Simpack Wheel-Rail Training BASIC

nullnullSIMPACK: Wheel/Rail Basic Training Analysis and Design of General Mechanical SystemsINTEC GmbH, Argelsrieder Feld 13, 82234 Wessling, Tel: 08153/92 88-0, Fax 08153/92 88-11, E-Mail: intec@simpack.de马玉坤 mayk@rails.com.cnnull Overview: SIMPACK Wheel/Rail Functionality The Track Joint, Degrees of Freedom The SIMPACK Default Wheelset Example: Setting Up a Default Wheelset Standard Track Models, Basic Contact Models Example: Building a Bogie Data Base Calculation of Nominal Forces SIMPACK General Plots with Wheel/Rail Specific Data Some Tips for Completing the Vehicle Topology of a Railway Vehicle Substructures in Wheel/Rail Models Basic Track Irregularities Ride Comfort Linearised Wheel/Rail Contact Eigenmode AnalysisContentsnullOverview: SIMPACK Wheel/Rail FunctionalityProfile LinearisationSpecialnullThe Track Joint Type 0707Imaginary track center lineJoint follows the track centerDefined from Isys to bodyAttention! z axis is downwards positive for wheel/rail models (according to UIC)nullThe SIMPACK Default Wheelset (1)3D Elements of Wheels and Rails$M_Wheel_ProfRef $M_Wheel_Contact$M_Rail_ProfRef $M_Rail_Contact$M_Rail_Track_Frame $M_Rail_Track_Camera$L_RailWheel$F_RW_Friction$S_Rail_ProfRef $S_Rail_Contact$S_Wheel_ProfRef $S_Rail_Track_Frame $S_Rail_Track_CameraNote 1: Every _Rail_ and _Wheel_ element exists for the left and the right wheel. Note 2: Replace _Wheel_ by the name of the wheelset body.  e.g. „$M_Wheelset1_ProfRef_Left“, „$L_RailWheel_Right_of_Wheelset1“, ...nullThe SIMPACK Default Wheelset (2)Markers$M_Wheel_ProfRef $M_Rail_ProfRef (here canted with rail) Wheel profile definition plane (e.g. taper line) Nominal wheel radius r0 $M_Wheel_Contact $M_Rail_Contact (both moving with the current contact point)Wheelset body-fixed reference frame (BFRF) Semi-wheelbase e0 Rail profile definition plane (e.g. middle of rail head) nullThe SIMPACK Default Wheelset (3)Track-Related Markers (moving with the wheelset along the track)$M_Rail_Track_Frame $M_Rail_Track_CameraSuperelevation unullThe SIMPACK Default Wheelset (4)$L_RailWheelConstraints and Force Elements8909$F_RW_Friction for tangential forces0989Both acting at same markers: FROM $M_Rail_Contact TO $M_Wheel_ContactnullThe SIMPACK Default Wheelset (5)$S_Rail_ProfRef $S_Rail_Contact$S_Wheel_ProfRef $S_Rail_Track_Frame $S_Rail_Track_CameraSensorsEach FROM Isys TO according marker.nullEXAMPLE: Setting Up a Default Wheelset (1)Pre-Processing Processing Post-Processing Body Definition Online Time Integration Joints Definition Track Definition Vehicle GlobalsnullEXAMPLE: Setting Up a Default Wheelset (2)Some Important Steps to Be Done First Change gravity to positive z direction (+9,81 m/s²) Adjust view to standard view: Wheel/Rail perspective viewnullEXAMPLE: 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 freedomnullEXAMPLE: Setting Up a Default Wheelset (4) Rename $B_body1 to $B_WS1 (Wheelset 1) Add body data Change 3D geometry of wheelset axlenullEXAMPLE: Setting Up a Default Wheelset (5) Set up the joint Generate wheel/rail elements Assemble systemnullConstraints and Dependent/Independent StatesDefault: s y z    - independent - independent - dependent - dependent - independent - independentIndependent: freely adjustable by user and model dynamics (description by differential equation of motion) Dependent: state results from kinematics (description by algebraic kinematical equation)Imagine laying the wheelset down onto the track with a crane  only s, y, ,  adjustablenullEXAMPLE: Setting Up a Default Wheelset (6)Pre-Processing Processing Post-Processing Body Definition Online Time Integration Joints Definition Track Definition Vehicle GlobalsnullStandard Track Models (1)Straight Track Radius Superelevation, with reference length Track lengthCurved Track with Constant Horizontal Curvature Track lengthCurve entry - curve passing - sign change of curvature (s-curve) - cross-over Radius Superelevation, with reference length Track length Further special parametersCurved Track with Variable Horizontal CurvaturenullStandard Track Models (2)SuperelevationSuperelevation uRotation about inner railRotation about centerlineSuperelevation