Table Of ContentConference Proceedings of the Society for Experimental Mechanics Series
Dario Di Maio
Javad Baqersad Editors
Rotating Machinery,
Optical Methods
& Scanning LDV
Methods, Volume 6
Proceedings of the 40th IMAC, A Conference and
Exposition on Structural Dynamics 2022
Conference Proceedings of the Society for Experimental Mechanics
Series
SeriesEditor
KristinB.Zimmerman
SocietyforExperimentalMechanics,Inc.,
Bethel,CT,USA
TheConferenceProceedingsoftheSocietyforExperimentalMechanicsSeriespresentsearlyfindingsandcasestudiesfrom
a wide range of fundamental and applied work across the broad range of fields that comprise Experimental Mechanics.
SeriesvolumesfollowtheprincipletracksorfocustopicsfeaturedineachoftheSociety’stwoannualconferences:IMAC,
AConferenceandExpositiononStructuralDynamics,andtheSociety’sAnnualConference&Expositionandwilladdress
criticalareasofinteresttoresearchersanddesignengineersworkinginallareasofStructuralDynamics,SolidMechanics
andMaterialsResearch.
Dario Di Maio • Javad Baqersad
Editors
Rotating Machinery, Optical Methods
& Scanning LDV Methods, Volume 6
Proceedings of the 40th IMAC, A Conference and Exposition
on Structural Dynamics 2022
Editors
DarioDiMaio JavadBaqersad
EngineeringTechnology KetteringUniversity
UniversityofTwente Flint,MI,USA
ENSCHEDE,Overijssel,TheNetherlands
ISSN2191-5644 ISSN2191-5652 (electronic)
ConferenceProceedingsoftheSocietyforExperimentalMechanicsSeries
ISBN978-3-031-04097-9 ISBN978-3-031-04098-6 (eBook)
https://doi.org/10.1007/978-3-031-04098-6
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Preface
RotatingMachinery,OpticalMethods&ScanningLDVMethodsrepresentoneofninevolumesoftechnicalpaperspresented
at the 40th IMAC, A Conference and Exposition on Structural Dynamics, organized by the Society for Experimental
Mechanics, and held February 7–10, 2022. The full proceedings also include volumes titled Nonlinear Structures &
Systems; Dynamics of Civil Structures; Model Validation and Uncertainty Quantification; Dynamic Substructures; Special
TopicsinStructuralDynamics&ExperimentalTechniques;SensorsandInstrumentation,Aircraft/AerospaceandDynamic
EnvironmentsTesting;TopicsinModalAnalysis&ParameterIdentification;andDataScienceinEngineering.
Eachcollectionpresentsearlyfindingsfromexperimentalandcomputationalinvestigationsonanimportantareawithin
structuraldynamics.
Theorganizerswouldliketothanktheauthors,presenters,sessionorganizers,andsessionchairsfortheirparticipationin
thistrack.
Flint,MI,USA JavadBaqersad
Overijssel,TheNetherlands DarioDiMaio
v
Contents
1 Introduction to Multipath Doppler Vibrometry (MDV) for Validating Complex Models Accurately
andWithoutContact.................................................................................................... 1
JeromeEichenbergerandJoergSauer
2 DICUsingLowSpeedCamerasonaScaledWindTurbineBlade................................................. 15
DavideMastrodicasa,CatarinaFerreira,EmilioDiLorenzo,BartPeeters,MárioAugustoPiresVaz,
andPatrickGuillaume
3 DataChallengesforStructuralHealthMonitoringofElectricalMachines ...................................... 27
AlexBinder,ConnerOzatalar,KendylWright,PhillipCornwell,andNicholasLieven
4 NeuromorphicDataProcessingforEvent-DrivenImageryforAcousticMeasurements........................ 37
Kevin Zheng, Jack Sorensen, Celeste DeVilliers, Alessandro Cattaneo, Fernando Moreu,
GregoryTaylor,andDavidMascareñas
5 TemplateMatchingandParticleFilteringforStructuralIdentificationofHigh-andLow-Frequency
Vibration.................................................................................................................. 43
NicholasA.Valente,CelsoT.doCabo,ZhuMao,andChristopherNiezrecki
6 Multi-Sensor Collaborative Sampling Schemes to Reconstruct Undersampled Mechanical System
SignalsforMachineryFaultDetection................................................................................ 51
SeanDetwiler,ErikBarbosa,KristenSteudel,JefferyTippmann,ChristianWard,andBrianWest
7 RegimeSortingforMultiscaleVibrationsandPhase-BasedMotionExtraction................................. 61
SeanCollierandTylerDare
8 DigitalImageCorrelationwithaNeuromorphicEvent-BasedImager............................................ 73
PeterMeyerhofer,AndreGreen,AlessandroCattaneo,andDavidMascareñas
9 Monitoring the Response of Electrical Components During Environmental Vibration Tests Using
