force-based assessment of weld geometry

ECSECS Presentation on Weld Geometry Standards and RAILPROFPresentation on Weld Geometry Standards and RAILPROF

www.esveld.comwww.esveld.com www.rail.tudelft.nlwww.rail.tudelft.nl

FORCE-BASED ASSESSMENTOF

WELD GEOMETRY

FORCE-BASED ASSESSMENTOF

WELD GEOMETRY

Coenraad EsveldCoenraad EsveldDelft University of Technology

Esveld Consulting ServicesDelft University of Technology

Esveld Consulting Services

TRACK LOADSTRACK LOADS • Wavelength λ• Frequency f• Wavelength λ• Frequency f λ =

λ =vf

λ[m]λ[m]

Rollin

Hertzian spring

Hertzian springW

Wheels

BogieBogie

Sprung mass

Sprung mass1000-100 Hz

1000-100 Hz

100-20 Hz

20-5 Hz

5-0.7 Hz

0.30.3 33 1010 120

Dynamic ForcesDynamic Forces Passenger comfort (Track Recording Cars)Passenger comfort (Track Recording Cars)

Tonnage [MGT]

% per 20 MGT

UIC 54 CWR 100% = 1700 km

0 50 100 150 200 250 300 350

NP 46 CWR 100% = 1300 km

TONNAGE BORNE ON NS PER 01-01-1988 TONNAGE BORNE ON NS PER 01-01-1988

25 - 30 years25 - 30 yearsInfraspeed contract ~ 750 - 900 MGTInfraspeed contract ~ 750 - 900 MGT

TONNAGE BORNE ON UNION PACIFIC TONNAGE BORNE ON UNION PACIFIC

DAMAGE DUE TO POOR WELD GEOMETRYDAMAGE DUE TO POOR WELD GEOMETRY

EXISTING WELD GEOMETRY STANDARDSEXISTING WELD GEOMETRY STANDARDS

For exampleVersine: 0 < p < 0.3 mmFor exampleVersine: 0 < p < 0.3 mm

p < 0.3 mmp < 0.3 mm

Grind off topGrind off top

Wheel follows rail irregularities;Dynamic part of contact force is governed by:Wheel follows rail irregularities;Dynamic part of contact force is governed by:

u(t) = z(t) M

dynF (t) = Mz(t)&&dynF (t) = Mz(t)&&

d zF = Mv

ACCELERATION APPROACHACCELERATION APPROACH

with:with:

dyn eF (t) M z(t)= &&dyn eF (t) M z(t)= &&

VELOCITY APPROACH (1)VELOCITY APPROACH (1)Assumption: Equivalent wheel mass is proportional to wavelength:Assumption: Equivalent wheel mass is proportional to wavelength:

1 1 vM ML M

L L f= =e

1 1 vM ML M

L L f= = 2 v

z zLπ

=&& &2 v

z zLπ

=&& &and:and:

The dynamic contact force as a function of the first time derivative:The dynamic contact force as a function of the first time derivative:

2 vF M z

= &dyn0

2 vF M z

VELOCITY APPROACH (2)VELOCITY APPROACH (2)

The dynamic contact force in terms of the spatial derivative, including calibration factor β:The dynamic contact force in terms of the spatial derivative, including calibration factor β:

M dzF v

L dxβ= 2

M dzF v

L dxβ=

QI ≤ 1: Accepted QI > 1: RejectedQI ≤ 1: Accepted QI > 1: Rejected

max, actual max,actual

dzF dx

QI 1 OKdzFdx

= = ≤ ⇒max, actual max,actual

dzF dx

QI 1 OKdzFdx

= = ≤ ⇒

QUALITY INDICES (QI)QUALITY INDICES (QI)

0dz 2 2

z 0.15 0.3 mraddx 3

π πλ

= = ≈0dz 2 2

z 0.15 0.3 mraddx 3

π πλ

= = ≈

RAIL MANUFACTURINGRAIL MANUFACTURING3mλ = 3mλ =

02z 0.3mm=02z 0.3mm=

z z sinπλ

= 02 x

z z sinπλ

2tot stat

M dzQ Q v

L dxdz 1 L 1

Qdx M v

= + ⇒

2tot stat

M dzQ Q v

L dxdz 1 L 1

Qdx M v

= + ⇒

EXTENSION TO HEAVY HAUL AND HSL (1)EXTENSION TO HEAVY HAUL AND HSL (1)

Total wheel load versus velocity:Total wheel load versus velocity:

Qmax is approximately 450/2 kN = 225 kNM = 2,000 kgQmax is approximately 450/2 kN = 225 kNM = 2,000 kg

Intervention values for Heavy Haul and HSL lines:Intervention values for Heavy Haul and HSL lines:

0.50.01985280/2High-Speed

1.40.05630100/2Heavy Haul

1.80.07040225/2Conventional

Norm value[mrad]

v [m/s][kN]

0.50.01985280/2High-Speed

1.40.05630100/2Heavy Haul

Norm value[mrad]

v [m/s][kN]

dz Mdx L

0.50.01985280/2High-Speed

1.40.05630100/2Heavy Haul

Norm value[mrad]

v [m/s][kN]

0.50.01985280/2High-Speed

1.40.05630100/2Heavy Haul

Norm value[mrad]

v [m/s][kN]

dz Mdx L

β⋅QΔ

FORCE-BASED STANDARDSFORCE-BASED STANDARDS

1.4 mrad50 kN100 km/h

InclinationFDynVelocity

3.2 mrad5 kN40 km/h

QI=1QI=1

NEW VERSUS OLD NORMNEW VERSUS OLD NORM

1.00.30Old Norm

0.70.21300 km/h

Inclination [mrad]

Versine[mm]

Velocity

0.90.27200 km/h

1.80.54140 km/h

2.40.7280 km/h

3.20.9640 km/h

20.3 1.0 mrad

πλπ

20.3 1.0 mrad

πλπ

z z sinπλ

= 02 x

z z sinπλ

2mλ = 2mλ =

02z02z

0z 0.3mm=0z 0.3mm=

For 80 km/h the new norm is 2.4 times more favorable than the old norm, provided short waves have been ground off.For 80 km/h the new norm is 2.4 times more favorable than the old norm, provided short waves have been ground off.

