Piezoceramic Block Simulation

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Section 1 - What Will You Learn in This Tutorial?

In this tutorial, you will learn how to set up a simple 2D transducer model with a backing and matching layer and extract outputs such as impedance, directivity plots and transmit sensitivities.

You will learn:

  • The Basic Simulation Workflow in OnScale Designer
  • How to set up a 3D model
  • How to create a simple geometry
  • How to simulate piezoelectric materials
  • How to calculate Impedance
  • How to plot a Mode Shape
What is PZT?: Lead zirconate titanate is an inorganic compound with the chemical formula Pb[ZrxTi1-x]O3 (0≤x≤1). Also called PZT, it is a ceramic perovskite material that shows a marked piezoelectric effect, meaning that the compound changes shape when an electric field is applied. It is used in a number of practical applications such as ultrasonic transducers and piezoelectric resonators. It is a white to off-white solid.

Section 2- Model Definition

Characteristics of the model:

Model:

PZT Block dimensions: 20 mm x 14 mm x 2 mm

 

Mesh Size:

0.1 mm

Output Results:

- Impedance

- Harmonic Mode Shape

Material Data:

Name CTS 3203HD
Code Name pmt3
Density 7820 kg.m-3
Bulk Velocity 4708.36 ms-1
Shear Velocity 1687.891 ms-1

Note: Material Data in OnScale are generally defined using the bulk velocity and the shear velocity parameters instead of the more traditional Elastic Modulus and Poisson's Ratio. You can check this page if you want to understand the relation between those parameters.

Section 3 - Why This Simulation?

Piezoceramics are the core material in many transducers and resonators and to be able to simulate their behavior accurately is a fundamental requirement.

To check how the simulation compares with experimental results, the resonances from impedance response is commonly used to validate the simulation.

Section 4 - The Simulation Process:

Let's go through the step by step tutorial and see how to simulate this in OnScale!

Step 1 - Create a New Project

  1. Click New Project to open up the New Project window
  2. Give the project a name
  3. Set Project working units
  4. Change Model Type to 3D Model
  5. Chose the project save location click '...' and choose an appropriate save location
  6. Click OK to save the dialog window
1_Project.png

Step 2 - Add the Materials from the Material DB

First we will add the materials needed from the material database. We will use pmt3 and water in this tutorial.

  1. Click Project Materials to open the database
  2. Expand Piezoelectric and add pmt3
  3. Click Done
2_Material.png

Step 3 - Create Basic Geometry Shapes

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

  1. Click Cuboid
  2. Change Material to pmt3
  3. Set End (mm): X (mm) = 10 and Y (mm) = 7 and Z (mm) = 2
3_Prim.png
 

Step 4 - Define a Time Function

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

  1. Click '+' to open the Define Input Time function window
  2. Change to Ricker Wavelet
  3. Click Insert to close the window. A record called timefunc_1 will be added to the window

time.png

Step 5 - Choose the right Mesh Size

We will now change the mesh settings to use 15 elements per wavelength

  1. Select Configuration
  2. Set Definitions to Advanced
  3. Set Elements Per Wavelength to 15

mesh.png

Step 6 - Create the two electrodes

  1. Click '+' to open the Load Definition window
  2. Change Creation Mode to Geometry Interface
  3. Change Geometry to primitive_1 (pmt3)
  4. Change Interfacing Item to side 6 (zmax)
  5. Click Create Load

4_Load.png

  1. Click '+' to open the Load Definition window
  2. Change Creation Mode to Geometry Interface
  3. Change Geometry to primitive_1 (pmt3)
  4. Change Interfacing Item to side 5 (zmin)
  5. Click Create Load

5_Load.png

We will need to edit the loads to create 2 electrodes, where we are driving the top electrode (load_1) and grounding the bottom electrode (load_2).

Change the properties of the electrode 1

  1. Click load_1
  2. Change Load Type to Voltage
  3. Change Area Scaling to 4.0
  4. Change Termination to timefunc_1
  5. Change Amplitude Scale Factor to 1

6_Load_Setup.png

Change the properties of the electrode 2

  1. Click load_2
  2. Change Load Type to Voltage
  3. Change Area Scaling to 4.0
  4. Change Termination to Ground

7_Load_Setup.png

Step 7 - Define the 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 the X Minimum boundary condition to Symmetry.
  3. Change the Y Minimum boundary condition to Symmetry.

8_Boundary.png

Step 8 - Define the Analysis Simulation Time

We will now set the model simulation time to be 5e-5 seconds

  1. Click Analysis
  2. Change Simulation Run Time (s) to 100e-06

9_Analysis.png

Step 9 - Define the Output Results

We will now define 1 output

Output Result 1: Shape Data

  1. Click '+' this will create a new output
  2. Change Output Type to  Shape Data
  3. Change Frequency to 70e3

10_Output.png

Step 10 - Run on the 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

11_Cloud_Scheduler.png

How to Get the 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
  4. Click Download all

12_Storage.png

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

Step 11 - Check the Simulation Results

Switch to the Post Processor

  1. Click this icon to access the Post Processor

ppswitch.png

Open Results, Calculate and Plot Impedance

  1. In the File Explorer, locate the Flex History File (.flxhst) & double left click to load it into the results manager
  2. Select the Charge record on load1
  3. Click Impedance
  4. Two new records will appear, double click on Impd:load1.amp to plot
13_Impedance.png

Note: Zoom into the plot by clicking and dragging a square box around the selected area. To undo zoom, right click in the plot window.

Mode Shape

  1. In the File Explorer, Locate the Shape Output File (.flxdato) & double Left Click
  2. Expand Mode Shapes and double Left Click yvel**
  3. Click Symmetry and activate symmetry in X and Y
  4. Right Click yvel and Plot Shape Movie
  5. Click on the Play icon to animate the mode shape
15_Mode_Shape.png
 
**You will be prompted to overwrite the view, Click Continue to plot:

14_Switch.png

Section 5 - 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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