參考講稿文稿

Content(1/2)Part2

MountVibrationAnalysis

IntroductioninVehicleNVH

PowerUnitMountVibrationAnalysisasPartofVehicleNVHInvestigation

Introduction

BasicEngineMountConceptInvestigation

NumericalInvestigationofPowerUnitMountVibrations

DefinitionsandBasicsaboutNVHEvaluationandPost-processing

PowerUnitVehicleExcitation

TheEngineMountCharacteristic

DifferentStiffnessDefinitionsandMeasurementSet-upDifferentBasicModelsforEngineMountRepresentation

ModellingofFrequencyandAmplitudeDependingMountCharacteristicsFEMBasedMountCharacteristicCalculation

ModellingofControlledEngineMounts

ContributionofExhaustSystemVibrationsandNoise

Outlook:CFDInvestigationforHydro-mounts(UDJ)

PowerUnitMountVibrationAnalysis

FigureNo.

2

Content(2/2)Part2

MountVibrationAnalysis

LevelConceptforPowerUnitMountVibrationAnalysisfromConcepttoDetailedDesignPhase

GeneralApproach

Examples

ExampleforModellingLevelM1–ComparisonSpeedSweepandEngineRun-up

ExampleforCompleteLevelConcept

ExampleforCompleteLevelConceptandComparisonwithMeasurements(CustomerExample)

SummaryandConclusions

PowerUnitMountVibrationAnalysis

FigureNo.

3

POWERUNITVEHICLEEXCITATION

MountVibrationAnalysis

PowerUnitMountVibrationAnalysis

FigureNo.

4

NUMERICALMOUNTVIBRATIONANALYSISVEHICLEINTEGRATION/EXCITATION

MountVibrationAnalysis

ExcitationCalculationforChassisVibrations

ExcitationinEngineMountingPoints:

forVehicle(ChassisandCarBody)VibrationandAcousticAnalysis

SimulationofInteriorNoiseContributionofEngineVibrations

MountVibrationsbetweenEngineandChassis

Excitationforcesatpowertrainmountsofapassengercarengine,

4000rpm,fullload

EXCITEEMO1joint:Automaticidentificationoffrequencydependentmodelparametersofenginemountsforthetimebasedcalculation

PowerUnitMountVibrationAnalysis

FigureNo.

5

CALCULATIONOFINTERIORNOISEOVERVIEW

MountVibrationAnalysis

Excitations:

Powertrain,road,intakeandexhaustsystems,wind

CarBody

Cabin

Trim

PowerUnitMountVibrationAnalysis

FigureNo.

6

Absorption

Damping

FluidVibration

StructureVibration

InteriorNoise

CALCULATIONOFINTERIORNOISESHORTEXCURSE

State-of-the-artintheVibro-acousticSimulations

MountVibrationAnalysis

ElementBasedMethods

deterministicmethods

simplepolynomialshapefunctions

finediscretization

EnergyBasedMethods:

statisticalmethods

highmodaloverlap

spatialaveragedresults

F

EM

GAP

frequency

~500Hz

~1500Hz

PowerUnitMountVibrationAnalysis

FigureNo.

7

SEA

EM/BEM/IF

VEHICLENVH

HYBRID(MODULAR)APPROACH

MountVibrationAnalysis

Experiment

Simulation

Excitation/Source

ModularApproach

MountVibrations

TransferthroughSub-frameChassis

TransferFunction

ConnectorPoints-Microphone

ConnectorPointVibrations

Superposition

Qi sources

Hi....transferfunctions

Vibrations

Noise

PowerUnitMountVibrationAnalysis

FigureNo.

8

SeatVibrations,..

HumanEar

Experiment Simulation

Validation

Noise:=Hi·Qi

Hi

Hi

Qi

Qi

VEHICLENVH

HYBRID(MODULAR)APPROACH

SoundPowerSource

MountVibrationAnalysis

atPass-byMicrophonePosition

Hybridapproachforbothinternalandexternalapplicable

Structuraltransferfunctionwithinpowerunit,viaenginemountsandviaSub-frameandChassis(optional)bysimulation

Reciprocalmeasurementofpass-bynoisetransferfunction:Soundpoweratthepass-bynoisepositiontoSoundpressureateachindividualsource

Pass-byMicrophones

SoundPower(P)

NoiseTransferFunction

Sound

Interior

Pressure(p)

Microphones

TransferFunctionsHi

SimulationExperiment

PowerUnitExcitation

PowerUnitMountVibrationAnalysis

FigureNo.

