Poster Pereira Manuel

7/31/2019 Poster Pereira Manuel

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Challenge E: Bringing the territories closer together at higher speeds

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Influence of Pantograph Characteristics on the Overhead ContactQuality for High Speed Trains

Joo Pombo, Jorge Ambrsio, Manuel Pereira

IDMEC/Instituto Superior Tcnico, Technical University of LisbonAv. Rovisco Pais 1, 1049-001 Lisbon, Portugal

Abstract

In general, the motorized units of the trainsets are powered through the pantograph-catenary system.The study of this system is of great interest to the railway industry as it contributes to decrease thenumber of incidents related to these components and to reduce the maintenance and interoperabilitydevelopment costs. In this work, a validated computational tool is used to study the pantograph-catenary interaction in order to assess on how the contact quality is sensitive to the pantographcomponents. For this purpose, several pantograph parameters are varied and the contact forceresults are compared against the ones obtained with the nominal case. These studies are performed

for high speed trains running at velocities of 250, 300 and 350 km/h.

1 IntroductionThe interaction between the moving rolling stock and the overhead contact line is one of the factorsthat limits the operating speed of railway vehicles and, consequently, is one of the research prioritiesin the railway community. These limitations concern not only the ability to collect energy at highspeeds but also address the interoperability of the overhead equipment when trains are required tooperate in different railway networks. The pantograph-catenary system should ideally run withrelatively low contact forces, in order to minimize wear and damage of the contacting elements, butwith high enough forces to prevent contact loss, which interrupt the power supply and promote theoccurrence of electric arcing. Therefore, the design of these systems aims at controlling thepantograph-catenary interaction phenomena maintaining the contact forces within admissible

operational intervals.From the mechanical point of view, the most important feature of the pantograph-catenary systemconsists in the quality of the contact between the contact wire(s) of the catenary and the registrationstrips of the pantograph. Therefore, the study of this system requires not only the correct modelling ofthe catenary and of the pantograph, but also a suitable contact model to describe the interactionbetween them. In this work, a validated computational tool is used to study the pantograph-catenaryinteraction. The software is composed by two modules, the Finite Element (FE) one is used todescribe the catenary and the Multibody (MB) module is applied to represent the pantograph. As theFE and the MB codes use different time integration algorithms, a co-simulation procedure that allowsthe communication between the modules using shared computer memory and suitable contact forcemodels, is implemented [1-3]. In order to enable industrial application, an extra concern of this toolwas the development of very efficient algorithms in what computational time is concerned.

Among the factors that affect the quality of the pantograph-catenary contact are those related to

the defects on the catenary or pantograph, environmental conditions, such as wind [4,5] and extremetemperatures [6], running dynamics of the railway vehicle and the deformability of the pantographmechanical system [7,8]. The study on how the characteristics of the structural components of thepantograph, and the respective linking elements, affect the quality of the pantograph-catenary contactconstitutes an issue seldom taken into account.

The work presented here aims at enhancing the understanding of the pantograph-catenaryinteraction phenomena by identifying the key parameters, associated to the pantograph, that affectthe contact forces and the accuracy of results. A multibody formulation is used to model thepantograph and the catenary is modelled in a linear finite element code. By using a co-simulationprocedure the dynamics of the pantograph is effectively coupled with that of the catenary,representing the complete system interaction [1,3]. A range of relevant interoperable designconfigurations of the pantograph are considered, including their geometric and mechanical featuressuch as masses, springs, dampers and registration strip characteristics. Since the pantograph-

catenary interaction is particularly sensitive to the type of catenary, a special attention will be paid tothe catenary configuration and to the corresponding elements used to build the models.


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The numerical simulations performed here involve varying the pantograph parameters in a rangeof +/- 10%, compare the contact forces against the ones obtained with the nominal case and discussthe results in face of the components that were varied. These studies can be viewed as a sensitivityanalysis for the pantograph components, which allow assessing on how much a variation of a mass,stiffness or damping property affects the contact quality on the overhead power system. The analysesare carried out for high speed trains running at velocities of 250, 300 and 350 km/h. The influence of

the modelling parameters on the pantograph-catenary interaction is assessed according to theEuropean standards [9,10]. In this regard, the characteristics of the contact forces and the loss ofcontact events are studied with detail.

2 Pantographs-Catenary Analysis Methodology2.1 Multibody methodology for pantograph modelling

The pantograph considered in this work is the Faiveley CX pantograph, shown in Figure 1, which isused in the French high speed trains. By performing laboratory tests, it is possible to represent thedynamic behaviour of the CX pantograph by the so-called lumped mass model, represented in Figure2. The mass, stiffness and damping properties of the lumped mass model are obtained experimentallyin such a way that its frequency response matches the one of the real pantograph.