uCenterline is elevatedReference length = railbasenullStandard Track Models (3)Curve Entry and Superelevation Ramp Curve entry: Superelevation ramp (length identical with curve entry):R = R =   RCurveR = RCurveStraight rampu = 0u = uCurveu = 0  uCurveSmoothed over distance 2hS-shaped rampu = 0u = uCurveu = 0  uCurveRadius and superelevation have to be negative for left-hand curvesFor standard tracks, also the form (s-shaped, linear) of the curve entry corre-sponds to the ramp.nullEXAMPLE: Setting Up a Default Wheelset (7) Set up an entry to a narrow curvenullEXAMPLE: Setting Up a Default Wheelset (8)Pre-Processing Processing Post-Processing Body Definition Online Time Integration Joints Definition Track Definition Vehicle GlobalsnullEXAMPLE: Setting Up a Default Wheelset (9)Vehicle Globals Set velocity Set profiles Click to apply settings for all wheelsets in the modelnullVehicle Globals Window (1)Gauge or railbaseVelocity in m/s or km/hSemi-wheelbase, nominal wheel radius, railbase/gauge, rail cantProfiles and parameter setsClick to finishWheelset type (set at „Generate/Update W/R Elements“)nullVehicle Globals Window (2)Friction force lawµWeighting factor for Kalker coefficientsProhibit/allow nega-tive normal force with zero friction force (physically incorrect but working)Kalker Coefficients: calculated according to current geometry or given by user On-line integration uses red curve Off-line integration uses blue curvenullEXAMPLE: Setting Up a Default Wheelset (10)Pre-Processing Processing Post-Processing Body Definition Online Time Integration Joints Definition Track Definition Vehicle GlobalsnullEXAMPLE: Setting Up a Default Wheelset (11) Start online calculation (sample interval = 10-1 s) Watch the show ... Try out the different standard viewsContact marker moves to flange and cantsBody-fixed reference marker rotatesFront ViewR/L WheelVehicle FrontnullEXAMPLE: Setting Up a Default Wheelset (12) Switch to Multipoint Contact Start online simulation againClick to finishSecond contact markernullMultipoint Contact (1)$M_Wheel_Contact_Flange $M_Wheel_Contact_Flange2$M_Rail_Contact_Flange $M_Rail_Contact_Flange2$F_RW_Friction_Flange $F_RW_Friction_Flange2$S_Wheel_Contact_Flange $S_Wheel_Contact_Flange2 Up to three different contacts per wheel (tread, flange, flange2/back of wheel) Additional wheel/rail elements: Each contact exists only in its designated profile section:TreadFlangeFlange2/ Back of wheelnullAdditional necessary parameter settings in .sys fileExample [...] marker ( 1 , $M_Rail_Contact_Right_of_WS1 ) = $B_Isys ! [-] Assignment: Marker -> Body marker ( 2 , $M_Rail_Contact_Right_of_WS1 ) = -97 ! [-] Built-In Orientation Type marker.cpar ( 1 , $M_Rail_Contact_Right_of_WS1 ) = 'UIC60' ! Rail Profile Type marker.cpar ( 2 , $M_Rail_Contact_Right_of_WS1 ) = 'S1002' ! Wheel Profile Type marker.cpar ( 3 , $M_Rail_Contact_Right_of_WS1 ) = 'MultiContact_3[deg]' ! Parameter-File Type marker.par ( 5 , $M_Rail_Contact_Right_of_WS1 ) = $M_Rail_ProfRef_Right_of_WS1 ! [] Reference Marker on Rail marker.par ( 6 , $M_Rail_Contact_Right_of_WS1 ) = $M_WS1_ProfRef_Right ! [] Reference Marker on Wheel marker.par ( 7 , $M_Rail_Contact_Right_of_WS1 ) = $M_WS1_Contact_Right ! [] Contact Marker on Wheel marker.par ( 20, $M_Rail_Contact_Right_of_WS1 ) = 5.0000000000E-01 ! [] Nominal Rolling Radius [m] marker.par ( 23, $M_Rail_Contact_Right_of_WS1 ) = 1 ! [] Contact Model marker.par ( 24, $M_Rail_Contact_Right_of_WS1 ) = -5.7999998331E-02 ! [] Left Bound For Flange [m] marker.par ( 25, $M_Rail_Contact_Right_of_WS1 ) = -3.5000000149E-02 ! [] Right Bound For Flange [m] marker.par ( 26, $M_Rail_Contact_Right_of_WS1 ) = 1.0000000475E-03 ! [] Increment for Bisection [m] marker.par ( 27, $M_Rail_Contact_Right_of_WS1 ) = 9.9999997172E-10 ! [] ATol for Bisection marker.par ( 28, $M_Rail_Contact_Right_of_WS1 ) = 9.9999997172E-10 ! [] RTol for Bisection marker.par ( 32, $M_Rail_Contact_Right_of_WS1 ) = $M_Rail_Contact_FlangeRight_of_WS1 ! [] Flange Marker 1 on Rail marker.par ( 33, $M_Rail_Contact_Right_of_WS1 ) = $M_Rail_Contact_Flange2Right_of_WS1 ! [] Flange Marker 2 on Rail marker.par ( 34, $M_Rail_Contact_Right_of_WS1 ) = $M_WS1_Contact_FlangeRight ! [] Flange Marker 1 on Wheel marker.par ( 35, $M_Rail_Contact_Right_of_WS1 ) = $M_WS1_Contact_Flange2Right ! [] Flange Marker 2 on Wheel marker.par ( 36, $M_Rail_Contact_Right_of_WS1 ) = -5.0000000000E-02 ! [] Bound. for Back of Wheel [m] [...]Multipoint Contact (2)Boundary between flange and back of wheel (e.g. top of flange) If equal to marker.par(24): no flange2 contact possible.Boundary between flange and treadLimit of back of wheel (wheel backplane) Coordinates w.r.t. wheel profile reference plane, always seen on right wheel (flange on the left) Adjust for every marker which has par(24,25,36)marker.par(24)marker.par(25)marker.par(36)-s +snullEXAMPLE: Setting Up a Default Wheelset (Finish) Switch back to Singlepoint (Remember to change the parameter sets. Press “Apply” after switching back to Singlepoint.) Increase velocity Switch to Elastic Contact Start online simulation again, 10-2 s intervalClick to finishDerailment occursnull One-sided spring/damper instead of constraint Additional wheel/rail elements: Deleted wheel/rail elements: Only possible with Singlepoint Contact Parameters (stiffness and damping) can be set at Contact Force settings in Vehicle GlobalsElastic Contact$F_RW_ElasCont$L_RailWheelnullWheel/Rail Contact in SIMPACK (1)1. Find the contact point2. Determine normal force3. Calculate tangential forcesnullWheel/Rail Contact in SIMPACK (2)Step 1: Finding the contact pointDefault 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 profilesOld 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 should not use the rigid method. It can cause numerical problems and is outdated.nullWheel/Rail Contact in SIMPACK (3)Step 2: Determining the normal forceDefault 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“ possibleAlternative 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“)nullWheel/Rail Contact in SIMPACK (4)Step 3: Calculating the tangential forcesDefault 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 µSeveral alternative methods (Switch between methods in Vehicle Globals window: „Contact Force“)nullWhen do the Default Settings not Suffice?OVERVIEW: Contact Models in SIMPACK (2)Contact Models in Comparison For ride comfort calculations with very poor track quality Use “Constraint (Rigid) Contact” with allowed negative normal forces For derailment analyses with wheel lift Use “Elastic Contact” For narrow curves (two contact points) For local traffic with back-of-wheel contact (three contact points) Use “Multipoint contact” For high angles of attack ( 5°) Use “Online Evaluation” nullEXAMPLE: Building a Bogie (1)Pre-Processing Processing Post-Processing Body Database Offline Time Integration General Plots Track Definition Body Definition Joints Definition Force Elements Nominal ForcesnullEXAMPLE: Building a Bogie (2)Preliminary Steps 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 basenullEXAMPLE: Building a Bogie (3)Create a New Model for the BogieRemember to set gravity to positive z direction adjust the view settingsSet Up the Bogie Frame Name $B_BF 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 Joint type 07 (general wheel/rail joint) with 6 DOF, but without wheel/rail elementsCentre of massBFRF marker (“to“ marker of type 07 joint)Plane of 3D primitive referenceTrack planenullEXAMPLE: Building a Bogie (4)3D Primitives: Wheel Rail Bogie and traversesnullEXAMPLE: Building a Bogie (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 mUse common abbreviations to keep names short. Otherwise you could get into trouble when working with substructures.nullEXAMPLE: Building a Bogie (6)Joint Position of the Bogie Frame s = 1.25 m z = 0 mImport two Wheelsets from Data Base Define two new bodies $B_WS_F and $B_WS_B Remove standard cuboid primitives Import wheelset data from body database for each new body Change joints to type 07 with 6 DOFs Generate wheel/rail elements for each wheelset s = 2.5 m (front wheelset) resp. 0 m (back wheelset) Assemble system: all bogie frame DOFs have to be independentHint: The bogie frame is kinematically completely independent because its position will be determined only by the suspension.nullEXAMPLE: Building a