9

HYBRIDAPPROACH/EXAMPLEINTERIORBOOMNOISE/DEFINITION

BoomNoise/Characteristic:

Annoyinghummingnoise,so-calledBOOM,causedbyInteriorCavityMode,

~20-150Hz(calledluggingboomorlowspeedboom),pronouncedforRearWheelDrives.

MainEngineOrders:Essentiallyby2nd(4Cyl.)/3rd(6Cyl.)

Thedrivelineamplifiesandexcitesthechassis(chassisorcarbodyresonance)andthechassisexcitesaninteriormodeinsidethepassengercompartment.

Dominatingexcitationistypicallytorquefluctuationandexcitationoftorsionalmodesinthedrivelinesystem.

Highspeed(or“normal”)boomismainlyaffectedbybendingmodesinthedriveline.

MountVibrationAnalysis

PowerUnitMountVibrationAnalysis

FigureNo.10

HYBRIDAPPROACH/EXAMPLE

INTERIORBOOMNOISE/TARGETSYSTEM

TheTargetSystem:

Bodyonframevehicleconstructionofapick-uptruck

4-cylinderturbo-chargedDieselengine

Manualtransmission(6-speedmanual);5thgearloadcaseonly

Rearwheeldrivenversion(beamaxleonleafsprings)ofapick-uptruck

Calculationofspeedrange;1100-1700rpmWOT

Componentstoconsider:Engine,TransmissionwithEntireDriveline(DMFW!),Chassis/Mounts,Wheels,Suspension(LeafSprings!),[CarBody,Compartment]

MBD-Modelling:Coupledtorsional/bendingapproachofdriveline,flexiblechassis/mounts

Mainresultsareforcesatchassismountingpositionsfromengine,drivelineandsuspension.Calculatedexcitationcombinedwithmeasuredtransferfunctionsofcarbodyandcompartment;gearconnectionstobeincluded.

MountVibrationAnalysis

PowerUnitMountVibrationAnalysis

FigureNo.11

HYBRIDAPPROACH/EXAMPLEINTERIORBOOMNOISE/MODEL

MountVibrationAnalysis

TheModellingApproach:

Creationofatransmission,driveline,suspensionmodelthataccuratelypredictsforcingfunctionsatframeattachment(mounting)points.

FlexibleFEMbasedstructuresforpowerunit,cranktrain,transmissionshafts/gears,driveline,chassis,rearaxlehousing,leafsprings.

Rigidbody(Ri3D)forcabin

Rearwheelsrunonarepresentationofthetestbedroller,usinggearjointsforroller-wheelconnection

EvaluationofdrivelineboombycalculationoftheexcitationbyEXCITEfromrunningdrivelinefordefinedoperatingconditionsatstationaryconditions.

Evaluationofresponseatchassismountingpointsofdrivelineandsuspension.

PowerUnitMountVibrationAnalysis

FigureNo.12

wheels

cardanshafts

(SHMmodel)

transmission

shafts&gears(SHMmodel)

chassisframe

(FEMmodel)

testbedroller(SHMmodel)

cranktrain(SHM

model)

rearleafspring(FEM

model)

engine(FEM

model)

cabin

stabilizerbar(FEMmodel)

sideshafts(SHM

model)

differential

(SHM

model)

gearsystem(SHM

model)

rearaxle(FEMmodel)

THEDRIVELINE

MODELINGHINTS/LEAFSPRINGS

MountVibrationAnalysis

LeafSpringsforInteriorBoomNoiseInvestigation

ModellingApproach:

