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MULTICRAFTINTERNATIONALJOURNALOFENGINEERING,SCIENCEANDTECHNOLOGYVOL1,NO1,2009,PP254271INTERNATIONALJOURNALOFENGINEERING,SCIENCEANDTECHNOLOGYWWWIJESTNGCOM2009MULTICRAFTLIMITEDALLRIGHTSRESERVEDACOMBINEDAPPROACHOFCOMPLEXEIGENVALUEANALYSISANDDESIGNOFEXPERIMENTSDOETOSTUDYDISCBRAKESQUEALMNOUBY1,DMATHIVANAN2,KSRINIVASAN11AU/FRGINSTITUTEFORCAD/CAM,ANNAUNIVERSITY,CHENNAI600025,INDIA2DIRECTOROFCAEINFOTECH,CHENNAI600020,INDIAEMAILSNOUBYLUXORGMAILCOMMNOUBY,MATHVANYAHOOCOMDMATHIVANAN；CORRESPONDINGAUTHORSABSTRACTTHISPAPERPROPOSESANAPPROACHTOINVESTIGATETHEINFLUENCINGFACTORSOFTHEBRAKEPADONTHEDISCBRAKESQUEALBYINTEGRATINGFINITEELEMENTSIMULATIONSWITHSTATISTICALREGRESSIONTECHNIQUESCOMPLEXEIGENVALUEANALYSISCEAHASBEENWIDELYUSEDTOPREDICTUNSTABLEFREQUENCIESINBRAKESYSTEMSMODELSTHEFINITEELEMENTMODELISCORRELATEDWITHEXPERIMENTALMODALTESTTHE‘INPUTOUTPUT’RELATIONSHIPBETWEENTHEBRAKESQUEALANDTHEBRAKEPADGEOMETRYISCONSTRUCTEDFORPOSSIBLEPREDICTIONOFTHESQUEALUSINGVARIOUSGEOMETRICALCONFIGURATIONSOFTHEDISCBRAKEINFLUENCESOFTHEVARIOUSFACTORSNAMELY；YOUNG’SMODULUSOFBACKPLATE,BACKPLATETHICKNESS,CHAMFER,DISTANCEBETWEENTWOSLOTS,SLOTWIDTHANDANGLEOFSLOTAREINVESTIGATEDUSINGDESIGNOFEXPERIMENTSDOETECHNIQUEAMATHEMATICALPREDICTIONMODELHASBEENDEVELOPEDBASEDONTHEMOSTINFLUENCINGFACTORSANDTHEVALIDATIONSIMULATIONEXPERIMENTSPROVEDITSADEQUACYTHEPREDICTEDRESULTSSHOWTHATBRAKESQUEALPROPENSITYCANBEREDUCEDBYINCREASINGYOUNG’SMODULUSOFTHEBACKPLATEANDMODIFYINGTHESHAPEOFFRICTIONMATERIALBYADDINGCHAMFERONBOTHSIDESOFFRICTIONMATERIALANDBYINTRODUCINGSLOTCONFIGURATIONSTHECOMBINEDAPPROACHOFMODELINGBRAKESQUEALUSINGCEAANDDOEISFOUNDTOBESTATISTICALLYADEQUATETHROUGHVERIFICATIONTRIALSTHISCOMBINEDAPPROACHWILLBEUSEFULINTHEDESIGNSTAGEOFTHEDISCBRAKEKEYWORDSDISCBRAKESQUEAL,FINITEELEMENTANALYSIS,EXPERIMENTALMODALANALYSIS,DESIGNOFEXPERIMENTS1INTRODUCTIONBRAKESQUEALISANOISEPROBLEMCAUSEDBYVIBRATIONSINDUCEDBYFRICTIONFORCESTHATCANINDUCEADYNAMICINSTABILITYAKAY,2002DURINGTHEBRAKINGOPERATION,THEFRICTIONBETWEENTHEPADANDTHEDISCCANINDUCEADYNAMICINSTABILITYINTHESYSTEMUSUALLYBRAKESQUEALOCCURSINTHEFREQUENCYRANGEBETWEEN1AND20KHZSQUEALISACOMPLEXPHENOMENON,PARTLYBECAUSEOFITSSTRONGDEPENDENCEONMANYPARAMETERSAND,PARTLY,BECAUSEOFTHEMECHANICALINTERACTIONSINTHEBRAKESYSTEMTHEMECHANICALINTERACTIONSARECONSIDEREDTOBEVERYCOMPLICATEDBECAUSEOFNONLINEARCONTACTEFFECTSATTHEFRICTIONINTERFACETHEOCCURRENCEOFSQUEALISINTERMITTENTOREVENRANDOMUNDERCERTAINCONDITIONS,EVENWHENTHEVEHICLEISBRANDNEW,ITOFTENGENERATESSQUEALNOISE,WHICHHASBEENEXTENSIVELYSTUDIEDWITHTHEGOALOFELIMINATINGTHENOISEHOWEVER,MECHANISTICDETAILSOFSQUEALNOISEARENOTYETFULLYUNDERSTOODJOEETAL,2008SEVERALTHEORIESHAVEBEENFORMULATEDTOEXPLAINTHEMECHANISMSOFBRAKESQUEAL,ANDNUMEROUSSTUDIESHAVEBEENMADEWITHVARIEDSUCCESSTOAPPLYTHEMTOTHEDYNAMICSOFDISCBRAKESKINKAIDETAL,2003THEREASONFORTHEONSETOFINSTABILITYHASBEENATTRIBUTEDTODIFFERENTREASONSSOMEOFTHEMAJORREASONSARETHECHANGEOFTHEFRICTIONCHARACTERISTICWITHTHESPEEDOFTHECONTACTPOINTSIBRAHIM,1994；OUYANGETAL,1998；SHINETAL,2002THECHANGEOFTHERELATIVEORIENTATIONOFTHEDISKANDTHEFRICTIONPADSLEADINGTOAMODIFICATIONOFTHEFRICTIONFORCEMILLNER,1978,ANDAFLUTTERINSTABILITYWHICHISFOUNDEVENWITHACONSTANTFRICTIONCOEFFICIENTCHOWDHARYETAL,2001；CHAKRABOTRYETAL,2002；VONWAGNERETAL,2003；VONWAGNERETAL,2004INFACT,RECENTLITERATUREREVIEWSKINKAIDETAL,2003；PAPINNIEMIETAL,2002HAVEREPORTEDONTHECOMPLEXITYANDLACKOFUNDERSTANDINGOFTHEBRAKESQUEALPROBLEMTHOUGHMUCHWORKWASDONEONTHEISSUEOFSQUEAL,ITREQUIRESCONTINUOUSSTUDYANDINVESTIGATIONTOREFINETHEPREDICTIONACCURACYOFFINITEELEMENTMODELSOFBRAKEASSEMBLIESTOGIVEBRAKEDESIGNENGINEERSAPPROPRIATETOOLSTODESIGNQUIETBRAKESTHEREARETWOMAINCATEGORIESOFNUMERICALMETHODSTHATAREUSEDTOSTUDYTHISPROBLEM1TRANSIENTDYNAMICANALYSISHUETAL,NOUBYETAL/INTERNATIONALJOURNALOFENGINEERING,SCIENCEANDTECHNOLOGY,VOL1,NO1,2009,PP2542712551999；ABUBAKARETAL,2006AND2COMPLEXEIGENVALUEANALYSISCURRENTLY,THECOMPLEXEIGENVALUEMETHODISPREFERREDANDWIDELYUSEDLILES,1989；LEEETAL,1998；BLASCHKEETAL,2000；BAJERETAL,2003；ABUBAKARETAL,2006；LIUETAL,2007；MARIOETAL,2008；DAIETAL,2008INPREDICTINGTHESQUEALPROPENSITYOFTHEBRAKESYSTEMINCLUDINGDAMPINGANDCONTACTDUETOTHEQUICKNESSWITHWHICHITCANBEANALYSEDANDITSUSEFULNESSINPROVIDINGDESIGNGUIDANCEBYANALYSINGWITHDIFFERENTOPERATINGPARAMETERSVIRTUALLYMANYRESEARCHERSINTHEIRSTUDIESONTHEDYNAMICSOFBRAKESYSTEMTRIEDTOREDUCESQUEALBYCHANGINGTHEFACTORSASSOCIATEDWITHTHEBRAKESQUEALFOREXAMPLELILES,1989FOUNDTHATSHORTERPADS,DAMPING,SOFTERDISCANDSTIFFERBACKPLATECOULDREDUCESQUEALWHILSTINCONTRAST,HIGHERFRICTIONCOEFFICIENTANDWEAROFTHEFRICTIONMATERIALWEREPRONETOSQUEALLEEETAL,1998REPORTEDTHATREDUCINGBACKPLATETHICKNESSLEDTOLESSUNIFORMOFCONTACTPRESSUREDISTRIBUTIONSANDCONSEQUENTLYINCREASINGTHESQUEALPROPENSITYHUETAL,1999BASEDONTHEDOEANALYSISFOUNDTHATTHEOPTIMALDESIGNWASTHEONETHATUSEDTHEORIGINALFINGERLENGTH,THEVERTICALSLOT,THECHAMFERPAD,THE28MMTHICKNESSOFDISC,ANDTHE10MMTHICKNESSOFFRICTIONMATERIALBROOKSETAL,1993FOUNDTHATBYSHIFTINGTHEPISTONSAWAYFROMTHELEADINGEDGEOFTHEPADSTHESYSTEMCOULDDESTABILISETHEYALSOREPORTEDTHATTHEPREDICTEDUNSTABLESYSTEMWASDUETOTHECOUPLINGOFTRANSLATIONALANDROTATI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