机械毕业设计外文翻译岩土材料的摩擦声波.docx

机械毕业设计外文翻译岩土材料的摩擦声波.docx

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机械毕业设计外文翻译岩土材料的摩擦声波

中文3280字

毕业设计（论文）外文资料翻译

学院：

机械工程学院

专业：

机械设计制造及其自动化

班级：

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外文出处：

TylerTJ,HillR,LaiE.Frictiongeneratedultrasoundfromgeotechnicalmaterials[J].Ultrasonics,2004,42

（1）:

169-172.

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1、外文原文；2、外文资料翻译译文。

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年月日

附件1：

Frictiongeneratedultrasoundfromgeotechnicalmaterials

TJTyler,RHill,ELai

Abstract

Drillingisaprocessinvolvedwithproductmanufacturingandforcivilengineers,sitepreparation.Theusualrequirementisforefficientmaterialremoval.Inthisstudy,thefrictionpairinteractiongeneratedbyadrillingprocessprovidesultrasoundinformationrelatedtoparametersforthegeotechnicalmaterialbeingdrilled,wherethedrillbithasnon-degradingultrasoniccharacteristicsandnoessentialrequirementformaterialremoval.Thisstudyhasconsideredmonitoringtheultrasonicsignalgeneratedbydrillingprocess,withaviewtocharacterisingtheparametersofthegeotechnicalmaterialbeingdrilledandprovidesanovelmethodtoidentifyorcharacterisegroundstructures.Drillingofgeotechnicalmaterialsystems,typicallyinvolvetheinteractionofarotatingprobeandagranularcompositemedium.Theappliedloadandangularvelocityaremeasuredtodeterminetheirrelevancetotheultrasonicsignal.Samplesofgranularmaterialshavebeengradedintocontrolledgrainsizeranges.Attentionhasbeenfocusedondeterminingtheeffectsontheultrasoundsignalofgrainsize,bulkdensityandthewatercontentofthegranularmaterial.Acomparisonbetweenthevariousgranularsamplesofthedifferentgrainsizes,density,watercontentandtheassociatedultrasonicsignalhasbeendone.Theeffectofeachvariable,andexistingtheoryfortheseeffectsiscommentedupon.Thebroadaimofthisresearchistoevaluateultrasonicmonitoringofdrillingandassessitspotentialforreal-timegeotechnicalgroundconditionmonitoringapplicationsandofferitasanalternativetoexistingmethods._2004PublishedbyElsevierB.V.

1.Introduction

Theultrasoundgeneratedfromasolid–solidfrictionpairhasbeenthemainfocusofresearchconcerningfriction-generatedultrasound,mainlyassociatedwithrotatingandreciprocatingmachines.Africtionalprocessdevelopedduringrelativemovementbetweencontactingmaterialshasaninherentlevelofwearthateventuallywouldresultinfailure.Monitoringtheultrasonicsignalgeneratedfrommachineryhasbecomeanalternativecondition-monitoringtool,asthegeneratedsignalcontainsinformationrelatedtothemicroconditionofthefrictionpair.Itispossibletodetectwhencomponentsofamachinearebecomingwornandathusreducetheriskofcatastrophicfailureleadingtoproductiondowntime.HolroydandRandall[1]discussedthesensitivityofusingacousticemission（AE）fordetectingchangesinlubrication,overloading,wearandreviewanumberofdifferenttechniquesusedtoanalysetheacousticsignature.FurthermethodologiesforanalysingthefrictiongeneratedacousticsignatureswerediscussedbyBukkapatnametal.[2]andprovideanovelanalysistechniquebasedonchaostheory,waveletsandneuralnetworks.Muchoftheresearchconcerningconditionmonitoringfocusesonthechangesinthesignalduetowear,butsomeresearchhavealsofocusedontheparametersassociatedwiththegeneratedacousticsignal.WorkbyDiei[3]monitoredtheacousticemissiongeneratedbytoolwearduringfacemillingandproposedapowerfunctionrelationshipbetweentheAERMSvoltageandtherateoffrictionalenergydissipationgivenbyAERMSekgssAaVTm=2e1TwherekandmareconstantsthatdependontheAEmeasuringsystemandthematerialpropertiesofthefrictionpair,gisafunctionofsurfaceroughnessandelasticpropertiesofthefrictionpair,ssistheshearstrengthoftheinterfacialmaterial,AaisthevisibleareaofcontactandVistheslidingvelocity.TheparametersgandAaessentiallydefinetherealareaofcontactandtherefore,theAERMSisafunctionoftherealareaofcontact,theshearstrengthandtheslidingvelocity.ResultsobtainedbyDiei’sworkalsoindicatedalinear

relationshipbetweentheAERMSandtheslidingvelocity.JiaaandDornfield[4]monitoredtheAEgeneratedbyapinondiskexperiment,highlightingthattheAEiscausedbyimpulsiveshockduetoasperitycollisionsandmicro-vibrationsexcitedbystick–slipphenomena.TheresearchshowsthattheAERMSincreaseswithloadwhilealinearrelationshipexistsbetweentherelativesurfacevelocityandtheAERMS.SarychevandShchavelin[5]describethefrictionalprocessandthegeneratedacousticemissionassociatedwithit.Twogeneralruleswereestablishedrelatingtherateofcountingtheacousticpulses（countrate）totheslidingspeedofthefrictionpairandtheappliedload.

