The Piezoresistivity, Domain Currents predefined multiphysics coupling interface (
), found under the
Structural Mechanics>Piezoresistivity branch (
) when adding a physics interface, combines the
Solid Mechanics and
Electric Currents interfaces to simulate the piezoresistive effect. This multiphysics interface is appropriate for situations when the thicknesses of the conducting and piezoresistive layers are resolved by the mesh.
When this multiphysics interface is added using the Model Wizard, a
Solid Mechanics interface and an
Electric Currents interface are added to the
Model Builder.
In addition, the Multiphysics Couplings node is added, which automatically includes the multiphysics coupling feature
Piezoresistivity, Domain Currents.
The participating Electric Currents interface by default adds the
Current Conservation, Piezoresistive node with its selection set to all domains. This node can also be added manually to the interface similar to any other material model therein. All piezoresistivity properties are entered in this node.
The Piezoresistivity, Domain Currents multiphysics coupling node can be active only on the selection where both features
Current Conservation, Piezoresistive and
Linear Elastic Material (or
Hyperelastic Material) are active.
When physics interfaces are added using the predefined couplings, for example Piezoresistivity, Domain Currents, specific settings are included with the physics interfaces and the coupling features.
For example, if both Solid Mechanics and
Electric Currents interfaces are added, COMSOL Multiphysics adds an empty
Multiphysics Couplings node. You can choose the available coupling feature
Piezoresistivity, Domain Currents, but the modified settings are not included. In this example, the
Current Conservation, Piezoresistive node needs to be added manually.
When setting up a model, the coordinate systems used for the participating physics interfaces should be consistent. In particular, the selected item for the Coordinate system menu under the
Solid Mechanics>Linear Elastic Material>Coordinate System Selection section should match the one for the
Coordinate system menu under the
Electric Currents>Current Conservation, Piezoresistive>Coordinate System Selection section.