Prepared YB April 2002

Laden Wagon with Y25 bogie

22T axle load
A/Rail model

The Template named ‘_Y25.tpl’ contains the template of a Y25 bogie in the tare condition.
The Template named ‘_Y25wagon_laden.tpl’ contains the template of a container wagon for the
assembly of the 22Tons axle load vehicle described here.

MASS PROPERTIES

Body M = kg Ixx = kg.m2 Iyy = kg.m2 Izz = kg.m2 Cog = m

(ARL)
1/2 body 40,000 47,500 510,000 500,500 1.87
Bogie 2,220 1,975 1,560 2,850 0.70
Axle box 20 5 5 5 0.42
Side bearer 25 10 10 10 0.84
Wst 1,300 688 100 688 0.42
● Wheelset tape circle distance = 1.5 [m]
● Rolling radius = 0.42 [m]
● Wagon body is separated in 2 rigid bodies with Cg +/- 4.815m along X-axis and linked with a revolute joint
with the torsion stiffness to be set up to match torsional test values or ∆Q/Q test when available
(reference_2): Torsional stiffness: 10.5 MN/m
● The side bearer mass and inertia can be modified according to the weight of the wagon for numerical
reasons. It is advisable to lower it down with a lighter vehicle.

GEOMETRY & LOADING PROPERTIES

● Bogie wheelbase = 1.80 metres

● Bogie pivot spacing = 15.70 metres

● Secondary total preload = 392,240.0 [N]

● Secondary side bearer preload (x2) = 19,282.0 [N]
● Secondary center bowl preload = 353,676.0 [N]
● Primary suspension preloads (tot) = 103,625.0 [N] per side
● Primary suspension preloads lad K = 37,450.0 [N] per bumpstop
(clearance = -18.725mm)
● Primary suspension preloads tare K = 14,362.5 [N] per coil spring
● Static Axle load (~22.0T) = 220,390.0 [N] per axle
● Static wheel load = 110,195.0 [N] per wheel

!! IMPORTANT NOTES:
The default Y25 template can be used to model wagons with various loads. The changes
have to be made at the subsystem level, following these rules:
● The two side bearers usually take 31% of the Tare Load; therefore the preloads
used here should not change.
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● The centre bowl alone takes the wagonload increase from the tare condition.
● For the primary suspension the equilibrium has to be found from the tare condition
adding the different loading stage:
○ Originally only the tare spring will take the load up to the 10mm clearance at
which the laden spring come into action.
○ Then find the equilibrium position considering the two springs in parallel. Be
careful of the different stages for the laden spring (i.e. if non-linear).
○ Input the preload in the tare spring and the position of the laden spring (e.g.
negative if laden).
Note: this method uses the assumption that the vertical position ARL of the bogie does not
change with loading.

SUSPENSION PROPERTIES

PRIMARY SUSPENSION

Suspension tare spring (A/Rail suspension element) / 2 per side:

dimensions from axle end: +/-0.135 +/-0.0 -0.094 (top) / 0.134 (bot) [m]
Properties: 7.0e5 7. 0e5 5.0e5 [N/m]
0.0 0.0 0.0 [Nm/rad]
Suspension Laden Spring (A/Rail bumpstop element):
dimensions from axle end: +/-0.135 +/-0.0 -0.094 (top) / 0.134 (bot) [m]
Properties: 10 (clearance in tare condition), -35.8 (22T laden case) [mm]
0.0 50 60 [mm]
0.0 100.0 700.0 [kN]
Lateral primary bumpstop (A/Rail bumpstop element) / 2 per side:
dimensions: one end on axle end (bogie) / the other on axle under wheel (abox)
Properties: 2.5 (clearance) [mm]
0.0 7.5 9.5 [mm]
0.0 23.13 220.00 [kN]

Out board friction surface (A/Rail Vforce element):

dimensions: +/- 0.15 0.0 0.0 (from axle end) [m]

Properties_Normal_Force: (defined using the a Spline 'BS1_out' and independant variable DX)
-5.0 0.0 2.0 [mm]
0.0 0.0 120.0 [kN]
This models the steel-to-steel contact. Tip: to create a straight-line interpolation between
two data points, a minimum of 4 'in-line' points is needed (see model).

