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FORCE-BASED ASSESSMENT
OFWELD GEOMETRY
FORCE-BASED ASSESSMENT
OFWELD GEOMETRY
Coenraad EsveldCoenraad EsveldDelft University of Technology
Esveld Consulting ServicesDelft University of Technology
Esveld Consulting Services
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DAMAGE DUE TO POOR WELD GEOMETRYDAMAGE DUE TO POOR WELD GEOMETRY
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EXISTING WELD GEOMETRY STANDARDSEXISTING WELD GEOMETRY STANDARDS
For example
Versine: 0 < p < 0.3 mm
For example
Versine: 0 < p < 0.3 mm
p < 0.3 mmp < 0.3 mm
Grind off topGrind off top
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The dynamic contact force as a function of the first
time derivative:
The dynamic contact force as a function of the first
time derivative:
VELOCITY APPROACHVELOCITY APPROACH
z
v
u(t) = z(t) M
K
2dyn
dzF C v* dx
2dyn
dzF C v* dx
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QI ≤ 1: Accepted QI > 1: Rejected
QI ≤ 1: Accepted QI > 1: Rejected
QUALITY INDICES (QI)QUALITY INDICES (QI)
max max
norm
norm
dzF dxQI 1 OK
dzFdx
max max
norm
norm
dzF dxQI 1 OK
dzFdx
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FORCE-BASED STANDARDSFORCE-BASED STANDARDS
Velocity FDyn Inclination
40 km/h 5 kN 3.2 mrad
80 km/h 15 kN 2.4 mrad
140 km/h 35 kN 1.8 mrad
200 km/h 65 kN 0.9 mrad
300 km/h 140 kN 0.7 mrad
100 km/h 50 kN 1.4 mrad
QI=1QI=1
Co
nve
ntio
nal
Co
nve
ntio
nal
HS
LH
SL
HH
HH
Imp
lem
ente
d in
RA
ILP
RO
FIm
ple
men
ted
in R
AIL
PR
OF
To
tal f
orc
e in
pri
nci
ple
22
5 k
NT
ota
l fo
rce
in p
rin
cip
le 2
25
kN
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NEW VERSUS OLD NORMNEW VERSUS OLD NORM
VelocityVersine
[mm]Inclination
[mrad]
40 km/h 0.96 3.2
80 km/h 0.72 2.4
140 km/h 0.54 1.8
200 km/h 0.27 0.9
300 km/h 0.21 0.7
Old Norm 0.30 1.0
0
dz 2z
dx2
0.3 1.0mrad2
0
dz 2z
dx2
0.3 1.0mrad2
0
2 xz z sin
0
2 xz z sin
2m 2m
02z02z
0z 0.3mm0z 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.
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LATERAL GEOMETRY STANDARDSLATERAL GEOMETRY STANDARDS
Velocity Versine
40 km/h 1.0 mm
80 km/h 0.7 mm
140 km/h 0.5 mm
200 km/h 0.5 mm
300 km/h 0.5 mm
QI=1QI=1
Imp
lem
ente
d in
RA
ILP
RO
FIm
ple
men
ted
in R
AIL
PR
OF
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ASSESSMENT OLD AND NEW ON PRORAILASSESSMENT OLD AND NEW ON PRORAIL
RP002432RP002432
RP002945RP002945
RP002949RP002949
RP003125RP003125
Old norm: Rejected, New: OK
Old norm: Rejected, New: OK
Old norm: OK, New: Rejected
Old norm: Rejected, New: Rejected
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SELECTION ON PRORAILSELECTION ON PRORAIL
0
0 .2
0 .4
0 .6
0 .8
1
Cum
ulat
ive
Fre
que
ncy
C D FM oerd ijk - D ord rech t (V S R T)
D e lft - D en H aag
Lage Zw a luw e - H o lland s D iep
0 1 2 3 4 5 6 7 8 9W eld Q ua lity Inde x [-] (140 km /h)
8 1%
60%
3 1%
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
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OLD VERSUS NEW STANDARDSOLD VERSUS NEW STANDARDS
0
0.2
0.4
0.6
0.8
1
Cum
ulat
ive
Fre
quen
cy
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Maximum Absolute Inclination of Weld Geometry (25 mm base) [mrad].
