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 Magnetorheological Elastomer-Based Variable Stiffness Flexible Coupling for Vibration Isolation.

2021 ◽  
Author(s):  
Thaer Mahmoud Syam ◽  
Ahmed Hegazi ◽  
Asan Muthalif ◽  
Yousif Badri
Keyword(s):  
Magnetic Field ◽  
Torsional Vibration ◽  
Vibration Isolation ◽  
Volume Fraction ◽  
Torsional Rigidity ◽  
Magnetic Field Effect ◽  
Variable Stiffness ◽  
Torsional Stiffness ◽  
Smart Composite Materials ◽  
The Magnetic Field

Magnetorheological elastomers (MRE) are smart composite materials by which their mechanical properties, such as stiffness, are changed under a magnetic field. In this article, the introduction of a variable stiffness coupling (VSC) fitted within a shaft for torsional vibration isolation that would adapt and change its attenuation frequency range is presented. The VSC concept on torsional vibration isolation is tested experimentally. MRE samples with 40% volume fraction are fabricated and manufactured using a 3D mold design and fixed within a coupling in a shaft to investigate the magnetic field effect on the torsional rigidity. Impact hammer test is conducted along with an accelerometer to obtain the transmissibility factor analysis. Results show that the vibration level decreases when the magnetic field increases. The 1st natural frequency of the system happened at 26 Hz and moved to 28 Hz when the applied current increases from 0 mT to 12.38 mT. MRE torsional stiffness increased from 37.4 N.m/rad to 61.6 N.m/rad when the current increased from 0 mT to 12.38 mT. The torsional damping coefficient showed a fluctuation in its variation as the damping effect of MR elastomer is ignored

Torsional vibration analysis of a rotating tapered sandwich beam with magnetorheological elastomer core

2018 ◽  
Vol 29 (11) ◽  
pp. 2406-2423 ◽  
Author(s):  
Saeed Bornassi ◽  
Hossein M Navazi
Keyword(s):  
Magnetic Field ◽  
Layer Thickness ◽  
Torsional Vibration ◽  
Vibration Analysis ◽  
Sandwich Beam ◽  
Vibration Characteristics ◽  
Magnetorheological Elastomer ◽  
Lagrange Equations ◽  
Rotating Speed ◽  
Setting Angle

In this study, the torsional vibration analysis of a rotating tapered sandwich beam with a magnetorheological elastomer core has been investigated. The magnetorheological elastomer material is used as a constrained damping layer embedded between two elastic constraining skins in order to improve the vibrational behavior of the sandwich beam. The three layers of the sandwich beam have rectangular cross-sections with symmetric arrangement. The problem formulation is set up based on the torsional theory of rectangular laminated plates. The assumed modes method and the Lagrange equations are used to derive the governing equations of motion of the system. The validity of the presented formulation is confirmed through comparison of the obtained results with those available in the literature. A detailed parametric study is carried out to investigate the effects of applied magnetic field, tapering ratios, magnetorheological elastomer layer thickness, rotating speed, hub radius, and setting angle on the free vibration characteristics of the sandwich beam. The results show that magnetic field intensity, magnetorheological elastomer layer thickness, and tapering ratio have significant influences on the torsional vibrating characteristics of the sandwich beam, and the effects of rotating speed and hub radius are considerable. The setting angle has no substantial effect on the torsional vibration characteristics.

Design and application of an improved vulcanization apparatus for magnetorheological elastomer

2020 ◽  
Vol 31 (14) ◽  
pp. 1676-1688
Author(s):  
Lili Fan ◽  
Guoping Wang ◽  
Fufeng Yang ◽  
Min Jiang ◽  
Xiaoli Dong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Dissipation ◽  
Circuit Simulation ◽  
Experimental Tests ◽  
Control Device ◽  
Control Area ◽  
Magnetorheological Elastomer ◽  
Consistency Test ◽  
Promising Application ◽  
Magnetic Field Generator

Magnetorheological elastomer is a new intelligent material, which shows a promising application prospect in the intelligent control area. In the molding of magnetorheological elastomer, vulcanization under magnetic field condition is the critical step. However, the traditionally used vulcanization apparatus cannot be applied in the preparation of magnetorheological elastomer directly for the unavailable magnetic field, uneven pressure, and serious heat dissipation. An improved vulcanization apparatus with magnetic field generator, support device, and temperature control device was designed. To ensure the rationality of the designs, magnetic circuit simulation, thermal simulation, and stiffness consistency test were conducted. Experimental tests showed that the vulcanization apparatus we designed applied well in the preparation of magnetorheological elastomers and magnetorheological elastomer isolator.

scholarly journals A new magnetorheological elastomer torsional vibration absorber: structural design and performance test

