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Dynamic Magnetostriction Characteristics of an Fe-Based Nanocrystalline FeCuNbSiB Alloy
Lei Chen,Ping Li,Yumei Wen 한국자기학회 2011 Journal of Magnetics Vol.16 No.3
The dynamic magnetostriction characteristics of an Fe-based nanocrystalline FeCuNbSiB alloy are investigated as a function of the dc bias magnetic field. The experimental results show that the piezomagnetic coefficient of FeCuNbSiB is about 2.1 times higher than that of Terfenol-D at the low dc magnetic bias Hdc = 46 Oe. Moreover, FeCuNbSiB has a large resonant dynamic strain coefficient at quite low Hdc due to a high mechanical quality factor, which is 3-5 times greater than that of Terfenol-D at the same low Hdc. Based on such magnetostriction characteristics, we fabricate a new type of transducer with FeCuNbSiB/PZT-8/FeCuNbSiB. Its maximum resonant magnetoelectric voltage coefficient achieves ~10 V/Oe. The ME output power reaches 331.8 ㎼ at an optimum load resistance of 7 ㏀ under 0.4 Oe ac magnetic field, which is 50 times higher than that of the previous ultrasonic-horn-substrate composite transducer and it decreases the size by nearly 86%. The performance indicate that the FeCuNbSiB/PZT-8/FeCuNbSiB transducer is promising for application in highly efficient magnetoelectric energy conversion.
Lei Chen,Yulin Luo 한국자기학회 2015 Journal of Magnetics Vol.20 No.4
The magnetoelectric (ME) characteristics for Terfenol-D/PZT laminate composite dependence on bias magnetic field is investigated. At low frequency, ME response is determined by the piezomagnetic coefficient d33,m and the elastic compliance S<SUP>H</SUP>33 of magnetostrictive material, d33,m and S<SUP>H</SUP>33 for Terfenol-D are inherently nonlinear and dependent on Hdc, leading to the influence of Hdc on low-frequency ME voltage coefficient. At resonance, the mechanical quality factor Qm dependences on Hdc results in the differences between the low-frequency and resonant ME voltage coefficient with Hdc. In terms of ΔE effect, the resonant frequency shift is derived with respect to the bias magnetic field. Considering the nonlinear effect of magnetostrictive material and Qm dependence on Hdc, it predicts the low-frequency and resonant ME voltage coefficients as a function of the dc bias magnetic field. A good agreement between the theoretical results and experimental data is obtained and it is found that ME characteristics dependence on Hdc are mainly influenced by the nonlinear effect of magnetostrictive material.
Topology Optimization of the Plate under Bending Moment by Using P1-nonconforming Element
Lei Chen(첸레이),Gang-Won Jang(장강원),Tae Hyun Baek(백태현) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5
When the Mindlin model is applied to analyze the thin plate under bending moment, the displacement of plate is much lower than the exact value. This phenomenon is caused by shear locking of model. Here, a new nonconforming quadrilateral element P1, which is one kind of discontinuous element and owns the Poisson locking-free property, was applied to Mindlin plate. The results prove that reduced P1- nonconforming element can solve shear locking problem. Topology optimal design of plate under bending moment was based on P1 nonconforming element, whose purpose was to obtain the minimum compliance for a given mass of plate. Topology optimal shape of the plate is verified by some typical bending plate model. This paper presents a new method to solve shear locking problem of Mindlin plate and it can be used to solve other domains.
Topology Optimization of Multilayer Plate Structures by Using P1- Nonconforming Element
Lei Chen(첸레이),Gang-Won Jang(장강원),Tae Hyun Baek(백태현) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Based on finite element method, topology optimization is applied to design optimal shape of a given design space. In this study, the multilayer plate structures are analyzed and extended to topology optimization design. In order to solving shear locking problem of thin plate caused by Mindlin-Reissner plate model, P1-nonconforming element and selective reduced integration are employed. P1 quadrilateral element is one kind of discontinuous and Poisson’ locking-free element. Furthermore, P1-nonconforming element has linear shape functions that are defined at middle point of each edge. Here, Darcy-Stokes fluid model and reinforcement plate model are applied on different layers. By calculating sensitivity analysis of multiobjective function, the minimum compliance and dissipated power of the model with given mass is obtained by method of moving asymptotes (MMA). Some numerical examples of multilayer plate structure are studied and compared with the reference results.
Dynamic Magneto-mechanical Behavior of Magnetization-graded Ferromagnetic Materials
Lei Chen,Yao Wang 한국자기학회 2014 Journal of Magnetics Vol.19 No.3
This study investigates the dynamic magneto-mechanical behavior of magnetization-graded ferromagnetic materials Terfenol-D/FeCuNbSiB (MF). We measure the dynamic magneto-mechanical properties as a function of the DC bias magnetic field (Hdc). Our experimental results show that these dynamic magneto-mechanical properties are strongly dependent on the DC bias magnetic field. Furthermore, the dynamic strain coefficient, electromechanical resonance frequency, Young’s moduli, and mechanical quality factor of Terfenol-D/FeCuNbSiB are greater than those of Terfenol-D under a lower DC bias magnetic field. The dynamic strain coefficient increases by a factor of between one and three, under the same DC bias magnetic field. In particular, the dynamic strain coefficient of Terfenol-D/FeCuNbSiB at zero bias achieves 48.6 nm/A, which is about 3.05 times larger than that of Terfenol-D. These good performances indicate that magnetization-graded ferromagnetic materials show promise for application in magnetic sensors.