Simpack Wheel-Rail Training BASIC [PDF]

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SIMPACK TRAINING Wheel/Rail Basics

SIMPACK: Wheel/Rail Basic Training Analysis and Design of General Mechanical Systems

方向华 Beijng Engineering Solution Provider Ltd. INTEC GmbH, Argelsrieder Feld 13, 82234 Wessling, Tel: 08153/92 88-0, Fax 08153/92 88-11, E-Mail: [email protected]

SIMPACK TRAINING Wheel/Rail Basics

Contents Î Overview: SIMPACK Wheel/Rail Functionality Î The Track Joint, Degrees of Freedom Î The SIMPACK Default Wheelset Î EXAMPLE: Setting Up a Default Wheelset Î Standard Track Models, Basic Contact Models Î Some Tips for Completing the Vehicle Î EXAMPLE: Building the Bogie Substructure Î EXAMPLE: Completing the Vehicle Î EXAMPLE: Linearised Wheel/Rail Contact Î EXAMPLE: Eigenmode Analysis Î EXAMPLE: Time Integration and General Wheel/Rail Specific Plots Î EXAMPLE: Basic Track Irregularities Î EXAMPLE: Ride Comfort Analysis and Design of General Mechanical Systems

Î Profile Generation Î EXAMPLE: Root Loci Î EXAMPLE: Critical Speed Î Independent Wheels (2)

SIMPACK TRAINING Wheel/Rail Basics

Overview: SIMPACK Wheel/Rail Functionality How to follow a given track

How to get wheel and rail into contact

Track Trackdefinition definition

Profile ProfilePreprocessor Preprocessor

Track TrackJoint Joint

Wheel/Rail Wheel/RailElements Elements

standard, standard,cartographic, cartographic,measured measured

How to calculate the tangential forces

for formeasured measuredprofiles profiles

==wheels wheels++rails railswith withprofiles profiles

3D 3DProfile ProfileContact Contact

Contact ContactForce ForceElements Elements

by byconstraints constraintsor orone-sided one-sidedsprings springs

Contact ContactPreprocessor Preprocessor

Contact ContactPreprocessor Preprocessor

for forpre-calculating pre-calculatingtangential tangentialforces forces

for forpre-calculating pre-calculatingcontact contactpoints points

Special

Profile ProfileLinearisation Linearisation (3)

SIMPACK TRAINING Wheel/Rail Basics

The Track Joint Type 07 6 Degrees of Freedom: Imaginary track center line

Defined from Isys to body Joint follows the track center

07

Alternatively: - 5 DOF (without γ) - 1 DOF (only s)

x y

z

s - along the track centre y - lateral z - vertical ϕ - roll angle (around s) ψ - yaw angle (around z) γ - pitch or rolling angle (around y)

Joint type 09: like type 07, but v = const. (5, 4 or 0 DOF)

Attention! Attention! zz axis axis is is downwards downwards positive positive for wheel/rail models (according for wheel/rail models (according to to UIC) UIC) (4)

SIMPACK TRAINING Wheel/Rail Basics

The SIMPACK Default Wheelset

(1)

$M_Wheel_ProfRef $M_Rail_ProfRef $M_Wheel_Contact $M_Rail_Contact $M_Rail_Track_Frame $M_Rail_Track_Camera $L_RailWheel $F_RW_Friction $S_Rail_ProfRef $S_Rail_Contact $S_Rail_Track_Frame $S_Rail_Track_Camera

$S_Wheel_ProfRef

3D Elements of Wheels and Rails

Note 1: Every _Rail_ and _Wheel_ element exists for the left and the right wheel. Note 2: Replace _Wheel_ by the name of the wheelset body. Î e.g. „$M_Wheelset1_ProfRef_Left“, „$L_RailWheel_Right_of_Wheelset1“, ...

(5)

SIMPACK TRAINING Wheel/Rail Basics

The SIMPACK Default Wheelset

(2)

Markers Wheel profile definition plane (e.g. taper line) Wheelset body-fixed reference frame (BFRF)

$M_Wheel_ProfRef $M_Rail_ProfRef (here canted with rail)

Nominal wheel radius r0

Semi-wheelbase e0

$M_Wheel_Contact $M_Rail_Contact (both moving with the current contact point)

Rail profile definition plane (e.g. middle of rail head) (6)

SIMPACK TRAINING Wheel/Rail Basics

The SIMPACK Default Wheelset

(3)

Track-Related Markers (moving with the wheelset along the track)

$M_Rail_Track_Frame

Superelevation u

$M_Rail_Track_Camera (7)

SIMPACK TRAINING Wheel/Rail Basics

The SIMPACK Default Wheelset

(4)

Constraints and Force Elements

$F_RW_Friction for tangential forces

$L_RailWheel

09

89

Both acting at same markers: FROM $M_Rail_Contact TO $M_Wheel_Contact

09

89

(8)

SIMPACK TRAINING Wheel/Rail Basics

The SIMPACK Default Wheelset

(5)

Sensors

$S_Wheel_ProfRef

$S_Rail_ProfRef $S_Rail_Contact

$S_Rail_Track_Frame $S_Rail_Track_Camera

Each FROM Isys TO according marker.