Figure 1: Faiveley CX pantograph

2.1.1 Rigid bodies data

The lumped mass model of the CX pantograph is build using a multibody methodology [11-16] inwhich each component is treated as a rigid body. This construction involves defining the data for therigid bodies, kinematic joints, linear force elements and registration strips for the pantograph-catenarycontact. The four rigid bodies used to represent the lumped mass pantograph are defined accordingto the data presented in Table 1. This information includes the mass, the inertia properties withrespect to their principal axes ( , , ) and the initial position and orientation of each body with respectto the reference frame ( , , x y z ) associated to the pantograph subsystem. The first column of thetable represents the reference numbers that identify the bodies in the model.

ID RigidBodyMass(Kg)

Inertia Properties (Kg.m ) Initial Position (m) Initial OrientationI / I / I x 0 / y 0 / z0 e 1 / e 2 / e 3

1 m 1 1.00 1.000 / 1.000 / 1.000 0.00 / 0.00 / 0.00 0.00 / 0.00 / 0.00

2 m 2 4.80 0.306 / 10.430 / 10.650 0.00 / 0.00 / 0.50 0.00 / 0.00 / 0.003 m 3 4.63 0.147 / 7.763 / 7.862 0.00 / 0.00 / 0.80 0.00 / 0.00 / 0.00

4 m 4 8.50 0.208 / 1.592 / 1.777 0.00 / 0.00 / 1.00 0.00 / 0.00 / 0.00

Table 1: Rigid bodies data for the CX lumped mass pantograph multibody model

A local reference frame ( , , ) is rigidly attached to the center of mass of each body in such a waythat the axes are aligned with the principal inertia directions of the bodies. In this way, the inertiatensor of the bodies is completely defined by the inertia moments I , I and I . Also notice that theinitial position and orientation of each body in the subsystem are given, respectively, by the location ofits center of mass and by the orientation of its local reference frame with respect to the subsystemreference frame ( , , x y z ).


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Figure 2: Lumped mass model of the CX pantograph

When defining the input data for the rigid bodies that compose the lumped mass pantograph, it isalso necessary to provide information about the external constant forces and moments that areassociated to each one of the bodies and that remain constant during the dynamic analysis. The onlyvalue that is not null is the vertical static contact force F Static on the upper body, as represented inFigure 2. This force has a value of 170 N and it represents the mean vertical force exerted upwardsby the pantograph head on the overhead contact line, and caused by the pantograph lifting device,whilst the pantograph is raised and the vehicle is at standstill.

2.1.2 Kinematic joints data

After the description of the data for the rigid bodies, it is necessary to define the information about thekinematic joints that compose the multibody model of the lumped mass CX pantograph. In amultibody system, the kinematic joints are used to connect the bodies in order to restrain some oftheir relative motions. Such joints are expressed as algebraic constraint equations that introducekinematic relations between the coordinates that describe the system [11-16].

In the case studied here three prismatic joints are used. The prismatic joints restrain the motion

between two bodies i and j , only allowing them to move along a common axis and without rotatingrelative to each other, as depicted in Figure 3. The kinematic conditions [12] require that the vectors s i and s j, belonging to bodies i and j and having constant magnitude, and the vector d, of variablemagnitude, remain collinear all the time. The additional condition that is necessary to define theprismatic joint requires that two perpendicular vectors h i and h j, on bodies i and j , always remainperpendicular. Therefore, five constraint equations are needed to define this kinematic joint, whichmeans that there is only one relative degree of freedom between two bodies connected by a prismatic

joint.

Figure 3: Prismatic joints in the lumped mass model

As input data, the prismatic joint requires the positions of points P and Q in bodies i and j . Noticethat the pair of points P i and Q i is defined in the body i coordinate frame, whereas the pair P j and Q j isdefined in the body j coordinate frame. All points must be defined in such a way that they are aligned

m 1

m 3

m 2

k 3-4

c 3-4

k 2-3

c 2-3

k 1-2

c1-2

m 4F Static Catenary

(j)

j

j

(i)

i

i

i

x

z

y

iPis

jP

jQ

iQ

s

d

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ir

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jh


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with the axis of the prismatic joint, as shown in Figure 3. In Table 2 the data required to define thekinematic joints for the multibody model of the CX pantograph is presented.