2021 ◽  
Vol 12 (1) ◽  
pp. 321-332
Author(s):  
Pu Gao ◽  
Hui Liu ◽  
Changle Xiang ◽  
Pengfei Yan ◽  
Taha Mahmoud
Keyword(s):  
Magnetic Field ◽  
Torsional Vibration ◽  
Performance Test ◽  
Magnetic Circuit ◽  
Circuit Simulation ◽  
Variable Stiffness ◽  
Vibration Absorber ◽  
Vibration Exciter ◽  
Magnetorheological Elastomer ◽  
The Magnetic Field

Abstract. The semi-active torsional vibration absorber can effectively reduce the torsional vibration of the power-train system. In this paper, a new type of variable stiffness torsional vibration absorber with a magnetorheological elastomer (MRE) as an intelligent controlling element is designed, and the modal analysis, frequency-tracking scheme, and damping effects have been studied. A transient dynamic simulation is utilized to validate the rationality of the mechanical structure, the magnetic field parameters of the absorber are matched, and the magnetic circuit simulation analysis and the magnetic field supply analysis are carried out to verify the closed magnetic circuit. The principle prototype of the innovative vibration absorber is manufactured, the magnetic field strength of the absorber is tested by a Gauss meter, and the results show the efficacy of magnetizing the vibration absorber with a conductive slip ring by solving the magnetizing problem of the rotating parts of the vibration absorber. A special-purpose test rig with a torsional vibration exciter as a power source has been implemented. A comparative experiment has been carried out to test the frequency shift characteristics and authenticate the vibration-reduction effect of the new MRE torsional vibration absorber.

Magnetorheological Elastomer based torsional vibration isolator for application in a prototype drilling shaft

2021 ◽  
pp. 146134842110446
Author(s):  
Thaer M. I. Syam ◽  
Asan G. A. Muthalif
Keyword(s):  
Magnetic Field ◽  
Torsional Vibration ◽  
Smart Materials ◽  
Magnetic Particles ◽  
Vibration Isolation ◽  
Drill String ◽  
Vibration Isolator ◽  
Magnetorheological Elastomer ◽  
Rotational Vibration ◽  
Active Vibration

Smart materials properties are altered using external stimuli such as temperature, pressure and magnetic field. Magnetorheological Elastomer (MRE) is a type of smart composite material consisting of a polymer matrix embedded with ferromagnetic particles. In the presence of an external magnetic field, its mechanical properties, such as stiffness, change due to the interaction between the magnetic particles, which have applications in vibration isolation. Unwanted vibration in machines can cause severe damage and machine breakdown. In this work, a semi-active vibration isolator using MRE is proposed for a potential application in a drilling system to isolate the torsional vibration. The MRE was fabricated with a 35% mass fraction (MF) consisted of silicon rubber and iron particles. It was fitted with aluminium couplers and attached to the shaft (drill string) to study its efficiency in vibration isolation under a magnetic field. Two tests were conducted on the drilling prototype setup used in this work; the first test was a hammer impact test. The torsional transfer function TTF analysis showed that the system’s natural frequency has shifted from 13.9 Hz to 17.5 Hz by the influence of increasing magnetic field around the MRE. The results showed that the continuous rotational vibration amplitude of the prototype is attenuated by more than 40%.

scholarly journals Online Identification and Verification of the Elastic Coupling Torsional Stiffness

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Wanyou Li ◽  
Zhuoye Chai ◽  
Mengqi Wang ◽  
Xinhuan Hu ◽  
Yibin Guo
Keyword(s):  
Torsional Vibration ◽  
Dynamic Stiffness ◽  
Working Environment ◽  
Torsional Stiffness ◽  
Normal Operation ◽  
Calculation Error ◽  
Dynamic Feature ◽  
Elastic Coupling ◽  
Time Operation ◽  
Improper Use

To analyze the torsional vibration of a diesel engine shaft, the torsional stiffness of the flexible coupling is a key kinetic parameter. Since the material properties of the elastic element of the coupling might change after a long-time operation due to the severe working environment or improper use and the variation of such properties will change dynamic feature of the coupling, it will cause a relative large calculation error of torsional vibration to the shaft system. Moreover, the torsional stiffness of the elastic coupling is difficult to be determined, and it is inappropriate to measure this parameter by disassembling the power unit while it is under normal operation. To solve these problems, this paper comes up with a method which combines the torsional vibration test with the calculation of the diesel shafting and uses the inherent characteristics of shaft torsional vibration to identify the dynamic stiffness of the elastic coupling without disassembling the unit. Analysis results show that it is reasonable and feasible to identify the elastic coupling dynamic torsional stiffness with this method and the identified stiffness is accurate. Besides, this method provides a convenient and practical approach to examine the dynamic behavior of the long running elastic coupling.

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.

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