(9)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset Pre-Processing

Processing

(1)

Post-Processing

Body Definition Joints Definition

(10)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset

(2)

Some Important Steps to Be Done First Create a new folder for training models and in a new model:

• Change gravity to positive z direction (+9,81 m/s²)

• Adjust view to standard view: Wheel/Rail perspective view

(11)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset

(3)

Characteristics Mass = 1000 kg Ixx = 1000 kgm² Iyy = 100 kgm² Izz = 1000 kgm² Track joint with 6 degrees of freedom

(12)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset

(4)

• Rename $B_body1 to $B_WS1 (Wheelset 1) • Add body data • Change 3D geometry of wheelset axle

(13)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset

(5)

• Set up the joint • Generate wheel/rail elements • Assemble system

(14)

SIMPACK TRAINING Wheel/Rail Basics

Constraints and Dependent/Independent States 6 joint states - 2 constraints = 4 degrees of freedom

Dependent: state results from kinematics (description by algebraic kinematical equation)

Wheelset

09

07

Independent: freely adjustable by user and model dynamics (description by differential equation of motion)

09

Constraint 6 DOF, with Constraint L W/R-Elements R

Default: s y z

ϕ ψ γ

-

independent independent dependent dependent independent independent

Imagine Imagine laying laying the the wheelset wheelset down onto the track down onto the track with with aa crane crane Æ Æ only only s, s, y, y, ψ ψ,, γγ adjustable adjustable (15)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset Pre-Processing

Processing

(6)

Post-Processing

Body Definition Joints Definition Track Definition

(16)

SIMPACK TRAINING Wheel/Rail Basics

Standard Track Models

(1)

Straight Track • Track length

Curved Track with Constant Horizontal Curvature • Radius • Superelevation, with reference length • Track length

Curved Track with Variable Horizontal Curvature Curve entry - curve passing - sign change of curvature (s-curve) - cross-over • Radius • Superelevation, with reference length • Track length • Further special parameters

Extension: Elastic Foundation (Ballast Mass) (17)

SIMPACK TRAINING Wheel/Rail Basics

Standard Track Models

(2)

Superelevation

Centerline is elevated Superelevation u Reference length = railbase

Rotation about inner rail

Superelevation u Rotation about centerline

(18)

SIMPACK TRAINING Wheel/Rail Basics

Standard Track Models

(3)

Curve Entry and Superelevation Ramp

R=∞

Curve entry:

Radius Radius and and superelevation superelevation have have to to be be negative negative for for leftlefthand curves hand curves

R = ∞ Æ RCurve R = RCurve

Superelevation ramp

u=0

u=

0Æ

u Curv

e

(length identical with curve entry):

u = uCurve u=0

u=

0Æ

u Cur

ve

u = uCurve

Smoothed over distance 2h

Straight ramp

For For standard standard tracks, tracks, also also the form (s-shaped, linear) the form (s-shaped, linear) of of the the curve curve entry entry correcorresponds to the ramp. sponds to the ramp.

S-shaped ramp

(19)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset

(7)

• Set up an entry to a narrow curve in the track definition window

(20)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting Up a Default Wheelset Pre-Processing

Processing

(8)

Post-Processing

Body Definition Joints Definition Track Definition Vehicle Globals

(21)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Contact in SIMPACK

(1)

1. Find the contact point

2. Determine normal force

3. Calculate tangential forces

(22)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Contact in SIMPACK

(2)

Step 1: Finding the contact point Default method: quasi-elastic • Takes a „virtual“ material elasticity into account • The resulting „virtual“ contact area is regularised (smoothed) and converted into a single contact point • Contact point moves steadily along the profiles

Old method: rigid • Contact point location is the minimum distance between profiles • Contact point can jump, e.g. on tread of S1002/UIC60 1:40 (Switch between methods in parameter set *.pp)

You You should should not not use use the the rigid rigid method. It can cause numerical method. It can cause numerical problems problems and and is is outdated. outdated. (23)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Contact in SIMPACK

(3)

Step 2: Determining the normal force Default method: constraint • Uses the constraint type 09 between rail and wheel contact markers • Normal force equals constraint force (negated) • Avoids high-frequency oscillations: fast • Only „pseudo wheel lift“ possible

Alternative method: elastic (one-sided spring/damper) • Uses the force element 18 between rail and wheel contact markers • Normal force equals spring/damper force • High-frequency oscillations can slow down the calculation • Real wheel lift possible (Switch between methods in Vehicle Globals window: „constraint“/„elastic“) (24)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Contact in SIMPACK

(4)

Step 3: Calculating the tangential forces Default method: Simplified non-linear theory (J. J. Kalker) • Standard FASTSIM algorithm • Uses Hertzian contact ellipse, derived from profile curvatures and normal force • Tangential forces T depend nonlinearly on creepage situation • Ratio |T| / |N| is limited by the friction coefficient µ

Several alternative methods

(Switch between methods in Vehicle Globals window: „Contact Force“)

(25)

SIMPACK TRAINING Wheel/Rail Basics

Some Tips for Completing the Vehicle Topology of a Railway Vehicle

Car body Secondary Suspension Bogie frame

07, 6 DOF, no W/R-Func.

Constraint R

W/R-Func.

07 6 DOF, with

Constraint L

Wheelset

07, 6 DOF, no W/R-Func.