Kinematic JointConnected

BodiesAttachment Points Local Coordinates (m)

Body i Body j i j i / i / i j / j / j

Pris 1-2 1 2 (0.00 / 0.00 / 0.00) P (0.00 / 0.00 / -1.00) Q (0.00 / 0.00 / 0.00) P (0.00 / 0.00 / 1.00) Q

Pris 2-3 2 3(0.00 / 0.00 / 0.00) P (0.00 / 0.00 / -1.00) Q

(0.00 / 0.00 / 0.00) P (0.00 / 0.00 / 1.00) Q

Pris 3-4 3 4(0.00 / 0.00 / 0.00) P (0.00 / 0.00 / -1.00) Q

(0.00 / 0.00 / 0.00) P (0.00 / 0.00 / 1.00) Q

Table 2: Kinematic joints data for CX lumped mass pantograph multibody model

2.1.3 Linear force elements data

The next step for the construction of the multibody model is the definition of the linear force elementsthat compose the CX lumped mass pantograph. These elements, depicted in Figure 2, represent the

internal forces that develop between the bodies that are connected by linear springs and dampers.Such internal forces depend on the relative motion between the bodies during the dynamic analysis.In Table 3 the data required to define the three linear force elements that exist in the lumped massmodel is presented, where k is the spring stiffness, L0 is the undeformed length and c is the dampingcoefficient.

LinearForce

Element

Spring Elements c (N.s/m)

Bodies Attach Pts Local Coord (m)Body i Body j k (N/m) L0 (m) i j I / I / i j / j / j

k1-2, c 1-2 1 176.39 32 1 2 0.0 / 0.0 / 0.0 0.0 / 0.0 / 0.0

k2-3, c 2-3 5400 0.3239 5 2 3 0.0 / 0.0 / 0.0 0.0 / 0.0 / 0.0

k3-4, c 3-4 6045 0.2138 10 3 4 0.0 / 0.0 / 0.0 0.0 / 0.0 / 0.0

Table 3: Linear force elements data for CX lumped mass pantograph model

The undeformed length of each spring L0 is calculated in such a way that the bodies are in staticequilibrium when the dynamic analysis starts. This means that the spring increment, resultant fromthe difference between the undeformed length and the assembled length of each spring, produces anelastic force that balances the gravity forces of the bodies that are supported by the spring.

2.1.4 Registration strips data

The last step for the construction of the multibody model of the CX pantograph is the definition of theregistration strips, i.e., the bodies that touch the catenary and to which the contact forces, resultantfrom the pantograph-catenary interaction, are applied to. In Table 4 the data required to define theregistration strip that exists on the CX lumped mass pantograph is presented, where points P and Q represent the start and end points of the pantograph collector.

Body Point P Local Coord. (m) Point Q Local Coord. (m)

/ / / /

4 0.000 / 0.350 / 0.000 0.000 / 0.350 / 0.000

Table 4: Registration strips data for CX lumped mass pantograph multibody model

2.2 Linear finite elements for catenary modelling

Catenaries are complex periodical structures, such as those presented in Figure 4. Examples oftypical structural elements involved in the catenary model are the contact, stitch and messengerwires, droppers and registration arms. Depending on the catenary system there are other elementsthat may have to be considered. In any case, the contact wire is the responsible for the contactbetween catenary and pantograph and, therefore, is the element that provides electrical power. The


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contact wire is characterized by a small cross-section compared to its length and built in a materialwith good electrical conductivity and mechanical properties such as copper or steel alloys. Themessenger wire prevents excessive sag caused by the contact wire weight. Both of these wires areconnected by vertical, tensile force elements called droppers.

Even in a single European country there is a large variety of aerial catenary systems in use withdifferent particularities in their construction. The contact and messenger wires are primarily

suspended at the masts. Depending on the topology of the track and on the exposure to transversalwinds the masts are placed at a distance of 27 m to 63 m from each other. To maintain a constantmechanical stiffness of the contact wire, a set of elements are used to suspend the contact wire atthese locations, which are specific of each catenary type. In the French 25 kV catenary represented inFigure 4 the contact wire is suspended by a low inertial element called the steady arm which is linkedto the registration arm. The latter is suspended with respect to the messenger wire by the stitch wireand is connected by a hinge to the mast. This solution aims at limiting the dynamic coupling betweenthe contact wire and the supporting elements. To minimize the spatial curve described by the contactwire and to maximize the wave propagation velocity of the contact wire a static load is applied to itsextremities. If seen from the top, the contact wire is suspended forming a zig-zag around thelongitudinal direction, designated by stagger. This geometric characteristic originates the variation ofthe contact point location on the collector, which enables a constant and optimized wear of thepantograph registration strip.

