Effects of Buffer Friction on the Vehicle Behavior in ... · Effects of Buffer Friction on the...
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Effects of Buffer Friction on the
Vehicle Behavior in Switch Series
Dipl.-Ing. Claudia Kossmann
Stadler Altenrhein AG (Switzerland)
Dipl.-Ing. Karl Tillmetz
Stadler Bussnang AG (Switzerland)
SIMPACK User Meeting 2014
Claudia Kossmann SIMPACK User Meeting 2011 2
Shunting Locomotive Eem 923 – On Track soon
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Shunting Locomotive Eem 923 – Introduction
• 2-frequency – Hybrid – Locomotive BUTLER
with Electric and Diesel power
• Ordered by SBB Cargo for Cargo- and Shunting-Services
• Maximum speed 120 km/h
• Weight 40 – 45 t
Shunting Locomotive Eem 923
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Switch Series – Simulation and Measurement
• Requirement: Tests in Switch Series (SBB Infra R I-50007)
• Evaluation of ΣY forces (also Ymax, Qmax and Y/Q)
• Comparison with s-variable limit value for – Standard Switches (Rmin = 185 m)
– Double-Slip Switches (Rmin = 160 m)
Sophisticated
Coupling and Buffer
model
Switch Series – Simulation of S-curves
• Loco Eem 923 in combination with standard coach EW IV on reference track ‘Lausanne Main Station’
• Effect of traction forces (Push/Pull: -150 / 0 / +150 kN)
– leading loco v=const.
– trailing loco with max. traction force
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2x R160
2x R185
Coupling and Buffer
• Real Screw Coupling built up of
several elements
• Buffer Contact as convex Plate (R ~ 1.5 m)
with Slip Surface
– Steel (greased)
– Plastic inlay (low friction)
• Coupler absorber elements
– Elastomer pads
e.g. ‘Miner ST-9-2/170’, ...
• Buffer absorber elements
– Steel friction (conical rings)
e.g. ‘Ringfeder BLS110’, ...
– Elastomer pads
e.g. ‘Miner T-63-10/417’, ...
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Coupler
absorber
End Stop
Hook
Buffer
absorber
End Stops
convex
Buffer Plate
with
Slip Surface
Hook Buffer
Link
Nut L Nut R
Spindle
(+Lever)
Rod
Bern
Rectangle*
Buffer Plate
Contact+Friction
Coupling and Buffer model
• Buffer surface modelled as
‘Spherical Buffer Contact’ (MM-100, FE-018)
with friction (FE-100)
• Both Coupler and Buffer Absorber
modelled as Hysteresis Elements (FE-104+FE-018)
– Measured characteristics for
compression and expansion (could be improved
with more capable force element)
– Mechanical end stops (Buffer) (additional damping needed
due to high ratio of stiffness to mass)
– Pre-stressed initial state
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Coupling characteristic
(tension) Buffer characteristic
(pressure)
end stop
* Minimal space for shunter (in German: Berner Raum)
no end stop (dip)
Coupling
Spindle
Coupling
Bush
Buffer Plate
Bush
Coupling and Buffer substructure: Pre-stressed initial state
• Initial screw-in of Coupling Spindle normally ~ 3 turns* (dx = 42 mm)
Pressure forces on all 4 Buffer Plate Bushes
Tension forces on both Coupling Bushes
Screw Coupling assumed to be stretched and stiff
• Pre-calculation of initial displacements to get the correct working point in between both hysteresis curves (depending on combination of Buffer and Coupling Bush characteristics)
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* in Swiss German ‘drü Chäs’ [drɥ xæs] (literal interpretation: ‘three cheeses’)
• Compensation of the initial displacement inside the substructure
to keep nominal car lengths of the connected wagons (wagons can be placed on track in a nominal s-position)
Switch Series – Simulation / Buffer Model – Animation
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2x R185 2x R160
Switch Series – Measurements in Lausanne
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(SBB I-AT-FBI-IA-TNZ)
2+2 = Y, Q Rad-Schiene-Kräfte (Messradsatz)
2+1 = ypp0 Beschl. am Radsatz (Radlager)
3+3 = ypp*,zpp* Beschl. auf Wagenfussboden
2+2 = ypp*,zpp* Beschl. auf Tilger
4+2+4 = dx+, dy+, dz+ Wege in der Primärstufe
2 = dy* Wege in der "Sekundär"stufe
1 Messradsatz
4 Beschleunigungsgeber
10 Weggeber
1 Zugkraft (ab FLG)
1 Geschwindigkeit (ab FLG)
Fahrtrichtung vorwärts 1 Strecke (Kilometrierung) - optional
1 Kreiselgeschwindigkeit um Hochachse
• Measured quantities for evaluation of running safety in
switches
– Sum Y-Forces: measured by
instrumented wheelset
– Lateral displacements of
primary suspension
dy ~ ΣY
Switch Series – Measurements
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Switch Series – Measurement Results
• Comparison of measured and simulated lateral displacement
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trailing wheelset
leading wheelset
Switch Series – Measurement Results
• Consideration of friction between buffers
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trailing wheelset
leading wheelset
Switch Series – Measurement Results
• Asymmetric behaviour caused by different surface material of
Coach EW IV:
- one buffer with steel
- one buffer with plastic plate
• Consideration of different
friction coefficients in model
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Switch Series – Measurement Results
• Consideration of different friction coefficients
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trailing wheelset
leading wheelset
Switch Series – Buffer surfaces
• High friction effects with steel to steel contact
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Switch Series – Buffer surfaces
• Friction reduction with plastic plates
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Conclusions
• Sophisticated buffer model used for simulation of running
behaviour in switch series
• Comparison of simulation and measurement showed that
wheel-rail-forces highly depend on friction between buffers
• SIMPACK simulation helped to evaluate the friction coefficient
and to optimise the buffer surface of the shunting locomotive
Eem 923
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