aScanningLaserDopplerVibrometer................................................................................ 81
CalebR.HeitkampandBenjaminL.Martins
10 AdvancedMeshReconstructionwithLow-BudgetRGBDHardwareforModalAnalysis ..................... 89
KaiHenningandDanielHerfert
11 StereoscopicHighSpeedCameraBasedOperationalModalAnalysisUsingaOne-Camera
Setup ...................................................................................................................... 97
MaxGille,MilesR.W.Judd,andDanielJ.Rixen
12 In-plane Vibration Measurement of an Aluminum Plate Using a Three-Dimensional Continuously
ScanningLaserDopplerVibrometerSystem......................................................................... 105
KeYuanandWeidongZhu
13 Measuring Full-Field Deformation in Ultra-High-Performance Concrete Structural Components
UsingTag-BasedRoboticVision....................................................................................... 117
SyedZohaibHassan,Peng“Patrick”Sun,TianchengWang,GeorgiosApostolakis,andKevinMackie
vii
viii Contents
14 DynamicBehaviourandMagneto-MechanicalEfficiencyofaContactlessMagnetic
Transmission............................................................................................................. 129
LucaDimauro,ElvioBonisoli,andMaurizioRepetto
15 Structural Damage Identification for Plate-Like Structures Using Two-Dimensional Teager Energy
Operator-WaveletTransform .......................................................................................... 139
WeiZhou,YongfengXu,JueseokKim
16 AVision-BasedQuantificationApproachforReinforcedConcreteTunnelLinerDelamination............... 155
QixiangTang,ShafiqueAhmed,PaulNoyce,andGinaCrevello
17 An Optical Temporal and Spatial Vibration-Based Damage Detection Using Convolutional Neural
NetworksandLongShort-TermMemory............................................................................ 159
CelsoT.doCaboandZhuMao
18 AHybrid-Attention-LSTM-BasedDeepConvolutionalNeuralNetworktoExtractModalFrequencies
fromLimitedDataUsingTransferLearning......................................................................... 167
MehrdadShafieiDizajiandZhuMao
19 Detecting and Reconstructing the 3D Geometry of Subsurface Structural Damages Using Full-Field
Image-BasedSensingandTopologyOptimization................................................................... 175
MehrdadShafieiDizaji,MohamadAlipour,DevinK.Harris,andZhuMao
20 OptimalKernelDesignfortheExtractionofSubtleMotionsUsingConvolutionalNeural
Network................................................................................................................... 181
MehrdadShafieiDizajiandZhuMao
Chapter 1
Introduction to Multipath Doppler Vibrometry (MDV) for
Validating Complex Models Accurately and Without Contact
JeromeEichenbergerandJoergSauer
Abstract The need to validate simulation models of complex mechanical structures continues to grow in importance to
increaseefficiencyinthedesignprocess.Thisisespeciallytruefornonlinearstructures(suchascompositepanelsandjointed
components) where it is critical to use an accurate full-field measurement method. Multipath Doppler vibrometry (MDV)
embodiesthemostrecentbreakthroughindynamiccharacterization.Itdelivershigh-qualityvibrationdataconsistentlyeven
forthemostadverseenvironmentsandprovidesthetestengineerwithareliabletoolthatisfastandeasytosetup.Thetest
objectismeasuredinitsunalteredformasitisnotnecessarytoapplyanysurfacetreatments.MDVcanbeappliedtoasingle
pointmeasurementandfor1Daswellas3Dscanningvibrometrytests.Thebenefitsareillustratedinthispaperbyvarious
applicationexamples.
Keywords MultipathDopplervibrometer · MDV · QTec · Vibrometry · Noncontact · FEmodelvalidation · Vibration
measurement · Qualitycontrol
1.1 Introduction
All mechanical structures fail sooner or later if the applied forces exceed the structural limits. These limits need to be
understood in depth so breakage can be avoided. Depending on the structure, the failure of just one component could
result in the catastrophic breakdown of an entire system. Therefore, design and test engineers work closely together in
productdevelopmenttosafelyachieveafasttime-to-market.Simulationsarevaluableinevaluatingmanydesigniterations
quickly;validationtests,ontheotherhand,areinstrumentalinmakingsurethemodelreflectsthereal-worldscenario.This
is important for critical components in aerospace, automotive, medical devices, civil structures, consumer electronics, and
manyotherproducts.
