Energy Absorption/Dissipation Performances of Magnetic-Sensitive Rubber (MSR) With Hollow Iron Balls

2015 ◽  
Author(s):  
Shengqiang Zhang ◽  
Lingyu Sun ◽  
Dingxin Leng ◽  
Bincheng Huang ◽  
Jun Xu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Energy Absorption ◽  
Strain Energy ◽  
Effective Strain ◽  
Stress Concentrations ◽  
Buffer Material ◽  
The Matrix ◽  
Thin Walled ◽  
Applied External Magnetic Field

A kind of novel smart buffer material, magnetic-sensitive rubber (MSR) with embedded thin-walled iron balls, is provided, and the energy absorption and energy dissipation properties are investigated numerically. Two kinds of representative volume elements (RVEs) of MSR specimens with solid or hollow iron balls are studied, respectively. Under uniaxial compression alone or combined with magnetic field, the relation between effective stress and effective strain and that between strain energy desity and total compression deformation for these two specimens are established, respectively. With the increase of strain, it is demonstrated numerically that the MSRs with hollow iron balls have better energy absorption/dissipation capability than previous MSRs with solid balls. And the applied external magnetic-field increases this capability more. Under compression, the stress concentrations in elastomer matrix around the hollow balls decrease, that could increase the ultimate compression loads before the matrix failures. This is beneficial for us to design lightweight and efficient buffers according to different application cases.

scholarly journals Correlation of composition, aspect ratio and magnetic resistance of multilayer micro- and nanowires of the “ferromagnetic / diamagnetic” type

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 5-13
Author(s):  
V. M. Fedosyuk
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Aspect Ratio ◽  
Aluminum Oxide ◽  
Giant Magnetoresistance ◽  
Pore Diameter ◽  
Ferromagnetic Layer ◽  
Type I ◽  
Magnetic Layers ◽  
The Matrix

 The results of study of the giant magnetoresistance coefficient (GMR) in multilayer micro- and nanowires based on successively alternating ferromagnetic (Co, CoNi and NiFe) and diamagnetic (Cu) layers are presented in the paper. The samples were obtained by electrochemical deposition into the matrix pores. Aluminum oxide was used as matrices. To establish the influence of the aspect ratio, matrices of two types were used: with a pore diameter of 8 µm and 170–200 nm and a variable thickness from 10 to 60 µm. Investigations of the GMR coefficient were carried out by measuring the current-voltage characteristics in external magnetic fields up to 130 mT. When using type I matrices (pore diameter 8 μm), a positive GMR coefficient (an increase in electrical resistivity in an external magnetic field) was noted, while when using type II matrices (pore diameter 170–200 nm), a negative GMR coefficient was established (a decrease in electrical resistance in an external magnetic field). This is due to the enhancement of the interactions of spin-polarized electrons in the magnetic layers through the copper layer through the RKKY exchange with an increase in the aspect ratio. A significant effect of the composition of the ferromagnetic layer (Co, CoNi, and NiFe) on the value  of the GMR coefficient is noted. The maximum value of the negative GMR coefficient (up to –27.5 %) was established for the CoNi-based nanowire system. The use of multilayer micro- and nanowires, electrolytically deposited in a matrix of aluminum oxide with the ability to control the GMR coefficients, opens up perspective use of these objects as sensitive elements (sensors) of a constant magnetic field, as well as devices for storing magnetic information with a vertical principle. 

Analysis of Fluid Film Lubrication of an MHD Journal Bearing Subjected to an Axially Applied External Magnetic Field

2013 ◽  
Vol 437 ◽  
pp. 136-139 ◽  
Author(s):  
Chin Lung Chang ◽  
Yu Min Li ◽  
Hsing Hui Huang ◽  
Jik Chang Leong
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Journal Bearing ◽  
Axial Direction ◽  
Eccentricity Ratio ◽  
Steady State Flow ◽  
Bearing Current ◽  
Applied External Magnetic Field ◽  
Film Lubrication ◽  
Fluid Film Lubrication

This work simulates the steady-state flow field in a magnetohydrodynamic journal bearing. A uniform magnetic field is applied in the axial direction across the bearing. Current results indicate that a crescent-shape secondary flow will develop at E = 0.8. The velocity profiles at the location of the minimum and maximum film thickness are almost independent of the strength of the external magnetic field unless the eccentricity ratio is relatively small and magnetic field is strong. There exists an eccentric dependent threshold Ha beyond which the shear stress on the journal increases with Ha while that on the bearing decreases.

Filamentation instability of a laser beam in an inhomogeneous plasma in an arbitrarily oriented external magnetic field

2013 ◽  
Vol 79 (5) ◽  
pp. 921-926
Author(s):  
A. HASANBEIGI ◽  
A. MOUSAVI ◽  
H. MEHDIAN
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
External Magnetic Field ◽  
Laser Beam ◽  
Short Pulse ◽  
Inhomogeneous Plasma ◽  
Plasma Inhomogeneity ◽  
Short Pulse Laser ◽  
Filamentation Instability ◽  
Applied External Magnetic Field

AbstractThe interaction of a short pulse laser beam with an inhomogeneous plasma has been studied in the presence of an obliquely applied external magnetic field. The dispersion relation and the analytical growth rate have been obtained solving the nonlinear wave equation. It is found that the growth rate and the cut-off wavenumber are strongly influenced by the direction and magnitude of the applied magnetic field. Moreover, the growth rate has been modified by plasma inhomogeneity.

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