Modeling Magnetostrictive Materials
Magnetostriction Coupling
Magnetostriction is an interaction between the mechanical and magnetic physics, where a magnetic field applied on magnetostrictive material generates the deformation of the material (direct effect or Joule effect), while a mechanical stress applied on it changes the material magnetization (inverse effect or Villari effect).
The magnetostrictive strain has a nonlinear dependence on the magnetic field and the mechanical stress in the material. However, the effect can be modeled using linear coupled constitutive equations if the response of the material consists of small deviations around an operating point (bias point). This type of coupling is reffed to as Piezomagnetic Effect.
In COMSOL Multiphysics, there are two multiphysics interfaces for modeling either linear or nonlinear magnetostriction, respectively:
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The Piezomagnetism Interface
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The Nonlinear Magnetostriction Interface
Both multiphysics interfaces, the Magnetostriction interfaces are constituted of one Solid Mechanics and one Magnetic Fields interface, which are coupled together via either Piezomagnetic Effect or Nonlinear Magnetostriction multiphysics coupling feature. Hence a magnetostriction problem contains solid and magnetic domains, with at least one domain shared by the two physics interfaces and with the magnetostriction coupling defined on it.