isea summer school – prato 3 rd june 2005 # marco pierini marco pierini – università di firenze...

ISEA Summer School – Prato 3rd June 2005 1

Marco Pierini Marco Pierini – Università di Firenze – Italy

[email protected]

FEM and Multibody Modelling of Luge Sled


Cooperation UNIFI – FISI (Italian Federation for Cooperation UNIFI – FISI (Italian Federation for Winter Sports)Winter Sports)

• Started in 2000Started in 2000

• Aim: Make the Sled easier to driveAim: Make the Sled easier to drive

FASTERFASTER


ObjectiveObjective

• Short period (Salt Lake City Olimpic games: 2002)Short period (Salt Lake City Olimpic games: 2002)

Small improvementSmall improvementSmall improvementSmall improvement

• Longer period (Torino Olimpic Games: 2006)Longer period (Torino Olimpic Games: 2006)

FEM and MB ModellingFEM and MB ModellingFEM and MB ModellingFEM and MB Modelling


Open problemsOpen problems

•Very small know-how•Very small know-how

No publications on previous workNo publications on previous work

No previous experience in ItalyNo previous experience in Italy

•Translate in “engineering sense” the athlete sensation/feeling •Translate in “engineering sense” the athlete sensation/feeling

It has no sense to build a sled that the athlete dos not like!!!!It has no sense to build a sled that the athlete dos not like!!!!


International Luge FederationInternational Luge Federation

natural tracknatural track artificial track artificial track


DescentDescent


Some rulesSome rules

• 21-25 kg for a single sled21-25 kg for a single sled

• ControlsControls– Temperature of the blades Temperature of the blades – Weight of the sled Weight of the sled – Overall weight of the athlete Overall weight of the athlete

• TrackTrack– Minimum length 1000 mMinimum length 1000 m– Maximum length 1300 mMaximum length 1300 m


More Interesting FactsMore Interesting Facts

• Competitions may be held in extreme weather conditions Competitions may be held in extreme weather conditions with a temperature as low as – 25°Cwith a temperature as low as – 25°C

• If an athlete loses any item during a run he/she will be If an athlete loses any item during a run he/she will be disqualified disqualified

• The time is measured with an accuracy of 1000th of a The time is measured with an accuracy of 1000th of a second second

• In case of snowfall the track is swept after a certain number In case of snowfall the track is swept after a certain number of athletes of athletes

• The athlete has to pass the finish line in contact with The athlete has to pass the finish line in contact with his/her sled his/her sled

• In order to participate in a competition the athletes require In order to participate in a competition the athletes require a valid license (medical check-up, valid insurance) a valid license (medical check-up, valid insurance)

• The athlete must wear the FIL safety helmet The athlete must wear the FIL safety helmet


The SledThe Sled

RuunersRuuners

SeatSeat

BridgesBridges

BladesBlades


Seat (also called Pod Seat)Seat (also called Pod Seat)


Front bridgeFront bridge


M8M8

Ruuners and BladesRuuners and Blades


Driving techniqueDriving technique


Max Acceleration 6gMax Acceleration 6g

Driving techniqueDriving technique

Max Speed 140 km/hMax Speed 140 km/h


Vertical & Transversal StiffnessVertical & Transversal Stiffness

Front ViewFront View

Vertical StiffnessVertical Stiffness

Rear ViewRear View

Transversal StiffnessTransversal Stiffness


Short period improvementShort period improvement

• Possible variation Possible variation

in the sledin the sled

Keeping in mind the rules!!!!Keeping in mind the rules!!!!

Modify the stiffness to fulfill the requirement of different tracks

Modify the stiffness to fulfill the requirement of different tracks

• Screw torqueScrew torque• Silent-BlockSilent-Block

• Steel pullSteel pull

Reduction of vibration transmitted to the athlete

Reduction of vibration transmitted to the athlete

Increase transversal stiffnessIncrease transversal stiffness


Position of the BridgesPosition of the Bridges

Different tickness of the bridgesDifferent tickness of the bridges

AimAim Change of the stiffness due to:Change of the stiffness due to:

Different Sled configuration (FEM)Different Sled configuration (FEM)

ForceForceWeightWeight


Different Sled configuration (results)Different Sled configuration (results)


