The Nonlinear Magnetostriction Interface
The Nonlinear Magnetostriction interface (), found under Electromagnetics–Structure Interaction () branch within the Structural Mechanics branch () or the Electromagnetics and Mechanics () branch within the AC/DC branch () when adding a physics interface, combines Solid Mechanics and Magnetic Fields together with the constitutive relationships required to model magnetostrictive materials and devices. Both the direct and inverse magnetostriction effects can be modeled.
When a predefined Magnetostriction interface is added from the Structural Mechanics branch () of the Model Wizard or from Add Physics windows, Solid Mechanics and Magnetic Fields interfaces are added to the Model Builder.
In addition, the Multiphysics node is added, which automatically includes the multiphysics coupling feature Nonlinear Magnetostriction.
The participating Solid Mechanics interface will use the default Linear Elastic Material feature with its selection set to all domains. The Magnetic Fields interface gets a default Ampère’s Law, Nonlinear Magnetostrictive feature with similar settings.
Such features can be also added manually to their corresponding interfaces similar to any other material models therein.
Input the mechanical material data in the corresponding node under Solid Mechanics, the magnetic and electrical properties under Ampère’s Law, Nonlinear Magnetostrictive, and the coupling data in the Nonlinear Magnetostriction multiphysics coupling node.
Use the Ampère’s Law, Nonlinear Magnetostrictive feature under Magnetic Fields to select the domains where the material is supposed to experience magnetostrictive coupling. When used without a counterpart under the Solid Mechanics interface (and/or without the coupling feature) Ampère’s Law, Nonlinear Magnetostrictive node acts as an ordinary Ampère’s Law feature set to use Analytic Magnetization Curve. The coupling data will have no effect.
All solid mechanics and magnetics functionalities for modeling are also accessible to include surrounding elastic solids or air domains. For example, add any solid mechanics material for other solid domain, a nonsolid model for air (via Ampère’s Law feature), or a combination. Note that in order to model a nonsolid magnetic material, you need to remove such domain from the domain selection for the entire Solid Mechanics interface. This is because all material models under that interface represent solid materials (with the Linear Elastic Material node being always present and active in all those domains, where it is not explicitly overridden by any other material model).
On the Constituent Physics Interfaces
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The Solid Mechanics interface is described in The Solid Mechanics Interface.
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The Magnetic Fields interface is described in The Magnetic Fields Interface.
Settings for Physics Interfaces and Coupling Features
When physics interfaces are added using the predefined multiphysics interfaces such as Nonlinear Magnetostriction, specific settings are included with the physics interfaces and the coupling features.
However, if physics interfaces are added one at a time, followed by the coupling features, these modified settings are not automatically included.
For example, if both Solid Mechanics and Magnetic Fields interfaces are added, COMSOL Multiphysics adds an empty Multiphysics node. You can choose the available coupling feature Nonlinear Magnetostriction but the modified settings are not included.
Physics Interfaces and Coupling Features
Coupling Feature
The Nonlinear Magnetostriction coupling node is used to couple the interfaces.
Additional Features
Additional nodes and subnodes available with this multiphysics interface are described with the interfaces where they are available. The Mechanical Damping and Thermal Expansion subnodes are available for the Magnetostrictive Material under the Solid Mechanics interface. The Ampère’s Law, Nonlinear Magnetostrictive node is described for the Magnetic Fields interface.
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Magnetostriction and Piezomagnetism
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Ampère’s Law, Nonlinear Magnetostrictive
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Modeling Magnetostrictive Materials
Nonlinear Magnetostrictive Transducer: Application Library path Structural_Mechanics_Module/Magnetomechanics/nonlinear_magnetostriction