Summary of the OnScale TOFD Simulation

This example shows a typical Time of Flight Diffraction (TOFD) inspection of an anisotropic weld. TOFD is a flexible technique, which relies on a range of mode converted signals to be effective. OnScale combines the capability of accurately simulating mode conversion in arbitrary geometries, with the speed to run large batches of TOFD models, making it an ideal tool for improving inspection setup.

Time of Flight Diffraction finds use in various industries who utilize NDT, from Oil and Gas to power generation. Originally developed for crack sizing, TOFD can also be used for everything from routine screening to corrosion mapping.

Technical details of the OnScale simulation

This simulation replicates the inspection of a pipe weld using TOFD. The model simulates a 5 MHz pressure wave propagating through the complex grain structure of an anisotropic weld and captures the resultant pressure signal at the receiver side. OnScale providesĀ a better understanding of how anisotropic structures areĀ evaluated using ultrasound. Simulating in the time-domain allows for direct comparison with practical inspections. In TOFD mode conversion occurs at the back wall, defects, and any boundaries between materials. OnScale allows all of these mode converted signals to be considered in a single model, providing more realistic insight into inspection behavior.

Computational Resources required for the OnScale simulation

For this model, we employed half symmetry. We captured the sectioned weld structure using Dream3D and imported into OnScale.

  • Elements: 42.8 million
  • Processor: 2 x 8 core Intel Xeon E5 Workstation
  • RAM: 4.8 GB
  • Time required: 22 minutes 25 seconds

The simulation produces a number of very useful outputs, including:

  • Coverage maps
  • Full wave propagation video
  • Output voltage on receive transducer (or received pressure signal)
  • Influence of arbitrary defects on receive signal

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