Properties_Friction_Force: (defined for Y and Z direction based on Nicola Bosso's model, ref_2).
Fy = ( V y . ) / SQRT(1+((Vm. )/(N. ))**2)
Fz = ( Vz . ) / SQRT(1+((Vm. )/(N. ))**2)
With: Vy = relative velocity along Y-axis
Vz = relative velocity along Z-axis
Vm = relative velocity in the Y-Z plane
= tangent at the origin of the force/velocity transfer function = 3.0e6Ns/m

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N = Normal force (X-component of the Vforce)

= coefficient of friction = 0.4

In board friction surface (A/Rail Vforce element):

dimensions: +/- 0.15 0.0 0.0 (from axle end) [m]

Properties_Normal_Force: (static part defined using the a Spline 'BS2_in' and independant variable DX
+ dynamic part from TAN( ) of vertical force in tare spring).
-6.0 -4.0 0.0 5.0 [mm]
-120.644 -0.644 0.0 0.0 [kN]
+ tan(21.26°).Fz (tare)
This models the pendular stiffness of the link and the steel-to-steel contact when the
clearance of 4mm is used up. This formulation assumes that the Lenoir Link always
remain at an angle of 21.26 degrees. Tip: to create a straight-line interpolation between
two data points, a minimum of 4 'in-line' points is needed (see model).

Properties_Friction_Force: (defined for Y and Z direction based on Nicola Bosso's model, ref_2).
Fy = ( V y . ) / SQRT(1+((Vm. )/(N. ))**2)
Fz = ( Vz . ) / SQRT(1+((Vm. )/(N. ))**2)
With: Vy = relative velocity along Y-axis
Vz = relative velocity along Z-axis
Vm = relative velocity in the Y-Z plane
= tangant at the origin of the force/velocity transfer function = 3.0e6Ns/m
N = Normal force (X-component of the Vforce)
= coefficient of friction = 0.4

SECONDARY SUSPENSION

Centre Bowl (A/Rail bush element):

Height: 0.545 (ARL) [m]
Properties: 60e6 60e6 60e6 [N/m]
0.0 0.0 0.0 [Nm/rad]

Centre bowl spherical friction (A/Rail VTorque element):

Height: 0.545 (ARL) [m]

Properties_Friction_Force: (defined for rotations about X, Y and Z axis based on Nicola Bosso's
model, ref_2).
Fx = ( Wx . ) / SQRT(1+((Wm. )/(r.N. ))**2)
Fy = ( Wy . ) / SQRT(1+((Wm. )/(r.N. ))**2)
Fz = ( Wz . ) / SQRT(1+((Wm. )/(r.N. ))**2)
With: Wx = relative rotational velocity about X-axis
Wy = relative rotational velocity about Y-axis
Wz = relative rotational velocity about Z-axis
Wm = absolute relative velocity between body and bogie at centre bowl
= tangent at the origin of the force/velocity transfer function = 3.0e6Ns/m
N = Normal force (Z-component of the centre bowl bush element)
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= coefficient of friction = 0.19

r = centre bowl radius [m]

Side bearer device / 1 per side (1 notional mass, 1 planar joint, 1 bush element, 1 Vforce element):
Location: 0.0 +/-0.85 -0.84 [m]
2
Notional mass properties: M = 25 kg; [Ixx = Iyy = Izz = 10 kg.m ]
Planar joint properties: links notional mass to wagon body to restrict movement in XY plane.
Perpendicular Prim-joint: eliminate the rotation of the side bearer in the XY plane.
Bush element properties: (between bogie frame and wagon body)
Preload = 19,282 N (fixed 31% of the tare load either side)
Fx=f(disp(x)): 0.126 kN/mm stiffness with 1mm clearance either side, then 60kN/mm stiffness
Fy=f(disp(y)): 0.116 kN/mm stiffness
Fz=f(disp(z)): 0.570 kN/mm stiffness with:
compression: bumbstop clearance of 12mm, then 60kN/mm stiffness
extension: lift up around 33.83mm vertical displacement

