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Rail Deflection
 

Rail Deflection

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

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

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Rail Deflection Rail Deflection Presentation Transcript

  • Track Deflection Measurement using Particle Image Velocimetry Hannes Gr äbe University of Pretoria Chair in Railway Engineering
  • Definition ? What is an Engineer Someone who knows how to measure !
  • Contents of presentation
    • Introduction
    • The need for deflection measurement
    • Applications of deflection measurement
    • Currents methods of track deflection measurement
    • The Particle Image Velocimetry (PIV) method
    • Measurements at three sites
    • Recent developments
    • Advantages of the system
    • Conclusions
  • Dynamic loading on non-rigid track deflection
  • Deflection measurement: Field tests
  • Deflection measurement: Lab testing
  • Deflection calculation: Analysis
  • Deflection measurement: Construction
  • Deflection measurement: Failures
  • Deflection measurement…
    • … is ESSENTIAL in:
    • Field tests
    • Laboratory tests
    • Numerical analysis
    • Construction
    • Failures and remedial measures
  • Instrumentation ? What capabilities should instrumentation have Reliability 1. Optical 2. Mechanical 3. Hydraulic 4. Pneumatic 5. Electrical Simplicity Quality Cost!
  • Track loading & deflection Ballast Subballast Subgrade 1 Subgrade 2
  • Electrical: Multi-Depth Deflectometer
  • MDD Installation
  • Field Instrumentation MDD module Load plate Soil sampling
  • MDD Results Time
  • Electrical: LVDT* * Linear Variable Differential Transducer
  • Electrical: LVDT* * Linear Variable Differential Transducer
  • Electrical: LVDT* * Linear Variable Differential Transducer
  • Mechanical: Sleeper deflection meter* * Design: Sakkie van der Linde
  • Mechanical: Geometry car measurements
  • Mechanical: Geometry car measurements Versine measurement Gauge measurement
  • Optical: Manual and digital level
  • Optic deflection measurement Particle Image Velocimetry (PIV) For optical track deflection measurement
  • Visual: Particle Image Velocimetry (PIV)
    • Particle Image Velocimetry (PIV) originated in the field of experimental fluid mechanics (Adrian, 1991)
    • Recent developments: Soil deformation measurements & Landfill settlement (White, Take & Bolton, 2003 & 2005)
    • 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.
      • The telescope magnifies the video images
      • Images are captured by the webcam
      • Images and analysed by a computer
      • Software calculation of horizontal and vertical displacement
  • Transnet Freight Rail PIV system
  • Target fixed to the rail
  • Target fixed to the rail * 2cm x 2cm square target
  • PIV Calibration
  • PIV System: Resolution * Standard deviation: 0.003 – 0.005mm
  • Applications of PIV Amandelbult Centurion Ermelo
  • Amandelbult
  • Amandelbult
  • Amandelbult PIV tests
  • Amandelbult: resolution
  • Amandelbult test results 32km/h 7km/h
  • Amandelbult: Camera vibration
  • Centurion station
  • Centurion station measurements Conventional track Tubular track
  • 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
  • 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
  • Ermelo Yard
  • Eremlo Yard
  • Ermelo Yard PIV measurements
  • Ermelo Yard PIV measurements
  • Ermelo Yard PIV measurements
  • 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)
  • Tubular vs. Conventional turnout
  • Comparative analysis A: End-of-beam C: End-of-beam B: Mid-beam
  • End of beam deflection: Position B A B C
  • Current developments
    • PIV system comprising single data analysis software license with multiple video cameras
    • Stabilisation of the camera (accelerometer measurements)
    • Noise reduction (increased resolution and optical zoom)
    • Higher frequency sampling
    • At least two research projects
    • conducted at Centurion
    • station
  • Advantages
    • Optical measurements
    • No calibration required
    • Equipment relatively simple, available and affordable
    • Data post-processing in the office
    • Calculation of track stiffness
    • Comparative analysis
    • Quick way of evaluating slacks, track
    • condition and transition areas
  • Acknowledgements
    • Transnet Freight Rail (Track Technology)
    • Tubular Track (Pty) Ltd.
    • Motswedi TLC Software
    • University of Pretoria
  • Questions… Thank you for your attention!
  • References
    • Adrian, R. J. Particle imaging techniques for experimental fluid mechanics. Ann. Rev. Fluid Mech ., 1991, 23, 261–304.
    • 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.
    • 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.
    • 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.
    • 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.