PreviousworkintroducedlaserDopplervibrometry(LDV)anditsbenefitstovariousapplications[1].Inthecurrentpaper,
thefocusisonmultipathDopplervibrometry(MDV),whichcarriesthetrademarkQTecatPolytec.MDVisrevolutionary,
anditsupersedesLDVinitscoredesignallowingtheusertoobtainreliabledatamorequickly.
The purpose of this paper is to demonstrate the benefits of MDV in different applications. Additionally, considerations
about the test setup and the excitation method will be touched upon because they are equally critical for performing
successfulmodelvalidations.Experimentalmodalanalysisandoperationalmodalanalysis(EMAandOMA)arediscussed,
andguidanceisprovidedforhowtopickthemostefficientexcitationmethod.
J.Eichenberger
Polytec,Inc.,Irvine,CA,USA
e-mail:[email protected]
J.Sauer
PolytecGmbH,Waldbronn,Germany
e-mail:[email protected]
©TheSocietyforExperimentalMechanics,Inc.2023 1
D.D.Maio,J.Baqersad(eds.),RotatingMachinery,OpticalMethods&ScanningLDVMethods,Volume6,Conference
ProceedingsoftheSocietyforExperimentalMechanicsSeries,https://doi.org/10.1007/978-3-031-04098-6_1
2 J.EichenbergerandJ.Sauer
1.2 MDVforReal-WorldApplications
Multipath Doppler vibrometry (MDV) is a novel technology and overcomes the limitations of optically uncooperative
surfaces.ItsupersedesconventionalLDVinthefollowingmanner:
1. MDV is more reliable. There is minimal risk of signal artifacts (like dropouts) due to low signal return. Consistent
resultswithsuperioropticalsensitivitycanbeexpectedeveninthemostdifficultsetupslikesteepincidenceangle,low
reflectivity,andspecklemotion.Thedatatracesinthetimedomainarefreeofartifactsenablingaccurateinterpretation
ofthedata.
2. MDViseasier.SettingupanMDViseasyasnosurfacetreatmentneedstobeappliedtothetestobject.
3. MDV is faster. In addition to faster setup times, the superior optical design eliminates the need for averaging in most
applications,leadingtodramaticallyreducedmeasurementtimes.
4. MDVenablesnewapplications.Newapplicationsandusecasesareemerginglikemeasurementsonbiologicaltissuein
uncontrolledenvironmentssuchasthehumanskinofapatientwhoisinmotion.Anotherexampleiscontinuousscanning
LDV(CSLDV)wherethelaserbeamiscontinuouslymovingacrossatestsurface.EmployingMDVtechnologyforthis
application,expectedtobecalledcontinuousscanningMDV(CSMDV),ispromisingtobesubstantiallymoresensitive
andfaster.
MDVisdesignedforreal-worldapplicationsinpotentiallyadverseenvironments,wheretheopticalpropertiesofthetest
surfacearenotwellcontrolled.ReliableperformanceoftheMDVgivesthetestengineerconfidenceinthedatawhilemaking
theacquisitionprocessefficientandhassle-freeonthemostchallengingtestarticles.
The robustness of MDV measurements is illustrated on a hand that is moving back and forth (Fig. 1.1). Human skin is
typicallyapooropticalreflectorandrepresentsoneofthemostchallengingopticalsurfacesforvibrometryespeciallywhen
there is significant amount of movement. The time trace of the hand motion is displayed in real time via a laptop screen.
Figure 1.2 shows the comparison of recorded time traces representing a standard LDV (top image) and an MDV (bottom
image). Both measurements were acquired with an MDV one after the other; however, in the top image, the multipath
vibrometerfeaturewasturnedoffmakingtheMDVactlikeastandardLDV.Nonetheless,thecomparisonisverycompelling
astheMDVshowsacleartimetracewhereasahighnumberofdropoutsarevisiblewithastandardLDVleadingtoareduced
signal-to-noiseratio(SNR).
In another illustration, 3D LDV and 3D MDV time traces were analyzed on a composite panel that was excited by an
impact hammer. Hammer excitation is common practice for modal testing as will be explained in the section Excitation
Methods.Thehammerimpactonasoftlysuspendedtestobject(alsocommonpractice)willcausesomerigidbodymotion.
Suchrigidbodymotiondoesn’tnegativelyaffectthemodaltestbutcanbeachallengeforopticalmeasurements.Incaseof
astandardLDV,thelateralcomponentoftherigidbodymotioncausesdropoutsinthevibrationsignal(seeleftplotinFig.
1.3).TheMDVpridesitselfasdropout-freeinthisapplicationaswell(rightplotofFig.1.3).
Fig.1.1 MDVmeasurementonahandthatismovingbackandforth(bluearrow).Thevelocitytraceofthehandmotionisdisplayedinrealtime