46%
New Standards300 140 80 40 km/h
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
3%
58%
73%Population 239 welds
0
0.2
0.4
0.6
0.8
1
Cum
ulat
ive
Fre
quen
cy
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Maximum Absolute Inclination of Weld Geometry (25 mm base) [mrad].
46%
New Standards300 140 80 40 km/h
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
3%
58%
73%Population 239 welds
QI norm at 140 km/h is 3 times more favorable than old norm
0
0.2
0.4
0.6
0.8
1
Cum
ulat
ive
Fre
quen
cy
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Maximum Absolute Inclination of Weld Geometry (25 mm base) [mrad].
46%
New Standards300 140 80 40 km/h
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
3%
58%
73%Population 239 welds
0
0.2
0.4
0.6
0.8
1
Cum
ulat
ive
Fre
quen
cy
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Maximum Absolute Inclination of Weld Geometry (25 mm base) [mrad].
46%
New Standards300 140 80 40 km/h
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
Old Norm (0 – 0.3 mm) isindependent of line speed16 % passed
3%
58%
73%Population 239 welds
QI norm at 140 km/h is 3 times more favorable than old norm
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y = 18,62x + 20,93
R2 = 0,09
0
50
100
150
0 0,25 0,5 0,75 1 1,25 1,5
versine [mm]
max
. dyn
. co
nta
ct f
orc
e [k
N] y = 4,33x
R2 = 0,91
0
50
100
150
0 5 10 15 20 25
max. discretised gradient (5 mm basis) [mrad]
max
. dyn
. co
nta
ct f
orc
e [k
N]
Low correlationforce and versineLow correlation
force and versineHigh correlation
force and QIHigh correlation
force and QI
CALCULATED DYNAMIC FORCESCALCULATED DYNAMIC FORCES
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Dynamic force linear with QI
Dynamic force linear with QI
Dynamic force linearwith train speed
Dynamic force linearwith train speed
0
20
40
60
80
100
120
140
160
0 2 4 6 8 10
max. weld slope [mrad]
F d
yn [
kN]
v = 300 km/h
v = 140 km/h
v = 80 km/h
v = 40 km/h
y = 0,28x
R2 = 0,98
0
20
40
60
80
100
0 50 100 150 200 250 300
train speed [km/h]
F d
yn [
kN]
slope: 5 mrad
CALCULATED DYNAMIC FORCESCALCULATED DYNAMIC FORCES
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AXLE BOX ACCELERATIONSAXLE BOX ACCELERATIONS
Dynamic amplification less
than 2.2
Dynamic amplification less
than 2.2
y = 0,23x + 1,11
R2 = 0,59
1
1,2
1,4
1,6
1,8
2
2,2
0 0,5 1 1,5 2 2,5 3
QI (140 km/h)
DA
F (
75
0 H
z)
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Procedure: Sample weld geometry with digital straightedge Filter measured signal Determine 1st derivative (inclination) Normalize with intervention value for line speed Calculate QI. QI < 1: OK, otherwise: grinding.
Procedure: Sample weld geometry with digital straightedge Filter measured signal Determine 1st derivative (inclination) Normalize with intervention value for line speed Calculate QI. QI < 1: OK, otherwise: grinding.
PRACTICAL IMPLEMENTATIONPRACTICAL IMPLEMENTATION
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PRACTICAL IMPLEMENTATIONPRACTICAL IMPLEMENTATION
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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
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DES
KTO
P
SO
FTW
AR
ED
ES
KTO
P
SO
FTW
AR
E
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.
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CONCLUSIONSCONCLUSIONS
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.
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