The Piezoelectricity, Layered Shell Interface

The interface (

) combines structural layered shells and electric currents in shells together with the constitutive relationships required to model the direct and inverse piezoelectric effects. The piezoelectric coupling can be formulated using either the strain-charge or stress-charge forms.

When a predefined interface is added from the branch (

) of the or from windows, and interfaces are added to the Model Builder.

In addition, the node is added, which automatically includes the multiphysics coupling feature .

The interface includes a feature. The interface includes a feature with similar settings. Such features can be also added manually to their corresponding interfaces similar to any other material model therein.

The Layered Piezoelectric Effectmultiphysics coupling node can be active only on the selection, where both features and are active.

You input both the mechanical and electrical material data under the Piezoelectric Material node. The data can be presented in either stress-charge or strain-charge form.

When it is used without an active Layered Piezoelectric Effect coupling feature, the Piezoelectric Material node works similarly to a Linear Elastic Material feature with the material data input limited to anisotropic form using Voigt notations. All the electric material data has no effect.

You use the Piezoelectric Layer feature under Electric Currents in Shells to select those domains, where the material is supposed to experience piezoelectric coupling. When used without a counterpart under the Layered Shell interface (or without the coupling feature), the Piezoelectric Layer node acts as an ordinary Dielectric Layer feature with its material data input limited to the electric permittivity only.

All structural and electrostatics functionality for modeling is also accessible to include surrounding elastic solids or air domains. For example, add any s material model for other solid domain, a dielectric model for air, or a combination. Note that in order to model a nonsolid dielectric domain, you need to remove such domain from the domain selection for the entire Layered Shell 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).

When physics interfaces are added using the predefined couplings, for example , 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 and interfaces are added, COMSOL Multiphysics adds an empty node. You can add the available coupling feature but the modified settings are not included.

	Coupling features are available from the context menu (right-click the Multiphysics node) or from the Physics toolbar, Multiphysics Couplings menu.

	Use the online help in COMSOL Multiphysics to locate and search all the documentation. All these links also work directly in COMSOL Multiphysics when using the Help system.

The Layered Piezoelectric Effect coupling node is used to couple the interfaces.

Additional nodes and subnodes available with this multiphysics interface are described with the interfaces where they are available. , , and subnodes are available for Piezoelectric Material under the Layered Shell interface. The feature is described for the Electric Currents in Layered Shells interface.