Presentation on Weld Geometry Standards and RAILPROF FORCE-BASED ASSESSMENT OF WELD GEOMETRY. Coenraad Esveld

Transcription

1 FORCE-BASED ASSESSMENT OF WELD GEOMETRY Coenraad Esveld Delft University of Technology Esveld Consulting Services 1

2 TRACK LOADS Wavelength λ Frequency f Frequency f λ = v f λ[m] Wavelength Rolling defects Ballast and and Formation Welds Dynamic Forces Passenger comfort (Track Recording Cars) Wheels Wheels Hz Hz Hertzian Hertzian spring spring Hz Hz Bogie Bogie Hz Hz Sprung Sprung mass mass Hz Hz

3 TONNAGE BORNE ON NS PER % per 20 MGT 30 UIC 54 CWR 100% = 1700 km NP 46 CWR 100% = 1300 km Infraspeed contract ~ MGT years Tonnage [MGT]

4 TONNAGE BORNE ON UNION PACIFIC 4

5 DAMAGE DUE TO POOR WELD GEOMETRY 5

6 EXISTING WELD GEOMETRY STANDARDS Grind off top p < 0.3 mm For example Versine: 0 < p < 0.3 mm 6

7 ACCELERATION APPROACH Wheel follows rail irregularities; Dynamic part of contact force is governed by: F dyn (t) = Mz(t) && z M u(t) = z(t) dz F = Mv dx 2 2 dz dyn α 2 K v 7

8 VELOCITY APPROACH (1) Assumption: Equivalent wheel mass is proportional to wavelength: F (t) = M z(t) && dyn e with: 1 1 v M e = ML = M L L f 0 0 and: 2 π z && = z & v L 8

9 VELOCITY APPROACH (2) The dynamic contact force as a function of the first time derivative: 2 π v F dyn = M z & L 0 The dynamic contact force in terms of the spatial derivative, including calibration factor β: F dyn = M β L 0 v 2 dz dx 9

10 QUALITY INDICES (QI) dz F dx = = F dz norm dx norm max, actual max,actual QI = = 1 OK QI 1: Accepted QI > 1: Rejected 10

11 RAIL MANUFACTURING λ = 3m 2z 0 = 0.3mm z 2 x = z 0 sin π λ z0 sin π λ dz 2 π 2 π = z 0 = mrad dx λ 3 11

12 EXTENSION TO HEAVY HAUL AND HSL (1) Total wheel load versus velocity: M dz Q = Q + β v tot 2 = stat + β L 0 dx dz 1 L 0 1 <Δ Q dx β M v 2 Q max is approximately 450/2 kn = 225 kn M = 2,000 kg 12

13 EXTENSION TO HEAVY HAUL AND HSL (2) 13

14 EXTENSION TO HEAVY HAUL AND HSL (3) Intervention values for Heavy Haul and HSL lines: [kn] ΔQ v [m/s] dz dx β M L 0 Norm value [mrad] Conventional 225/ Heavy Haul 100/ High-Speed 280/

15 FORCE-BASED STANDARDS Velocity F Dyn Inclination Conventional HSL HH 40 km/h 80 km/h 140 km/h 200 km/h 300 km/h 100 km/h 5 kn 15 kn 35 kn 65 kn 140 kn 50 kn 3.2 mrad 2.4 mrad 1.8 mrad 0.9 mrad 0.7 mrad 1.4 mrad Implemented in RAILPROF Total force in principle 225 kn QI=1 15

16 NEW VERSUS OLD NORM z λ = 2m 2 x = z 0 sin π λ z0 sin π λ 2z 0 z 0 = 0.3mm Velocity 40 km/h 80 km/h 140 km/h Versine [mm] Inclination [mrad] dz 2 π = z0 dx λ 2 π = mrad km/h 300 km/h Old Norm For 80 km/h the new norm is 2.4 times more favorable than the old norm, provided short waves have been ground off. 16

17 LATERAL GEOMETRY STANDARDS Velocity 40 km/h 80 km/h 140 km/h 200 km/h 300 km/h Versine 1.0 mm 0.7 mm 0.5 mm 0.5 mm 0.5 mm Implemented in RAILPROF QI=1 17

