Rotating Machinery, Hybrid Test Methods, Vibro-Acoustics & Laser Vibrometry, Volume 8: Proceedings of the 35th IMAC, A Conference and Exposition on Structural Dynamics 2017

154 Pages·2017·10.08 MB·English

by  Dario Di Maio

Conference Proceedings of the Society for Experimental Mechanics Series
Dario Di Maio · Paolo Castellini Editors
Rotating Machinery, Hybrid
Test Methods, Vibro-Acoustics
& Laser Vibrometry, Volume 8
Proceedings of the 35th IMAC, A Conference and Exposition
on Structural Dynamics 2017
Conference Proceedings of the Society for Experimental Mechanics Series
SeriesEditor
KristinB.Zimmerman,Ph.D.
SocietyforExperimentalMechanics,Inc.,
Bethel,CT,USA
Moreinformationaboutthisseriesathttp://www.springer.com/series/8922
Dario Di Maio • Paolo Castellini
Editors
Rotating Machinery, Hybrid Test Methods,
Vibro-Acoustics & Laser Vibrometry,
Volume 8
Proceedings of the 35th IMAC, A Conference and Exposition
on Structural Dynamics 2017
123
Editors
DarioDiMaio PaoloCastellini
MechanicalEngineering DIISM
UniversityofBristol UniversitàPolitecnicadelleMarche
Bristol,UK Ancona,Italy
ISSN2191-5644 ISSN2191-5652 (electronic)
ConferenceProceedingsoftheSocietyforExperimentalMechanicsSeries
ISBN978-3-319-54647-6 ISBN978-3-319-54648-3 (eBook)
DOI10.1007/978-3-319-54648-3
LibraryofCongressControlNumber:2017935572
©TheSocietyforExperimentalMechanics,Inc.2017
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Preface
Rotating Machinery, Hybrid Test Methods, Vibro-Acoustics & Laser Vibrometry represent one of ten volumes of technical
papers presented at the 35th IMAC, A Conference and Exposition on Structural Dynamics, organized by the Society for
Experimental Mechanics, and held in Garden Grove, California, January 30–February 2, 2017. The full proceedings also
includevolumesonNonlinearDynamics;DynamicsofCivilStructures;ModelValidationandUncertaintyQuantification;
Dynamics of Coupled Structures; Sensors and Instrumentation; Special Topics in Structural Dynamics; Structural Health
Monitoring & Damage Detection; Shock & Vibration, Aircraft/Aerospace and Energy Harvesting, and Topics in Modal
Analysis&Testing.
Eachcollectionpresentsearlyfindingsfromexperimentalandcomputationalinvestigationsonanimportantareawithin
StructuralDynamics.Topicsrepresentpapersonenablingtechnologiessuchas:rotatingmachinery,vibro-acousticsandlaser
Vibrometry,advancesinwindenergyandhybridtestingmethods.
Theorganizerswouldliketothanktheauthors,presenters,sessionorganizers,andsessionchairsfortheirparticipationin
thistrack.
Bristol,UK DarioDiMaio
Ancona,Italy PaoloCastellini
v
Contents
1 StrategiesforTestingLargeAerospaceStructureswith3DSLDV................................................ 1
DanielP.Rohe
2 ModalModelValidationUsing3DSLDV,GeometryScanningandFEMofaMulti-Purpose
DronePropellerBlade .................................................................................................. 13
Daniel J. Alarcón, Karthik Raja Sampathkumar, Kamenzky Paeschke, Tarun Teja Mallareddy,
SvenAngermann,AndreasFrahm,WolfgangRüther-Kindel,andPeterBlaschke
3 EffectofDryFrictionDampingontheDynamicResponseofHelicopterTailShaft ............................ 23
OnurOzaydinandEnderCigeroglu
4 NonlinearDynamicAnalysisofaSpiralBevelGearedSystem .................................................... 31
SiarDenizYavuz,ZihniBurcaySaribay,andEnderCigeroglu
5 EstimatingMaterialWavespeedUsingtheWavenumberTransformofRectangular
PlateModeShapes....................................................................................................... 41
MicahR.Shepherd
6 In-OperationWindTurbineModalAnalysisviaLPV-VARModeling............................................ 47
L.D.Avendaño-Valencia,E.N.Chatzi,andS.D.Fassois
7 StructuralDamageIdentificationUsingFreeResponseMeasuredbyaContinuouslyScanning
LaserDopplerVibrometerSystem .................................................................................... 59
Y.F.Xu,Da-MingChen,andW.D.Zhu
8 MitigationofStructural-AcousticModeCouplinginaModalTestofaHollowStructure..................... 71
RyanSchultzandBenPacini
9 Applicationsof3DScanningLaserDopplerVibrometrytoanArticlewithInternalFeatures ................ 85
BryanWitt,BrandonZwink,andRonHopkins
