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Rail Deflection

Presented by: Prof. Hannes Grabe at the 2009 Railways and Harbours Conference in Cape Town.

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Rail Deflection

  1. 1. Track Deflection Measurement using Particle Image Velocimetry Hannes Gr äbe University of Pretoria Chair in Railway Engineering
  2. 2. Definition ? What is an Engineer Someone who knows how to measure !
  3. 3. Contents of presentation <ul><li>Introduction </li></ul><ul><li>The need for deflection measurement </li></ul><ul><li>Applications of deflection measurement </li></ul><ul><li>Currents methods of track deflection measurement </li></ul><ul><li>The Particle Image Velocimetry (PIV) method </li></ul><ul><li>Measurements at three sites </li></ul><ul><li>Recent developments </li></ul><ul><li>Advantages of the system </li></ul><ul><li>Conclusions </li></ul>
  4. 4. Dynamic loading on non-rigid track deflection
  5. 5. Deflection measurement: Field tests
  6. 6. Deflection measurement: Lab testing
  7. 7. Deflection calculation: Analysis
  8. 8. Deflection measurement: Construction
  9. 9. Deflection measurement: Failures
  10. 10. Deflection measurement… <ul><li>… is ESSENTIAL in: </li></ul><ul><li>Field tests </li></ul><ul><li>Laboratory tests </li></ul><ul><li>Numerical analysis </li></ul><ul><li>Construction </li></ul><ul><li>Failures and remedial measures </li></ul>
  11. 11. Instrumentation ? What capabilities should instrumentation have Reliability 1. Optical 2. Mechanical 3. Hydraulic 4. Pneumatic 5. Electrical Simplicity Quality Cost!
  12. 12. Track loading & deflection Ballast Subballast Subgrade 1 Subgrade 2
  13. 13. Electrical: Multi-Depth Deflectometer
  14. 14. MDD Installation
  15. 15. Field Instrumentation MDD module Load plate Soil sampling
  16. 16. MDD Results Time
  17. 17. Electrical: LVDT* * Linear Variable Differential Transducer
  18. 18. Electrical: LVDT* * Linear Variable Differential Transducer
  19. 19. Electrical: LVDT* * Linear Variable Differential Transducer
  20. 20. Mechanical: Sleeper deflection meter* * Design: Sakkie van der Linde
  21. 21. Mechanical: Geometry car measurements
  22. 22. Mechanical: Geometry car measurements Versine measurement Gauge measurement
  23. 23. Optical: Manual and digital level
  24. 24. Optic deflection measurement Particle Image Velocimetry (PIV) For optical track deflection measurement
  25. 25. Visual: Particle Image Velocimetry (PIV) <ul><li>Particle Image Velocimetry (PIV) originated in the field of experimental fluid mechanics (Adrian, 1991) </li></ul><ul><li>Recent developments: Soil deformation measurements & Landfill settlement (White, Take & Bolton, 2003 & 2005) </li></ul><ul><li>This research: Based on work by Bowness et al. (2006): Monitor Railway Track Displacements by using a webcam attached to a telescope, and a target attached to the side of the rail. </li></ul><ul><ul><li>The telescope magnifies the video images </li></ul></ul><ul><ul><li>Images are captured by the webcam </li></ul></ul><ul><ul><li>Images and analysed by a computer </li></ul></ul><ul><ul><li>Software calculation of horizontal and vertical displacement </li></ul></ul>
  26. 26. Transnet Freight Rail PIV system
  27. 27. Target fixed to the rail
  28. 28. Target fixed to the rail * 2cm x 2cm square target
  29. 29. PIV Calibration
  30. 30. PIV System: Resolution * Standard deviation: 0.003 – 0.005mm
  31. 31. Applications of PIV Amandelbult Centurion Ermelo
  32. 32. Amandelbult
  33. 33. Amandelbult
  34. 34. Amandelbult PIV tests
  35. 35. Amandelbult: resolution
  36. 36. Amandelbult test results 32km/h 7km/h
  37. 37. Amandelbult: Camera vibration
  38. 38. Centurion station
  39. 39. Centurion station measurements Conventional track Tubular track
  40. 40. Centurion measurements Tubular Track: Platform 2 (Rail & Beam deflection) -2.0 -1.5 -1.0 -0.5 0.0 0.5 0.0 2.0 4.0 6.0 8.0 10.0 12.0 Time (s) Deflection (mm) Rail Beam
  41. 41. Centurion measurements Tubular and Conventional Track Comparison -2.0 -1.5 -1.0 -0.5 0.0 0.5 0.0 2.0 4.0 6.0 8.0 10.0 12.0 Time (s) Deflection (mm) Tubular Conventional
  42. 42. Ermelo Yard
  43. 43. Eremlo Yard
  44. 44. Ermelo Yard PIV measurements
  45. 45. Ermelo Yard PIV measurements
  46. 46. Ermelo Yard PIV measurements
  47. 47. PIV measurements Ermelo: Rail , Beam , Grout , Formation Deflection -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 30 35 40 45 50 55 Time (s) Deflection (mm)
  48. 48. Tubular vs. Conventional turnout
  49. 49. Comparative analysis A: End-of-beam C: End-of-beam B: Mid-beam
  50. 50. End of beam deflection: Position B A B C
  51. 51. Current developments <ul><li>PIV system comprising single data analysis software license with multiple video cameras </li></ul><ul><li>Stabilisation of the camera (accelerometer measurements) </li></ul><ul><li>Noise reduction (increased resolution and optical zoom) </li></ul><ul><li>Higher frequency sampling </li></ul><ul><li>At least two research projects </li></ul><ul><li>conducted at Centurion </li></ul><ul><li>station </li></ul>
  52. 52. Advantages <ul><li>Optical measurements </li></ul><ul><li>No calibration required </li></ul><ul><li>Equipment relatively simple, available and affordable </li></ul><ul><li>Data post-processing in the office </li></ul><ul><li>Calculation of track stiffness </li></ul><ul><li>Comparative analysis </li></ul><ul><li>Quick way of evaluating slacks, track </li></ul><ul><li>condition and transition areas </li></ul>
  53. 53. Acknowledgements <ul><li>Transnet Freight Rail (Track Technology) </li></ul><ul><li>Tubular Track (Pty) Ltd. </li></ul><ul><li>Motswedi TLC Software </li></ul><ul><li>University of Pretoria </li></ul>
  54. 54. Questions… Thank you for your attention!
  55. 55. References <ul><li>Adrian, R. J. Particle imaging techniques for experimental fluid mechanics. Ann. Rev. Fluid Mech ., 1991, 23, 261–304. </li></ul><ul><li>Bowness, D., Lock, A. C., Powrie, W., Priest, J. A. and Richards, D. J. Monitoring the dynamic displacements of railway track. Proc. IMechE , 2006, Vol. 221 Part F: J. Rail and Rapid Transit. </li></ul><ul><li>Van der Linde, I. The performance of the four Tubular turnouts which were installed during May – June 2007 in Ermelo shunting yard. Progress Report 1, A P.E.C. Report, 2008, May. </li></ul><ul><li>White, D. J., Take, W. A., and Bolton, M. D. Soil deformation measurement using particle image velocimetry (PIV) and photogrammetry. Géotechnique , 2003, 53(7), 619–631. </li></ul><ul><li>White, D. J. and Bolton, M. D. Displacement and strain paths during plane-strain model pile installation in sand. Géotechnique , 2004, 54(6), 375–397. </li></ul>

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Presented by: Prof. Hannes Grabe at the 2009 Railways and Harbours Conference in Cape Town.

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