東北大学 · 材料科学
ベンジャミン・デュシャルン教授の研究室は、フェロエレクトリック素子やフェロ磁性材料の非線形な電磁機械的挙動を、物理的現象に即した定式化に基づいてモデル化することを柱としています。特に、誘電ヒステリシスや磁気ヒステリシの周波数依存性、局所的損失分布の高精度な予測に注力しており、分類性能の向上と非破壊評価技術の開発を目的としています。近年では、波力からのエネルギー回収に応用可能なピエゾエレクトリック素子の最適化や、可視光応答型フェロエレクトリックのモデル化にも進んでいます。
Figures are computed from collected data and may differ slightly.
The properties of ferroelectric ceramics strongly depend on the electromechanical loading and their measurement conditions. In this paper, a nonlinear phenomenological one-dimensional model based on the dry friction concept is presented to describe the hysteretic polarization behaviour. Dielectric permittivities versus dc electric field (or capacitance C versus voltage V) loops are determined for the characterization of ferroelectric material. The ε33 coefficient is used for the ceramic characte
We propose an approach to solve the coupled problem of the magnetic field penetration into soft ferromagnets and a frequency dependent magnetic hysteresis. The magnetic field diffusion is related to the macroscopic eddy currents. The hysteresis model is related to the microscopic eddy currents derived from the magnetic domain wall movements, and is responsible for the frequency dependence of hysteresis loops. In this paper, based on a lumped model and fractional derivative operators, we demonstr
We propose an original approach to solve the coupled problem of alternative magnetic field penetration inside a toroidal soft ferromagnetic sample and frequency dependent magnetic hysteresis. Local repartition of ferromagnetic losses depends on the instantaneous material properties and on the frequency of the excitation field waveform. A correct solution to the model, with respect to this repartition, implies a higher resolution in two dimensions of the diffusion equation including local dynamic
Recycling ambient energies with electric generators instead of employing batteries with limited lifespans has motivated a large scientist community over two decades. Sea waves exhibit a large energy density. The amount of energy that could be extracted from the sea waves is very high. This work describes a technique of sea wave energy extraction based on a piezoelectric conversion and an analogy with thermodynamic Ericsson loops. By synchronizing external electric field to the maximum and the mi
Post-treatment and rescaling is made possible to plot local hysteresis cycles from the measurement of local magnetic Barkhausen noise (BN). If the material is homogeneous and if similar excitation conditions are imposed, the local hysteresis cycles obtained are comparable to the classical magnetic hysteresis cycles B(H) (the cross section magnetic average induction B as a function of the surface tangential excitation field H ). These local BN hysteresis cycles provide interesting clues about the
Open papers in the app to read, cite, and organize with AI.
