Vienna University of Technology SIMULATION OF THE … · SIMULATION OF THE DYNAMIC BEHAVIOUR OF AN...

Institut Institut für für MechanikMechanik

SIMULATION OF THE DYNAMIC BEHAVIOUR OF AN AIRCRAFT LANDING

GEAR DURING LANDING

SIMULATION OF THE DYNAMIC SIMULATION OF THE DYNAMIC BEHAVIOUR OF AN AIRCRAFT LANDING BEHAVIOUR OF AN AIRCRAFT LANDING

GEAR DURING LANDINGGEAR DURING LANDING

01 / 17

Reinhard LernbeissReinhard Lernbeiss

SIMPACK User Meeting 2004SIMPACK User Meeting 2004

Vienna University of Technology

ViennaVienna University of University of TechnologyTechnology


TaskTask and and problemproblem definitiondefinition

02 / 17 Simulation of the dynamic behaviour of an aircraft landing gear during landing

EMB 190

•• AnalyticalAnalytical--numericalnumerical studystudy of of thethe shockshock strutstrutapplyingapplying dynamicdynamic loadsloads

•• Simulation of Simulation of thethe shockshock strutstrut withwith SIMPACKSIMPACK

•• Simulation of Simulation of landinglanding and and brakingbraking of of thethe EMB 190EMB 190withwith SIMPACKSIMPACK

Liebherr

Task and problem definition Analytical-numerical study

Shock strut with SIMPACK Landing/Braking simulation

•• Model of Model of thethe regional regional airlinerairliner EMBRAER EMB 190EMBRAER EMB 190withwith SIMPACKSIMPACK forfor thethe simulationsimulation of of manoeuvresmanoeuvreson on groundground oror closeclose to to groundground


Nose landing gearNose landing gear

•• max. Takemax. Take--Off Off WeightWeight: 50300 kg: 50300 kg

•• max. max. LandingLanding WeightWeight: 43000 kg: 43000 kg

•• 96 96 passengerspassengers, 4, 4--5 5 cockpitcockpit//cabincabin crewcrew



EMBRAER EMB 190EMBRAER EMB 190



Main landing gearMain landing gear


Main Main landinglanding geargear



Left main landing gear

forward

4 Brake Discs fixed

3 Carbon BrakeDiscs rot.

compressed

Oil

Air orNitrogen




Model of Model of thethe shockshock strutstrutconsideringconsidering bouncebounce//reboundrebound and and bendingbending





FILM FILM


DynamicDynamic PhenomenaPhenomena






•• StaticStatic bendingbending deflectiondeflection

•• Bernoulli Bernoulli beambeam usingusingtransformationtransformation matricesmatrices

•• FE FE MethodMethod•• StaticStatic bendingbending deflectiondeflection•• Analysis of Analysis of EigenfrequenciesEigenfrequencies•• Analysis Analysis withwith dynamicdynamic loadsloads



5.17 mm700 mm17.06 mm200 mm

Bending deflection

Ax. compressionF=10kN

AnalyticalAnalytical--numericalnumerical studystudy



EquationsEquations of Motion of Motion –– FEFE--ModelModel



( )t+ + =&& &M u Du K u f

( ) [0,0,0,0,0,0, ( ) ,0 ]Tt F t=f

2 ( )F F Fm x d x k x P t+ + =&& &

Part 1 Part 2

AnalyticalAnalytical--numericalnumerical studystudy



ModellingModelling thethe shockshock strutstrut in SIMBEAM in SIMBEAM -- SIMPACKSIMPACK



Marker resp.constraintsConnectionBeam 1 and 2

Marker resp.constraintsat fixed support

Beam 2

compression

Beam 1

ShockShock strutstrut withwith SIMPACKSIMPACK



EigenfrequenciesEigenfrequencies (Hz)(Hz)



ff11 ~ 10.5Hz~ 10.5Hz

ff22 ~ 125 Hz ~ 125 Hz

displacement u

deflection w

ShockShock strutstrut withwith SIMPACKSIMPACK



LandingLanding



touch down

touch downElevator ForceWing LiftAttitude

LandingLanding//BrakingBraking SimulationSimulation



Animation of Animation of simlationsimlation resultsresults: : landinglanding and and brakingbraking





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r r s LS k k sβ= + .... control parameter

0

0 1

1 2

2

u

u u

u

S SS S SS S SS S

≥> ≥> ≥>

.... decrease of brake pressure

.... keep brake pressure

.... keep last brake pressure rate

.... increase of brake pressure

( ) /r R R

F R RL

F

r gv rsv

β = Ω ⋅− Ω=

& .... normalized angular acceleration

.... longitudinal slip

AntiAnti SkidSkid System System






NumericalNumerical simulationsimulation resultsresults



main landing gearnose landing gear

Vertical force [kN] at (elastic) main and (rigid) nose landing gear




Animation of Animation of LandingLanding and and BrakingBraking

withwith AntiAnti SkidSkid SystemSystem





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Deflection w [mm] of centre of tyre Deflection w [mm] of centre of tyre

elasticelastic shockshock strutstrut rigidrigid shockshock strutstrut







Deflection w [mm] of centre of tyre Deflection w [mm] of centre of tyre

elasticelastic shockshock strutstrut rigidrigid shockshock strutstrut




longitudinal deceleration [m/s2]longitudinal deceleration [m/s2]


16a / 17 Simulation of the dynamic behaviour of an aircraft landing gear during landing


•• Tyre Tyre modelmodel forfor touchtouch downdown

•• Investigation of Investigation of ShimmyShimmy--PhenomenaPhenomena

•• ApplicationApplication of of elasticelastic fuselagefuselage

Open Open problemsproblems -- OutlookOutlook


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