This is a modelling guide to help you get started simulating Time of Flight Diffraction (TOFD) systems in OnScale. In this initial example you will be shown how to get the impedance of a basic 2D TOFD model created using the symbol language.

What is symbol?: Check out these articles to get more familiar with OnScale's scripting language symbol.

Model Description

This 2D model is a simple Time of Flight Diffraction (TOFD) inspection of a steel block consisting of a defect, a transmitter and receiver. When a defect is present in the test piece, there is a diffraction of the wave from the top and bottom tips of the crack. Using the measured time of flight of the pulse, the depth of the crack tips can be calculated.


Download and Open the Model

Download: TOFD 2D Model

OnScale Input Files have the file extension *.flxinp. To open the downloaded file:

  1. Open OnScale 
  2. Select Analyst Mode
  3. Select the Menu button in the top left of the application
  4. Select Open

Preview Model


Preview model is used to view the geometry dimensions and material assignment of a model to ensure the script is correct. To preview a model, select the Preview Model icon in the Home tab of the application ribbon.


Note: Preview model will display data from any grph commands that come before the prcs command. If you have more than one grph command, you can cycle through the graphics by continuously selecting Preview Model. To close the preview, select Stop Preview.

Run Model on Cloud 

To run the model on the cloud, select the Run on Cloud button in the Home tab of the application and follow these steps:

  1. Click Select and open the file you wish to run (TOFD_2D.flxinp)
  2. Select Estimate
  3. Select Run

Download Results

  1. From the Home tab, select the Storage icon
  2. Select the Refresh icon to refresh storage
  3. Select the Job Name from the dropdown menu
  4. Select the Download button
  5. Select Download All

Choose a directory to download the results to. These results will be stored in the folder: TOFD_2D-YYYYMMDD-HHMMSS\1 where YYYYMMDD-HHMMSS is the current date and time.

Switch to Post Processor

Post Processor is a suite of tools used to visualise and analyse output data generated from OnScale simulations. Switch to Post Post Processor.


What kind of analysis can I do in Post Processor? Find out here.

Analyse Results

To plot the pressure signal measured at the receiver, follow these steps:

  1. In File Explorer, navigate to the download directory and double click the file 'TOFD_2D.flxhst' to open it
  2. In Results Manager, select the time average 'avrg rxav:Average' by left clicking it

What's Next?

Perform a parametric sweep using this model

Check out how to create this model using our graphical based Designer Mode

Get more familiar with OnScale's 3 Modes and their capabilities