18 ASSESSMENT OLD AND NEW ON PRORAIL RP RP Old norm: Rejected, New: OK Old norm: OK, New: Rejected RP RP Old norm: Rejected, New: OK Old norm: Rejected, New: Rejected 18

19 1 SELECTION ON PRORAIL % Cumulative Frequency % 31% 1.8 mrad (140 km/h) Limit at 80 km/h 100 welds per group CDF Moerdijk - Dordrecht (VSRT) Delft - Den Haag Lage Zwaluwe - Hollands Diep Weld Quality Index [-] (140 km/h) 19

20 1 OLD VERSUS NEW STANDARDS New Standards km/h Cumulative Frequency % Population 239 welds 58% 46% 3% Old Norm (0 0.3 mm) Independent of line speed 16 % passed Maximum Absolute. Inclination of Weld Geometry (25 mm base) [mrad] 20

21 DYNAMIC FORCE max. dyn. contact force [kn] y = 18,62x + 20,93 R 2 = 0,09 max. dyn. contact force [kn] y = 4,33x R 2 = 0, ,25 0,5 0,75 1 1, versine [mm] max. discretised gradient (5 mm basis) [mrad] Low correlation force and versine High correlation force and QI 21

22 HSL STANDARD The value of 0.5 mrad as max. inclination for HSL was changed to 0.7 mrad based on 100 measurements of new HSL rails; 97 % of rails is better than 0.7 mrad QI = 1; Standard can only be achieved by QI via Electronic Straightedge In new tracks apply grinding train (Plasser GWM). 22

23 RAIL & WELD GEOMETRY HSL % Cumulative distribution % QI = mrad Welds Rails QI for 300 km/h 23

24 1 WELD GRINDING HSL-SOUTH WITH GWM Cumulative Frequency (%) % % mrad CDF before grinding train after grinding train Weld Quality Index [-] 24

25 WELD STRAIGHTENING VIA STRAIT 25

26 F ~ 300 kn STRAIT 26

27 WELD GRINDING VIA PLASSER GWM 27

28 PLASSER GWM EXAMPLES Esveld, C.: STRAIT: Innovative Straightening of Welds, Rail International, Schienen der Welt, July

29 PRACTICAL IMPLEMENTATION (1) Procedure: Sample weld geometry with digital straightedge Filter measured signal Determine 1 st derivative (inclination) Normalize with intervention value for line speed Calculate QI. QI < 1: OK, otherwise: grinding. 29

30 PRACTICAL IMPLEMENTATION 30

31 EXAMPLES OF PDA SCREENS (1) 31

32 EXAMPLES OF PDA SCREENS (2) 32

33 EXAMPLES OF PDA SCREENS (3) Now seconds added 33

34 PDA SCREEN V = 140 km/h QI = 1.06 QI uniquely shows where to grind 34

35 RAILPROF INTERIOR 35

36 Data transfer to PC 36

37 DESKTOP SOFTWARE All data and graphs can be shown on a PC; Results in pdf-format can directly be ed to customer. 37

38 Example of HSL-South 38

39 CONCLUSIONS (1) 1. Theory based on first derivative works fine in practice; 2. Steel straightedge is absolutely inadequate; 3. Instead electronic straightedges with QI (RAILPROF); 4. High correlation of force and QI, low correlation with versine; 5. With RAILPROF QI measurement: You see what you do; Higher quality; Less rejections provided short waves are ground properly (also negative welds allowed); Extension of life cycle. 39

40 CONCLUSIONS (2) 6. New, high quality rails have a first derivative < 0.7 mrad; 7. Mechanical grinding (GWM) is inevitable to achieve such an accuracy for weld geometry; 8. The presented concept is very well applicable to heavy haul tracks and high-speed tracks. 40

41 CONCLUSIONS (3) 9. Validation will be carried out early 2006 by TU Delft: Dynamic track force measurements at welds for different trains at different speeds; Axle box acceleration measurements; RAILPROF measurements; Statistical analysis to determine relationships. Force Measurements with Gotscha RAILPROF Geometry Axle Box Accelerations 41

42 SOME EXAMPLES OF HSL SOUTH RP xml Serial year, month, day hh,mm,ss START OF DESKTOP SOFTWARE 42

43 43