Torsionalfluctuation(=maineffectforlowspeedboom)andbendingvibrationsincluded

Flexibledrivelineconsistsof:CrankTrain

Transmission–DriveShafts–Differential

SideShafts–Wheels

Gearjointatdifferentialincludedtoinducecorrectsupportforces

Universaljointsbetweencardanshafts

Powerunit,frame,rearaxle,leafspringsandchassisascondensedFEMmodels

Wheelsdrivenontestbedrollertoensurecorrectforceexcitationatrearsuspension;contactwheel–rollerenabledbyGEARandNONLjoints

Non-linearclutchandDMFcharacteristic

torquefluctuation

Importantaxialforceonfrontbushingofrearleafspring

→mainexcitationpathforboomnoise

verticalforce

PowerUnitMountVibrationAnalysis

FigureNo.13

rearleafspringmodel

HYBRIDAPPROACH/EXAMPLEINTERIORBOOMNOISE

MountVibrationAnalysis

InteriorBoomNoiseInvestigation

Investigation:

Variationof:

Non-linearclutchcharacteristics,Flywheelconfigurations(SMF,DMF)Suspensionbushingcharacteristics

Additionaltorsionalvibrationdamperindriveline

Improvementofnoisetransferfunctions(NTF)onchassisandbracketside

Effectofsofteningfrontleafspringbushed

PowerUnitMountVibrationAnalysis

FigureNo.14

NoiseLevel[rdB(A)]

EngineSpeed[rpm]

THEENGINEMOUNTCHARACTERISTICMEASUREMENTANDMATHEMATICALMODELS

MountVibrationAnalysis

Measurement

MountCharacteristic

MathematicalRepresentation

60000

54000

force/displ.RandomNoise

48000

42000

force/displ.Sinus

36000

30000

24000

18000

12000

6000

0

100

300

500

700

900

1100

FrequencyinHz

PowerUnitMountVibrationAnalysis

FigureNo.

15

Stiffness(N/mm)

ENGINEMOUNT

FREQUENCYDEPENDENTCHARACTERISTC

MountVibrationAnalysis

Actualtargetofdetailedmountvibrationanalysisisbetween0–1kHz

Mountjointsshowsignificantfrequencydependedcharacteristic,especiallyinhigherfrequencyrange(>300Hz)

Thisrequiresextendedjointmodels

EXCITEiscalculatingintimedomainduetothehighnon-linearitiesinthesystem(i.e.bearings)

Thereforeconsiderationoffrequencydependencyistobedonebyspecialmathematicaljointmodels,assembledbysprings,massesanddampers

Frequencydependencyformountjointsisverysensitiveandcanhardlybepredicted.

Thereforemeasureddatafromexperimentwithrealmountsispreferred

Target:Considerationoffrequencydependentenginemountcharacteristicsbasedonmeasureddata

FigureNo.16

→resultsforsinusandrandomnoiseexcitation

PowerUnitMountVibrationAnalysis

Stiffness(N/mm)

60000

54000 force/displ.

RandomNoise

48000

42000

force/displ.Sinus

36000

30000

24000

18000

12000

6000

0

100 300 500 700 900 1100

FrequencyinHz

MountVibrationAnalysis

DifferentStiffnessDefinitionsand

MeasurementSet-up

PowerUnitMountVibrationAnalysis

FigureNo.17

TESTBEDSET-UPFORANDDIFFERENTSTIFFNESSDEFINITIONS

MountVibrationAnalysis

FE

z

engine→shaker

E

d2m2

c

chassis→frame

zB

FB

Shaker/

ShakerTable

Mount

FE

z

E

AVLtypicmeasuresc

zB=0

pointstiffn

Frame

FE

zE=0

zE=0

Mount

Mount

zB

z

B

FB

PowerUnitMountVibrationAnalysis

FigureNo.18

OutputStiffnessK*BB

InputStiffnessK*EE

Mount zE

ally

ross zB=0

ess F

B

CrossPointStiffnessK*BE

c2

1

z…applieddisplacementbyshaker

F…measuredforcebyforcetransducer

TESTBEDSET-UPFORANDDIFFERENTSTIFFNESSDEFINITIONS

MountVibrationAnalysis

FE

z

E

d2

m

c

2

zB

FB

K*BB

K*EE

K*BE

PowerUnitMountVibrationAnalysis

FigureNo.