LATERAL GEOMETRY STANDARDSLATERAL GEOMETRY STANDARDS

0.5 mm300 km/h

VersineVelocity

0.5 mm200 km/h

0.5 mm140 km/h

0.7 mm80 km/h

1.0 mm40 km/h

QI=1QI=1

ASSESSMENT OLD AND NEW ON PRORAILASSESSMENT OLD AND NEW ON PRORAIL

RP002432RP002432

RP002945RP002945

RP002949RP002949

RP003125RP003125

Old norm: Rejected, New: OK

Old norm: OK, New: Rejected

Old norm: Rejected, New: Rejected

SELECTION ON PRORAILSELECTION ON PRORAIL

CDFMoerdijk - Dordrecht (VSRT)Delft - Den HaagLage Zwaluwe - Hollands Diep

0 1 2 3 4 5 6 7 8 9Weld Quality Index [-] (140 km/h)

1.8 mrad (140 km/h)1.8 mrad (140 km/h)

Limit at 80 km/hLimit at 80 km/h

100 welds per group100 welds per group

OLD VERSUS NEW STANDARDSOLD VERSUS NEW STANDARDS

0 1 2 3 4 5 6 7 8 9 10 11 12 13Maximum Absolute Inclination of Weld Geometry (25 mm base) [mrad].

New Standards300 140 80 40 km/h

Old Norm (0 – 0.3 mm)Independent of line speed16 % passed

73% Population 239 welds

DYNAMIC FORCEDYNAMIC FORCE

y = 18,62x + 20,93R2 = 0,09

0 0,25 0,5 0,75 1 1,25

versine [mm]

N] y = 4,33x

R2 = 0,91

0 5 10 15 20

max. discretised gradient (5 mm basis) [mrad]m

Low correlationforce and versineLow correlation

force and versineHigh correlation

force and QIHigh correlation

force and QI

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 StraightedgeIn new tracks apply grinding train (Plasser GWM).

HSL STANDARDHSL STANDARD

RAIL & WELD GEOMETRY HSLRAIL & WELD GEOMETRY HSL

100.00

QI for 300 km /h

W eldsRails

97 %97 %

CDFbefore grinding trainafter grinding train

0 1 2 3 4 5Weld Quality Index [-]

WELD GRINDING HSL-SOUTH WITH GWMWELD GRINDING HSL-SOUTH WITH GWM

WELD STRAIGHTENING VIA STRAITWELD STRAIGHTENING VIA STRAIT

F ~ 300 kNF ~ 300 kNSTRAITSTRAIT

WELD GRINDING VIA PLASSER GWMWELD GRINDING VIA PLASSER GWM

PLASSER GWM EXAMPLESPLASSER GWM EXAMPLES

Esveld, C.: ‘STRAIT: Innovative Straightening of Welds, Rail International, Schienen der Welt, July 1983.

Procedure:Sample weld geometry with digital straightedgeFilter measured signalDetermine 1st derivative (inclination)Normalize with intervention value for line speed Calculate QI.QI < 1: OK, otherwise: grinding.

PRACTICAL IMPLEMENTATION (1)PRACTICAL IMPLEMENTATION (1)

PRACTICAL IMPLEMENTATIONPRACTICAL IMPLEMENTATION

EXAMPLES OF PDA SCREENS (1)EXAMPLES OF PDA SCREENS (1)

Now seconds addedNow seconds added

PDA SCREENPDA SCREEN

V = 140 km/hQI = 1.06V = 140 km/hQI = 1.06

QI uniquely shows where to grindQI uniquely shows where to grind

RAILPROF INTERIORRAILPROF INTERIOR

Data transfer to PC

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

CONCLUSIONS (1)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.

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.

CONCLUSIONS (2)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.

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.

CONCLUSIONS (3)CONCLUSIONS (3)9. Validation will be carried out early 2006 by TU Delft:

Dynamic track force measurements at welds for different trains atdifferent speeds;Axle box acceleration measurements;RAILPROF measurements;Statistical analysis to determine relationships.

9. Validation will be carried out early 2006 by TU Delft:Dynamic track force measurements at welds for different trains atdifferent speeds;Axle box acceleration measurements;RAILPROF measurements;Statistical analysis to determine relationships.

RAILPROF Geometry

Force Measurements with Gotscha

Axle Box Accelerations

SOME EXAMPLES OF HSL SOUTHSOME EXAMPLES OF HSL SOUTH

START OF DESKTOP SOFTWARESTART OF DESKTOP SOFTWARE

RP430320051017133533.xmlRP430320051017133533.xmlSerialSerial year, month, dayyear, month, day hh,mm,sshh,mm,ss

www.esveld.comwww.esveld.com

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