Creep behavior of magnetorheological gels
10 Mar 2020-Mechanics of Advanced Materials and Structures (Taylor & Francis)-Vol. 27, Iss: 13, pp 1031-1039
TL;DR: Magnetorheological (MR) gels belong to a group of smart materials whose attributes can be altered when it is exposed to an external magnetic field as mentioned in this paper, and the investigation on the creep beh...
Abstract: Magnetorheological (MR) gels belong to a group of smart materials whose attributes can be altered when it is exposed to an external magnetic field. In this paper, the investigation on the creep beh...
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TL;DR: The collected test results point to the examined materials being characterized by extensive rheological properties, which leads to the conclusion that it is necessary to conduct further tests in this area.
Abstract: Materials characterized by magnetorheological properties are non-classic engineering materials. A significant increase in the interest of the scientific community about this group of materials could be observed over the recent years. The results of research presented in this article are oriented on the examination of the said materials’ mechanical properties. Stress relaxation tests were carried out on cylindrical samples of magnetorheological elastomers loaded with compressive stress, for various values of magnetic induction (B1 = 0 mT, B2 = 32 mT, B3 = 48 mT, and B4 = 64 mT) and temperature (T1 = 25 °C, T2 = 30 °C, and T3 = 40 °C). The results of these tests indicate that the stiffness of the examined samples increased along with the increase of magnetic field induction, and decreased along with the increase of temperature. On this basis, it has been determined that: the biggest stress amplitude change, caused by the influence of magnetic field, was σ0ΔB = 12.7%, and the biggest stress amplitude change, caused by the influence of temperature, was σ0ΔT = 11.3%. As a result of applying a mathematical model, it was indicated that the stress relaxation in the examined magnetorheological elastomer, for the adopted time range (t = 3600 s), had a hyperbolic decline nature. The collected test results point to the examined materials being characterized by extensive rheological properties, which leads to the conclusion that it is necessary to conduct further tests in this area.
7 citations
Cites methods from "Creep behavior of magnetorheologica..."
...The carbonyl iron powders are commonly used magnetic particles in the process of MRE preparation [31]....
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TL;DR: In this paper , the deformation-dependent magneto-mechanical properties of magnetorheological gel (MRG) under different working modes, i.e., quasi-static and dynamic, have been systematically analyzed and compared.
Abstract: Controlled over an external magnetic field, rheological response of magnetorheological gel (MRG), a smart composite that could change according to a specific stimulation, could be reversible and adjustable. This paper sheds light on the large deformation-dependent magneto-mechanical property of MRG under different working mode, i.e. quasi-static and dynamic mode, which has rarely been systematically analyzed and compared. The viscoelastic and hysteretic properties of MRG were evaluated by three kinds of experiments that were conducted under different strain excitations—linearly monotonic and cyclic strain, and harmonically cyclic strain. The results reveal that shear stress and normal stress display opposite trend with the increase of strain under quasi-static monotonic loading. A simple parametric model is proposed to describe the shear stress of MRG under quasi-static loading. Furthermore, for quantitatively characterizing the Payne effect of MRG under dynamic loading, the classical Maier-Goritz model predicting the Payne effect of material was modified by introducing a magnetic dipole theory that considers the effect of magnetic field on Payne effect. The magnetic dipole theory is established based on triangular double-chain rather than the conventional single chain. Moreover, in the presence of a magnetic field, the hysteretic loop of MRG would occur a overshoot phenomenon under dynamic working mode, which could not been found under quasi-static cyclic mode. Also, dynamic loading, compared with quasi-static one, could enable MRG to dissipate more energy. This paper is possibly conducive to understanding the working mechanisms about microstructures of MRG and designing MRG-based vibration control devices.
7 citations
TL;DR: In this paper , the effect of temperature on rheological properties of magnetorheological (MR) gel is investigated under rotational steady shear and oscillatory dynamic shear.
Abstract: In this paper, the effect of temperature on rheological properties of magnetorheological (MR) gel is investigated under rotational steady shear and oscillatory dynamic shear. A kind of fluid-like MR gel (MRG) was firstly synthesized by mixing carbonyl iron powder (CIP) with polymer matrix. Then, the relationship between yield stress, normal stress of MRG and shear rate under six temperatures and four magnetic field strengths were studied by rotational shear experiments. The results demonstrate that the dependence of shear stress on temperature displays an opposite tendency in comparison with that of normal stress on temperature. Moreover, maximum yield stress, one of the most important parameter of MR materials, decreases with the increment of temperature. Under oscillatory dynamic shear test, storage and loss moduli and normal stress of MRG all increase with temperature when a magnetic field is applied, which presents a contrary trend in the absence of a magnetic field. Related mechanisms about the alternation of microstructures of MRG were proposed to explain the above-mentioned phenomena. This paper is helpful in fabricating semi-active engineering devices using MR materials as a medium.
TL;DR: In this paper , a modified viscoelastic resistance model is proposed, which can describe the interaction between the matrix and particles, including consistency coefficient, flow behavior index, particle size, and motion velocity.
Abstract: The rheological properties and shear performance of magnetorheological (MR) gels have been extensively studied based on experimental methods. However, viscoelastic theoretical models that can quantify the interaction between the matrix and particles, as well as numerical simulations on the mechanical properties and the microstructure evolution of MR gels, are still relatively few and need to be further investigated. In this paper, based on the non-Newtonian fluid equation and Kelvin viscoelastic model, a modified viscoelastic resistance model is proposed, which can describe the interaction between the matrix and particles. The consistency coefficient, flow behavior index, particle size, and motion velocity are considered comprehensively in the viscoelastic resistance equation. Based on the established theoretical model, the numerical simulation approach is developed to study the evolution of chain-like microstructures and the shear properties of MR gels. The response time of MR gels under different magnetic fields and matrixes is analyzed from the perspective of energy. It shows that the effect of magnetic field intensity on the shear strength of MR gels is consistent with the magnetization characteristics of particles. The maximum shear stress and flow stress are significantly affected by viscosity parameters of the matrix and shear rate, which are related to the strength of shear-bearing chains and recombination rate of dissociative chains. The relevant influence mechanism of the microstructures on the macroshear properties is explored.