Primary Suspension

(26)

SIMPACK TRAINING Wheel/Rail Basics

Substructures in Wheel/Rail Models

(1)

The Idea • Bogies are complicated devices, and built in at least twice in most wheel/rail models Æ preferrably model as a substructure

The Problem • In substructures, no changing or deleting of their components is possible (only parameter settings) • The switching between constraint and elastic contact is not allowed if the wheelsets are within the substructure Substructure „Bogie“ (2x)

Car body

Bogie frame and related parts

2 Wheelsets

(27)

SIMPACK TRAINING Wheel/Rail Basics

Substructures in Wheel/Rail Models

(2)

Two Workarounds • Include wheelsets into substructure if no change of contact model (constraint/elastic) is intended • Include wheelsets into substructure and resolve substructure dependency before changing the contact model

The Solution • Exclude wheel-rail elements of wheelsets from substructures and define them in main model using dummy bodies

Car body

Substructure „Bogie“ (2x)

9

2 x 2 Wheelsets

Dummy Dummy bodies bodies have have neglectable neglectable masses ( « 0.001kg) and masses (« 0.001kg) and inertia inertia moments. Their most important moments. Their most important elements elements are are their their markers. markers.

Bogie frame and related parts

0 DOF 2 x 2 WS_Dummy

(28)

SIMPACK TRAINING Wheel/Rail Basics

Substructures in Wheel/Rail Models

(3)

The Solution • The wheelsets within the substructure contain all the mass and inertia properties along with the relevant markers, i.e. for primary suspension • For correct positioning of the wheelsets within the substructure create new markers in Isys for the O DOF joints.

Main Model with Dummy Wheelsets

Substructure Bogie

(29)

SIMPACK TRAINING Wheel/Rail Basics

Substructures in Wheel/Rail Models

(3)

Using Dummy Bodies for Connnecting Substructures • Many connections: primary/secondary springs, dampers, . . . • Simplify by introducing one or more dummy bodies per substructure

0 DOF

Car Car body body

Dummy Dummy body body

(several)

07, 6 DOF

2 Wheelsets

07, 6 DOF 0 DOF

Wheelsets Wheelsets Dummy_Wheelsets Dummy_Wheelsets (2x)

Bogie Bogie frame, frame, related related parts parts and and wheelsets wheelsets

Bogie Bogie frame frame and and related related parts parts

07, 6 DOF

Secondary springs, dampers, anti-roll bar, ...

(30)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure Pre-Processing

Processing

Body Database

Offline Time Integration

(1)

Post-Processing

Track Definition Body Definition Joints Definition

(31)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(2)

Preliminary Steps, Wheelset • Set up a new body “$B_WS_Training”. DO NOT generate Wheel/Rail Elements. Type of joint irrelevant. Refer to example: “Setting Up a Default Wheelset” • Add markers for axlebox/primary suspension y = ± 1,0 m

• Save wheelset to data base

(32)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(3)

Create a New Body for the Bogie Frame Centre of mass

Plane of 3D primitive reference Track plane

• Name $B_BF

BFRF marker

• m = 3000 kg • Centre of mass z = -0.6 m • Ixx = 1500 kgm², Iyy = 2500 kgm², Izz = 2800 kgm² • I-Tensor relative to centre of mass

(33)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(4)

3D Primitives: Wheel Rail Bogie and traverses Distance right left L1

H2 H1 L2 B1

(34)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(5)

Markers for Primary and Secondary Suspension • Primary: x = ± 1.25 m, y = ± 1 m, z = -0.5 m • Secondary: x = 0 m, y = ± 1 m, z = -0.8 m

BFRF

Use Use common common abbreviations abbreviations to to keep keep names names short. short. Otherwise Otherwise you you could could get get into into trouble trouble when when working working with with substructures. substructures.

• Save Body to Database (35)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(6)

Create a New Model “Bogie Substructure”

BFRF, Bogie_frame

• Create two markers on Isys for wheelsets (x = ±1.25, z = -0.5) • Two new bodies, “WS1” and “WS2”. Import wheelsets from database. 0 DOF Joints to respective markers on Isys. • New Body “Bogie_Frame” from Database, Joint type 07 (general wheel/rail joint) with 6 DOF, but without wheel/rail elements. Remember! Only joints from Isys may be re-connected in main model (36)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(6)

Create a New Model “Bogie Substructure”

BFRF, Bogie_frame and Wagon_dummy

• New body “Wagon_dummy”. Mass and inertias 1.0e-6. • Create marker “Wagon_dummy_Connect” for connection to wagon, z = -1 • Create identical marker “Isys_Connect” and replace joint markers accordingly • Generate appropriate primitive. Use new marker as reference marker. • Add markers for SS. Use identity function to markers on frame. (37)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure Pre-Processing

Processing

Body Database

Offline Time Integration

(7)

Post-Processing

Track Definition Body Definition Joints Definition Force Elements Database

(38)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(8)

Primary Suspension • Type 05: spring/damper parallel compact • FROM marker on bogie frame Why? Why? •• Stiffness/damping Stiffness/damping definitions definitions are are given given in in body body reference reference system system of of FROM FROM body body –– they they would would rotate rotate ifif wheelset wheelset were were FROM FROM body body •• rr xx FF torques torques are are applied applied on on FROM FROM body body

• Use “Identity to...” feature • Check with “Info - Force Elements” that rabs is near zero (precondition for calculation of nominal forces with compact force elements) • Generate 3D scaled springs PtP