Properties_Friction_Force: (define side bearer friction in the X-Y plane based on Nicola Bosso's
model, ref_2).
Fx = ( Vx . ) / SQRT(1+((Vm. )/(N. ))**2)
Fy = ( V y . ) / SQRT(1+((Vm. )/(N. ))**2)
With: Vx = relative velocity along X-axis
Vy = relative velocity along Y-axis
Vm = total relative velocity in the X-Y plane
= tangant at the origin of the force/velocity transfer function = 3.0e6Ns/m
N = Normal force (Z-component of the side bearer bush element)
= coefficient of friction = 0.35

Note: for all the friction force element, a variable is introduced to avoid division by zero and simulation
failure.

ADDITIONAL FEATURES

Turn table communicators:

single output communicators (x2) (in bogie template)

Name matching names entity minor role part name

table1 table1 mount inherit .wheelset1_part
table2 table2 mount inherit .wheelset2_part

Body wagon communicators: (x2) (for each half of the body wagon template)

Name matching names entity minor role part name

Body_front body mount front .ges_body_front
Body_rear body mount rear .ges_body_rear

Cruise control Communicators: (x1) (in coach body template) (only in 12.0)
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1. build a 'construction frame' where the force that controls the speed of the body has to be applied.
2. Orient the local Z-axis to have the same direction as the Global X-axis (i.e. -90,-90,0 in euler
sequence)
3. Create the following communicator:

Name matching names entity minor role part name

traction traction marker inherit .ges_body_front

Wagon body accelerometers:

Two markers attached to the wagon body were created above each bogie. Requests were created for the
lateral and vertical accelerations at these points.

SIMULATION SETTINGS

These are suggested settings for the static and dynamic analysis, but they can vary depending on the
type on analysis.

Static:
EQUILIBRIUM/
, ALIMIT = 5D
, ERROR = 0.001
, IMBALANCE = 0.1
, MAXIT = 100
, PATTERN = T:F:T:F:T:F:T:F:T:F
, STABILITY = 0.5
, TLIMIT = 0.001

Dynamic:
INTEGRATOR/
, GSTIFF
, HINIT = 0.00001
, HMAX = 0.001
, CORRECTOR = MODIFIED

VALIDATION NOTES

Parameter tuning:
● This parameter has to be tuned up for the friction to behave properly. A low value will lower down
the amount of friction and will give unsuitable results particularly at low frequency. A too high
value can generate solver problems for the sharper changes of force in the friction elements.
● The parameter has an influence on the vehicle stability mainly due to the changes in damping for
the bogie yaw.
● A suitable value for the parameter could range from 1.0E+06 to 8.0E+06 but it is advisable to test it
before hand depending on the type of analysis to be performed, the speed to be used, and the
frequency of the inputs.

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Hunting:
The Y25 bogie shows unstable hunting behaviour even at low speed. A test was perform with an initial
disturbed track of 30m and then undisturbed track. The vehicle was run at 15, 25 & 35m/s and for all
speed it was seen to be unstable wandering from flange to flange (see picture below). In reality the Y25
bogie is known to be unstable even at low speed and this behaviour could well be accurate.
Nevertheless further validation needs to be performed, and further test on the influence of the
Parameter on the hunting behaviour (here =3.0e6).

REFERENCES

Ref_1: "Resistance of Railway Vehicles to Derailment and Roll-Over", Railway Group Standard,
GM/RT2141, RAILTRACK PLC.

Ref_2: "Simulation of a freight bogie with friction damper", Bosso N., Gugliotta A., Somà A.,
Politecnico di Torino, 5th ADAMS/Rail users conference, Harlem, The Netherlands - May
2000.

Ref_3: "Validation of Dynamic Simulations of Rail Vehicles with Friction Damped Y25 Bogies", Evans
J.R., Rogers P.J., AEA Technology plc, Vehicle System Dynamics Supplement 28 (1998),
Swets & Zeitlinger.

Y25 Laden A/Rail page 6 April 2002