10 TheMeasurementofaNonlinearResonantDecayUsingContinuous-ScanLaserDoppler
Vibrometry............................................................................................................... 97
DavidA.Ehrhardt,MatthewS.Allen,andTimothyJ.Beberniss
11 Vibro-AcousticModulationofaSpinningApparatusforNondestructiveEvaluation........................... 105
Martin J. Ward, Wesley E. Scott, Nicholas M. Diskerud, Alessandro Cattaneo, John D. Heit,
andJohnD.Bernardin
12 NonlinearPhaseSeparationTestingofanExperimentalWing-EngineStructure............................... 115
L.Renson,J.P.Noël,D.A.W.Barton,S.A.Neild,andG.Kerschen
13 WindTurbineHealthMonitoring:CurrentandFutureTrendswithanActiveLearningTwist............... 119
N.Dervilis,A.E.Maguire,E.Papatheou,andK.Worden
vii
viii Contents
14 Nonlinear3DDynamicModelofanAutomotiveDualMassFlywheel............................................ 131
G.Quattromani,A.Palermo,F.Pulvirenti,E.Sabbioni,andF.Cheli
15 InvestigationofNotch-TypeDamageIdentificationbyUsingaContinuouslyScanningLaser
DopplerVibrometerSystem............................................................................................ 143
Da-MingChen,Y.F.Xu,andW.D.Zhu
Chapter 1
Strategies for Testing Large Aerospace Structures with 3D SLDV
DanielP.Rohe
Abstract The 3D Scanning Laser Doppler Vibrometer (3D SLDV) has the ability to scan a large number of points with
highaccuracycomparedtotraditionalrovinghammeroraccelerometertests.The3DSLDVhasdisadvantages,however,in
thatitrequiresline-of-sightfromthreescanninglaserheadstothepointbeingmeasured.Thismeansthatmultiplescanscan
become necessary to measure large or complex parts, and internal components cannot typically be measured. In the past,
largeaerospacestructurestestedatSandiaNationalLaboratoriestypicallyhaveusedahandfulofaccelerometerstationsand
instrumented internal components to characterize these test articles. This work describes two case studies that explore the
advantagesanddifficultiesinusinga3DSLDVtomeasurethesametestarticleswithamuchhigherresolutionscanofthe
exterior.Thisworkproposesstrategiesforcombiningalargenumberofaccelerometerchannelswithahighresolutionlaser
scan.Itexplorestheuseofmirrorsandlaserheadmountstoenableefficientre-alignmentofthelaserswiththetestarticle
whenmanyscansarenecessary,anditdiscussesthedifficultiesandpitfallsinherentwithperformingsuchatest.
Keywords 3D (cid:129) SLDV (cid:129) Aerospace (cid:129) Modal
1.1 Introduction
ScanningLaserDopplerVibrometryhasbeenshowntohaveadvantagesovertraditionalmountedsensors[1].Forexample,
it allows for non-contact measurements which do not mass-load the test article. Additionally, a finer measurement point
resolutioncanoftenbeachievedthroughtheuseofscanningmirrorsinthelaserheadswhicharemuchmoreprecisethana
rovinghammerorrovingaccelerometertest.Itcanalsobequickertosetupascanof,forexample,100measurementpoints
thantomount100accelerometersonthetestarticleorperform100rovinghammerimpacts.Thislastresultsuggeststhatthe
3DSLDVmaybewell-suitedforperformingtestswithlargenumbersofmeasurementpoints,forexamplealargeaerospace
structure.
There are, however, some disadvantages to SLDV that might impede such a test. 3D SLDV requires line-of-sight from
eachofthethreelaserheadstothemeasurementpointofinterest.Thisoftenprecludesthemeasurementofthemotionsof
internal components of the test article, which can often times be the measurements that designers are most interested in.
Additionally,scansmayneedtobeperformedfrommultipledirectionstomeasureallsidesofthetestarticle,andtheseextra
alignmentstepsmaysignificantlyincreasethetimerequiredtoperformatest.
Thisworkinvestigatestheeffectivenessofusingthe3DSLDVsystemtoperformahigh-resolutionscanoftheexteriorof
alargeaerospacestructureusingtwocasestudies.Itdiscussesstrategiesforincorporatingalargenumberofaccelerometer
channels, as well as using mirrors and laser head mounts to enable efficient re-alignment of the lasers with the test article
whenmanyscansarenecessary.
SandiaNationalLaboratoriesisamulti-programlaboratorymanagedandoperatedbySandiaCorporation,awhollyownedsubsidiaryofLockheed
MartinCorporation,fortheU.S.DepartmentofEnergy’sNationalNuclearSecurityAdministrationundercontractDE-AC04-94AL85000.