19

F K*BE z

B 1H K* E

BB BB

KBB*jf

FBjf

zBjf

KBE*jf

FBjf

zEjf

Identificationc1,c2,d2,m2

FB

zE FE

Measurement

c2

1

KEE*jf

FEjf

zEjf

InputStiffnessK*EE

CrossPointStiffnessK*BEOutputStiffnessK*BB

MEASUREMENTOFCROSSPOINTSTIFFNESS

MountVibrationAnalysis

CrossPointStiffnessK*BE

Measurementresults:

Dynamiccrosspointstiffnesscharacteristicsversusfrequency;eitherasmagnitude/phaseorcomplex(real/imaginarypart)values

Dataisusedasinputfordynamicmodelofenginemountingcharacteristics

PowerUnitMountVibrationAnalysis

FigureNo.20

K*jfFBjf

BE zjf

E

engine

zE

d2 engine

c1 m2 mount

chassis FB

c2

MEASUREMENTSET-UPFORDETERMINATIONOFMOUNTCHARACTERISTIC

MountVibrationAnalysis

MeasurementProcedure:

Measurementofresultantdisplacementviaaccelerometersandforceviaforcetransducer

Performmeasurementsonrealenginemounts

Themountisplacedbetweentheshaker(movablepart)tableandtheframe

Useenginemountalonew/obracketsasthosearerepresentedasseparateFEMstructuresinthemodel

Measurementisdonebetweensameconnectorpositionsasinsimulationmodel

Measureofcross-pointstiffnessfordifferentshakerfrequencies(f~3-10Hz)

Excitationbysinusoidalsweepmethod

Forcetransducer

(FBbetweenframeandmount)

Accelerometers(onshakertableandontheframenexttotheaccelerometer)tomeasurerelative

displacementz=zE–zB(displacementofthemount)

PowerUnitMountVibrationAnalysis

FigureNo.21

→chirpsignalorband-limitedwhitenoise(random)signalarenotrecommendedduetomixtureofsingleharmonicsandnon-constantexcitationamplitude

FB

CrossPointStiffnessK*BE

frame

zE FE

shakertable

Measurement

MEASUREMENTOFCROSSPOINTSTIFFNESSREMARKS

MountVibrationAnalysis

Remarks:

Themountingcharacteristicisverysensible!

Noeigenmodesofthetestfacility(testrigofstiffsteelprofiles)areallowedinsidetheevaluatedtargetfrequencyrange!Checkbypre-testw/omount.

Thesamemountsasusedfortherunningengineonthetestbedhavetobemeasured.

Forcomparisonofdifferentmeasuredresultsandevaluationofresultvariation2identicalmountsshouldbemeasuredinaddition(→scatterband).

Measurementsshouldbeperformedbeforeenginerun(newmounts)andagainafterenginerun(usedmounts)todetermineinfluenceofmaterialaging/fatigueonstiffnesscharacteristics.

Measurementshouldtobeperformedinall3directionsofthemounts(asfaraspossible)

Consideredfrequencyrange:0to1kHz(maindirection,lowerlimitsforotherdirections)

Accuracyofresultsbetweensimulationandmeasurementforvibrationresponse:Targetvaluesare±3dBupto250Hzand±5dBupto1kHzofvelocitylevels

PowerUnitMountVibrationAnalysis

FigureNo.

22

ENGINEMOUNTMODELSFORDIFFERENTFREQUENCYDEPENDENTCHARACTERISTICS

MountVibrationAnalysis

m1

c2

m2

d1

c3

d3

c1

Kelvin-VoigtModel(NONL)

Constantinfrequencydomain,butamplitudedependent

StandardSolidModel(SLS)

MiniOscillatorModel(EMO1)

MiniOscillatorExtendedModel

(EMO1)

RequiredJointModelComplexityandTypeisDependingontheFrequencyRangeofInterest

PowerUnitMountVibrationAnalysis

FigureNo.23

DynamicStiffness[Ns/mm]

DynamicStiffness[Ns/mm]

DynamicStiffness[Ns/mm]