(39)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(9)

Secondary Suspension • Type 05: spring/damper parallel compact • FROM marker on Wagon_dummy Why? Why? •• rr xx FF torques torques are are applied applied on on FROM FROM body body

• Use “Identity to...” feature • Check with “Info - Force Elements” that rabs is near zero (precondition for calculation of nominal forces with compact force elements) • Generate 3D scaled springs, PtP

(40)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Building the Bogie Substructure

(10)

Creating a Database • Within the current directory create a database folder along with the necessary standard subfolders

• Transfer the Wheelsets and Bogie (sys and ani files) from the user specific database to the new database • Transfer the substructure (sys and ani files) to the database • Copy body “Wagon” from training database to new database • Remember to set the model specific database path before using database components. Also necessary for opening substructures within the database

(41)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle

(1)

Vehicle Data s=

0

1.25 2.5

10.75

19 20.25 21.5

WS3

WS4 2.5 m

WS2

Bogie_II

m

WS1 Bogie_I

19 m

Car body: • m = 32000 kg

Primary suspension:

• Ixx = 56000 kgm², Iyy = 2.e06 kgm², Izz = 2.e06 kgm² w.r.t. cg • zcg = -1.8 m

• cx = 3.e07 N/m, cy = 4.e6 N/m, cz = 1.2e06 N/m • dx = 15000 Ns/m, dy = 2000 Ns/m, dz = 4000 Ns/m

Secondary suspension: • cx = 150000 N/m, cy = 150000 N/m, cz = 450000 N/m • dx = dy = 32000 Ns/m, dz = 20000 Ns/m

(42)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle

(2)

Creating the main model

• New model “Vehicle” (not in Database) • Set gravity and standard wheel/rail view • Define a straight track • Create four dummy wheelsets (1.0e-6 mass and inertias) with appropriate joints and wheel/rail elements • Assign the corresponding “s” co-ordinates • Save backup model as “Vehicle_START”

(43)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle

(3)

Creating the main model

• Create new body “Wagon” and import body from database • Assign joint type 07, 6 DOF with corresponding “s” co-ordinate Do not generate W/R elements • Import bogie substructures from database. • Assign corresponding “s” co-ordinates to the bogie frames • Re-connect the wheelsets and wagon-dummies to the appropriate markers

(44)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle Pre-Processing

Processing

Body Database

Offline Time Integration

(4)

Post-Processing

Track Definition Body Definition Joints Definition Force Elements Database Nominal Forces

(45)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle

(5)

Nominal Forces • Nominal forces guarantee the static equilibrium of the system for a given state • Railway vehicles are mostly modelled according to a drawing (given state). This means that nominal forces in z direction have to be set (pre-stress forces of the suspension)

• Nominal forces can be calculated manually (e.g. from the weight forces of the bodies) or automatically

(46)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle

(6)

Calculation of Nominal Forces: Preliminary Steps • Set global velocity of 1 m/s (Vehicle Globals window) • Save the bogie model • Perform a Test Call (Assembly Test) and make sure that there are no unrealistic high accelerations: ================================================================================ ================================================================================ Joint Joint Accelerations Accelerations ZGPP(1:nzj,joint_name) ZGPP(1:nzj,joint_name) ================================================================================ ================================================================================ zgpp($J_S_Bogie_II__J_Bogie_Frame) zgpp($J_S_Bogie_II__J_Bogie_Frame) zgpp($J_S_Bogie_I__J_Bogie_Frame zgpp($J_S_Bogie_I__J_Bogie_Frame )) zgpp($J_Wagon )) zgpp($J_Wagon zgpp($J_WS4_dummy )) zgpp($J_WS4_dummy

== -1.2106986D-10 -1.2106986D-10 8.3560125D-09 8.3560125D-09 == -1.9118044D-10 -1.9118044D-10 8.2853727D-09 8.2853727D-09 == 0.0000000D+00 0.0000000D+00 0.0000000D+00 0.0000000D+00 == -2.3209192D-04 -2.3209192D-04 -1.1988399D-10 -1.1988399D-10

Most accelerations are near zero: o.k. IfIf there there are are unrealistic unrealistic accelerations accelerations (e.g. (e.g. greater greater than than 100 100 m/s²) m/s²) there there could could be be an an error error in in the model Æ double-check joints, forces etc. the model Æ double-check joints, forces etc.

1.0649356D+01 1.0649356D+01 -1.3927304D-08 -1.3927304D-08 -4.9563528D-13 -4.9563528D-13 -2.0178309D-10 -2.0178309D-10 1.0649356D+01 1.0649356D+01 -1.3808954D-08 -1.3808954D-08 0.0000000D+00 0.0000000D+00 -3.1863406D-10 -3.1863406D-10 9.8100004D+00 9.8100004D+00 0.0000000D+00 0.0000000D+00 0.0000000D+00 0.0000000D+00 0.0000000D+00 0.0000000D+00 1.2342693D-22 1.2342693D-22 6.0863385D-12 6.0863385D-12 -7.9274563D-10 -7.9274563D-10 -1.1604212D-03 -1.1604212D-03

z acceleration of bogie frames and carbody: Not unrealistic, because from gravity, but have to be eliminated in order to bring the system into equilibrium

(47)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle

(7)