Figure 4: Representation of a SNCF 25 kV suspended catenary and its 3D finite element modelThe motion of the catenary is characterized by small rotations and deformations in which the only

nonlinear effect is the slacking of the droppers. Therefore, catenaries are typically modelled by usinglinear finite elements. The main catenary elements, the contact and messenger wires are modelled byusing pre-tensioned Euler-Bernoulli beams.

2.3 Co-simulation of the multibody and finite element codes

The analysis of the pantograph-catenary interaction is done by two independent codes, thepantograph code, which uses a multibody formulation, and the catenary code, that is a finite elementsoftware. Both programs can work as stand-alone codes. The structure of the communicationbetween the codes is shown in Figure 5. The multibody code provides the finite element code with thepositions and velocities of the pantographs registration strips. The finite element code calculates thecontact force, using any suitable contact law, and the location of its application points in thepantographs and catenary, using geometric interference. These forces are applied to the catenary, inthe finite element code, and to the pantograph model, in the multibody code. Each code handlesseparately the equations of motion of each subsystem based on the shared force information.

Figure 5: Structure of communication scheme between the MB and the FE codes

FEM - Catenary

Contactcatenary - pantograph

234 ( )1 1 ncontact K e

f n

MB - Pantograph,strip stripr r

Position,Velocity

, Pcontact stripf s

Force, Point

ir Pir

X

Z

i

i

Pis

P

i

Y

ir Pir

X

Z

i

i

Pis

P

i

Y

contact f

FEM - Catenary

Contactcatenary - pantograph

234 ( )1 1 ncontact K e

f n

MB - Pantograph,strip stripr r

Position,Velocity

, Pcontact stripf s

Force, Point

ir Pir

X

Z

i

i

Pis

P

i

Y

ir Pir

X

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Pis

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contact f

ir Pir

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ir Pir

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contact f


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The compatibility between the two integration algorithms imposes that the state variables of thetwo subsystems are readily available during the integration time but also that a reliable prediction ofthe contact forces is also available at any given time step. The key of the synchronization procedurebetween the multibody and finite element codes is the time integration, which must be such that it isensured the correct dynamic analysis of the pantograph-catenary system, including the loss andregain of contact. The only restriction that is imposed in the integration algorithm of the multibody

code is that its time step cannot exceed the time step of the finite element code. A detailed descriptionon the co-simulation algorithm of the multibody and finite element codes can be found in literature [1-3].

3 Study of the pantograph-catenary interactionIn the following, the pantograph-catenary interaction is studied in order to assess on how the contactquality is sensitive to the pantograph components. Hence, several pantograph parameters are variedin a range of +/- 10% and the contact force results are compared against the ones obtained with thenominal case. The studies are performed for high speed trains running on a straight track of 1.2 kmlength at velocities of 250, 300 and 350 km/h. Notice that, following the international regulations [9],all contact force results are filtered with a low pass filter with a cut-off frequency of 20 Hz.

3.1 Reference caseThe reference case considered here corresponds to the complete overhead electric power systemthat is modelled for the SNCF 25 kV LN2 catenary and for the CX lumped mass pantograph, both withthe characteristics described in previous section. The simulation conditions are pictured in Figure 6.

Figure 6: Representation of the simulation conditions

3.2 Influence of the static contact force

In order to evaluate the impact of the static contact force on the pantograph-catenary interaction,dynamic analyses are performed considering that the vertical force F Static exerted upwards on thecontact wire by the pantograph head, as represented in Figure 2, has values of 187 N (+10%) and153 N (-10%). Notice that this force, which is applied by the pantograph lifting device, has a nominalvalue of 170 N. All other simulation conditions remain unchanged with respect to the nominal case.

The contact force results between four consecutive masts of the catenary are presented in Figure7 for velocities of 250, 300 and 350 km/h. It is observed that the pantograph-catenary interaction

strongly depends on the trainset speed. In fact, the amplitude of the contact forces increasessignificantly with the velocity.

V = 250 km/h V = 300 km/h V = 350 km/h

Figure 7: Influence of the static force - contact force results

Catenary


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The consequences on the contact quality of varying the static force are also visible in the resultspresented in Figure 7. These repercussions are assessed here based on the analysis of severalstatistical parameters [9,10] associated to the contact forces, namely the maximum and minimumvalues, the average (mean) value F m , the standard deviation and the statistical minimum of contactforce, which is given by the following equation:

3 Min mStat F (1)In Figure 8, the contact force statistical parameters, obtained by varying in +/- 10% the pantograph

static force, are compared against the ones obtained with the nominal case. The results show that themaximum and minimum contact force values generally increase with the static force but in aproportion different from static force variation (+/- 10%). On the other hand, the statistical meanvalues of the contact force vary in the same proportion of the static force variation (+/- 10%). Thestandard deviation has a weak correlation with static force variation, being much more dependent onthe trainset velocity. During the dynamic analyses, no contact loss events are detected which meansthat the interruption of power supply and the occurrence of electric arcing are not likely to occur.

