# Section 1 - What will you learn in this tutorial?

In this tutorial you will learn how to set up a simple 3D model of 1-3 Piezocomposite with 100 pillars using the designer mode basic geometry shapes.

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 display and post-process your results
What is a 1-3 Composite?: 1-3 Piezocomposites have become the material of choice for many high performance ultrasound transducers. A variety of piezo-composite materials can be made by combining piezoelectric elements with a passive polymer such as epoxy or active polymer. Classification of composites come according to their connectivity there are many options to choose from 2-2, 1-3, 3-3.

We are building a 1-3 piezo-composite structure in this tutorial.

# Section 2- Problem Definition

### Characteristics of the model:

 Model: 2400 μm x 2400 μm x 1000 μm with a ceramic pillars  339.5 μm x 339.5 μm x 1000 μm Mesh Size: 30 Elements / Wavelength Analysis Time: 1e-4 seconds Output Results: - Mode Shape Data of displacement in Y at a frequency of 1e6

### Material Data:

 Name: Vantico HY1300/ CY1301 CTS 3203HD Code Name: hard pmt3 Density: 1149 kg.m-3 7820 kg.m-3 Bulk Velocity: 2536 m.s-1 4708.359 m.s-1 Shear Velocity: 1179 m.s-1 1687.891 m.s-1

# Section 3 - Why this simulation?

Modelling and simulating composite array devices with FEA provides a lot of insights to design and fabricate the best ultrasonic sensors. It allows to create designs which are cost-efficient even before starting making some prototypes.

With OnScale, you can set up various geometrical features as parameters that can then be tested virtually by simulation, allowing you to choose the best combination of materials and sizes, while preventing costly design mistakes.

In this simulation we will apply 2 electrodes on both sides of the composite and observe the behaviour of the composite.

This model can be used as a starting point for anyone looking to design a transducer using a composite structure as the active element of the device. This device will have 100 pillars using CTS 3203HD piezoceramic and a hardset epoxy filler. We will build a model with 25 pillars and apply symmetry in X and Z as our thickness will be through Y to achieve a 100 pillar composite.

In the results, the model will appear as a half cylinder when plotted in the post processor.

# Section 4 - Step-by-step Video Tutorial:

The following video will teach you step by step how to simulate the Piezo Composite transducer model presented in this tutorial:

All the step are also detailed in text format in the next section. Check it out.

# Section 5 - The Simulation Process:

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

## Step 1 - Create a New Project

1. Click New Project this will open the New Project window
2. Name the project '1-3_Comp' (optional user can choose alternative name)
3. Change Distance to mm
4. Make sure Model Type is set to 3D Model
5. Choose an appropriate save location for the project
6. Click OK

## Step 2 - Add the Materials from the Material DB

First we will add the materials needed from the material database. We will use pzt4 and water in this tutorial.

1. Click Project Materials this will open the Materials Database window
2. Expand the Piezoelectric tab
3. Double click pmt3 to add that material to the Project Materials
4. Expand the Epoxy tab
5. Double click hard to add that material to the Project Materials
6. Expand pmt3 tab and then expand the Piezoelectric sub-tab then change the poling direction to Y+
7. Click Done

## Step 3 - Create Basic Geometry Shapes

We will make use of the geometric primitives available in Designer. We will use the Cuboid primitive twice. Primitives can be patterned out along the axis so we only need to create one pillar and pattern it out to achieve the full model.

Primitive 1

1. Click the Cuboid icon to add a  primitive
2. Set Material to hard
3. Set End (mm): X (mm) = 0.48, Y (mm) = 1, Z (mm) = 0.48
4. Right click the workspace and select Reset View
5. Click anywhere in the workspace to move rotate and move the model around

Primitive 2

1. Right click primitive_1 and select Duplicate Selection this will create a copy of the primitive called primitive_2
2. Set Material to pmt3
3. Set X (mm) = 0.08, Y (mm) = 0.0, Z (mm) = 0.08
4. Set X (mm) = 0.40, Y (mm) = 1.0, Z (mm) = 0.40

## Step 4 - Pattern out the structure

1. Select both primitives
2. Change Pattern Type to Linear
3. Set X = 5, Y = 1, Z = 5
4. Set X = 0.48, Y = 0, Z = 0.48

## Step 5 - 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

## Step 6 - Choose appropriate meshing

We will now change the mesh settings to use 30 elements per wavelength.

1. Expand Model
2. Expand Mesh
3. Select Configuration
5. Set Elements Per Wavelength to 30
6. Expand Mesh Velocity
7. Set Mesh Velocity value to 1179

## Step 7 - Define loads

1. Click '+' to open the Load Definition Window
2. Change Creation mode to Geometry Interface
3. Change Geometry to primitive_2 (pmt3)
4. Change Interfacing Item to side 4 (ymax)

1. Change Creation mode to Geometry Interface
2. Change Geometry to primitive_2 (pmt3)
3. Change Interfacing Item to side 3 (ymin)

### Change the properties of the electrode 1

2. Change Load Type to Voltage
3. Change Area Scaling to 4
4. Set Termination to timefunc_1

### Change the properties of the electrode 2

2. Change Load Type to Voltage
3. Set Termination to Ground

## Step 8 - Set domain boundaries

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 Z Minimum to Symmetry

Leave all other boundary conditions as there default free

## Step 9 - Set the simulation time

We will now set the model simulation time to be 1e-4 seconds

1. Click Analysis
2. Set Simulation Run Time to 1e-4

## Step 10 - Request outputs

We will now define 1 output, we will request the solver generates a mode shape showing displacement in Y

1. Click '+' to add a new output
2. Change Output Type to Shape Data
3. Change Array Type and Array Component to Displacement and Y
4. Set Frequency to 1e6 Hz

## Step 11 - Running your simulation 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. Change number of CPUs to 16 (this is to decrease Solve Time, choose what best suits your Core Hour spend)
4. Click Estimate
5. Click Run

### 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

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

## Step 12 - Using the post processor to plot results

### Switch to the Post Processor

1. Click this icon to access the Post Processor

### Open Results

1. Click File Explorer
3. Open the shape.flxdato file (double click)
4. Open the 1-3_Comp.flxhst file (double click)
5. Click Results Manager

### Plot Mode Shape (Y Displacement)

1. Right click ydsp and select Plot Shape Movie
2. Click Model Graphics
3. Click Symmetry
4. Apply symmetry on X and Z axis
5. Change Scale Factor to 0.02
6. Enable Save Video
7. Choose an appropriate save location and name the give video a title. Close window
8. Click Play. Watch your Mode Shape. A mode shape video should now be in your save directory

### Calculate & Plot Impedance

1. Click the Reset Viewport Icon and select Reset Current Viewport
2. Select the history 'pize load1: Charge'
3. Select Impedance button
4. Double click Impd:load1.amp to plot the impedance
5. Click Log yAxis

# Section 6 - 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 of your own.

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