Calculation of Nominal Forces • Choose “Linear System” method (faster) • Select all force directions that have an associated stiffness (here all forces: click “Init. with all Possible Forces”) • Perform calculation

(48)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Setting up the complete vehicle

(8)

Calculation of Nominal Forces • Check the results: - very similar values for symmetric forces - small residual accelerations • Save results, force selection and settings • Reload the model in the 3D window • Another Test Call shows that the remaining accelerations have disappeared: ================================================================================ ================================================================================ Joint Joint Accelerations Accelerations ZGPP(1:nzj,joint_name) ZGPP(1:nzj,joint_name) ================================================================================ ================================================================================ zgpp($J_S_Bogie_II__J_Bogie_Frame) zgpp($J_S_Bogie_II__J_Bogie_Frame) zgpp($J_S_Bogie_I__J_Bogie_Frame zgpp($J_S_Bogie_I__J_Bogie_Frame )) zgpp($J_Wagon )) zgpp($J_Wagon zgpp($J_WS4_dummy )) zgpp($J_WS4_dummy

== == == ==

-6.4947233D-07 -6.4947233D-07 -6.4978020D-07 -6.4978020D-07 -7.3374536D-06 -7.3374536D-06 -2.1663677D-07 -2.1663677D-07

-1.7113615D-09 -1.7113615D-09 7.2216306D-07 7.2216306D-07 -9.3747062D-10 -9.3747062D-10 1.8447694D-09 1.8447694D-09 -4.3026497D-10 -4.3026497D-10 8.2260129D-10 8.2260129D-10 1.1689246D-10 1.1689246D-10 3.8505569D-06 3.8505569D-06 -9.3885937D-11 -9.3885937D-11 -6.5032494D-10 -6.5032494D-10 7.2816717D-22 7.2816717D-22 3.3011020D-11 3.3011020D-11

1.6621004D-10 1.6621004D-10 1.6709679D-10 1.6709679D-10 1.1722622D-07 1.1722622D-07 -1.3536010D-10 -1.3536010D-10

3.9063063D-07 3.9063063D-07 3.9011178D-07 3.9011178D-07 3.8159908D-05 3.8159908D-05 -6.0977707D-03 -6.0977707D-03

(49)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Linearisation, Eigenmode Analysis Pre-Processing

Processing

Body Database

Offline Time Integration

Track Definition

Eigenmode Analysis

(1)

Post-Processing

Body Definition Joints Definition Force Elements Database Nominal Forces Linearisation

(50)

SIMPACK TRAINING Wheel/Rail Basics

Linearisation, Eigenmode Analysis (2) Linear Calculation Methods: Overview Eigenmodes

Frequency analysis

Spectral analysis

4Root loci

4Guiding forces

4critical parameters

4Accelerations

4Guiding forces and accelerations: statistical reaction to statistically defined excitations

4coupling mechanism

Advantages

Advantages

Advantages

4very small computing time

4small computing time

4small computing time

4analysis of the transfer function performance

4realistic excitations

Disadvantages

Disadvantages

Disadvantages

4no non-linear dependencies

4no non-linear dependencies

4no non-linear dependencies

4view to the complete vehicle performance

(51)

SIMPACK TRAINING Wheel/Rail Basics

Linearisation, Eigenmode Analysis (3) Equivalent Conicity λ Plot of the wheelset‘s equivalent conicities depending on the linearization amplitude. The equivalent conicity is related to the cone angle βe of a double cone: λ = tan(βe). The „Klingel equation“:

L = 2π

re 2 tan β e

Attention: Attention: With With wheel wheel radii radii greater greater than than ~~ 550 550 mm, mm, there there is is no stable solution for the no stable solution for the linearisation. linearisation. This This can can lead lead to to unsymmetrical unsymmetrical plots, plots, but but the the calculation will be correct! calculation will be correct!

indicates the wavelength of the sinusoidal movement of a double cone on an ideal track.

βe

(52)

SIMPACK TRAINING Wheel/Rail Basics

Linearisation, Eigenmode Analysis (4) Linearisation Methods in SIMPACK Calculation of

Before Before using using linear linear calculation calculation methods, methods, the the wheel/rail wheel/rail contact contact should be linearised. should be linearised.

• equivalent conicity λ = tan(βe), • roll angle parameter σ = ϕ/y ·e0, • contact angle parameter ε = e0 ·Δβ/y

by means of • Harmonic Linearisation (default method): Minimisation of the mean square difference of the non-linear local wheel radius function and the linear function λ·y to be approximated • Equivalent Linearisation (according to Deutsche Bahn): Determination of the wave period L of the wheelset with non-linear profiles, leading to equivalent conicity λ. Calculation of σ and ε by Harmonic Linearisation. • User-defined coefficients

(53)

SIMPACK TRAINING Wheel/Rail Basics

Linearisation, Eigenmode Analysis (5) Linearisation in SIMPACK • Set a straight track • Switch to linear contact geometry • Choose harmonic linearisation • Choose linearisation amplitude, usually 3 mm • Profiles are linearised; parameters appear in echo area.

