The Piezomagnetic Material node defines the linear magnetoelastic material properties. 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
Piezomagnetism multiphysics interface together with a
Piezomagnetism multiphysics coupling node and
Ampère’s Law, Piezomagnetic node in the corresponding
Magnetic Fields interface.
Piezomagnetic Material node is added by default to the
Solid Mechanics interface when adding a Piezomagnetism multiphysics interface. This material model available for 3D, 2D, and 2D axisymmetry.
By adding the following subnodes to the Piezomagnetic Material node you can incorporate other effects:
The Piezomagnetic node is only available with some COMSOL products (see
https://www.comsol.com/products/specifications/).
Select a Constitutive relation —
Strain-magnetization form or
Stress-magnetization form. For each of the following, the default uses values
From material. For
User defined, enter other values in the matrix or field as needed.
Check the Use multiplicative formulation check box to use a formulation based on the multiplicative decomposition of elastic and inelastic (piezomagnetic) strains.
If any material in the model has a temperature dependent mass density, and From material is selected, the
Volume reference temperature list will appear in the
Model Input section. As a default, the value of
Tref is obtained from a
Common model input. You can also select
User defined to enter a value or expression for the reference temperature locally.
Select a Formulation —
From study step (default),
Total Lagrangian, or
Geometrically linear to set the kinematics of the deformation and the definition of strain. When
From study step is selected, the study step controls the kinematics and the strain definition.
To have full control of the formulation, select either Total Lagrangian, or
Geometrically linear. When
Total Lagrangian is selected, the physics will force the
Include geometric nonlinearity check box in all study steps.
Select a Strain decomposition —
Automatic (default),
Additive, or
Multiplicative to decide how the inelastic deformations are treated. This option is not available when the formulation is set to
Geometrically linear.
The Strain decomposition input is only visible for material models that support both additive and multiplicative decomposition of deformation gradients.
Select the Calculate dissipated energy check box as needed to compute the energy dissipation.
Select the Reduced integration check box to reduce the integration points for the weak contribution of the feature. Select a method for
Hourglass stabilization —
Automatic,
Manual, or
None to use in combination with the reduced integration scheme. The default
Automatic stabilization technique is based on the shape function and shape order of the displacement field.
When Shear stabilization is selected, enter a stabilization shear modulus,
Gstb. The value should be in the order of magnitude of the equivalent shear modulus.
When Volumetric stabilization is selected, enter a stabilization bulk modulus,
Kstb. The value should be in the order of magnitude of the equivalent bulk modulus.