Multiphysics modeling of laminated Galfenol transduction devices.

Galfenol is an attractive giant magnetostrictive material for transducer design because of its competitive strain capabilities, mechanical robustness, and high magnetic permeability. The latter two properties are particularly interesting as they allow exploration of a design space inaccessible to other active materials, both giant magnetostrictive and piezoelectric. Especially noteworthy is the ability to roll Galfenol into thin sheets from which laminated assemblies may be economically produced. Lamination is an effective mitigation scheme against eddy current losses and in this paper the authors explore transducers based on this construction. Much of this work builds on the designs of World War II era magnetostrictive transducers developed at the Harvard Underwater Sound Laboratory. Modeling these transducers as electro‐magneto‐mechano‐acoustical devices can be first achieved in a limited sense with a one‐dimensional model; this model is valuable for rapid simulation during the early design process. Many of the physical phenomena present in the transducer, however, are inherently beyond the limitations of the one‐dimensional model. For this reason, the authors have turned to a multiphysics approach for a comprehensive transducer simulation. In this modeling environment, the coupled differential equations describing the transduction are implemented in a three‐dimensional finite element analysis.