Papers by Keyword: Magnetostriction

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Authors: Ming Li
Abstract: A more exact general analytical formula of preditcting the magnetostrictive coefficient is derived for any aspect ratio based the deflection difference between the x and y directions. The curvatures are found by minimizing the total energy of the system, which taking into account shear strain energy. The in-plane stress distribution including shear stress for short specimen is also given by the ANSYS® finite element package to illustrate the role of shear strain in the deformation of magnetostrictive film-substrate system.
Authors: Ming Li, Hui Ming Zheng
Abstract: Recently, the inconsistencies are pointed out by previous authors for the problem of finding the strains, stresses and energy densities observed in isotropic elastic magnetostrictive materials that are in the form of thin films deposited on non-magnetic substrates. We discuss the reason of such inconsistencies that the total normal stresses should be the sum of the stresses caused by the external mechanical force and magnetic field. We show that such a situation can be realized in many of the current models used to make predictions for magnetostrictive structures and the inconsistencies can be explained.
Authors: Cheng Bao Jiang, Li Hong Xu, Tian Li Zhang, Tian Yu Ma
Abstract: Co and Si were selected as substitutes to improve performance of TbDyFe giant magnetostrictive alloys for special purpose, respectively. The results showed that the Co-doped Tb0.36Dy0.64Fe2 alloys can possess giant magnetostriction over a wide temperature range from -80 to 100 . Optimum magnetostriction, high electrical resistivity and improved corrosion resistance was obtained in Tb0.3Dy0.7(Fe1-xSix)1.95 system. High performance grain-aligned rods with <110> preferred orientation have been successfully prepared by zone melting unidirectional solidification. This paper also presents the design and fabrication of Giant Magnetostrictive Actuator (GMA) for active vibration control with oriented TbDyFe rods. Experimental results showed that the GMA possesses good static and dynamic performance. Excellent damping effect, 20-30 dB under the frequency range from 10 Hz to 120 Hz was obtained.
Authors: I. Bica, Maria Balasoiu, A.I. Kuklin
Abstract: Results on anisotropic magnetorheological elastomers magnetoelasticity are presented and discussed. In the dipole approximation, and considering the MRE as a continuous linear body, the effects of magnetic field on its main elastic properties (linear deformations and Young module) are investigated. Experimental evidences that the compression of the cylindrical bar is influenced by the intensity of the longitudinal magnetic field and the Young module of the MRE sample increases with the intensity H of the longitudinal magnetic field are obtained and the results discussed.
Authors: Masaki Fujita, Takehito Ikeuchi, Akihiro Koyama, Muneyuki Imafuku, Shun Fujieda, Shigeru Suzuki
Abstract: Fe-Ga alloys are used for practical magnetostrictive materials. The understanding of mechanical properties under magnetic field is very important for their application to vibration power generation devices. Especially, Poisson’s ratio is one of key parameters because it is strongly related with the volume change of materials. In the study, we investigated actual behavior of Poisson’s ratio due to magnetostriction, instead of just the mechanical one. The sample was cube-oriented Fe-18mol%Ga single crystal disc. Static magnetic fields were applied in various directions parallel to (001). Strain values in various directions were measured by strain gauge and X-ray diffraction. And then, tri-axial strain analysis for single crystal was carried out. Theoretically, Poisson’s ratio due to magnetostriction is known to be 0.5, (volume conservative), value is close to the mechanical one, 0.45. On the other hand, we found that Poisson’s ratio exhibits anisotropic behavior despite the elastic constants are equivalent in [010] and [001]. This phenomenon is attributable to the magnetic domain structure under zero magnetic field. In this presentation, we will discuss this apparent Poisson’s ratio considering the volume strain and magnetostriction comprehensively.
Authors: Zhang Meng, Yan Wen, Li Tao, Jiang Wei, Wang Shuai
Abstract: Introducing the principle, which the magnetostrictive displacement sensor is based on, and the gauging to small shifting is given in this paper. These sensor possess the peculiarities of high precision, long-life and easy to assemble. The gauging to small shifting belongs to the major characteristics test to artillery. On account of the faultiness existing testing means, this method is submitted to the characteristics test of artillery. Which magnetostrictive displacement sensor is applied to the shifting measure. By means of tests, the conclusion could be given that this method is easy to operate, automatic, high testing precision and widely used.
Authors: E.V. Harin, E.N. Sheftel’, A.I. Krikunov
Abstract: A method for direct measuring the magnetostriction of ferromagnetic films (deposited on nonmagnetic substrates) in using an atomic force microscope was suggested. In measuring the magnetostriction for films 10 [mm] in length and 0,2 [μm] in thickness, which were deposited on substrates 200 [μm] thick, the minimum measured magnetostriction magnitude is ~10-7. The procedure was tested for Ni and Fe films. The magnetostriction magnitudes measured for the films are comparable with those obtained by other magnetostriction-measuring methods. The effect of alloying with zirconium and nitrogen on the magnetostriction of nanocrystalline Fe films was studied.
Authors: K.S. Ryu, J.S. Park, Cheol Gi Kim, Youn Ho Cho, Derac Son
Authors: Yusuke Onuki, Ryuji Ukai, Shigeo Sato, Shun Fujieda, Kozo Shinoda, Kentaro Kajiwara, Masugu Sato, Shigeru Suzuki
Abstract: Fe-Ga alloys show large magnetostriction, which strongly depends on crystal orientation. This phenomenon is associated to some degree with large elastic anisotropy. In this study, white X-ray diffraction with micro-beam synchrotron radiation was used to evaluate the microscopic stresses evolved in a polycrystalline Fe-Ga alloy under tensile loading. In the analysis, the large elastic anisotropy of the Fe-Ga alloy was focused. The stress distribution in the alloy microstructure under tensile loading was estimated using a finite element method (FEM) simulation that considered the dependence of the elasticity on the crystal orientation. The crystal orientation of grains in the polycrystalline Fe-Ga alloy was measured using electron backscatter diffraction. The FEM simulation showed that the stress distribution in the microstructure depended on the crystal orientation. The X-ray diffraction stress analysis indicated that under tensile loading, the stresses in the alloy depended on the crystal orientation. This finding is similar to the results obtained from the FEM simulation, although the absolute values of the stresses may have reflected the effects of heterogeneous deformation on the stress distribution.
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