V = 250 km/h V = 300 km/h V = 350 km/h

Figure 8: Influence of the static force - statistical parameters

3.3 Influence of the mass m 2

The purpose now is to analyse the influence of the mass m 2 on the pantograph-catenary interaction.Hence, dynamic analyses are performed considering that the lower mass of the pantograph hasvalues of 5.28 kg (+10%) and 4.32 kg (-10%), whereas the nominal value is 4.8 kg. All the othersimulation conditions remain unchanged.

In Figure 9, the contact force statistical parameters, obtained by varying in +/- 10% the mass m 2,are compared against the ones obtained with the nominal case. The results show that the variation ofthe mass m 2 has a small effect on the contact force statistical parameters. This effect is onlynoticeable for the maximum force values when running at a velocity of 350 km/h. During the dynamicanalyses, no contact loss events are detected.

V = 250 km/h V = 300 km/h V = 350 km/hFigure 9: Influence of the mass m 2 - statistical parameters

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Max Min Mean St Deviat Stat Min

C o n

t a c t

F o r c e

( N )

F = 153N (-10%)F = 170N (Nominal)

F = 187N (+10%)

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C o n

t a c t

F o r c e

( N )

F = 153N (-10%)F = 170N (Nominal)

F = 187N (+10%)

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350


C o n

t a c t

F o r c e

( N )

F = 153N (-10%)

F = 170N (Nominal)

F = 187N (+10%)

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C o n

t a c t

F o r c e

( N )

m2 = 4.32kg (-10%)

m2 = 4.8kg (Nominal)m2 = 5.28kg (+10%)

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C o n

t a c t

F o r c e

( N )

m2 = 4.32kg (-10%)

m2 = 4.8kg (Nominal)m2 = 5.28kg (+10%)

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C o n

t a c t

F o r c e

( N )

m2 = 4.32kg (-10%)

m2 = 4.8kg (Nominal)m2 = 5.28kg (+10%)


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In order to assess the impact of the mass m 3 on the pantograph-catenary interaction, several dynamicanalyses are performed considering that the middle mass of the pantograph has values of 5.093 kg(+10%) and 4.167 kg (-10%). Notice that its nominal value is 4.63 kg.

In Figure 10, the contact force statistical parameters, obtained by varying in +/- 10% the mass m 3,are compared against the ones obtained with the nominal case. The results show that the variation ofthe mass m 3 has a minor influence on the contact force statistical parameters. This effect is onlyevident for the maximum force values when running at a velocity of 350 km/h. No contact loss eventsare detected during the dynamic analyses.

V = 250 km/h V = 300 km/h V = 350 km/h

Figure 10: Influence of the mass m 3 - statistical parameters


In this case study, the objective is to evaluate the influence of the mass m 4 on the interaction betweenthe pantograph and the overhead contact line. Thus, dynamic analyses are performed considering

that the upper mass of the pantograph has values of 9.35 kg (+10%) and 7.65 kg (-10%), whereas itsnominal value is 8.5 kg.In Figure 11, the contact force statistical parameters, obtained by varying m 4 in +/- 10%, are

compared against the ones obtained with the nominal case. The results show that, in general, thevariation of the mass m 4 has a small effect on the contact force statistical parameters. The exceptionis the maximum force values. During the dynamic analyses, no contact loss events are detected.

V = 250 km/h V = 300 km/h V = 350 km/h

Figure 11: Influence of the mass m 4 - statistical parameters

3.6 Influence of the spring stiffness k 1-2

With the purpose of assessing the impact of the spring stiffness k 1-2 on the pantograph-catenary

interaction, dynamic analyses are performed considering that this quantity has values of 1.1 N/m(+10%) and 0.9 N/m (-10%). Notice that its nominal value is 1.0 N/m.

