PMUT 2D

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This tutorial will show you how to create a simple Piezoelectric Micromachined Ultrasonic Transducer (PMUT) with an Aluminum Nitride active layer with top/bottom electrodes residing in a Silicon substrate and operating into a water load.

New Project 

  1. Click New Project this will open the New Project window
  2. Name project PMUT_2D (optional choose preferred title)
  3. Set Distance to um
  4. Change Model Type to 2D Axi-Symmetric Model and select Axi Y
  5. Choose an appropriate save location click '...' to do so 
  6. Click OK

Materials 

This tutorial will make use of a project material file please download the attached file and save/move it to the same working directory as the project file.

Click the link below to download the material file needed for this tutorial.

  1. Click Project Materials to open the Materials Database window
  2. Click the red arrow icon and select Import User Project Materials From File
  3. Expand aln and change the poling direction to Y+
  4. Click Done 

Primitives

We will make use of the geometric primitives available in Designer. We will use 6 Rectangle primitives.

Primitive 1

  1. Click Rectangle 
  2. Change Material to si
  3. Set X (um) = 32.5 and Y (um) = 7.5

Note: After making changes to X and Y right click the workspace and select Reset View

Primitive 2

  1. Right click primitive_1 and select Duplicate Selection this will create primitive_2
  2. Change Material to void
  3. Set Y (um) = 3
  4. Set X (um) = 22.5 and Y (mm) = 6

Primitive 3

  1. Right click primitive_2 and select Duplicate Selection this will create primitive_3
  2. Change Material to moly
  3. Set Y (um) = 6
  4. Set Y (um) = 6.25

Primitive 4

  1. Right click primitive_3 and select Duplicate Selection this will create primitive_4
  2. Change Material to aln
  3. Set Y (um) = 6.25
  4. Set Y (um) = 7.25

Primitive 5

  1. Right click primitive_4 and select Duplicate Selection this will create primitive_5
  2. Change Material to moly
  3. Set Y (um) = 7.25
  4. Set Y (um) = 7.5

Primitive 6

  1. Right click primitive_1 and select Duplicate Selection this will create primitive_6
  2. Change Material to watr
  3. Set Y (um) = 7.5
  4. Set Y (um) = 20

Project Settings

This example will use a frequency of interest of 30MHz. We will adjust the project settings to make use of this.

  1. Click Project Settings
  2. Expand Frequency of Interest
  3. Set Value (Hz) = 3e7

Time Function

We will now add a Ricker Wavelet drive function for later use as out loads require a time function be set.

  1. Time '+'
  2. Change Ricker Wavelet
  3. Set Value (Hz) = 3e7
  4. Insert 

Circuits

A circuit will be added to damp the response.

  1. Click '+' to open the Define Circuit Definition window
  2. Click Element_0 
  3. Double click Resistor to add that component to the circuit
  4. Click Element_1
  5. Set the resistance of the component to 50 
  6. Click Insert

Mesh

We will use the Basic mesh settings in Medium as defaulted.

Loads

This model needs two loads as it is a piezoelectric model. The top electrode will drive the model and the bottom will be connected to ground

Load 1

  1. Click '+' this will open the Load Definition window 
  2. Change Creation Mode to Geometry Interface
  3. Select primitive_3 (moly)
  4. Select primitive_4 (aln)
  5. Click Create Load

Load 2

  1. Click '+' this will open the Load Definition window 
  2. Change Creation Mode to Geometry Interface
  3. Select primitive_5 (moly)
  4. Select primitive_4 (aln)
  5. Click Create Load

Edit Load Properties 

Load 1

  1. Click load_1 
  2. Change Load Type to Voltage
  3. Assign Groundto Termination

Load 1

  1. Click load_1 
  2. Change Load Type to Voltage
  3. Assign circuit_1 to Circuit
  4. Assign timefunc_1 to Termination

Boundary Conditions 

We will need to change the X minimum boundary condition to Symmetry as this model is symmetrical along that axis.

  1. Click Domain Boundaries
  2. Change X Minimum to Symmetry 
  3. Change X Maximum to Free
  4. Change Y Minimum to Fixed
  5. Change Y Maximum to Absorbing

Analysis

We will now set the model simulation time to be 1e-6 seconds

  1. Click Analysis 
  2. Set Simulation Run Time (s) to 1e-6

Outputs

Two outputs will be defined 

Output 1

  1. Click '+' to add the output record output_1 to the tree
  2. Change Output Type to Time History
  3. Change Array Type to Displacement 
  4. Change Array Component to Y
  5. Change Y to 7.5 (it defaults to the project working units)

Output 2

  1. Click '+' to add the output record output_2 to the tree
  2. Change Output Type to Shape Data
  3. Change Array Type to Displacement 
  4. Change Array Component to Y
  5. Change Frequency to 5e6 Hz

Run Model on Cloud

At this point the model is completely set up and it can now be run on the cloud.

  1. Click Run on Cloud 
  2. The option to rename your job. This is how it will appear in the storage
  3. Click Estimate 
  4. Click Run

Downloading Simulation Results 

The simulation results will need to be downloaded from the cloud storage in order to analyse the results in the post processor. More experience users may also be able to process Time Histories in Review.

  1. Click Storage this opens the window shown above
  2. Locate the job 
  3. Click Download and select Download all

Choose an appropriate save location when the file explorer pops up and click Select Folder to close the window.

Switch to the Post Processor 

  1. Click this icon to access the Post Processor 

Open Results 

  1. Click File Explorer
  2. Expand the folder containing the results just downloaded, double click the PMUT_2D.flxhst
  3. Double click the PMUT_2D-shape.flxdato
  4. Click Results Manager

Plot Mode Shape (Y Displacement)

  1. Expand the tabs
  2. Double click ydsp to plot the mode shape
  3. Click Animated Plot 
  4. Change Scale Factor to 0.05
  5. Change Number of Loops to 3
  6. Click Play. Watch your Mode Shape 

Plot Time History 

  1. Click Reset Viewport
  2. Click Reset Current Viewport
  3. Double click ydsp
  4. Set Plot Title to Y-Displacement on Top Electrode
  5. Set Y-Axis Label to Displacement

Try for yourself 

Now that we have introduced you to the tutorial try have a play around with some of the settings, add some other outputs, or use this model as a starting point for your own.

 

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