Magnetostriction and Inverse Magnetostriction

Magnetostriction is a property of ferromagnetic materials that causes their deformation during the process of magnetization. The structure of such materials is divided into domains, each of which is a region of uniform magnetic polarization. When a magnetic field is applied, the domains rotate causing a change in the material's dimensions. This change in the material's dimensions is due to the anisotropic crystalline structure of the material – it takes more energy to magnetize a crystalline material in one direction than another. For example, the steel used for the thin laminations in transformers is manufactured by passing it through a series of rollers to achieve the desired thickness. Consequently its crystalline structure – and associated magnetic domains – differs along the direction in which it was rolled (the rolling direction) versus the transverse direction.

Magnetostriction – and Inverse Magnetostriction – can be regarded as an energy transduction (or transformation) from magnetic to mechanical and vice-versa. It can also be described as a bidirectional magneto-mechanical coupling between the mechanical and magnetic fields in the magnetostrictive material. It is magnetostriction that causes the low-pitched humming sound that can be heard coming from transformers – caused by the changing magnetic field produced by oscillating AC currents. For detailed information on these properties, refer to Magnetostriction Modeling of Magnetic Materials in the technical notes section.

• Magnetostriction/inverse magnetostriction properties can be applied to Maxwell 2D/3D magnetostatic and transient solutions through customizable Magnetostriction and Inverse Magnetostriction material properties.
• Maxwell Desktop supplies the magnetostriction and inverse magnetostriction material properties to the Maxwell solver. The solver then calculates force density with magnetostriction force components included.
• For Maxwell magnetostatic solutions, if any material used has the Inverse Magnetostriction property defined, Maxwell Desktop saves the initial H field, which is generated by the solver without exterior stress/strain applied, in the project results.
• Magnetostriction and inverse magnetostriction are applicable to Maxwell 2D/3D Magnetostatic design one-way and two-way coupling with Ansys Mechanical system.