Bogie (7)Define a TracknullEXAMPLE: Building a Bogie (8)Pre-Processing Processing Post-Processing Body Database Offline Time Integration General Plots Track Definition Body Definition Joints Definition Force Elements Nominal ForcesnullEXAMPLE: Building a Bogie (9)Primary Suspension Type 05: spring/damper parallel compact FROM marker on bogie frame Use “Identity to...” feature Check with “Info - Force Elements” that rabs is near zero (precondition for calculation of nominal forces with compact force elements)Why? Stiffness/damping definitions are given in body reference system of FROM body – they would rotate if wheelset were FROM body r x F torques are applied on FROM bodynullEXAMPLE: Building a Bogie (10)Pre-Processing Processing Post-Processing Body Database Offline Time Integration General Plots Track Definition Body Definition Joints Definition Force Elements Nominal ForcesnullNominal 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 automaticallynullEXAMPLE: Building a Bogie (11)Calculation of Nominal Forces: Preliminary Steps Set global velocity of 10 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 Accelerations ZGPP(1:nzj,joint_name) ================================================================================ ZGPP($J_WS_B) = 9.4416557D-08 3.5558345D-07 1.3818905D-14 -1.8048022D-08 2.3516961D-06 4.7206718D-07 ZGPP($J_WS_F) = 9.6635120D-08 3.5785239D-07 1.2013822D-14 -1.8163186D-08 2.3667099D-06 4.8315963D-07 ZGPP($J_BF ) = 3.1647477D-08 -4.0850997D-06 1.0649262D+01 4.0851000D-05 4.9563528D-13 3.1647476D-07z acceleration of bogie frame: Not unrealistic, because from gravity, but has to be eliminated in order to bring the system into equilibriumMost accelerations are near zero: o.k.If there are unrealistic accelerations (e.g. greater than 100 m/s²) there could be an error in the model  double-check joints, forces etc.nullEXAMPLE: Building a Bogie (12)Calculation of Nominal Forces Select “Linear System” method (faster) Select the nominal forces in z direction of every primary spring for calculation Perform calculationnullEXAMPLE: Building a Bogie (13)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 Accelerations ZGPP(1:nzj,joint_name) ================================================================================ ZGPP($J_WS_B) = 1.8531921D-07 2.3304777D-07 1.1616952D-14 -1.1828595D-08 4.6889871D-06 9.2656543D-07 ZGPP($J_WS_F) = 1.8618630D-07 2.4226214D-07 9.8283231D-15 -1.2296279D-08 4.7054404D-06 9.3090072D-07 ZGPP($J_BF ) = 4.7909070D-08 -4.4238911D-09 -5.0030864D-07 4.4238911D-08 0.0000000D+00 4.7909069D-07nullEXAMPLE: Building a Bogie (14)Pre-Processing Processing Post-Processing Body Database Offline Time Integration General Plots Track Definition Body Definition Joints Definition Force Elements Nominal ForcesnullEXAMPLE: Building a Bogie (15)Offline Time Integration Configure time integration Start simulation and measurementsIf necessary: stepsize reduction for harsh curve entriesShould be standard for Wheel/RailnullEXAMPLE: Building a Bogie (16)Pre-Processing Processing Post-Processing Body Database Offline Time Integration General Plots Track Definition Body Definition Joints Definition Force Elements Nominal ForcesnullGeneral Plot with Wheel/Rail Specific DataUseful Wheel/Rail Related DataWheelset lateral position in track Wheelset yaw angle Creepage (longitudinal, lateral, spin) Normal force N, traction forces Tx , Ty Traction coefficients fx , fy = Tx/N, Ty/N Wheel forces Y, Q Frictional power P Contact point coordinates on wheel/on rail Longitudinal contact point shift Semi-axes a, b of the Hertzian ellipse Area of the Hertzian ellipse Ratio of the semi-axes a/b Current Kalker coefficients C11, C22, C23 . . .y coordinate of track joint (07/09)  coordinate of track joint In contact coordinate system In contact coordinate system; towards wheel In wheelset reference system; towards rail For local contact point, wheel, wheelset, or vehicle In wheel or rail profile reference system, along y axis In wheel profile reference system, along x axisOutput values of W/R friction force elements (type 89)nullEXAMPLE: Building a Bogie (17)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 fron