Assessment of dynamic characteristics of thin cylindrical sandwich panels with magnetorheological core

Based on the equivalent single-layer linear theory for laminated shells, free and forced vibrations of thin cylindrical sandwich panels with magnetorheological core are studied. Five variants of available magnetorheological elastomers differing in their composition and physical properties are considered for smart viscoelastic core. Coupled differential equations in terms of displacements based on the generalized kinematic hypotheses of Timoshenko accounting for transverse shears with coefficients depending on the complex shear modulus for a smart core are used to govern vibrations of cylindrical panels. Assuming conditions of simple support for straight and curvilinear edges, solutions in the explicit form describing natural modes as well as an equation with respect to the required complex eigenfrequencies are found. To predict the shell response to an external harmonic force, the general solution of non-homogeneous governing equations is derived in the form of series in natural modes. To estimate damping capability of magnetorheological elastomers under consideration, the principle tunable parameters, the lowest natural frequencies and associated logarithmic decrements are calculated for the same panels with different magnetorheological elastomers under the action of a magnetic field of different intensities. Finally, the amplitude–frequency plots for magnetorheological elastomer-based panels of different opening angles with and without magnetic field are presented.

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DESIGN CONCEPT OF TEST STAND FOR DETERMINING PROPERTIES OF MAGNETORHEOLOGICAL ELASTOMERS

Acta Mechanica et Automatica ◽

10.2478/ama-2013-0022 ◽

2013 ◽

Vol 7 (3) ◽

pp. 131-134 ◽

Cited By ~ 2

Author(s):

Mirosław Bocian ◽

Jerzy Kaleta ◽

Daniel Lewandowski ◽

Michał Przybylski

Keyword(s):

Magnetic Field ◽

Mechanical Properties ◽

Smart Materials ◽

Vibration Damping ◽

Test Stand ◽

Design Concept ◽

Special Test ◽

Magnetorheological Elastomers ◽

Vibration Dampers

Abstract 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.

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Controllable field-free switching of perpendicular magnetization through bulk spin-orbit torque in symmetry-broken ferromagnetic films

Nature Communications ◽

10.1038/s41467-021-22819-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Xuejie Xie ◽

Xiaonan Zhao ◽

Yanan Dong ◽

Xianlin Qu ◽

Kun Zheng ◽

...

Keyword(s):

Magnetic Field ◽

Domain Walls ◽

Single Layer ◽

Ferromagnetic Film ◽

Effective Field ◽

Composition Gradient ◽

Spin Orbit ◽

Interlayer Exchange Coupling ◽

Magnetization Switching ◽

Perpendicular Magnetization

AbstractProgrammable magnetic field-free manipulation of perpendicular magnetization switching is essential for the development of ultralow-power spintronic devices. However, the magnetization in a centrosymmetric single-layer ferromagnetic film cannot be switched directly by passing an electrical current in itself. Here, we demonstrate a repeatable bulk spin-orbit torque (SOT) switching of the perpendicularly magnetized CoPt alloy single-layer films by introducing a composition gradient in the thickness direction to break the inversion symmetry. Experimental results reveal that the bulk SOT-induced effective field on the domain walls leads to the domain walls motion and magnetization switching. Moreover, magnetic field-free perpendicular magnetization switching caused by SOT and its switching polarity (clockwise or counterclockwise) can be reversibly controlled in the IrMn/Co/Ru/CoPt heterojunctions based on the exchange bias and interlayer exchange coupling. This unique composition gradient approach accompanied with electrically controllable SOT magnetization switching provides a promising strategy to access energy-efficient control of memory and logic devices.

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SIMULATION OF NONLINEAR MAGNETORHEOLOGICAL PARTICLE-FILLED ELASTOMERS

International Journal of Computational Materials Science and Engineering ◽

10.1142/s2047684113500188 ◽

2013 ◽

Vol 02 (03n04) ◽

pp. 1350018

Author(s):

SHULEI SUN ◽

XIONGQI PENG ◽

ZAOYANG GUO

Keyword(s):

Magnetic Field ◽

Shear Modulus ◽

Young’S Modulus ◽

Applied Magnetic Field ◽

Smart Materials ◽

Young's Modulus ◽

Particle Volume ◽

Magnetorheological Elastomers ◽

Maxwell Stress Tensor ◽

Element Simulation

Polymer matrix filled with ferromagnetic particles is a class of smart materials whose mechanical properties can be changed under different magnetic field. They are usually referred to as magnetorheological elastomers (MREs). A finite element simulation was presented to describe the mechanical behavior of MREs with the nonlinearity of the particle magnetization being incorporated. By introducing the Maxwell stress tensor, a representative volume element (RVE) was proposed to calculate the Young's modulus and shear modulus of MREs due to the applied magnetic field. The influences of the applied magnetic field and the particle volume fractions in the shear modulus and Young's modulus were studied. Results show that the shear modulus increases with the magnitude of the applied magnetic field, while the Young's modulus decreases.

