Primitives: FBAR 3D Tutorial

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Summary

This tutorial demonstrates how to set up a 3D FBAR using primitives in the Designer Workspace.

Note: Primitives can only be used when the project model type is set to 3D

This example covers: 

  • Using primitives
  • Primitive model property changes
  • Material Assignment
  • Basic voltage loads and drive functions
  • Meshing
  • Boundary conditions 
  • Analysis
  • Model Outputs

Creating a 3D Project

Open up designer mode and select New Project, select the folder you wish to save the project in. Change model working units to and set the model type to 3D Model.

Materials 

Click the Project Materials button in the Home tab of the ribbon to add materials to project. Add the following materials:

  • Piezoelectric -> aln
  • Metal -> alum
  • Misc -> si

Once aln is in the project material database expand the Piezoelectric section of the material and change it's poling direction to Z+.

Using Primitives

Primitives can be created via the Site Tool or the new Primitives section added to the Home tab.

In the Model Tree go to Setup > Primitives > + to add a primitive to the workspace.

For the first primitive, set the properties: 

  • Cubiod
  • 3D
  • Material = si
  • X End = 3.375e-5
  • Y End = 6.75e-5
  • Z End = = 1e-5

Select Insert to add primitive to the workspace.

Add another primitive and set the properties: 

  • Cubiod
  • 3D
  • Material = alum
  • X Beg = 2.5e-6
  • X End = 3.375e-5
  • Y Begin = 2.5e-6
  • Y End = 6.5e-5
  • Z Begin = 1e-5
  • Z End = 1.04e-5

The model should now look similar to the following:

Add a third, fourth and fifth primitive with the following properties:

Primitive 3

  • Cubiod
  • 3D
  • Material = aln
  • X Beg = 2.5e-6
  • X End = 3.375e-5
  • Y Begin = 2.5e-6
  • Y End = 6.5e-5
  • Z Begin = 1.04e-5
  • Z End = 1.14e-5

Primitive 4

  • Hexahedron
  • 3D
  • Material = alum
  • x1 = 8.75e-6, y1 = 4e-5, z1 = 1.14e-5
  • x2 = 1.5e-5, y2 = 1.5e-5, z2 = 1.14e-5
  • x3 = 3.375e-5, y3 = 1.5e-5, z3 = 1.14e-5
  • x4 = 3.375e-5, y4 = 5.25e-5, z4 = 1.14e-5
  • x5 = 8.75e-6, y5 = 4e-5, z5 = 1.18e-5
  • x6 = 3.375e-5, y6 = 1.5e-5, z6 = 1.18e-5
  • x7 = 3.375e-5, y7 = 1.5e-5, z7 = 1.18e-5
  • x8 = 3.375e-5, y8 = 5.25e-5, z8 = 1.18e-5

Primitive 5

  • Cubiod
  • 3D
  • X Beg = 5.625e-6
  • X End = 3.375e-5
  • Y Begin = 8.75e-6
  • Y End = 5.875e-5
  • Z Begin = 8.5e-6
  • Z End = 1e-5
  • Material = set initially to alum in site tool and then change to void in properties window

The final geometry will look as follows:

Project Settings

Go to Project Settings in the Model Tree and change the frequency of interest to 2e9 (user must check the frequency of interest checkbox to specify own value)

Drive Function

To define a drive function go to Setup > Forcing Functions > Time > +

Click '+' to bring up the Define Input Drive Function Window. Set the parameters as shown in the image below:

Click insert to create the function the time function, timefunc_1 will appear in the model tree.

Mesh

To change mesh settings go to Model > Mesh 

Change definition type to Defined in Properties window and set Element Size to 2.5e-7.

Loads

To define a new load go to Model Tree > Model > Boundary Conditions > Loads > + this will bring up the load definition window.

In the load definition window set Creation Mode to Geometry Interface, Geometry to primitive_4(alum) and Interfacing Item to primitive_3 (aln). Select Create Load to add load to workspace. This will create a load in the Model Tree named load_1

Create a second load (load_2) with the following properties:

  • Creation Mode = Geometry Interface
  • Geometry = primtive_3(aln)
  • Interfacing Item = primitive_2(alum)

Once the loads have been added to the model their properties can be set to the following:

load_1

  • Load Type = Voltage
  • Termination = timefunc_1
  • Amplitude Scale Factor = 1

load_2

  • Load Type = Voltage
  • Termination = Ground

Domain Boundaries:

To set boundary conditions follow Model Tree > Model > Boundary Conditions > Domain Boundaries set the following boundaries:

  • XMIN = Fixed
  • XMAX = Symmetry
  • YMIN = Fixed
  • YMAX = Fixed
  • ZMIN = Absorbing
  • ZMAX = Free

Simulation Time: 

To set the simulation time follow Model Tree > Model > Analysis > Properties > Simulation Run Time > Enter 5e-7 as the value. Set Time Factor to 0.95.

Model Outputs:

Add an output to the simulation by selecting Model Tree > Model > Outputs > +

To edit the properties of this output go to Model Tree > Model > Outputs > output_1 > Properties

To output maximum acoustic pressure from the model, set the following:

  • Output Type = Field Data 
  • Array Type = Acoustic Pressure
  • Field Type = Maximum

This model can now be run on the cloud or locally.  Once the job has finished the results can be downloaded and opened in the post processor for further analysis. 

Demo Video

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Comments

1 comment
  • Very helpful. can you tell me how i can get Impedance(ohm)vs Frequency, Phase(Degree)vs Frequency and Quality Factor vs Frequency Representation graph.

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