Investigation on the Dynamic Shearing Characteristics of Magnetic Responsive Gel

2011 ◽  
Author(s):  
Katsuaki Sunakoda ◽  
Naoki Yamamoto ◽  
Hiroshi Nasuno ◽  
Hirohisa Sakurai
Keyword(s):  
Magnetic Field ◽  
Physical Properties ◽  
Storage Modulus ◽  
Smart Materials ◽  
Loss Modulus ◽  
Active Vibration Control ◽  
Hysteresis Loops ◽  
Active Vibration ◽  
Magneto Rheological ◽  
Dynamic Shearing

Material which would be largely changed its physical properties such as storage modulus and loss modulus under magnetic field has a potential of application on industrial fields. Magneto-rheological (MR) fluid has been widely studied since its viscosity is changed under magnetic field, but it is restricted for application of the industrial fields as it has liquid nature. Authors are proceeding with the development of magnetic responsive gels which contain the magnetic responsive particles in consideration of their prior studies. Three kinds of magnetic gels are selected and dynamic shearing characteristics are examined. Storage modulus and loss modulus are obtained under different dynamic frequencies and different magnetic fluxes. Some physical properties such as storage modulus and loss modulus are largely changed by applying magnetic field. The developed gels have an effect of energy dissipation, judging from hysteresis loops of stress-strain. And these smart materials have a potential of semi active vibration control materials.

MRE-Based Adaptive-Tuned Dynamic Absorber With Self-Sensing Function for Vibration Control of Structures

2014 ◽  
Author(s):  
Toshihiko Komatsuzaki ◽  
Toshio Inoue ◽  
Yoshio Iwata
Keyword(s):  
Vibration Control ◽  
Smart Materials ◽  
Active Vibration Control ◽  
Dominant Frequency ◽  
Displacement Sensor ◽  
Dynamic Vibration Absorber ◽  
Active Vibration ◽  
Dynamic Absorber ◽  
Magneto Rheological ◽  
Strain Signal

Magneto-rheological elastomer (MRE) is known as class of smart materials whose elastic property can be varied by the applied external magnetic field. For the use of semi-active vibration control, any kind of external sensor such as accelerometer or displacement sensor is usually used to monitor the real-time response of structures while leaving cost, proper installation and maintenance problems for real applications. In addition to the field-dependent stiffness change property of MRE, the electrical resistance of the composite is also changed by the induced strain within the elastomer providing a new self-sensing feature as a multifunctional material. In the present study, a novel dynamic vibration absorber having self-sensing function and adaptability using Magneto-rheological elastomer is developed. The natural frequency of the absorber is instantaneously tuned to a dominant frequency extracted from the strain signal. The damping performance of the absorber is investigated by applying the absorber to a fundamental base-excited 1-dof vibration system. Investigations show that the vibration of the target structure exposed to a non-stationary disturbance can be satisfactorily reduced by the proposed frequency-tunable dynamic absorber without the use of an external sensor, at the exceeding performance in comparison to conventional passive-type dynamic absorber.

scholarly journals Damping in magnetorheological elastomers under compressive stress

2019 ◽  
Vol 254 ◽  
pp. 06002 ◽  
Author(s):  
Mateusz Kukla ◽  
Krzysztof Talaśka ◽  
Ireneusz Malujda
Keyword(s):  
Smart Materials ◽  
Hysteresis Loops ◽  
Machine Construction ◽  
Vibration Absorbers ◽  
Magnetorheological Elastomers ◽  
Practical Applications ◽  
Mechanical Hysteresis ◽  
Compressive Stresses ◽  
Active Vibration ◽  
Energy Absorbers

Magnetorheological elastomers are an important area of study in non-classical engineering materials. These are smart materials, in which some of the physical properties are dependent on the applied magnetic field. This unique property allows to suggest new, innovative practical applications. It is therefore relevant to carry out studies in the possible application of magnetorheological elastomers in machine construction. The present article presents the results of study regarding the properties of the discussed materials subject to compressive stresses. Particular attention is given to the observed growth of surface area of mechanical hysteresis loops, which is evidence of the possibility to change the damping properties of magnetorheological elastomers. This property can be utilized in the construction of different types of machines and devices. These mostly applies to energy absorbers such as active vibration absorbers.

scholarly journals Investigation on the Mechanical Properties of MRE Compounds

Machines ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 36 ◽  
Author(s):  
Renato Brancati ◽  
Giandomenico Di Massa ◽  
Stefano Pagano
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Smart Materials ◽  
Testing Machine ◽  
Static Test ◽  
Vibration Isolators ◽  
Elastomeric Matrix ◽  
Magneto Rheological ◽  
Stiffness And Damping ◽  
Rheological Effect

This paper describes an experimental investigation conducted on magneto-rheological elastomers (MREs) with the aim of adopting these materials to make mounts to be used as vibration isolators. These materials, consisting of an elastomeric matrix containing ferromagnetic particles, are considered to be smart materials, as it is possible to control their mechanical properties by means of an applied magnetic field. In the first part of the paper, the criteria adopted to define the characteristics of the material and the experimental procedures for making samples are described. The samples are subjected to a compressive static test and are then, adopting a testing machine specially configured, tested for shear periodic loads, each characterized by a different constant compressive preload. The testing machine is equipped with a coil, with which it is possible to vary the intensity of the magnetic field crossing the sample during testing to evaluate the magneto-rheological effect on the materials’ characteristics in terms of stiffness and damping.