07 Dec 2022
TL;DR: In this article , the authors used hydrogel-based magnetorheological plastomer (HMRP) for low-force sensing in the presence and absence of magnetic field.
Abstract: The higher demand for sensors and actuators devices is a result of machines and robotic devices incorporating electronics devices in its system. Intelligent material like hydrogel-based magnetorheological plastomer (HMRP) can be considered for its potential to be used in such system, particularly in a low force sensing system. However, the studies on HMRP’s potential to be used in a low force detecting system has not been further explored. In this paper, HMRP with 0 wt. % to 15 wt.% of graphite were fabricated and their resistance was tested under applied force ranging from 0 N - 5 N. The resistance was also measured in the absence and presence of magnetic field. With 15 wt.% of graphite, the resistance in the HMRP samples could reach as low as ~3000 Ω while applying load up to 5 N resulted in resistance as low as ~600 Ω in the absence of magnetic field. In the presence of 0.141 mT of magnetic field, the resistance of HRMP sample with 15 wt.% of graphite could reach as low as ~2500 Ω. The establishment of this relationship indicates that HMRP has the potential to be used in a sensing system.Clinical Relevance– This research can be used as a base to help in improving methods for physiology or therapy.
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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
"Creep behavior of magnetorheologica..." refers background in this paper
...Magnetorheological (MR) materials are composed of magnetic particles in a polymer matrix and/or carrier fluid that can be controlled under the influence of an applied magnetic field [5, 6]....
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TL;DR: In this article, a method to fabricate isotropic magnetorheological (MR) elastomers under natural conditions was presented, and a simple self-assembled microstructure was proposed to explain the inherent magnetoviscoelasticity of MR elastomer prepared in the absence of a magnetic field.
Abstract: This paper presents a new method to fabricate isotropic magnetorheological (MR) elastomers under natural conditions. In the absence of a magnetic field, a variety of MR elastomer samples made of carbonyl iron particles, silicon rubber and silicone oil, were fabricated. Their dynamic viscoelastic properties were characterized by a measurement system developed by our group. Also, the microstructure of the samples was observed by a scanning electron microscope. The effects of iron particles and additives on the MR effect and the relationship between microstructure and mechanical properties were investigated. Furthermore, a simple self-assembled microstructure was proposed to explain the inherent magnetoviscoelasticity of MR elastomers prepared in the absence of a magnetic field. The analytical results of the model are in agreement with experimental data. The study is also expected to provide a good guide for designing and preparing new MR elastomers.
294 citations
TL;DR: In this paper, the authors investigated the influence of fabrication conditions on the performance of magnetorheological elastomers (MR Elastomers) such as matrix type, external magnetic flux density, and temperature, plasticizer and iron particles.
Abstract: Magnetorheological Elastomers (MR Elastomers or MREs) are a kind of novel smart material, whose mechanical, electrical, magnetic properties are controllable under applied magnetic fields. They have attracted increasing attentions and broad application prospects. But conventional MREs are limited to wide applications because their MR effects and mechanical performances are not high enough. This paper aims to optimize the fabrication method and to fabricate good natural rubber based MREs with high modulus by investigating the influences of a variety of fabrication conditions on the MREs performances, such as matrix type, external magnetic flux density, and temperature, plasticizer and iron particles. Among these factors, the content of iron particles plays a most important contribution in shear modulus. When the iron particle weight fraction is 80% and the external magnetic flux density is 1 T, the field-induced increment of shear modulus reaches 3.6 MPa, and the relative MR effect is 133%. If the iron weight fraction increases to 90%, the field-induced increment of shear modulus is 4.5 MPa. This result has exceeded the best report in the literatures researching the MREs on the same kind of matrix. The dynamic performances of MREs were also experimentally characterized by using a modified Dynamic Mechanical Analyzer (DMA) system. The effects of strain amplitude and driving frequency on viscoelastic properties of MREs were analyzed.
278 citations
TL;DR: In this article, the authors developed an adaptive tuned vibration absorber (ATVA) based on unique characteristics of magnetorheological elastomers (MREs), whose modulus can be controlled by an applied magnetic field.
Abstract: Traditional dynamic vibration absorber (DVA) is widely used in industries as a vibration absorption equipment. However, it is only effective at narrow working frequency range. This shortcoming has limited its stability and application. This paper develops an adaptive tuned vibration absorber (ATVA) based on unique characteristics of magnetorheological elastomers (MREs), whose modulus can be controlled by an applied magnetic field. This ATVA works in shear mode and consists of dynamic mass, static mass and smart spring elements with MREs. Based on the double pole model of MR effects, the shift-frequency capability of the ATVA has been theoretically and experimentally evaluated. The experimental results demonstrated that the natural frequency of the ATVA can be tuned from 27.5 Hz to 40 Hz. To study its vibration absorption capacity, a beam structure with two ends supported has been employed. To analyze the vibration absorption capacity, a dynamic model of coupling beam and absorber has been established. Both the calculation and experimental results show that the absorption capacity of the developed ATVA is better than the traditional TVA and can achieve as high as 25 dB which was justified by the experiment.
210 citations