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C o n

t a c t

F o r c e

( N )

m3 = 4.167kg (-10%)

m3 = 4.63kg (Nominal)

m3 = 5.093kg (+10%)

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C o n

t a c t

F o r c e

( N )

m3 = 4.167kg (- 10%)


m3 = 5.093kg (+10%)

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C o n

t a c t

F o r c e

( N )

m3 = 4.167kg (-10%)


m3 = 5.093kg (+10%)

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350


C o n

t a c t

F o r c e

( N )

m4 = 7.65kg (-10%)


m4 = 9.35kg (+10%)

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C o n

t a c t

F o r c e

( N )

m4 = 7.65kg (-10%)


m4 = 9.35kg (+10%)

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C o n

t a c t

F o r c e

( N )

m4 = 7.65kg (-10%)


m4 = 9.35kg (+10%)


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The comparison between the nominal case and the contact force statistical parameters obtainedby varying k 1-2 in +/- 10% is presented in Figure 12. The results show that the variation of this quantityhas negligible influence on the most of the statistical parameters. Minor effects are observed for themaximum and minimum force values when running at velocities of 300 and 350 km/h. Furthermore,during the dynamic analyses, no contact loss events are detected.

V = 250 km/h V = 300 km/h V = 350 km/hFigure 12: Influence of the spring stiffness k 1-2 - statistical parameters


The idea now is to analyse the influence of the spring stiffness k 2-3 on the pantograph-catenaryinteraction. Hence, dynamic analyses are performed considering that k 2-3 has values of 5940 N/m(+10%) and 4860 N/m (-10%), whereas its nominal value is 5400 N/m.

In Figure 13, the statistical parameters, obtained by varying in +/- 10% the stiffness k 2-3 , arecompared against the ones obtained with the nominal case. The results show that the variation of thisquantity influences the maximum and minimum force values and has a negligible influence on theother statistical parameters. During the dynamic analyses, no contact loss events are detected.

V = 250 km/h V = 300 km/h V = 350 km/hFigure 13: Influence of the spring stiffness k 2-3 - statistical parameters


In order to assess the impact of the spring stiffness k 3-4 on the pantograph-catenary interaction,dynamic analyses are performed considering that k 3-4 has values of 6649.5 N/m (+10%) and 5440.5N/m (-10%). Notice that its nominal value is 6045 N/m.

In Figure 14, the statistical parameters of the contact force results, obtained by varying in +/- 10%the stiffness k 3-4, are compared against the ones obtained with the nominal case. The results showthat this element of the pantograph model influences the maximum and minimum force values,especially for the higher velocity of 350 km/h. Furthermore, it has a negligible effect on the otherstatistical parameters. No contact loss events are detected during the dynamic analyses.

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C o n

t a c

t F o r c e

( N )

k1-2 = 0.9N/m (-10%)

k1-2 = 1.0N/m (Nom)

k1-2 = 1.1N/m (+10%)

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C o n

t a c

t F o r c e

( N )

k1-2 = 0.9N/m (-10%)

k1-2 = 1.0N/m (Nom)

k1-2 = 1.1N/m (+10%)

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C o n

t a c

t F o r c e

( N )

k1-2 = 0.9N/m (-10%)

k1-2 = 1.0N/ m (Nom)

k1-2 = 1.1N/ m (+10%)

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C o n

t a c

t F o r c e

( N )

k2-3 = 4860N/m (-10%)

k2-3 = 5400N/m (Nom)

k2-3 = 5940N/m (+10%)

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C o n

t a c

t F o r c e

( N )

k2-3 = 4860N/m (-10%)

k2-3 = 5400N/m (Nom)

k2-3 = 5940N/m (+10%)

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C o n

t a c

t F o r c e

( N )

k2-3 = 4860N/m (-1 0%)

k2-3 = 5400N/m (No m)

k2-3 = 5940N/m (+10%)


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V = 250 km/h V = 300 km/h V = 350 km/h

Figure 14: Influence of the spring stiffness k 3-4 - statistical parameters

3.9 Influence of the damping coefficient c 1-2

The purpose now is to analyse the influence of the damping coefficient c 1-2 on the pantograph-catenary interaction. Hence, dynamic analyses are performed considering that this pantographsuspension element has values of 35.2 N.s/m (+10%) and 28.8 N.s/m (-10%), whereas the nominalvalue is 32 N.s/m.

In Figure 15, the contact force statistical parameters, obtained by varying c 1-2 in +/- 10%, arecompared against the ones obtained with the nominal case. The results show that the variation of thisquantity influences the maximum and minimum force values, especially for the velocities of 300 and350 km/h, and has a negligible influence on the other statistical parameters. During the dynamicanalyses, no contact loss events are detected.

