Solid Mechanics
Next the physics feature settings are added to the model. These include the pressure forces acting on the sensor, the applied sense voltage, and other appropriate boundary conditions.
First choose the domains for the Solid Mechanics interface.
1
In the Model Builder window, under Component 1 (comp1) click Solid Mechanics (solid) .
2
In the Settings window for Solid Mechanics, locate the Domain Selection section.
3
From the Selection list, choose Linear Elastic. (This selection is defined in the Geometry sequence.)
Apply the structural symmetry boundary condition on the symmetry boundaries.
Symmetry 1
1
In the Physics toolbar, click Boundaries and choose Symmetry .
2
In the Settings window for Symmetry locate the Boundary Selection section. From the Selection list, choose XZ Symmetry Plane.
Symmetry 2
1
In the Physics toolbar, click Boundaries and choose Symmetry .
2
In the Settings window for Symmetry locate the Boundary Selection section. From the Selection list, choose YZ Symmetry Plane.
Note: The electrical symmetry boundary condition (the Zero Charge feature) is applied by default.
The motion of the structure is constrained in most directions by the structural symmetry boundary conditions. However, the whole device can still slide up and down the z-axis. Apply a point constraint to prevent this.
Prescribed Displacement 1
1
In the Physics toolbar click Points and choose Prescribed Displacement .
2
Select Point 44 only.
3
In the Settings window for Prescribed Displacement locate the Prescribed Displacement section. Select the Prescribed in z direction checkbox, leaving the input field at the default value of 0.
Apply a boundary load to represent the pressure acting on the top surface of the diaphragm.
Boundary Load 1
1
In the Physics toolbar click Boundaries and choose Boundary Load .
2
Select Boundary 13 only.
3
In the Settings window for Boundary Load locate the Force section.
-
From the Load type list, choose Pressure.
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In the p text field, enter p0.