Piezoelectric Material

The node defines the piezoelectric material properties either in stress-charge form using the elasticity matrix and the coupling matrix, or in strain-charge form using the compliance matrix and the coupling matrix. It is normally used together with a multiphysics coupling node and a corresponding node in the interface. This node is added by default to the interface when adding a multiphysics interface.

This material model requires one of these products: Structural Mechanics Module, MEMS Module, or Acoustics Module.

When working with layered shells, you almost invariably take the material data from what has been defined using , , or nodes. It is however possible to override some data from a node too.

In order to have a correct model, all layers must have been assigned material data for all boundaries selected in the settings for the interface. The override rules for the material models in the Layered Shell interface cannot enforce this, in the same way as for other physics interfaces. You can have several nodes with the same (or partially overlapping) geometrical selections, but with different layer selections.

By adding the following subnodes to the node you can incorporate many other effects:

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Initial Stress and Strain

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Thermal Expansion (for Materials)

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Mechanical Damping

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Coupling Loss

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Dielectric Loss


	When the Piezoelectric Material node is added to the Layered Shell interface in the absence of an active Layered Piezoelectric Effect multiphysics coupling node, the material behaves similarly to a Linear Elastic Material node. The elastic properties will correspond to the elasticity or compliance matrix entered (see below). The piezoelectric effect is then not included in the equation system.


	See also Piezoelectric Material in the Structural Mechanics Theory chapter.

Shell Properties

Select the layer or layers for which this material model is to be used.

Table 6-4: Layer Selections; Piezoelectric Material
Selection	Use All Layers	Selection of Individual Layers
Boundary	Same as interface selection when the node is added.	When Use all layers is not selected. Only a subset of the layers selected in the parent can be selected.

Data given in the other sections of this node applies to all layers. Thus, if you enter material data explicitly, rather relying on the default option, you will override that material property for all selected layers.

Piezoelectric Material Properties

Select a — or . For each of the following, the default uses values . For enter other values in the matrix or field as needed.

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For , select an (cE).

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For a , select a (sE).

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Select a (d).

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Select a (erS or erT).

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Enter values for the Dr.

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Select a (p).


	For entering these matrices, use the following order (Voigt notation), which is the common convention for piezoelectric materials: xx, yy, zz, yz, xz, zy.

Density

If any material in the model has a temperature dependent mass density, and is selected, the list will appear in the section. As a default, the value of Tref is obtained from a . You can also select to enter a value or expression for the reference temperature locally.