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Buckling of sandwich panels with transversely flexible core: Correction of the equivalent single-layer model using thick-faces effect

Journal of Sandwich Structures & Materials ◽

10.1177/1099636218789604 ◽

2018 ◽

Vol 22 (5) ◽

pp. 1612-1634 ◽

Cited By ~ 6

Author(s):

J Jelovica ◽

J Romanoff

Keyword(s):

Finite Element ◽

Transverse Shear ◽

Sandwich Panels ◽

Shear Deformation Theory ◽

Single Layer ◽

Element Model ◽

Layer Model ◽

The Core ◽

Truss Core ◽

Single Layer Model

Modeling a periodic structure as a homogeneous continuum allows for an effective structural analysis. This approach represents a sandwich panel as a two-dimensional plate of equivalent stiffness. Known as the equivalent single-layer, the method is used here to analyze bifurcation buckling of three types of sandwich panels with unidirectional stiffeners in the core: truss-core, web-core and corrugated-core panels made of an isotropic material. The transverse shear stiffnesses of these panels can differ by several orders of magnitude, which cause incorrect buckling analysis when using the equivalent single-layer model with the first-order shear deformation theory. Analytical solution of the problem predicts critical buckling loads that feature infinite number of half-waves in the direction perpendicular to the stiffeners. Finite element model also predicts buckling modes that have non-physical, saw-tooth shape with infinite curvature at nodes. However, such unrealistic behavior is not observed when using detailed three-dimensional finite element models. The error in the prediction of the critical buckling load is up to 85% for the cases considered here. The correction of the equivalent single-layer model is proposed by modeling the thick-faces effect to ensure finite curvature. This is performed in the finite element setting by introducing an additional plate with tied deflections to the equivalent single-layer plate. The extra plate is represented with bending and transverse shear stiffness of the face plates. As a result, global buckling is predicted accurately. Guidelines are proposed to identify the sandwich panels where ordinary model is incorrect. Truss-core and web-core sandwich panels need the correction. Corrugated-core panels without a gap between plates in the core have smaller shear orthotropy and do not need the correction. Modeling the thick-faces effect ensures correct results for all cases considered in this study, and thus one should resort to this approach in case of uncertainty whether the ordinary equivalent single-layer model is valid.

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Elastic Properties of Magnetorheological Elastomers in a Heterogeneous Uniaxial Magnetic Field

International Journal of Molecular Sciences ◽

10.3390/ijms19103045 ◽

2018 ◽

Vol 19 (10) ◽

pp. 3045 ◽

Cited By ~ 6

Author(s):

Takehito Kikuchi ◽

Yusuke Kobayashi ◽

Mika Kawai ◽

Tetsu Mitsumata

Keyword(s):

Magnetic Field ◽

Elastic Properties ◽

Uniform Magnetic Field ◽

Large Strain ◽

Small Strain ◽

Experimental Results ◽

The Other ◽

Magnetorheological Elastomers ◽

Other Hand ◽

Strain Model

Magnetorheological elastomers (MREs) are stimulus-responsive soft materials that consist of polymeric matrices and magnetic particles. In this study, large-strain response of MREs with 5 vol % of carbonyl iron (CI) particles is experimentally characterized for two different conditions: (1) shear deformation in a uniform magnetic field; and (2), compression in a heterogeneous uniaxial magnetic field. For condition (1), dynamic viscoelastic measurements were performed using a rheometer with a rotor disc and an electric magnet that generated a uniform magnetic field on disc-like material samples. For condition (2), on the other hand, three permanent magnets with different surface flux densities were used to generate a heterogeneous uniaxial magnetic field under cylindrical material samples. The experimental results were mathematically modeled, and the relationship between them was investigated. We also used finite-element method (FEM) software to estimate the uniaxial distributions of the magnetic field in the analyzed MREs for condition (2), and developed mathematical models to describe these phenomena. By using these practicable techniques, we established a simple macroscale model of the elastic properties of MREs under simple compression. We estimated the elastic properties of MREs in the small-strain regime (neo–Hookean model) and in the large-strain regime (Mooney–Rivlin model). The small-strain model explains the experimental results for strains under 5%. On the other hand, the large-strain model explains the experimental results for strains above 10%.

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Orbital response of single-layer antimony to external magnetic field

Physical Review B ◽

10.1103/physrevb.102.155412 ◽

2020 ◽

Vol 102 (15) ◽

Author(s):

G. V. Pushkarev ◽

I. A. Iakovlev ◽

D. A. Prishchenko ◽

E. A. Stepanov ◽

V. V. Mazurenko ◽

...

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Single Layer

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Effects of punch size, magnetic field, and magnetorheological elastomers medium on forming T-shaped thin-walled Inconel 718 tubes

Chinese Journal of Aeronautics ◽

10.1016/j.cja.2020.09.032 ◽

2020 ◽

Author(s):

Qiucheng YANG ◽

Cheng CHENG ◽

Ali Abd EL-ATY ◽

Chunmei LIU ◽

Shenghan HU ◽

...

Keyword(s):

Magnetic Field ◽

Inconel 718 ◽

Magnetorheological Elastomers ◽

Thin Walled

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Magnetorheological Hybrid Elastomers Based on Silicone Rubber and Magnetorheological Suspensions with Graphene Nanoparticles: Effects of the Magnetic Field on the Relative Dielectric Permittivity and Electric Conductivity

International Journal of Molecular Sciences ◽

10.3390/ijms20174201 ◽

2019 ◽

Vol 20 (17) ◽

pp. 4201 ◽

Cited By ~ 4

Author(s):

Bica ◽

Bunoiu

Keyword(s):

Magnetic Field ◽

Dielectric Permittivity ◽

Silicone Rubber ◽

Silicone Oil ◽

Relative Dielectric Permittivity ◽

Magnetorheological Elastomers ◽

Magnetorheological Suspensions ◽

Alternating Electric Field ◽

Graphene Nanoparticles ◽

The Magnetic Field

Hybrid magnetorheological elastomers (hMREs) were manufactured based on silicone rubber, silicone oil, carbonyl iron microparticles, graphene nanoparticles and cotton fabric. Using the hMREs, flat capacitors (FCs) were made. Using the installation described in this paper, the electrical capacitance and the coefficient of dielectric losses of the hMREs were measured as a function of the intensity of the magnetic field superimposed over an alternating electric field. From the data obtained, the electrical conductivity, the relative dielectric permittivity and magnetodielectric effects are determined. It is observed that the obtained quantities are significantly influenced by the intensity of the magnetic field and the amount of graphene used.

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