Magnetostrictive Material

The node defines the magnetostrictive material properties.

In case of linear magnetostriction model, the material data can be entered either in the strain-magnetization form using the elasticity matrix and the coupling matrix, or in stress-magnetization form using the compliance matrix and the coupling matrix. It is normally used as part of Magnetostriction multiphysics interface together with a multiphysics coupling node and node in the corresponding interface. node is added by default to the interface when adding a Magnetostriction multiphysics interface.


	When the Magnetostrictive Material node is added to the Structural Mechanics interface in the absence of an active Magnetostriction multiphysics coupling node, the material behaves similarly to a Linear Elastic Material node with some limitations on the format for the elastic material data input. All the magnetic material data and coupling data will have no effect. The magnetostrictive effect is then not included in the corresponding equation system.

By adding the following subnodes to the node you can incorporate other effects:

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Initial Stress and Strain

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Thermal Expansion (for Materials)

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Mechanical Damping


	See also Magnetostriction in the Structural Mechanics Theory chapter.

The node is only available with some COMSOL products (see https://www.comsol.com/products/specifications/).

Linear Magnetostrictive Material Properties

Select a — or . For each of the following, the default uses values . For , enter other values in the matrix or field as needed.

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For , select a (sH).

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For a , select an (cH).

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Select a (dHT or eHS).

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Select a (μrT or μrS).

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Select a (p).


	For entering these matrices, use the following order (Voigt notation), which is the common convention for magnetostrictive materials: xx, yy, zz, yz, xz, zy.

Density

If any material in the model has a temperature dependent mass density, and is selected, the list will appear in the section. As a default, the value of Tref is obtained from a . You can also select to enter a value or expression for the reference temperature locally.


	The density is needed for dynamic analysis or when the elastic data is given in terms of wave speed. It is also used when computing mass forces for gravitational or rotating frame loads, and when computing mass properties (Computing Mass Properties).

See also

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Mass Density and Volume Reference Temperature.

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Using Common Model Input

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Default Model Inputs and Model Input in the COMSOL Multiphysics Reference Manual.

Nonlinear Magnetostrictive Material Properties

See the corresponding theory section Nonlinear Magnetostriction.

Geometric Nonlinearity

If a study step is geometrically nonlinear, the default behavior is to use a large strain formulation in all domains. There are, however, some cases when the use of a small strain formulation for a certain domain is needed. In those cases, select the check box. When selected, a small strain formulation is always used, independently of the setting in the study step. The check box is not selected by default to conserve the properties of the model.

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Magnetostriction

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Modeling Magnetostrictive Materials

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Modeling Geometric Nonlinearity

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Ampère’s Law, Magnetostrictive

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The Magnetic Fields Interface in the COMSOL Multiphysics Reference Manual.

Energy Dissipation

You can select to compute and store various energy dissipation variables in a time dependent analysis. Doing so will add extra degrees of freedom to the model.

To display this section, click the button (

) and select in the dialog box.

Select the check box as needed to compute the energy dissipated.

Quadrature Settings

Select the check box to reduce the integration points for the weak contribution of the feature. Select a method for — , , or to use in combination with the reduced integration scheme. The default stabilization technique is based on the shape function and shape order of the displacement field.

Control the hourglass stabilization scheme by using the option. Select (default) or .

When is selected, enter a stabilization shear modulus, Gstb. The value should be in the order of magnitude of the equivalent shear modulus.

When is selected, enter a stabilization bulk modulus, Kstb. The value should be in the order of magnitude of the equivalent bulk modulus.

Location in User Interface

Context Menus

Ribbon

Physics tab with selected: