科研之友
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摘要
Magnetostrictive materials are distinguished by an inherent coupling between their mechanical and magnetic processes which is manifested as a direct (actuator) and an inverse (sensor) effect. The piezomagnetic equations for modeling these attributes can be derived from the thermodynamic potentials, with the usual assumptions regarding adiabatic conditions (negligible heat exchange) and isothermal conditions. The terms d and d* are often used to represent the actuator and sensor coupling coefficients that relate strain to field, and stress to magnetic induction respectively, with equivalence of these two terms for any given operating point imposed to satisfy energy conservation. In this paper, we present experimental results which suggest that the operating regimes in which differences in these terms have been observed also exhibit atypical trends in their closed-loop energy transduction cycles. The paper presents results from experimental studies in which closed-loop cyclic loading of Galfenol samples was conducted, with measurement of magnetostriction and magnetization as a function of magnetic field and compressive stress. The work done on/by the sample is calculated based on the measurements and the anomalous trends on work done on/by the samples will be discussed.
- 出版日期2011-7
- 单位东北大学
