Experimental investigation on the effect of magnetic field on strain dependent dynamic stiffness of magnetorheological elastomer

2016 ◽  
Vol 55 (11-12) ◽  
pp. 993-1001 ◽  
Author(s):  
Umanath R. Poojary ◽  
K. V. Gangadharan
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Dynamic Stiffness ◽  
Magnetorheological Elastomer ◽  
Strain Dependent

Design of a stiffness variable flexible coupling using magnetorheological elastomer for torsional vibration reduction

2019 ◽  
Vol 30 (15) ◽  
pp. 2212-2221 ◽  
Author(s):  
Kang-Hyun Lee ◽  
Jae-Eun Park ◽  
Young-Keun Kim
Keyword(s):  
Magnetic Field ◽  
Torsional Vibration ◽  
Dynamic Stiffness ◽  
Torsional Stiffness ◽  
Magnetorheological Elastomer ◽  
Dynamic Disturbance ◽  
Flexible Coupling ◽  
Base Matrix ◽  
Stiffness Variation ◽  
Magnetic Field Generator

In this study, the design of an magnetorheological elastomer flexible coupling whose torsional stiffness can be controlled by an embedded magnetic field generator is proposed. It is designed to minimize the torsional vibration transmission between shafts adaptively to the dynamic disturbance. The coupling insert is composed of magnetorheological elastomer which is a smart material whose stiffness can be controlled by an external magnetic field. This article also proposes a compact magnetic field generator which can be fitted inside the coupling hubs, to control the torsional stiffness of the magnetorheological elastomer. The finite element method was used to design and estimate the dynamic stiffness variation of the magnetorheological elastomer coupling due to the applied magnetic field and disturbance frequency. Also, torsional vibration experiments were conducted to validate the performance of the proposed magnetorheological elastomer coupling. Results showed that it can adaptively tune in a range of frequencies between 16.8 and 23.5 Hz and has 95.7% stiffness variation under magnetic field of 150mT. The proposed system is expected to achieve a higher MRE effect with a softer base matrix.

scholarly journals Material modeling of frequency, magnetic field and strain dependent response of magnetorheological elastomer

2021 ◽  
Author(s):  
Umanath R. Poojary ◽  
K. V. Gangadharan
Keyword(s):  
Magnetic Field ◽  
Constitutive Relations ◽  
Operating Conditions ◽  
Material Behavior ◽  
Material Modeling ◽  
Magnetorheological Elastomer ◽  
Proposed Model ◽  
Fitness Value ◽  
Frequency Magnetic Field ◽  
Strain Dependent

AbstractAccurate modeling of material behavior is very critical for the success of magnetorheological elastomer-based semi-active control device. The material property of magnetorheological elastomer is sensitive to the frequency, magnetic field and the input strain. Additionally, these properties are unique for a particular combination of matrix and the filler loading. An experimental-based characterization approach is costly and time consuming as it demands a large amount of experimental data. This process can be simplified by adopting material modeling approach. The material modeling of magnetorheological elastomer is an extension of conventional viscoelastic constitutive relations coupled with hysteresis and magnetic field sensitive attributes. In the present study, a mathematical relation to represent the frequency, magnetic field and strain dependent behavior of magnetorheological elastomer is presented. The viscoelastic behavior is represented by a fractional zener element and the magnetic field and strain dependent attributes incorporated in the model by a magnetic spring and linearized Bouc-–Wen element, respectively. The proposed model comprised of a total of eight parameters, which are identified by minimizing the least square error between the model predicted and the experimental response. The variations of each parameter with respect to the operating conditions are represented by a generalized expression. The parameters estimated from the generalized expression are used to assess the ability of the model in describing the dynamic response of magnetorheological elastomer. The proposed model effectively predicted the stiffness characteristics with an accuracy, more than 94.3% and the corresponding accuracy in predicting the damping properties is above 90.1%. This model is capable of fitting the experimental value with a fitness value of more than 93.22%.

Modelling and experimental characterisation of a compressional adaptive magnetorheological elastomer isolator

2021 ◽  
pp. 107754632110253
Author(s):  
Emiliano Rustighi ◽  
Diego F Ledezma-Ramirez ◽  
Pablo E Tapia-Gonzalez ◽  
Neil Ferguson ◽  
Azrul Zakaria
Keyword(s):  
Magnetic Field ◽  
Silicone Rubber ◽  
Magnetic Interaction ◽  
Iron Particle ◽  
Material Model ◽  
Rubber Matrix ◽  
Magnetorheological Elastomer ◽  
Volume Percentage ◽  
Shock Absorbers ◽  
Percent Concentration

This article proposes a simple physical-based model to describe and predict the performance of axially compressed magnetorheological elastomer cylinders used as vibration and shock absorbers. The model describes the magnetorheological elastomer macroscopic stiffness changes because of an externally applied magnetic field from a microscopic composite cell of silicone rubber and carbonyl iron particle. Despite neglecting the material hyperelasticity, anisotropy and adjacent magnetic interaction, the model describes effectively the effect of the magnetic field on the macroscopic modulus of elasticity. The changes in the mechanical properties with the induced magnetic field are measured on samples of different particle concentration based on volume percentage, that is, 10 and 30 percent concentration of iron particles in a silicone rubber matrix. The manufacturing process of the samples is detailed, as well as the experimental validation of the effective stiffness change under a magnetic field in terms of transmissibility and mobility testing. However, the prediction seems to be limited by the linear elastic material model. Predictions and measurements are compared, showing that the model is capable of predicting the tunability of the dynamic/shock absorber and that the proposed devices have a possible application in the reduction of mechanical vibrations.

Numerical Dynamic Analysis of a Single Link Soft Robot Finger

2013 ◽  
Vol 459 ◽  
pp. 449-454 ◽  
Author(s):  
Elango Natarajan ◽  
Ahmad Athif Mohd Faudzi ◽  
Viknesh Malliga Jeevanantham ◽  
Muhammad Rusydi Muhammad Razif ◽  
Ili Najaa Aimi Mohd Nordin
Keyword(s):  
Room Temperature ◽  
Natural Frequencies ◽  
Dynamic Stiffness ◽  
Mode Shapes ◽  
Soft Robot ◽  
Fundamental Frequencies ◽  
Single Link ◽  
Hyper Elastic ◽  
Finger Model ◽  
Strain Dependent

In this paper, a solid, single link soft robot finger was modeled with SILASTIC P-1 Silicone, supplied by Dow Corning®. The material is anon-linear hyper elastic, strain dependent, room temperature vulcanized (RTV) rubber. When the fingers are actuated for grasping and object manipulation, they vibrate with excessive amplitudes, which will disturb the precise positioning of the fingers. Vibration analysis through numerical simulation was conducted in ANSYS®V12. The first ten fundamental frequencies and their mode shapes were numerically computed and presented from modal analysis. The lowest natural frequency of the finger model was found to be 2.14 Hz. The dynamic stiffness of the finger model was then computed from the natural frequencies. It was found to be nonlinear in nature. The dynamic characteristics of the finger model during the excitation between 1 Hz and 1000 Hz were studied in transient analysis. The peak acceleration occurred at 9.3 Hz, while the peak velocity occurs at 3.75 Hz and 4.8 Hz with the magnitude of 0.013 mm/s.

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