2023年全國(guó)碩士研究生考試考研英語一試題真題（含答案詳解+作文范文）_第1頁
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1、附錄一附錄一英文科技文獻(xiàn)翻譯英文科技文獻(xiàn)翻譯英文原文英文原文：ExperimentalinvestigationoflasersurfacetexturedparallelthrustbearingsPerfmanceenhancementsbylasersurfacetexturing(LST)ofparallelthrustbearingsisexperimentallyinvestigated.Testresultsarecomp

2、aredwithatheeticalmodelgoodcrelationisfoundovertherelevantoperatingconditions.AcomparisonoftheperfmanceofunidirectionalbidirectionalpartialLSTbearingswiththatofabaselineuntexturedbearingispresentedshowingthebenefitsofLST

3、intermsofincreasedclearancereducedfriction.KEYWDS:fluidfilmbearingssliderbearingssurfacetexturing1.IntroductionTheclassicaltheyofhydrodynamiclubricationyieldslinear(Couette)velocitydistributionwithzeropressuregradientsbe

4、tweensmoothparallelsurfacesundersteadystatesliding.Thisresultsinanunstablehydrodynamicfilmthatwouldcollapseunderanyexternalfceactingnmaltothesurfaces.Howeverexperienceshowsthatstablelubricatingfilmscandevelopbetweenparal

5、lelslidingsurfacesgenerallybecauseofsomemechanismthatrelaxesonemeoftheassumptionsoftheclassicalthey.Astablefluidfilmwithsufficientloadcarryingcapacityinparallelslidingsurfacescanbeobtainedfexamplewithmacromicrosurfacestr

6、uctureofdifferenttypes.Theseincludewaviness[1]protrudingmicroasperities[2–4].AgoodliteraturereviewonthesubjectcanbefoundinRef.[5].Merecentlylasersurfacetexturing(LST)[6–8]aswellasinletrougheningbylongitudinaltransversegr

7、ooves[9]weresuggestedtoprovideloadcapacityinparallelsliding.TheinletroughnessconceptofTonder[9]isbasedon‘‘effectiveclearance’’reductionintheslidingdirectioninthisrespectitisidenticaltothepartialLSTconceptdescribedinref.[

8、10]fgeneratinghydrostaticeffectinhighpressuremechanicalseals.VeryrecentlyWangetal.[11]demonstratedexperimentallyadoublingoftheloadcarryingcapacityfthesurfacetexturedesignbyreactiveionetchingofSiCthebearinglengththisoptim

9、umvalueishp=1.25.ItwasfurtherfoundinRef.[12]thatanoptimumvalueexistsfthetexturedptionadependingonthebearingaspectratioLB.Thisbehaviisshowninfigure2fabearingwithLB=0.75atvariousvaluesoftheareadensitySp.Ascanbeseenintheran

10、geofSpvaluesfrom0.18to0.72theoptimumavaluevariesfrom0.7to0.55respectively.Itcanalsobeseenfromfigure2thatfa0.85nooptimumvalueexistsfSpthemaximumloadWincreaseswithincreasingSp.Hencethelargestareadensitythatcanbepractically

11、obtainedwiththelasertexturingisdesired.Itisalsointerestingtonotefromfigure2theadvantageofpartialLST(a1)overthefullLST(a=1)fbearingapplications.AtSp=0.5fexampletheloadWata=0.6isaboutthreetimeshigherthanitsvalueata=1.Afull

12、accountofthisbehaviisgiveninRef.[12].3.ExperimentalThetestedbearingsconsistofsinteredSiCdisks10mmthickhaving85mmouterdiameter40mminnerdiameter.Eachbearing(seefigure3)comprisesaflatrot(a)asixpadstat(b).Thebearingswereprov

13、idedwithaniginalsurfacefinishbylappingtoaroughnessaverageRa=0.03lm.Eachpadhasanaspectratioof0.75whenitswidthismeasuredalongthemeandiameterofthestat.ThephotographsoftwopartialLSTstatsareshowninfigure4wherethetexturedareas

14、appearasbrightermattsurfaces.Thefirststatindicated(a)isaunidirectionalbearingwiththepartialLSTadjacenttotheleadingedgeofeachpadsimilartothemodelshowninfigure1.Thesecondstat(b)isabidirectionalversionofapartialLSTbearingha

15、vingtwoequaltexturedptionsa2oneachofthepadends.ThelasertexturingparameterswerethefollowingdimpledepthdimplediameterdimpleareadensitySp=0.60.03.Thesedimpledimensionswereobtainedwith4pulsesof30nsduration4mJeachusinga5kHzpu

16、lsatingNd:YAGlaser.Thetexturedptionoftheunidirectionalbearingwasa=0.73thatofthebidirectionalbearingwasa=0.63.Ascanbeseenfromfigure2boththeseavaluesshouldproduceloadcarryingcapacityvaryclosetothemaximumtheeticalvalue.Thet

17、estrigisshownschematicallyinfigure5.Anelectricalmotturnsaspindletowhichanupperholderoftherotisattached.Asecondlowerholderofthestatisfixedtoahousingwhichrestsonajournalbearinganaxialloadingmechanismthatcanfreelymoveinthea

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