SEMI-ACTIVE VIBRATION CONTROL OF A ROTATING SHAFT BY USING A MAGNETO RHEOLOGICAL DAMPER

2015 ◽  
Author(s):  
Aldemir Ap Cavalini Jr ◽  
Edson Hideki Koroishi ◽  
Adriano Silva Borges ◽  
Luiz Gustavo Pereira ◽  
Valder Steffen Jr
Keyword(s):  
Vibration Control ◽  
Active Vibration Control ◽  
Rotating Shaft ◽  
Active Vibration ◽  
Magneto Rheological

Magnetic Field Analysis of the Actuator in a Semi-Active Vibration Control of the Beam with MR Fluid

2015 ◽  
Vol 759 ◽  
pp. 37-44
Author(s):  
Mateusz Romaszko ◽  
Łukasz Łacny
Keyword(s):  
Magnetic Field ◽  
Vibration Control ◽  
Field Distribution ◽  
Active Vibration Control ◽  
Magnetic Field Distribution ◽  
Field Analysis ◽  
Mr Fluid ◽  
Active Vibration ◽  
Comparison Of The Results ◽  
The Magnetic Field

In this study the analysis of the magnetic field distribution of an electromagnet is presented. This electromagnet is used as an actuator in a semi-active vibration control of the three-layer beam with MR fluid. Two separate numerical methods are used for the purpose of calculating the magnetic field distribution. The first method is based on the Finite Element Method and implemented using ANSYS software. The second, simplified one is based on the assumption that the electromagnet can be substituted by a simple magnetic circuit divided into separate paths, with each sub-path defined by the value of reluctance of the corresponding electromagnet part. The comparison of the results from both methods with the ones obtained from an experiment is also presented and analyzed in the paper.

An Experimental Study on Basic Characteristics of a Magneto-Rheological Grease Damper

2015 ◽  
Author(s):  
Yusuke Sato ◽  
Hiroshi Sodeyama ◽  
Makoto Hayama ◽  
Shin Morishita
Keyword(s):  
Vibration Control ◽  
Dispersion Medium ◽  
Fine Particles ◽  
Active Vibration Control ◽  
Test Results ◽  
Active Vibration ◽  
Derived Design ◽  
Basic Characteristics ◽  
Fluid Dampers ◽  
Magneto Rheological

As one of the semi-active vibration control devices for mechanical or civil structures, magneto-rheological fluid dampers have been enthusiastically studied and developed since the 1990s. A new magneto-rheological material for such dampers has been developed to provide a practical solution to the significant common drawback of sedimentation of ferromagnetic fine particles in the fluid. Industrial grease is used as the dispersion medium in this material. The thickener to be added in the grease to control the rheological properties seems to prevent separation of the particles from the dispersion medium. Several performance tests were carried out with a proto-type of the damper with the newly developed magneto-rheological grease, namely, the magneto-rheological grease damper. Based on the test results, the energy dissipation capabilities of the damper and the basic characteristics of the magneto-rheological grease were verified to provide semi-active vibration control. Moreover, the analytically-derived design formulae for the damper were improved on the basis of the test results.

Analysis of Magneto Rheological Fluid Journal Bearing

2019 ◽  
Vol 895 ◽  
pp. 152-157 ◽  
Author(s):  
B. Narasimha Rao ◽  
A. Seshadri Sekhar
Keyword(s):  
Magnetic Field ◽  
Newtonian Fluid ◽  
Carrying Capacity ◽  
Smart Materials ◽  
Journal Bearing ◽  
Fluid Film ◽  
Load Carrying Capacity ◽  
Mr Fluid ◽  
Load Carrying ◽  
Magneto Rheological

Magneto Rheological (MR) fluids are a class of smart materials where the shear stress is not directly proportional to rate of shear. The viscosity of fluid changes as magnetic field changes and hence this phenomenon is very useful in bearing-rotor system for attenuating the vibrations. In the present study the application of MR fluid as lubricant instead of Newtonian fluid in the journal bearing is explored through steady state, dynamic characteristics and stability. MR fluid film has been modeled as per Bingham rheological model. FEM with three node triangular elements has been used to solve the Reynolds equation both for the Newtonian fluid film and MR fluid film. The results show the load carrying capacity in the case of MR fluid journal bearing is higher than that of using the Newtonian fluid. The load carrying capacity increases with the increasing magnetic field for all eccentricity ratios. The results also show better stability of the bearing using MR fluid at higher eccentricity ratios. The unbalance response of the rotor mounted on the journal bearing using MR fluid is also estimated to be lower than that of with the Newtonian fluid.

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