Definitions
Next add a nonlocal coupling to compute a derived global quantity from the model. These operators can be convenient for postprocessing and for setting up the model, for example to include integral quantities in the equation system. Here an average operator is added so that the average displacement of the diaphragm can be computed and a point integration is used to make available the displacement of the centerpoint of the diaphragm.
Average 1
1
In the Definitions toolbar click Nonlocal Couplings
and choose Average
.
2
In the Settings window for Average locate the Source Selection section. From the Geometric entity level list, choose Boundary.
3
Select Boundary 12.
Note:
There are several methods to select a geometric entity. To select, for example, a boundary, place the cursor over the boundary in the graphics window. If the required boundary is not highlighted in red then rotate the scroll wheel of the mouse until the boundary is highlighted, then click to select it (the up and down arrow keys can also be used instead of the scroll wheel). Alternatively, click the Paste Selection button
. In the Paste Selection dialog, in the Selection text field, type 12 (the boundary number) and then click OK. Another method is to use the Selection list
to display a list of the available boundary numbers (available from the Home > Windows menu if you are using windows, or from the Windows menu on other platforms). Boundaries are added to the selection by first clicking on the boundary and then clicking Add to Selection
. To add several boundaries, hold the Ctrl key down when clicking.
Integration 1
1
In the Definitions toolbar click Nonlocal Couplings
and choose Integration
.
2
In the Settings window for Integration locate the Source Selection section. From the Geometric entity level list, choose Point.
3
Select Point 4 only.
Next, define selections to simplify the setup of materials and physics features.
Explicit 1
1
In the Definitions toolbar click Explicit
.
2
Select Domain 3 and 4 only.
3
In the Label text field enter
Electrostatics
.
and choose Average 
.
. In the Paste Selection dialog, in the Selection text field, type 12 (the boundary number) and then click OK. Another method is to use the Selection list 
to display a list of the available boundary numbers (available from the Home > Windows menu if you are using windows, or from the Windows menu on other platforms). Boundaries are added to the selection by first clicking on the boundary and then clicking Add to Selection 
. To add several boundaries, hold the Ctrl key down when clicking.
and choose Integration 
.
.