Dashboard TOFD / Section 2: TOFD Theory / Overview Section 2

Content & Objectives

Section 2: TOFD Theory

  • Butt welds
  • Digital instrument, pulser/receiver, digitizer, filters, gain
  • Probes, frequency spectrum, signal waveform
  • Wedges, hard wedges
  • Scanner, encoder
  • Huygens’ principal, diffraction
  • Snell’s law, incident vs. refracted, critical angles
  • TOFD A-Scan, phase shift, phase difference, averaging
  • PCS, transit time, depth calculation, height calculation, position uncertainty
  • Beam spread, beam spread in-wedge, beam spread in-part, frequency spectrum
  • Lateral wave, backwall, mode-converted backwall
  • Dead zones, accuracy, resolution
  • B-Scan, gray scale
  • Whisker effect, parabolic cursors
  • Non-parallel and parallel scans
  • Multiple scans
  • Influence of frequency on coverage, dead zones
  • Influence of wedge angle on time scale, coverage
  • Influence of PCS on dead zones, resolution, coverage
  • How to optimize the digitizing frequency, filters, averaging, time window, sensitivity, PRF
  • Calibration of the beam index point, velocity
  • Scanning speed
  • Wedge delay calibration, lateral wave straightening, lateral wave removal
  • Interactive exercises on setups, beam index point and velocity calibration, scanning
  • Interactive exercises on wedge delay calibration and lateral wave straightening
  • Section’s test
Interactive Exercices57
Section's Test1