SLS

ExtendedMiniOscillator

MassModel

MassModel

FREQUENCYDEPENDANTMOUNTMODELEMO1

AUTOMATEDMODELSET-UPBASEDONMEASUREMENT

MountVibrationAnalysis

EXCITEEMO1ModelSet-up:

Performmeasurementswithrealmount

Readingmeasureddynamicstiffnessforeachdirection

Approximationofmeasuredcurves

AutomatedparameteridentificationforEMO1jointbyuseofanintegratedoptimizationalgorithm

Outputofjointparametersforthe

RealPartofFRF

600

EXCITEkernel

Measurement

Approximation

Identification

400

200

0

-200

IdentifiedEXCITE

-400

-600

ModelCharacteristic

100150200250300350400450

Frequency(Hz)

500

550

600

650

ImaginaryPartofFRF

1200

Measurement

Approximation

1000

Identification

800

600

400

200

0

-200

100150200250300350400450500

Frequency(Hz)

550

600

650

PowerUnitMountVibrationAnalysis

FigureNo.24

Dyn.Stiffness(N/mm^2)

Dyn.Stiffness(N/mm^2)

Measurement

MountVibrationAnalysis

Modellingof

FrequencyandAmplitudeDependingMountCharacteristics

PowerUnitMountVibrationAnalysis

FigureNo.25

EXTENDEDMOUNTMODELS

AMPLITUDEANDFREQUENCYDEPENDENTMOUNT

MountVibrationAnalysis

ExtendedEngineMountModel

SystemDescription:

Frequencydependency(measuredforonepreload)–availableforSLSandEMO1

Amplitudedependency(variationofpreloadatmeasurement)

Thisisinputforextendedjointmodel.Resultisamplitudeandfrequencydependentcharacteristics.

ModeldefinedasMATLABmodelandrunsinco-simulationwithEXCITE

Measurementforsinglefrequenciesbysinussweepmethod

EMO1-joint(originalmodelhasconstantstiffnessparametersforc1)

PowerUnitMountVibrationAnalysis

FigureNo.26

k[N/mm]

500

measurement

400 quadr.model

300 meanstiffness200

100

0

0 2 4 6 8

x[mm]

EXTENDEDMOUNTMODELS

AMPLITUDEANDFREQUENCYDEPENDENTMOUNT

MountVibrationAnalysis

ExtendedEngineMountModel

Interpolationforcompletefrequencyandamplitudedependingstiffnessmap

PowerUnitMountVibrationAnalysis

FigureNo.

27

k[N/mm]

crossstiffness

Alternativelycompletemapcouldbemeasured,whichisverycostlyandtimeconsumingandshouldbeavoidedtherefore.

500

measurement

400 quadr.model

300 meanstiffness200

100

0

0 2 4 6 8

x[mm]

MountVibrationAnalysis

FEMBasedMountCharacteristicCalculation

PowerUnitMountVibrationAnalysis

FigureNo.28

FEMBASEDSTIFFNESSCALCULATION

MountVibrationAnalysis

DetermineMaterialModel

FEMmodelingofenginemountsusingnon-linearmaterialmodel

Materialmodelistunedbymeasuredstiffnesscharacteristicformainloadingdirection

ValidatedFEMmodelcanbeusedtocalculatestiffnesscharacteristicsforotherloaddirections(longitudinalandbending),wheremeasurementeffortistoohigh.

Materialmodelcanbeusedforsimilarmountsw/onecessityofmeasurements

FigureNo.29

FEMModelSet-up

Measurement

MainLoadDirection

Validationandtuningofmaterialmodel

StiffnessCharacteristic

FEMAnalysis

CalculationofallDirections

StiffnessCharacteristic

c2

m1

c1

c3

ParameterizationofEXCITEModel

m2

c

4

PowerUnitMountVibrationAnalysis

FEMBASEDSTIFFNESSCALCULATIONMATERIALMODEL

MountVibrationAnalysis

TypicallyfollowinghastobeconsideredwithintheFEManalysis:

Pre-load

Contact(non-linearity)

Non-linearmaterialmodel(ofrubbermaterial)

Rubber-likematerials,whicharecharacterizedbyarelativelylowelasticmodulusandhighbulkmodulusareusedinawidevarietyofstructuralapplications.