V = 250 km/h V = 300 km/h V = 350 km/h

Figure 15: Influence of the damping coefficient c 1-2 - statistical parameters


In order to assess the impact of the damping coefficient c 2-3 on the pantograph-catenary interaction,several dynamic analyses are performed considering that this suspension component of thepantograph has values of 5.5 N.s/m (+10%) and 4.5 N.s/m (-10%). Notice that its nominal value is 5.0N.s/m.

In Figure 16, the contact force statistical parameters, obtained by varying c 2-3 in +/- 10%, arecompared against the ones obtained with the nominal case. The results show that the variation of thisdamping coefficient affects the maximum and minimum force values, especially for the velocity of 350km/h. No contact loss events are detected during the dynamic analyses.

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C o n t a c

t F o r c e

( N )

k3-4 = 5440.5N/m (- 10%)

k3-4 = 6045N/m (Nom)

k3-4 = 6649.5N/m (+10%)

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C o n t a c

t F o r c e

( N )

k3-4 = 5440.5N/m (-10%)

k3-4 = 6045N/m (Nom)

k3-4 = 6649.5N/m (+10%)

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C o n t a c

t F o r c e

( N )

k3-4 = 5440.5N/m (-10%)

k3-4 = 6045N/m (Nom)

k3-4 = 6649.5N/ m (+10%)

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C o n

t a c t

F o r c e

( N )

c1-2 = 28.8Ns/ m (-10%)

c1-2 = 32.0Ns/ m (Nom)c1-2 = 35.2Ns/ m (+10%)

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C o n

t a c t

F o r c e

( N )

c1-2 = 28.8Ns/m (- 10%)

c1-2 = 32.0Ns/m (Nom)c1-2 = 35.2Ns/m (+10%)

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C o n

t a c t

F o r c e

( N )

c1-2 = 28.8Ns/m ( -10%)

c1-2 = 32.0Ns/ m (Nom)c1-2 = 35.2Ns/m (+10%)


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V = 250 km/h V = 300 km/h V = 350 km/h



The last component of the pantograph model analysed here is the damping coefficient c 3-4. So,dynamic analyses are performed considering that c 3-4 has values of 11 N.s/m (+10%) and 9 N.s/m (-10%), whereas the nominal value is 10 N.s/m.

In Figure 17, the contact force statistical parameters, obtained by varying c 3-4 in +/- 10%, arecompared against the ones obtained with the nominal case. The results show that the variation of thisdamping coefficient affects the maximum and minimum force values, especially for the velocity of 300and 350 km/h. During the dynamic analyses, no contact loss events are detected.

V = 250 km/h V = 300 km/h V = 350 km/h


4 ConclusionsThe work proposed here uses a computational tool based on a co-simulation procedure between amultibody methodology, used to describe the pantograph system, and a finite element code, used tomodel the catenary. The purpose is to identify the main characteristics of the pantograph model thatinfluence the quality of the overhead contact. Several pantograph components are varied and thestudy is carried out for high-speed trains running at several velocities.

The results presented here show that the most important factor influencing the pantograph-catenary interaction is the trainset speed. In fact, as the speed increases, the amplitude of the contactforces grows significantly, despite the average value remaining nearly the same.

With respect to the components of the pantograph model that influence the contact between thepantograph and the overhead contact line, it is observed that the static contact force, exerted upwardsby the pantograph head on the catenary, is the most relevant one. It affects all contact force statisticalparameters considered here.

Relatively to the other elements that compose the pantograph model, despite smaller, influencesare also observed when varying the masses m 4, the spring stiffnesses k 2-3 and k 3-4 and all the

damping coefficients c 1-2 , c 2-3 and c 3-4. Nevertheless, these components only affect the maximum andminimum force values. The other statistical parameters are nearly non-sensitive to the variation of thepantograph model elements studied here.

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C o n t a c

t F o r c e

( N )

c2-3 = 4.5Ns/m (-10%)

c2-3 = 5.0Ns/m (Nom)

c2-3 = 5.5Ns/m (+10%)

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C o n t a c

t F o r c e

( N )

c2-3 = 4.5Ns/m (-10%)

c2-3 = 5.0Ns/ m (Nom)

c2-3 = 5.5Ns/m (+10%)

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C o n t a c

t F o r c e

( N )

c2-3 = 4.5Ns/ m (-10%)

c2-3 = 5.0Ns/m (Nom)

c2-3 = 5.5Ns/m (+10%)

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C o n

t a c t

F o r c e

( N )

c3-4 = 9.0Ns/m (-10%)

c3-4 = 10.0Ns/ m (Nom)

c3-4 = 11.0Ns/ m (+10%)