(54)

SIMPACK TRAINING Wheel/Rail Basics

Linearisation, Eigenmode Analysis (6) Calculation • Copy all states to linearisation state • Save the model and start eigenvalue calculation • Visualise eigenforms in model setup (3D animation and State Plots)

Make Make sure sure that that the the residual residual accelerations accelerations in in the the model model are are near zero! near zero! (55)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Time Integration and Plots (1) Pre-Processing

Processing

Post-Processing

Body Database

Offline Time Integration

General Plots

Track Definition

Eigenmode Analysis

Body Definition Joints Definition Force Elements Database Nominal Forces Linearisation

(56)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Time Integration and Plots (2) Offline Time Integration • Configure time integration If necessary: stepsize reduction for harsh curve entries Should be standard for Wheel/Rail

• Start simulation and measurements

(57)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Time Integration and Plots (3)

Output values of W/R friction force elements (type 89)

Useful Wheel/Rail Related Data Wheelset lateral position in track

y coordinate of track joint (07/09)

Wheelset yaw angle

ψ coordinate of track joint

Creepage (longitudinal, lateral, spin)

In contact coordinate system

Normal force N, traction forces Tx , Ty

In contact coordinate system; towards wheel

Traction coefficients fx , fy = Tx/N, Ty/N Wheel forces Y, Q

In wheelset reference system; towards rail

Frictional power P

For local contact point, wheel, wheelset, or vehicle

Contact point coordinates on wheel/on rail Longitudinal contact point shift

In wheel or rail profile reference system, along y axis

Semi-axes a, b of the Hertzian ellipse

In wheel profile reference system, along x axis

Area of the Hertzian ellipse Ratio of the semi-axes a/b Current Kalker coefficients C11, C22, C23 ...

(58)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Time Integration and Plots (4) General Plot • Open general 2D plot • Define curves: wheelsets’ and bogie’s lateral position, wheelsets’ yaw angle, wheel forces Y and Q for all four wheels, contact point coordinates on wheels and rail for the front wheelset, frictional power for both front wheels

(59)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Basic Track Irregularities (1) Pre-Processing

Processing

Post-Processing

Body Database

Offline Time Integration

General Plots

Track Definition

Eigenmode Analysis

Body Definition Joints Definition Force Elements Database Nominal Forces Linearisation Track Irregularities

(60)

SIMPACK TRAINING Wheel/Rail Basics

Basic Track Irregularities

(2)

Types of Definitions Stochastic

User-defined

Measured data

Generated from predefined power spectrum (ORE/ERRI)

Sinus excitation etc.

Input from file

Generated from userdefined power spectrum

Input functions

Application to Track and Rails Track-related

Rail-related

uG

(61)

SIMPACK TRAINING Wheel/Rail Basics

Basic Track Irregularities

(3)

From PSD to excitations • PSD = Power Spectral Density • Power spectra describe the power distribution of a stochastic signal, phase information is not included

• Transformation to distance domain by superposing many sine excitations with amplitudes given by PSD • Phases are set by a random generator

(62)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Basic Track Irregularities

(4)

Create a PSD by Predefined Polynomial Click on „Spectral Analysis“ and „Plot“ in order to visualise the PSD

• Defined in ORE B176 • Widely applicable for standard cases • PSD is approximated with a polynomial

Gauge Gauge excitations excitations are are not not prepredefined. You may use the cross defined. You may use the cross level level polynom polynom for for these, these, too. too.

Reference velocity is set automatically by Vehicle Globals (63)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Basic Track Irregularities

(5)

Use the PSD for Excitation definition • Select “Track-related” in the track definition window

• Set a smoothing length for the start

• Choose type 08 for vertical excitation

(64)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Basic Track Irregularities

(6)

Set Parameters • ID 1..5 must be unique for each excitation direction (random start value) • If nfreq = fmax / fmin, the PSD is correctly modelled, but the signal is periodic with a rather small period. If nfreq ≠ fmax / fmin, the signal is quasi-periodic, but the PSD is not correct for low frequencies. • Frequency dimension must be [1/m] • Frequency grid should be aequidistant, otherwise the PSD is not modelled correctly.

(65)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Ride Comfort (1) Pre-Processing

Processing

Post-Processing

Body Database

Offline Time Integration

General Plots

Track Definition

Eigenmode Analysis

Ride Comfort

Body Definition Joints Definition Force Elements Database Nominal Forces Linearisation Track Irregularities

(66)

SIMPACK TRAINING Wheel/Rail Basics

EXAMPLE: Ride Comfort (2) • Start a new calculation with the defined track irregularities • Output vertical bogie acceleration in General 2D plot

• Apply Ride Index filter “ISO vertical”

Be Be careful careful when when handling handling with with PSDs, PSDs, FFT FFT etc. etc. in in frequency frequency domain. domain. Double-check Double-check all all results. results.

(67)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation (1) Pre-Processing

Processing

Post-Processing

Body Database

Offline Time Integration

General Plots

Track Definition

Eigenmode Analysis

Ride Comfort

Body Definition Joints Definition Force Elements Database Nominal Forces Linearisation Track Irregularities Profile Generation

(68)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(2)

Besides standard W/R profile combinations like S1002/UIC60, SIMPACK offers the possibility to insert user defined profiles.

Measured Profiles: Wheel or Rail

For this reason the shown definition cycle is used.

Preprocessor 1: Profile Approximation

SIMPACK Profile: Tab. Spline-Function

r0,R0

SIMPACK MBS Set Up

r0,R0

See also „How to Create WheelRail Profiles for SIMPACK“.