Force Weigth

Original 9 405 11,1 0 0,60 0

Optimal 10 305 11,7 -5% 0,30 +52%

Modified 1 9 305

Distance between bridges [mm]

Bridges Tickness

0,63 +5%

UXmax

14,4 -30%

UY

Different Sled configuration (results)Different Sled configuration (results)


Steel PullSteel Pull

AimAim Increase transversal StiffnessIncrease transversal Stiffness


Traction testTraction test

Ultimate force 8000 N

Calculate (FEM) max Force 800 N


Force Weigth

UY UXmax

Original 9 40511,1

00,600

0

With pull 9 4059.13

+18%0,114

+420%

Bridges Tickness

Distance between Bridges

[mm] [mm]

MOD3FILO1 7 40514,8 -33%

0,130 +360%

DIST305f 9 30512,4 -12%

0,131 +360%

Steel pullSteel pull


Control of the torqueControl of the torque

M1=14 NmM1=14 Nm

M2=19 NmM2=19 Nm

M3=24 NmM3=24 Nm


Control of the torque (results)Control of the torque (results)

Torque M2

Torque M1


Silent-blockSilent-block



MassMass

Max AccelerationMax Acceleration

FEMFEM

Force acting on the Silent-blockForce acting on the Silent-block

N1470

4smg6kg100

F2


Silent-block (results)Silent-block (results)

Configurationdeformation

[mm]difference

%Original 0,230 0

Buttonhole 0,357 55

5 holes 0,337 47


Short period improvement Short period improvement

• Reverse engineering of the SledReverse engineering of the Sled

• Development of the MB-FEMDevelopment of the MB-FEM

Aim: development of MB-FEM model able to simulate the descentAim: development of MB-FEM model able to simulate the descent

StepsSteps


CAD ModelCAD

Model

Reverse EngineeringReverse Engineering

Phisical Model

Phisical Model



InstrumentsInstruments

“FARO Arm”“FARO Arm”

CADCAD

Software “Anthrocam”Software “Anthrocam”



Very important to use the same reference systemVery important to use the same reference system


• Scanning ModeScanning Mode


• Point ModePoint Mode

Acquisition TechniquesAcquisition Techniques

CAD ModelCAD Model


MB-FE ModelingMB-FE Modeling

• MSC Adams MSC Adams

Simplied modelSimplied model

Accurate modelAccurate model




Made with rigid body elementMade with rigid body element

Ruuner + BladeRuuner + Blade

BridgesBridges

Center of gravity of athlete

Center of gravity of athlete



Interaction between solidInteraction between solid

Function “Contact”Function “Contact”


Simulation of contact and frictionSimulation of contact and friction




Use of spheres for the contactUse of spheres for the contact




FF

Seconda configurationSeconda configuration - No DOF

- No Friction

- Lateral Forces

- No DOF

- No Friction

- Lateral Forces

First configurationFirst configuration - 1 DOF

- Friction

- 1 DOF

- Friction




)Fv1(LogkF CL

General Force: (Lateral Force)General Force: (Lateral Force)


No lateral forcesNo lateral forces





Simplied modelSimplied modelWith lateral ForcesWith lateral Forces




Common characteristicsCommon characteristics

Inertial propertiesInertial properties

Silent-block are also modeledSilent-block are also modeled

All parts are geometrically correct and flexibleAll parts are geometrically correct and flexible

Spheres to simulate the contactSpheres to simulate the contact

Main differerencesMain differerences

Lateral ForcesLateral Forces




CAD ModelCAD Model

ParasolidParasolid

FEM modelFEM model

Flexible partsFlexible parts




Adams modelAdams model



Accurate modelAccurate modelFirst SimulationFirst Simulation

Entrance in the labyrinthEntrance in the labyrinth


Second SimulationSecond Simulation



Turn constant radiusTurn constant radius


Salt Lake City Olympic Games 2002Salt Lake City Olympic Games 2002 Armin Zoeggeler. IV Run Armin Zoeggeler. IV Run


Armin Zoeggeler

Gold Medal

Salt Lake City Olympic Games 2002

Armin Zoeggeler

Gold Medal

Salt Lake City Olympic Games 2002

isea summer school – prato 3 rd june 2005 # marco pierini marco pierini – università di firenze...

Documents

isea summer school prato

nm slide

n slide

descent slide

kmh slide

faster slide

bridge slide

silentblock slide