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C o n

t a c t

F o r c e

( N )

c3-4 = 9.0Ns/m (-10%)

c3-4 = 10.0Ns/m (Nom)

c3-4 = 11.0Ns/m (+10%)

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C o n

t a c t

F o r c e

( N )

c3-4 = 9.0Ns/m (-10%)

c3-4 = 10.0Ns/ m (Nom)

c3-4 = 11.0Ns/m (+10%)


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12

AcknowledgementsThis paper describes work undertaken in the context of the PantoTRAIN project, PANTOgraph and

Catenary Interaction: Total Regulatory Acceptance for the Interoperable Network (www.triotrain.eu).PantoTRAIN is a collaborative project medium-scale focused research project supported by the

European 7th Framework Programme, contract number: 234015.References[1] Ambrsio, J., Pombo, J., Rauter, F. and Pereira, M., "A Memory Based Communication in the

Co-Simulation of Multibody and Finite Element Codes for Pantograph-Catenary InteractionSimulation", Multibody Dynamics , (Bottasso C.L., Ed.), Springer, Dordrecht, The Netherlands,pp. 211-231, 2008.

[2] Rauter, F., Pombo, J., Ambrsio, J. and Pereira, M., "Multibody Modeling of Pantographs forCatenary-Pantograph Interaction", IUTAM Symposium on Multiscale Problems in Multibody System Contacts , (P. Eberhard, Ed.), Springer, Dordrecht, The Netherlands, pp. 205-226,2007.

[3] Rauter, F., Pombo, J., Ambrsio, J., Pereira, M., Bobillot, A. and Chalansonnet, J., "Contact

Model for the Pantograph-Catenary Interaction", JSME International Journal of System Design and Dynamics , 1, No. 3, pp. 447-457, 2007.[4] Bocciolone, M., Resta, F., Rocchi, D., Tosi, A. and Collina, A., "Pantograph Aerodynamic

Effects on the Pantograph-Catenary Interaction", Vehicle System Dynamics , 44 , S1, pp. 560-570, 2006.

[5] Pombo, J., Ambrsio, J., Pereira, M., Rauter, F., Collina, A. and Facchinetti, A., "Influence ofthe Aerodynamic Forces on the Pantograph-Catenary System for High Speed Trains", Vehicle System Dynamics , 47 , No. 11, pp. 1327-1347, 2009.

[6] EUROPAC Project no, 012440, "Modelling of Degraded Conditions Affecting Pantograph-Catenary Interaction", Technical Report EUROPAC-D22-POLI-040-R1.0, Politecnico di Milano,Milan, Italy, 2007.

[7] Ambrsio, J., Rauter, F., Pombo, J. and Pereira, M., "A Flexible Multibody Pantograph Model

for the Analysis of the Catenary-Pantograph Contact", Multibody Dynamics: Computational Methods and Applications , (Blajer et al., Ed.), Springer, Dordrecht, The Netherlands, 2010.

[8] Rauter, F., Ambrsio, J., Pombo, J. and Pereira, M., "Effect of the Pantograph Flexibility on theContact Quality of the Pantograph-Catenary Interface", Proceedings of 21st International Symposium on Dynamics of Vehicles on Roads and Tracks (IAVSD 2009) , Stockholm,Sweden, August 17-21, 2009.

[9] EN 50318, "Railway applications - Current collection systems - Validation of simulation of thedynamic interaction between pantograph and overhead contact line", 2002.

[10] EN 50367, "Railway applications - Current collection systems - Technical criteria for theinteraction between pantograph and overhead line", 2006.

[11] Haug, E., "Computer Aided Kinematics and Dynamics of Mechanical Systems", Allyn andBacon, Boston, Massachussetts, 1989.

[12] Nikravesh, P. E., "Computer-Aided Analysis of Mechanical Systems", Prentice-Hall, EnglewoodCliffs, New Jersey, 1988.

[13] Pereira, M. and Ambrsio, J., "Computational Dynamics in Multibody Systems", KluwerAcademic Publishers, Dordrecht, The Netherlands, 1995.

[14] Roberson, R. E. and Schwertassek, R., "Dynamics of Multibody Systems", Springer-Verlag,Berlin, Germany, 1988.

[15] Schiehlen, W., "Advanced Multibody System Dynamics - Simulation and Software Tools",Kluwer Academic Publishers, Dordrecht, The Netherlands, 1993.

[16] Shabana, A. A., "Dynamics of Multibody Systems", 2nd Edition, Cambridge University Press,Cambridge, United Kingdom, 1998.

Poster Pereira Manuel

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