An energy based model [W. D. Armstrong, J. Appl. Phys. 81, 2321 (1997); J. Atulasimha, Ph.D. thesis, Aerospace Engineering, University of Maryland, College Park, MD, 2006] is employed to predict the actuation ((λ-H and B-H at various compressive stresses) and sensing behavior (B-σ and ε-σ at various bias fields) of single-crystal FeGa alloys. The significant feature of this formulation is that, in addition to modeling actuation behavior, the sensing behavior can be predicted based on parameters estimated from the actuator characteristics. These predictions are then validated against experimental data for furnace cooled 19 at. % [100] oriented single-crystal FeGa alloys. Furthermore, an attempt is made to couple the energy-based sensing model with a lumped-parameter model that simulates the magnetic interaction between the magnetostrictive specimen and the magnetic circuit comprising the transducer. This enables a prediction of the variation in field through the sample due to changes in reluctance of the magnetostrictive sample with stress, as well as the impact of this variation in field on the B-σ and ε-σ curves. These predictions are benchmarked against experimental data, wherein the bias field varies due to change in sample reluctance with application of compressive stress while the drive current to the transducer is maintained constant.
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