations ranging...
Abstract: Controllable magnetorheological (MR) fluid devices have reached the stage where they are in commercial production. Such devices are finding application in a variety of real world situations ranging...

574 citations

Journal ArticleDOI
TL;DR: In this paper, a quasi-static dipole model is presented to examine the magnetoviscoelastic effect of these elastomer composites and the model is semi-empirical in that it may be fit to experimental data over a broad range of applied magnetic fields.
Abstract: The mechanical response of elastomer composites to applied magnetic fields is examined. These elastomer composites consist of carbonyl iron particles embedded within a molded elastomer matrix. The composite is subjected to a strong magnetic field during curing, which causes the iron particles to form columnar structures that are parallel to the applied field. This special composite geometry is known to enhance the mechanical response to the application of post-cured magnetic fields. Experimental data is presented that shows that up to a 0.6 MPa change in mechanical shear modulus (which represents 30-40% change in modulus for the materials tested) is possible in response to an applied magnetic field for a composite containing 30% (V/V) iron particles. A simple quasi-static dipole model is presented to examine the magnetoviscoelastic effect of these elastomer composites. The model is semi-empirical in that it may be fit to experimental data over a broad range of applied fields by adjusting a parameter that ...

491 citations