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Phased Array

Phased Array. Topics. Introduction to Ultrasonic Phased Array New Techniques Industrial Applications Advantages Challenges The Future. What is Phased Array?. Multi-element transducers and instrumentation Electrically steer and/or focus ultrasound. How does it work ?.

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Phased Array

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  1. Phased Array

  2. Topics • Introduction to Ultrasonic Phased Array • New Techniques • Industrial Applications • Advantages • Challenges • The Future

  3. What is Phased Array? • Multi-element transducers and instrumentation • Electrically steer and/or focus ultrasound

  4. How does it work ? • Transmission (Tx) • Elements pulsed at controlled time intervals • Control of beam direction and focusing • The delays are known as Tx Focal Laws Beam Steering Wave front formed by constructive interference between wavelets Beam Focusing

  5. How does it work ? (cont’d) • Reception (Rx) • RF waveforms received by each element are delayed, then averaged • Delays used to align the signals = Rx Focal Laws • Ultrasound reflects from defect • Elements receive ultrasound at different times due to the different beam paths • Signals then aligned by electronic circuitry

  6. How does it work ? (cont’d) Single point of focus What if the defect lies beyond the focus point ?

  7. How does it work ? (cont’d) Solution = Dynamic Depth Focusing Focal Zone • Rx Focal Laws are modified for each element • Result = Extended Focal zone

  8. How does it work ? (cont’d) Example - Dynamic Depth Focusing (DDF) Single Focus 25mm • Good Near Surface • Poor Backwall Single Focus 75mm • Poor Near Surface • Good Backwall Dynamic Focus 25 to 75mm • Good Near Surface • Good Backwall

  9. Summary • Transmitted (TX) ultrasonic beams can be electronically steered and focused • Received (RX) ultrasound can also be steered and focused • Focussing over an extended range, not only at a single point = Dynamic Depth Focusing

  10. New Techniques

  11. Sectorial scan Multiple Focal Laws • Beam is swept through many angles • Wide coverage of the specimen Side Drilled Holes Backwall

  12. Electronic / Linear scanning • Each PRF cycle • Aperture moves through the length of the array • No raster movement required • Full volumetric coverage achieved Each PRF cycle • Aperture moves through the length of array • No raster movement required • Full volumetric weld coverage achieved

  13. Linear scanning • Physical scan movement in one axis only • Full axial weld coverage achieved

  14. Industrial Applications

  15. Corrosion mapping - Aircraft Lap Joins • Probe with flexible membrane • rides over rivets • detects corrosion under lap joints

  16. Corrosion detection – inaccessible areas Inspect area under reinforcement plate Defect Geometry Reflections

  17. Composite testing– Aircraft structure Composite Structure Honeycomb Core Disbond Disbond

  18. Pipeline inspection – Zone Discrimination (AUT) Zone 1 Zone 2 Zone 3 Zone 4 Zone5 Zone 6 • Weld zoned - inspect with focused waves from both sides. (Up/Down stream) • Fast, reliable weld inspection (ASME/ASTM/API compliant) • Mechanics simpler & more reliable • Conventional UT = 1 probe per zone • Phased Array = 1 probe covers all zones

  19. Pipeline inspection (Cont’d) Recording Threshold Shaded area shows TOF Colours indicate Above / Below Acceptance thresholds Amplitude Data Threshold breaking defects. Data from Down-stream channels Data from Up-stream Chanels

  20. Pipeline inspection (Cont’d) Automated scanner incorporates TD Handy-ScanRX TD Focus-Scan mounted In vehicle

  21. Complex geometries - Turbine blade root

  22. Advantages • One transducer covers many angles (improved coverage) • Increased inspection speed • Can produce Compression or Shear waves • Greater resolution (improved flaw sizing) • Much improved signal to noise ratio • Increased penetration & sensitivity • Improved POD • Focus control (point & ddf) • Improved visual representation (imaging)

  23. Challenges • Array footprint can be large • Probe cable, very delicate • Application / equipment set-up can be complex • Trained / experienced personnel • Applied application information

  24. The Future of Phased Array Inspection • Cheaper, faster, smaller instrumentation • More qualified/experienced personnel • Improvement of Codes & Standards • Wider application of phased array UT • Tools for application simulation

  25. Thank you for your attention

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