Preprocessor 2: Contact + Friction

Evalution Tables: Contact + Friction

SIMPACK Calculation Modules

SIMPACK MBS Data Base

(69)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(3)

The SIMPACK W/R profile generation can be divided into two major stages. First the approximation of the W/R profile is carried out. The SIMPACK Profile Approximation Preprocessor is located at > SIMPACK PreProcess. W/R Profile Approximation . Profile type

Profile selection Axis orientation of data Scaling of data Distance of knots Profile extension Tolerance of approximation

Plot selection

Save profile

Perform profile approximation

(70)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(4)

The SIMPACK W/R Preprocessor expects the measured data of the wheel or rail profile being defined in the shown data format. The data file with the measured profile data has to be saved within the directory SIMPACK_USER/SIMPACK.8xxx/run/dat/wheel_rail_profiles_measured/

.

two lines for comments

Number of lines with measured data value pairs

Y coordinate of measured profile data Z coordinate of measured profile data

Note: The maximum number of value pairs is limited to 600 ! The Y coordinate has to be increasing. Normally the measured data is given in the unit [mm]. For data in the unit [m] the scaling parameter within the W/R Preprocessor has to be adapted. (71)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(5)

Within the SIMPACK W/R Preprocessor it is assumed that the wheel and the rail profile is a rightside profile (see picture below). The Y axis is always orientated to the right side of the profile. In the default case SIMPACK set the Z axis upwards, but the switch of the axis orientation within the SIMPACK W/R Preprocessor allows to offer measured data with downwards orientation of the Z axis. Rail profile

Wheel profile +Z

+Z 2

+Y

+Y 1

2

1

( In opposite to the shown situation the Z axis can be orientated downwards.)

The range of the Y coordinate of the measured data depends on the selected contact model. Normally, if no contact at the back of the wheel is expected, the shown area between the dotted lines 1 and 2 will be suitable for the SIMPACK profile approximation. The vertical areas e. g. of the rail profile are defined by the profile extensions within the SIMPACK W/R Preprocessor. Note: Please avoid to define vertical profile areas within your measured data. These areas are often responsible for problems of the profile approximation. (72)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(6)

After every profile approximation check the profile‘s run, gradient and curvature within the SIMPACK W/R Preprocessor!

If the profile approximation is carried out correctly, the generated SIMPACK profile should be saved in the directory > SIMPACK_USER/SIMPACK.8xxx/run/dat/wheel_rail_profiles . (73)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(7)

At the second stage of W/R profile generation the contact and friction tables suitable for the selected contact model are created. This is done after selecting the favoured W/R profile combination within the SIMPACK Vehicle Globals window and hitting the button „Apply as defaults“.

After generating the contact and friction tables please check these tables by the offered diagrams. (74)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(8)

According to the chosen wheel/rail profile combination the so called *.pp file has to be adapted. The *.pp file (OnePointContact.pp, MultiContact.pp, etc.) represents a list of parameters used for generating the contact tables of the wheel/rail contact (see picture below). All contact parameter files are located within the directory > SIMPACK_user/SIMPACK.85xx./run/dat/wheel_rail_profiles/ . ** RIGID CONSTRAINT MESH PARAMETER 4 0 0.0D0 0.0D0 -0.035D0 25 4 10 0.1000 -0.030D0 0.0150D0 0.001D0 -3.000D0 3.000D0 0.200D0

'SDEG' 'IROT, AROT, X1JUMP; IROT = 0 : COMPUTE ROTATION ANGLE' 'SJUMP' 'NBAS1, NADD1, NBAS2' 'WEIGHT-FLANGE' 'YMIN, YMAX, DELY' 'PHIMIN, PHIMAX, DELPHI'

** GEOMETRICAL & FRICTIONAL MESH PARAMETER 2 0 0.0D0 0.0D0 -0.035D0 25 0 10 1.0D0 -0.030D0 0.0150D0 0.001D0 -3.000D0 3.000D0 0.200D0

'SDEG' 'IROT, AROT, X1JUMP; IROT = 0 : COMPUTE ROTATION ANGLE' 'SJUMP' 'NBAS1, NADD1, NBAS2' 'WEIGHT-FLANGE' 'YMIN, YMAX, DELY' 'PHIMIN, PHIMAX, DELPHI'

Essential parameters for adaption of the *.pp file are: SJUMP Ymin, Ymax SBOUND

** METHOD USED TO COMPUTE DATA FOR TABULATING 1 -0.0250D0 0.0002D0

' METHOD OF COMPUTING THE INPUT DATA FOR WHEEL_RAIL GEOMETRICAL FUNCTIONS' ' ( CONSTRAINT / CONTACT POINT / FRICTION PARAMETER )' ' SBOUND : SEPARATION: FINE / COARESE GRID FOR WGEEL COORDINATE' ' DELS1 : INCREMENT OF FINE DISCRETIZATION IN VICINITY OF FLANGE'

(75)

SIMPACK TRAINING Wheel/Rail Basics

Wheel/Rail Profile Generation

(9)

SBound SJump

The diagram Constraint Z shows the range of the area between Ymin and Ymax. These two parameters descibe the range of the area around the change from the tread to the flange. In the shown case Ymin can be chosen with a value of Ymin = -0.02 m, Ymax with a value of Ymax = 0,02 m.