Thesematerialsarecommonlysubjectedtolargestrainsanddeformations.

Hyper-elasticmaterialsexperiencelargestrainsanddeformations.

Differentmaterialmodels,whichpredictlarge-scalematerialdeflectionanddeformationscanbeused:Basically2typesareused:

Incompressible

Compressible

PowerUnitMountVibrationAnalysis

FigureNo.30

FEMBASEDSTIFFNESSCALCULATIONMATERIALMODEL

MountVibrationAnalysis

Incompressible

Mooney-Rivlinworkswithincompressibleelastomerswithstrainupto200%.Forexample,rubberforanautomobiletireorenginemount.

Arruda-Boyceiswellsuitedforrubberssuchassiliconandneoprenewithstrainupto300%.Thismodelprovidesgoodcurvefittingevenwhentestdataarelimited.

Ogdenworksforanyincompressiblematerialwithstrainupto700%.Thismodelgivebettercurvefittingwhendatafrommultipletestsareavailable.

Compressible

Blatz-Koworksspecificallyforcompressiblepolyurethanefoamrubbers.

Hyperfoamcansimulateanyhighlycompressiblematerialsuchasacushion,spongeorpadding

PowerUnitMountVibrationAnalysis

FigureNo.

31

FEMBASEDSTIFFNESSCALCULATIONMATERIALMODEL

MountVibrationAnalysis

→TypicalmaterialmodelforrubbermountsistheMooney-Rivlindefinition.

In1951,RivlinandSundersdevelopedahyper-elasticmaterialmodelforlargedeformationsofrubber.

Thismaterialmodelisassumedtobeincompressibleandinitiallyisotropic.

TheformofstrainenergypotentialforaMooney-Rivlinmaterialisgivenas:

3)c01(I23)1/d(J1)2

W=c10(I1

Where

c10

,c01and

d

arematerialconstantsand

Wistheelasticpotentialorstrainenergydensityfunction.

Thehyper-elasticconstantsinthestrainenergydensityfunctionofamaterialaredefinedbyitsmechanicalresponse.

ThereforeitisnecessarytoassesstheMooney-Rivlinconstantsofthematerialstoobtainsuccessfulresultsofahyper-elasticmaterials.

Forhyperelasticmaterials,simpledeformationtests(consistingofsixdeformationmodels)canbeusedtodeterminetheMooney-Rivlinhyper-elasticmaterial.

PowerUnitMountVibrationAnalysis

FigureNo.

32

MountVibrationAnalysis

ActiveNoiseControl

ModellingofControlledEngineMounts

PowerUnitMountVibrationAnalysis

FigureNo.33

ACTIVENOISECONTROL

MountVibrationAnalysis

ActiveNoiseControl:

Objective:Realizationofintelligent,highperformingadaptivematerialsystemsfornoisereductioninthesamemannerascommonpassiveorlightweightmaterialsareused.

Activenoisereductioninenginedynamicssimulation:

source:InMAROverview

Controlofstructuralvibrationsoflinear-elasticFE-structure

example:vibrationofoilpan

source:

www.ifr.uni-hannover.de

PowerUnitMountVibrationAnalysis

FigureNo.34

Controlofthevibrationatconnectionsofbodies

example:enginemountvibration

Activemountingoftheengine

METHODOLOGYOFTHECONTROLSYSTEM

MountVibrationAnalysis

InterfacetoControlSystem

InterfaceSolutiontoMATLAB?/Simulink?:

InterfaceispreparedasS-FunctionblockforSimulink

EXCITEPowerUnitandEXCITETimingDriveprovidedisplacementsandvelocitiesforselectedDoFs

MATLABreturnsforcesandmomentsforthelinkedDoFs

MATLABcanrunonthesameoraremotemachine

PowerUnitMountVibrationAnalysis

FigureNo.35

DLL TCP/IP

Matlab?Interface(S-function)

Simulink?

MATLAB?/Simulink?