ThegeneralruleforthedependenceofthecountrateN_ontheslidingvelocityisintheform:

N_AtBvXe2TwhereAandBareconstantsandXP1.Asimilarrelationshipalsoappliesforthedependenceoftheloadonthecountrate,buttheexponentX61.AfurtherrelationshipwasexpressedrelatingtheAEactivitytotheregimeoffrictioninelasticcontact:

N_akN0:

71h0:

71A0:

71cr0:

90R1:

60aVe3TwhereNisthenormalload,hthegeneralisedelasticmodulus,Acthecounterareaofcontact,rthesurfaceasperitytipradius,Raisthesurfaceroughnessandkisacoefficientofproportionality.FurtherworkbyBaranov[6]producedtwomodelsrelatingthefrictionalparametersofthefrictionpairtotheacousticparameters;countrateandacousticenergy.Themodelforthecountrateisbasedontheassumptionthattherateofcountingacousticpulsesisdirectlyproportionaltothenumberofcontactpointsformedperunittime.WorkbyHenriqueetal.[7]studiedparticlecollisionsdownaninclinedslopeandthenumberofacousticeventswereusedtomonitorthenumberofcollisions（contacts）generatedwhenaballwasrolleddowntheslope.Themodelfortheacousticenergyrelatesthemechanicalpotentialenergygeneratedduringtheelasticdeformationofacontactingasperitytotheamplitudedistributionoftheacousticsignal.TheenergymodeldoesnottakeintoconsiderationtheeffectsofwearandisbasedontheAEgeneratedduetoelasticcontact.

Currentstudiesinfriction-generatedacousticshaveshownthattheacousticsignalscontaininformationrelatingtothematerialparametersofthefrictionpair.Theworkinthisstudyusestheacousticsignalasatooltocharacterisethematerialpropertiesofthefrictionpair.TheideaforthisstudyoriginatesfromastudybyHill[8]forScientifics,whenitbecameapparentthatmonitoringtheultrasoundgeneratedbyadrillingprocessprocesshadpotentialforgroundconditionmonitoring.Theoverallaimofthisworkistodevelopamethodofcharacterisinggeotechnicalmaterialsusingatypicaldrillingprocessandmonitoringtheultrasoundgeneratedduetotheinteractionbetweenthedrilltipandthegeotechnicalmaterial.

2.Experimentaldesign

Asimplifieddrillingarrangementhasbeenconstructedwherearotatingprobeisusedtomaximisethefrictionattheprobe-tip–granularcontact.Theprobestringisdesigned,usingasuitablecouplingdevice,sothattheultrasonicsignalistransmittedfromtheprobetiptoastationarypiezoelectricsensor.Thesignalisamplifiedby60dBandfilteredbetween250and500kHz.Thecapturedsignalisthereforeinthemid-ultrasonicrangeandrelatestothetransducermonitoringfrequencyused.AschematicdiagramoftheexperimentalarrangementcanbeseeninFig.1.Theproberotates,whilebeingsubmergedinagranularmediumofcontrolledparticlesize,initialdensityandwatercontent.Thefeedrateandangularvelocityweresettoaconstant

valueandtheappliedload,countrateandultrasonicenergyweresimultaneouslymonitored.Theeffectsoftheparticlesize,densityandwatercontentontwoultrasonicparameters（countrateandenergy）havebeeninvestigatedandthesystemaimstobeafutureoptionforgroundconditionmonitoring.

3.Results

TheeffectofloadonthecountratecanbeseeninFig.2a.Thesignalvaluesontheleftofthefigurecorrespondtotheprobetipnotbeingincontactwiththegranularmedium.Whentheprobeispushedintothegranularmaterialtheloadincreases.Thedatahighlightsastabilizatio（reduction）inthecountrateandisreferredtoasthe‘‘characteristiccountrate’’foraparticularfrictionpair.Thestabilisationofthecountratemeansthatnomoreoscillationsarebeingproducedduetoanincreaseintheloadandthereforethesignalamplitudeisonlysubjecttoamplitudeincrease.Differentgradesofparticulatematerialhavebeenusedandthecharacteristiccountratemonitored.Theresultsindicatethatalowercharacteristiccountrateoccursastheaverageparticlesizeisincreased.EightsamplesofsandwereusedandthecharacteristiccountrateiscomparedwiththeparticlesizeinFig.2b.LargerparticlesizesproducefewercontactsandthereforetheresultsagreewiththeassumptionstatedbyBaranovetal.[6]that,therateofcountingisproportionaltothenumberofcontactsformedperunittime.TheresultsinFig.2crevealthatthewatercontenthaslittleeffectonthecharacteristiccountrate.Fourrangesofgrainsizehavebeenusedandthecountrateisplottedagainstthemasspercentagewatercontent.Thereisasmallvariationinthecountratebuttheseparationinthesignalsgeneratedbythe

differentparticlesizesstillexist.Resultshaverevealedthatthecountratevaluedoesnotsignificantlychangeduetotheadditionofwaterandthatthecountratesignalismainlydependentonthenumberofcontactsformed.Therefore,regardlessofthewatercontentof