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Semi-active torsional vibration isolation utilizing magnetorheological elastomer

Marzuki W. M. R. W., Muthalif A. G. A., Nordin N. H. D.

Vibrations in Physical Systems

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2018

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Vol. 29

art. no. 2018014

EN

In rotating machinery, unattenuated excessive torsional vibration leads to damage and excessive wear. This type of vibration, which is transferred from one structure to another can be estimated using torsional transmissibility factor (TTF). The value of the TTF describes the ratio of output to input and reaches its peak at the natural frequency. Hence, the ability to vary coupling stiffness of two rotating shafts will allow the control of the TTF towards better performance and preventions from fatigue loading. Traditionally, passive rubbers are used as a flexible coupling in between two shafts. However, the constant passive stiffness of the material limits its performance. To address this issue, an adaptive coupling based on magnetorheological elastomer (MRE) is proposed to achieve better TTF at varying frequencies. Mathematical modelling, simulation study and experimental results of MRE for torsional vibration isolation are presented in this work. Natural frequency obtained from the TTF shows an increase of about 3 Hz when current changed from 1 to 6 A.

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Test setup for examination of magneto-mechanical properties of magnetorheological elastomers with use of a novel approach

Bocian M., Kaleta J., Lewandowski D., Przybylski M.

Archives of Civil and Mechanical Engineering

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2016

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Vol. 16, no. 3

294--303

EN

This paper presents an experimental setup aiming at evaluating the magneto-mechanical and damping properties of the thermoplastic magnetorheological elastomer (MRE). The idea of the system is to create controllable conditions similar to those present in a vehicles and other mechanical constructions and to make it possible to determine parameters only relating to the MRE material itself. The test stand is based on four samples stimulated with highly effective Halbach arrays. The upper plate of the test stand is excited with use of a modal shaker to assure a constant impact force value during each test. This enables control of impact character and allows automation of the test stand. The last section of this paper presents preliminary test conducted to find the resonance frequency dependence on the impact force of the system for a constant value of magnetic field. The results indicate non-linear behavior of the material and therefore exclude use of the simple Kelvin-Voight model based approach for damping properties determination, that is a commonly used model for description of different materials.

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Assessment of the Suitability of MREs as a Material Used for Fabrication of Robot Grippers

Malujda I., Talaśka K., Kukla M.

Machine Dynamics Research

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2013

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Vol. 37, No. 1

77-84

EN

This article presents the results of tests carried out on one of magnetorheological elastomers based on silicone rubber matrix. The matrix was improved by addition of 10-20μm powdered Fe-Si alloy with 4wt% Si content. The matrix curing process did not involve external magnetic field. The specimens contained different amounts of ferromagnetic particles (by weight). The subject of research was to assess the suitability of magnetorheological elastomers (MRE) as material for fabricating industrial robot grippers. For this purpose a gripper-object model was built. It was used for comparing the Shore A hardness depending on the current in the coil generating the magnetic field.

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Design concept of test stand for determining properties of magnetorheological elastomers

Bocian M., Kaleta J., Lewandowski D., Przybylski M.

Acta Mechanica et Automatica

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2013

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Vol. 7, no. 3

131--134

EN

Magnetorheological elastomers (MRE) are “SMART” materials that change their mechanical properties under influence of magnetic field. Thanks to that ability it is possible to create adaptive vibration dampers based on the MRE. To test vibration damping abilities of this material special test stand is required. This article presents design concept for such test stand with several options of testing.