CONTROLSYSTEMRIGIDCHASSIS

MountVibrationAnalysis

PossibleApplications

EXCITEPowerUnit:

InMAR

Externaljoints,loads,dampingfunctions

Electricmotor(externalmoment),hybridengines,onewayclutch,twodiskclutch,...

SpecificApplicationExamples:AxialSurface-to-SurfaceContact

Multi-BodyModelwithMATLABLink

EXCITETimingDrive:

Controlofvariablevalvetrains,electro-magneticvalvetrains

Integrationofnon-usualcomponents(e.g.pneumaticsprings,…)

General

Anykindofelectric-mechanicalcontrolmechanismConnectionwithotherCAEtoolswithMATLAB

S-Functioncapability

FigureNo.36

PowerUnitMou

CoMA

trolmechanismTLAB/SIMULINK

Interface

MATLAB

ntVibrationAnalysis

Factor

displacement,velocity

force

ControlledEngineMount

CONTROLSYSTEM

RIGIDCHASSIS/RESULTS

Impactofcontrol:

Mountingforceinverticaldirectionandcontrolforce

MountVibrationAnalysis

Vertical

Force

1000

MountingForce(Uncontrolled)MountingForce(Controlled)ControlForce

500

0

-500

-1000

-1500

0

1440

2880

CrankAngle(deg)

4320

5760

Impactofcontrol:

Verticaldisplacementsofcontrolledsystemvs.uncontrolled

VerticalDisplacement

-99

-99.25

-99.5

-99.75

UncontrolledControlled

-100

0

1440

2880

CrankAngle(deg)

4320

5760

PowerUnitMountVibrationAnalysis

FigureNo.37

Force(N)

Displacement(mm)

CONTROLSYSTEM

RIGIDCHASSIS/RESULTS

MountVibrationAnalysis

Absolutevalueofvelocityintimedomain(un-/controlledstate)

Velocityoverengineorders

(un-/controlledstate)

PowerUnitMountVibrationAnalysis

FigureNo.38

Velocity(dB)

Velocity(mm/s)

AmplitudeofVelocity

120

100 10dB

80

UncontrolledControlled

60

0 2 4 6 8 10

Order

AbsoluteValueofVelocity

300

Uncontrolled

225 Controlled

150

75

0

0 1440 2880 4320 5760

CrankAngle(deg)

CONTROLLEDENGINEMOUNTSFLEXIBLECHASSIS

MountVibrationAnalysis

EngineMountsControlSystemincludingFlexibleCar-Body

SystemDescription:

TheModelIncludes

EngineForcesStructureoftheEngine

ModelofControlledEngineMountsStructureoftheBody-in-White

SimplifiedModelofWheelMounts

Co-SimulationofAVLEXCITEwithSimulink?viaLink-to-MATLAB

PowerUnitMountVibrationAnalysis

No.39

Figur

CONTROLLEDENGINEMOUNTSANALYSISRESULTS

MountVibrationAnalysis

EngineMountsControlSystemincludingFlexibleCar-Body

ResultsoftheActiveEngineMountsVelocityLevels

Difference

-9.6dB

-6dB

MeanvelocitylevelindB(5.5·10-8m/s)

FigureNo.40

PowerUnitMountVibrationAnalysis

Mount Mount

(engineside) (carside)

Driver’sSeat

Uncontrolled

Controlled

(car’svertical)

Controlled(engine’svertical)

92.2 75.6

91.9 71.4

91.7 66.0

66.8

62.6

60.8

CONTROLLEDENGINEMOUNTSANALYSISRESULTS

MountVibrationAnalysis

EngineMountsControlSystemincludingFlexibleCar-Body

ImpactoftheControlonaSystemwithFlexibleCar-Body

AbsoluteValueofVelocityVersusEngineOrders

NetPowerConsumptionoftheControlleratOneMount

Uncontrolled

Controlled(car’svertical)Controlled(engine’svertical)