The diagram Wheel Contact Coordinate helps to find suitable values for the parameters Sjump and Sbound. Sjump describes the point where the change between tread and flange takes place (Y coordinate does not change very much, S coordinate changes a lot). Sbound represents the begin of a fine discretization of the wheel profile within the change from the tread to the flange. In the shown case Sjump can be chosen with a value of Sjump = -0.035 m, Sbound with a value of Sbound = 0,025 m. (76)

SIMPACK TRAINING Wheel/Rail Basics

Example: Root Loci (1) Pre-Processing

Processing

Post-Processing

Body Database

Offline Time Integration

General Plots

Track Definition

Eigenmode Analysis

Ride Comfort

Body Definition

Root Loci

Joints Definition Force Elements Database Nominal Forces Linearisation Track Irregularities Profile Generation

(77)

SIMPACK TRAINING Wheel/Rail Basics

(1)

• Real / imaginary plot of the eigenvalues • parameterised by vehicle velocity

damping > 0: instable!

• shows if any eigenvalues become instable with increasing velocity • plus signs grow with increasing velocity • yaw mode shows characteristic behaviour

eigenvalues independent upon velocity

de y aw cr m ea o se de , v e s w da lo ith mp cit v in y eh g icl e

Root Loci

(78)

SIMPACK TRAINING Wheel/Rail Basics

Root Loci

(2)

Parameter Variation of Eigenmodes • Open Parameter Variation configuration window • Select ParVar case “Root_loci” • Set start and end velocity [km/h]

• No results need to be defined • Perform Parameter Variation / Eigenfrequency

(79)

SIMPACK TRAINING Wheel/Rail Basics

Root Loci

(3)

Parameter Variation of Eigenmodes • Open Parameter Variation Plot “Eigenfrequency” • Adjust settings • Click on “Plot”

(80)

SIMPACK TRAINING Wheel/Rail Basics

Root Loci

(4)

Parameter Variation of Eigenmodes • Switch to “Min-Damping” representation • Curve connects the minimum damped eigenvalues • Curve crosses the zero axis at critical speed

Damping > 0: critical speed at ca. 280 km/h

(81)

SIMPACK TRAINING Wheel/Rail Basics

Example: Critical Speed (1) Pre-Processing

Processing

Post-Processing

Body Database

Offline Time Integration

General Plots

Track Definition

Eigenmode Analysis

Ride Comfort

Body Definition

Root Loci

Joints Definition

Critical Speed

Force Elements Database Nominal Forces Linearisation Track Irregularities Profile Generation

(82)

SIMPACK TRAINING Wheel/Rail Basics

Critical Speed

(2)

• Plot of critical speed against conicity (or other parameter) • Determined with special method: fast and accurate

v

• Automatic iteration of critical speed

λ

(83)

SIMPACK TRAINING Wheel/Rail Basics

Example: Critical Speed

(3)

• Open ParVar configuration window • Select ParVar case “Critical_Speed” • Start and end velocity [km/h] need not to be set here, only the type

• Second (middle) loop variates e.g. equivalent conicity, σ and ε

(84)

SIMPACK TRAINING Wheel/Rail Basics

Example: Critical Speed

(4)

Parameter Variation of Critical Speed • No results need to be defined • Select “Generate Quasilinear WheelRail Profiles” in pre-calculations level 2

Every Every time time you you select select the the linear linear wheelwheelrail profiles to be variated in any rail profiles to be variated in any form form (wheel (wheel radius, radius, linear linear parameters parameters λ, λ, σ, σ, ε, ε, ...): ...): Use Use the the pre-calculation! pre-calculation! Otherwise Otherwise the the variation variation does does not not work. work.

(85)

SIMPACK TRAINING Wheel/Rail Basics

Example: Critical Speed

(5)

Parameter Variation of Critical Speed • Set parameters of iteration method: Initial value, increment, maximum and precision in [km/h] (as selected in inner loop configuration)

(inner loop - automatic iteration)

v

e iterates to critical speed with given precision f next value of middle loop: same procedure and so on

d raises with increment until critical damping or maximum is reached c initial value

λ (middle loop)

If necessary, set frequency range to be searched for critical eigenvalue

„Linear method“ is faster. Disable if results seem strange

(86)

SIMPACK TRAINING Wheel/Rail Basics

Example: Critical Speed

(6)

Parameter Variation of Critical Speed • Open Parameter Variation Plot “Critical Parameter” • Click on “Plot” • Other representations are only available if there are a middle and also an outer loop

(87)

SIMPACK TRAINING Wheel/Rail Basics

Extra: Independent Wheels • Three bodies: Axle bridge, left wheel, right wheel • Axle bridge: joint type 07 • Wheels: joint type 02 (essential)

02

Primary Suspension

Attention: Attention: Make Make sure sure to to

Constraint R

07, 6 DOF

•• relate relate the the inertia inertia tensors tensors to to the the centers centers of of gravity! gravity!

Bogie frame Constraint L

•• set set the the wheels‘ wheels‘ centers centers of of gravity to the true y position gravity to the true y position of of the the wheel wheel bodies, bodies, and and

W/R Elements

Axle bridge

Right wheel

02

07, 6 DOF,

• Wheel bodies’ reference frames situated in the track middle, like the reference frame of the axle bridge

Left wheel

• Wheel/Rail Elements located on wheel bodies

(88)