The Piezoresistivity, Shell predefined multiphysics coupling
interface (
), found under the
Structural Mechanics>Piezoresistivity branch (
) when adding a physics interface, is used when the structural layer is thin enough to be treated by the
Shell interface, but the conducting and piezoresistive layers are still much thinner than the structural layers.
When this multiphysics interface is added using the Model Wizard, a
Shell interface and an
Electric Currents, Shell interface are added to the
Model Builder.
In addition, the Multiphysics Couplings node is added, which automatically includes the multiphysics coupling feature
Piezoresistive Effect, Shell.
The participating Electric Currents, Shell interface by default adds the
Piezoresistive Material 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 Piezoresistive Effect, Shell multiphysics coupling node can be active only on the selection where both a
Piezoresistive Material and a
Linear Elastic Material feature are active.
When physics interfaces are added using the predefined couplings (for example, Piezoresistivity, Shell) specific settings are included with the physics interfaces and the coupling features.
For example, if both Shell and
Electric Currents, Shell interfaces are added, COMSOL adds an empty
Multiphysics Couplings node. You can choose the available coupling feature
Piezoresistive Effect, Shell but the modified settings are not included. In this example the
Piezoresistive Material 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
Shell>Linear Elastic Material>Shell Local System>Coordinate System Selection section should match the one for the
Coordinate system menu under the
Electric Currents, Shell>Piezoresistive Material>Coordinate System Selection section.