Simulation and Validation of an Anisotropic Magnetorheological Elastomers Mold with Various Alignment Angles

2018 ◽  
Vol 772 ◽  
pp. 66-70
Author(s):  
Ilham Bagus Wiranto ◽  
Ubaidillah ◽  
Dody Ariawan ◽  
Faishal Harish ◽  
Saiful Amri Mazlan ◽  
...  

In this study, anisotropic magnetorheological elastomers (MREs) mold design with capability of aligning the filler in several angles (0 ̊, 45 ̊, and 90 ̊) were developed. The mold was equipped with electromagnet coil to generate the magnetic flux. The distribution of magnetic flux density in the mold and inside the chamber was investigated by using finite element magnetic analysis. Magnetic flux density of 0.3 T was considered best value to form good particle alignment in the matrix. Moreover, the mold design was fabricated using same material as in the simulation. The magnetic flux density was taken at casing wall and measured by gauss-meter. The data was compared with simulation results. The differences between experimental and simulation is in the range of 6-40 mT. Since the difference is insignificant, it can be said that the data is valid. Finally, the model can be used for further magnetic flux density prediction inside the chamber. In the simulation, it was found that the current needed to generate at least 0.3 T inside the chamber for 0 ̊, 45 ̊, and 90 ̊ are 0.2A, 0.1A, and 3A, respectively.

Author(s):  
Nader Mohseni Ardehali ◽  
Masoud Hemmatian ◽  
Ramin Sedaghati

Hard magnetic particle–based magnetorheological elastomers are novel magnetoactive materials in which, unlike the soft particle–based magnetorheological elastomers, the particles provide magnetic poles inside the elastomeric medium. Therefore, the stiffness of the hard magnetic particle–based magnetorheological elastomers can be increased or decreased by applying the magnetic field in the same or opposite direction as the magnetic poles, respectively. In the present work, the viscoelastic properties of hard magnetic particle–based magnetorheological elastomers operating in shear mode have been experimentally characterized. For this purpose, hard magnetic particle–based magnetorheological elastomers with 15% volume fraction of NdFeB magnetic particles have been fabricated and then tested under oscillatory shear motion advanced rotational magneto-rheometer to investigate their viscoelastic behavior under varying excitation frequency and magnetic flux density. The influence of the shear strain amplitude and driving frequency is examined under various levels of applied magnetic field ranging from −0.2 to 1.0 T. Finally, a field-dependent phenomenological model has been proposed to predict the variation of storage and loss moduli of hard magnetic particle–based magnetorheological elastomers under varying excitation frequency and applied magnetic flux density. The results show that the proposed model can accurately predict the viscoelastic behavior of hard magnetic particle–based magnetorheological elastomers under various working conditions.


Author(s):  
Ashkan Dargahi ◽  
Ramin Sedaghati ◽  
Subhash Rakheja

Static and dynamic properties of six magnetorheological elastomers (MRE) with iron particles volume fraction ranging from 12.5% to 40% were experimentally characterized under shear mode operation. The experiments were designed on the basis of standardized methods defined in ISO-1827 and ISO-4664. The static shear stress-shear strain data obtained under strains up to 30% were used to quantify absolute and relative MR effects of the MREs as functions of magnetic flux density in the 0 to 450 mT range. The MRE specimen with highest iron particles fraction and a softening agent revealed greatest MR effect. The dynamic characteristics of this MRE specimen were then evaluated under harmonic excitations in the 0.1–50 Hz frequency range with shear strain amplitude and magnetic flux density ranging from 2.5 to 20%, and 0 to 450 mT, respectively. The data were then utilized to evaluate elastic and loss shear moduli of the specimen.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.


Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5304
Author(s):  
Ce Liang ◽  
Yanchi Zhang ◽  
Zhonggang Li ◽  
Feng Yuan ◽  
Guang Yang ◽  
...  

As an auxiliary function of the wireless power transfer (WPT) system, coil positioning can solve the power and efficiency degradation during power transmission caused by misalignment of the magnetic coupler. In this paper, a Hall sensor array is used to measure the change of magnetic flux density. By comparing the multisensor data fusion results with the preset data obtained from the coil alignment, the real-time accurate positioning of the receiving coil can be realized. Firstly, the positioning model of the receiving coil is built and the variation of magnetic flux density with the coil misalignment is analyzed. Secondly, the arrangement of the Planar 8-direction symmetric sensor array and the positioning algorithm based on data fusion of magnetic flux density variations are proposed. In order to avoid coil positioning misalignment caused by the unstable magnetic field distribution which is actually affected by the change of mutual inductance during automatic guided vehicle (AGV) alignment, the constant current strategy of primary and secondary sides is proposed. Finally, the coil positioning experimental platform is built. The experimental results show that the coil positioning method proposed in this paper has high accuracy, and the positioning error is within 4 cm.


Sign in / Sign up

Export Citation Format

Share Document