PowerUnitMountVibrationAnalysis

FigureNo.41

CONTRIBUTIONOFEXHAUSTSYSTEMTOVIBRATIONANDNOISE

MountVibrationAnalysis

PowerUnitMountVibrationAnalysis

FigureNo.42

Exhaustsystemrearpart

ExhaustSystemMounts

Exhaustsystemfrontpart

(Flexible)coupling

EXHAUSTSYSTEMSIMULATIONOVERVIEW

MountVibrationAnalysis

1D/3DCFDFluidAcousticAnalysis

EngineVibrationbyMBS

GasDynamicExcitation

SimulationTargetsare:

vibrationsatmountingpoints

shell(structureborne)noise

(structuraltemperaturesandstress/strain)

CFDandMBSisusedforrealisticboundaryconditionsforFEManalysis

Allsimulationsareperformedtransientforcompleteenginecyclesintimedomain

MountPointVibrations

SurfaceVibrationofExhaustSystem

NoiseRadiation

OrificeNoise

ExcitationofChassis

ExteriorNoise

InteriorNoise

PowerUnitMountVibrationAnalysis

FigureNo.43

SIMULATIONOFEXHAUSTSYSTEMSBOUNDARYCONDITIONS

MountVibrationAnalysis

Fortheradiatedshellnoiseandthevibrationsofthemountingsystemgasflowexcitationandvibrationscausedbythepowerunithavetobetakenintoconsideration.

Vibrationsofthepowerunitsystemarederivedfrommulti-bodydynamicanalysis(MBS).

GaspressureexcitationisbasedonsurfacepressuredistributionprovidedbyCFDanalysis.

StructuraltemperaturesareoflessimportanceforNVHinvestigationofexhaustsystems,butmeantemperaturehastobeconsideredforcorrectmaterialanddampingproperties

Vibrationexcitationfromrunning/vibratingpowerunit

Vibrationexcitationduetogasflow

Temperatureloadduetonearwallgastemperatures(fordurabilityissues)

PowerUnitMountVibrationAnalysis

FigureNo.44

SIMULATIONOFEXHAUSTSYSTEMSTARGETSOFINVESTIGATION

MountVibrationAnalysis

Localstructuraltemperatures(fordurabilityissues)

Localstressesduetovibrationsandthermalload

Structurebornenoise(shellnoise)

Pressureexcitationofchassisbyradiatednoisefromtheexhaustsystem(airpath)

Pressureexcitationonbottomchassisstructure200Hz(6000min-1)basedonnoiseradiationfromtheexhaustsystem.

Vibrationstothechassis(structuralpath)

ForcesatMountPositionsofChassisunderTransientEngineRun-up(2ndOrderExcitation)

10

BetragderKraftaneinerEinleitepositionam

VSD,

NSDstromauf,

NSDstromab.

1

0.1

0.01

30

50

100

150

200

PowerUnitMountVibraFtrieoqnueAnnza[Hlyzs]is

FigureNo.45

Kraft[N]

EXHAUSTSYSTEMVIBRATIONSRESULTS

MountVibrationAnalysis

Contributionstructureandairbornenoise

Contributionofexhaustnoisetototalnoise

80

50

70

60

40

50

30

40

20

30

10

20

0

10

DifferenzzumgemessenenGesamtpegel

-10

0

4

3

2

1

0

soundpressureatdriver'srightear

-20

excitedviamounting

,air:

,sum

BeitragzumInnenger?usch

-30

30

50

100

150

200

frequency[Hz]

50

100

Frequenz[Hz]

150

200

Noiselevelatdriversearbasedonboth,directstructuralexcitationbyvibration(structuralpath)andnoiseradiationtothechassis(airpath)fromtheexhaustsystem

Upperdiagram:Differenceofexhaustnoisetototalnoise

Lowerdiagram:maximumcontributionfromexhaustnoisetototalnoise

FigureNo.46

PowerUnitMountVibrationAnalysis

eff.pressure[dBA(210-5Pa)]

Schalldruck[dB]

Schalldruck[dB]

BASICINVESTIGATIONINHYDRO-MOUNTSOUTLOOK

MountVibrationAnalysis

source:

source:

www.ph.co.kr

PowerUnitMountVibrationAnalysis

FigureNo.47

SIMULATIONOFHYDRO-MOUNTSCHARACTERISTIC

MountVibrationAnalysis

Hydro-mountsar