D.P.Rohe((cid:2))
StructuralDynamicsDepartment,SandiaNationalLaboratories,P.O.Box5800-MS0557,Albuquerque,NM,87185,USA
e-mail:[email protected]
©TheSocietyforExperimentalMechanics,Inc.2017 1
D.DiMaio,P.Castellini(eds.),RotatingMachinery,HybridTestMethods,Vibro-Acoustics&LaserVibrometry,Volume8,
ConferenceProceedingsoftheSocietyforExperimentalMechanicsSeries,DOI10.1007/978-3-319-54648-3_1
2 D.P.Rohe
1.2 ChallengesAssociatedwithLargeAerospaceTest Articles
Aerospacetestarticlesaregenerallylarge,complexstructuresthathavehighprogrammaticvalue.Asaresultoftheirsize,a
largenumberofmeasurementpointsmaybenecessarytoachieveafineresolutionscanoftheexteriorofthestructure.Due
tothesequentialnatureoftheSLDVmeasurement,thiscanresultinlongtesttimes,especiallyconsideringthatthelasermay
needtoberepeatedlyalignedwiththestructuretoscandifferentsectionsofthetestarticle.Therefore,timesavingstrategies
shouldbeimplementedwheneverpossible.Forexample,performingamultiple-inputtestwiththreeshakersattachedwould
reduce the amount of measurement time by a factor of three compared to performing three single-input tests sequentially.
Also, because of the potentially large number of alignments, it is important to develop an efficient way of repositioning
the laser heads, because the alignment procedure is the most labor intensive portion of the SLDV test. Additionally, the
SLDV measurement may need to be supplemented with a large number of accelerometer channels measuring the internal
componentsoftheaerospacestructure.
Because large aerospace structures are often very valuable and costly to replace, it is standard procedure to minimize
damagetothetestarticleintheeventthatthetestboundaryconditions(e.g.bungeecords)shouldfail.Thistypicallyinvolves
notliftingthetestarticlehigherthannecessaryfromitssupportedpositionatrest.Arequirementsuchasthiscansignificantly
limit the placement of the laser heads as they try to scan the bottom of the test article; there may not be enough room
underneaththetestarticle,soanalternativestrategymustbedevised,potentiallyusingadifferentsafetycatch.
Evenforatoporsidescanofatestarticle,theremaynotbeadequatespacetoplacethelaserheadswhenconsideringthe
placementofshakersandthefootprintsoftheshakerstandsorlasertripods.Settingupforsuchascanmaynotbetrivial.
Bungeecords,shakers,andaccelerometercablingmayalloccludethepathofthelaserbeamsresultinginportionsofthetest
articlethatareunmeasurable.
1.3 CaseStudy Tests
Two test articles were used as case studies for performing tests on large aerospace structures. The first test article, shown
schematically in Fig. 1.1, was conical with fewer external features and contained 58 channels of internal accelerometers.
This test article was used to refine the approach before moving to the second, larger test article. The second test article is
shownschematicallyinFig.1.2.
1.3.1 ConicalStructureModalTest
Because shaker testing is more often used on large aerospace structures, shaker testing was investigated in this work. To
excite all of the modes in the bandwidth of interest, three shakers were attached simultaneously to the aft end of the test
article in the three principal directions. Initially MB-50 shakers were used, but they occluded much of the aft end of the
test article, and the stands required to support these shakers had a very large footprint which would interfere significantly
withthelaserheadtripods.Insteadsmaller,lighterLabworksMT-161shakerswereused,andthesecouldbesupportedby
Fig.1.1 Conicaltestarticle
1 StrategiesforTestingLargeAerospaceStructureswith3DSLDV 3
Fig.1.2 Emptybombcasetestarticle
Fig.1.3 ShakersupportstrategiesusingMB-50(left)andMT-161(right)shakers
asingleframemadefrom95mmopticalrail.AsonecanobserveinFig.1.3,thesmallershakerssupportedontheoptical
railsystemprovidedmuchbetterline-of-sightfortheSLDVsystem.Bungeecordswereusedtosupportthetestarticle,and
retro-reflectivetapewasappliedtothesurfaceateachmeasurementpoint.
1.3.1.1 DataAcquisitionSetup
Becausethe3DSLDVdataacquisitionsystem(DAS)onlysupportedeightadditionalmeasurementchannels,the58channels
ofinternalaccelerometermeasurementshadtobemeasuredbyaseparateDAS.A64-channelVXIDASwasusedforthis
purpose. The signals from the three drive point accelerometers and three force gauges were split to both systems so each
couldcomputefrequencyresponsefunctions(FRFs).SimilardataacquisitionparameterswereusedbetweenthetwoDASs.
Currenttopoweralloftheintegratedelectronicpiezoelectric(IEPE)accelerometerswassuppliedbytheVXIDAS,sothis
outputwasdisabledintheSLDVDAS.
Randomwhitenoisewasappliedtotheshakersfromthe3DSLDVsources.Thiseasedthetriggeringandsynchronization
requirements between thetwodataacquisitionsystems.TheSLDVsystemwassettomeasure30averages, butduetothe