Time of Flight Diffraction 2D (TOFD)

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2D model to simulate a Time of Flight Diffraction (TOFD) inspection of a steel block containing a defect. This model will be created using primitives in Designer.

New Project 

Before we begin we must create a new project.

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  1. Click New Project this opens the New Project window
  2. Choose model name 
  3. Change working units to mm 
  4. Change Model Type to 2D Model
  5. Click ... to choose a directory to save the project
  6. Click OK to create the project.

Project Settings 

  1. Click Project Settings 
  2. Expand the Frequency of Interest tab
  3. Set value to 5e6 Hz

Materials

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

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  1. Click Project Materials to open the Material Database
  2. Expand the Misc tab
  3. Double click 'Rexolite - rxlt' to add this to Project Materials 
  4. Copy the same process as step 2 & 3 and add stainless steel to the project materials 
  5. Click Done to close the Material Database

Primitives

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

Primitive 1

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  1. Click to add a Rectangle to the workspace
  2. Click primitive_1
  3. Change material to stst
  4. Set X (mm) = 28 and Y (mm) = 15

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
  2. Click primitive_2
  3. Change material from steel to void
  4. Set X (mm) = 13.75 and Y (mm) = 5
  5. Set X (mm)  =14.25 and Y (mm) = 10

Primitive 3

  1. Click to add a Polygon to the workspace
  2. Change material to rxlt
  3. Set number of points to 5
  4. Set X (mm) = 2e-3 and Y (mm) = 15e-3
  5. Set X (mm) = 2e-3 and Y (mm) = 17.5e-3
  6. Set X (mm) = 6.5e-3 and Y (mm) = 19e-3
  7. Set X (mm) = 11e-3 and Y (mm) = 19e-3
  8. Set X (mm) = 11e-3 and Y (mm) = 15e-3

Primitive 4

  1. Click to add a Polygon to the workspace
  2. Change material to rxlt
  3. Set number of points to 5
  4. Set X (mm) = 26e-3 and Y (mm) = 15e-3
  5. Set X (mm) = 17e-3 and Y (mm) = 15e-3
  6. Set X (mm) = 17e-3 and Y (mm) = 19e-3
  7. Set X (mm) = 21.5e-3 and Y (mm) = 19e-3
  8. Set X (mm) = 26e-3 and Y (mm) = 17.5e-3

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 Drive Function window 
  2. Change to Ricker Wavelet 
  3. Set Drive Frequency to 5e6 Hz (same as Frequency of Interest)
  4. Click Insert to close the window. A record called timefunc_1 will be added to the window 

Mesh

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

mesh4.png

  1. Expand Model
  2. Expand Mesh
  3. Select Configuration
  4. Set Definitions to Advanced 
  5. Expand Mesh Velocity
  6. Set Mesh Velocity Value to 2350

Create a New Load

  1.  Click '+' to open the Load Definition window
  2. Change Creation Mode to geometry Interface 
  3. Change Geometry to primitive_3 (rxlt) and change Interfacing Item to Background (void)
  4. Click Create Load

Upon clicking Create Load a record load_1 will be added to the Model Tree after this you can close the Load Definition window 

Edit Load Properties 

 

  1. Click load_1
  2. Change Load Type to Pressure
  3. Set Driving Function to timefunc_1
  4. Set X (mm) = 3 and Y (mm) = 15
  5. Set X (mm) = 5 and Y (mm) = 19

Boundary Conditions

  1.  Click Domain Boundaries
  2. Set X minimum to Absorbing
  3. Set X Maximum to Absorbing 
  4. Set Y Minimum to Free
  5. Set Y Maximum to Free

Analysis

We will now set the model simulation time to be 1.6e-5 seconds

  1. Click Analysis 
  2. Change Simulation Run Time (s) to 5e-05

Outputs

We will now define 2 outputs, a time history of the acoustic pressure on the front of the defect will be recorded and the maximum pressure array will be outputted 

Output 1

  1. Click '+' this will create a new output 
  2. Change Output Type to Field Data
  3. Change Array Type to Acoustic pressure
  4. Change Field Type to Maximum

Output 2

  1. Click '+' this will create a new output 
  2. Change Output Type to Time History 
  3. Change Array Type to Acoustic pressure
  4. Set X = 24 and Y = 18

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 click 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 job simulation folder. Open the flxdato file and the flxhst file (double click them)
  3. Click Results Manager 

Plot Time History 

  1. Double click aprs to plot acoustic pressure 
  2. Set plot title to Acoustic Pressure Recorded at Output (optional title)
  3. Set Y-Axis Label to Acoustic Pressure 

Plot Data Array (Maximum Pressure)

  1.  Click Reset Viewport and choose Reset All Viewports
  2. Double click apmx to plot the maximum pressure data array

Model Graphics

  1. Click Model Graphics 
  2. Click Surface Plot
  3. Click the workspace and move to rotate the model
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