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P-olI JM.J・mcch.SCi・PergmmonEreB3・10“・VollOppp・鯛7-6蝿.PTlnledInGreatBritain
ANEIASTICSTRIPINPLANEROLLINGCONTACT
R.H・BENTAエL↑andKL、JoHNsoNUmive”ityofCambridgo,EngIand
(RCceit)ed23ZWUcm6erl967,α砥i〃ret)iUed/bmO15jlfq趣1968)
Sunmm1ry-ThoproblemofanelaBticBtrippassingbetweentworo1lersi8conBidemdby meanBofanumericGLImOthod・ABanrBtBtepitiBassumedthatthecontactingBurmcesmovetogetherwithoutmutua1slippingBothataBhe&rBtrEssiBdevelopedatthecontact interf配0.Compari8onoftheseBheGuPstreBseBwiththenomnalcontactstre88eBBhowthab,mgenoml,micro・B1ipmuBtoccurwithinth⑧nip,albeitconfinedtotheextrcmeedgeof ●
contact・Ar6gimeofslippingiBBuggested・moreBultBprovidedetail8ofthecontactBtre8ses,theindentationofthoBtripbythe
roUerathecontactwidth,andthoBpeedatwhichtheBtrippaB8Gsfhroughthenipin relationtothemtationalBpeedoftheI℃lle頭.
NOTATION
SufIixl祀屈岡totheStrip,BuHix2mfbr8totheindentingmU⑧r・ahalfcontactwidth
amhalfconmctwidthdeiinedbytheIIertz8olutioniftheBtripisinnniいlythick
A=qkUo bhalf8tripthiclmessfbrfreestrip,Btripthicknessfbrtyre B=b化
chalfLwidthoftriangular⑧lement ●
Ccumulativeslipbetweencent”ofcontactandslipregnon dindentationofBtripbyroUercbtz=0 ,=。〃enon-dimensionalcontacteccentricity,intennsora
EYOung#BmoduluS ノinstantaneo垣pointvelocityFbulkperiphemlvelocity Aノームーハ,thovelocityofBlip
]nmtheNaperiqnlogarithm Nnormalloadperunitwidth
jD(工LP(X)nomnalBurfncostrcssdiBtribution9(苑),9(X)BhearBurfnce8trC四diBtribution
pavemgecontactpr巴ssum
P⑩mammumnormalBtIもssdennedbytheHertz8olutionifthe8tripisinBnitelythick
P(X)=p(XVp Q(X)=9(X)/何
rhunlmowninapproximatenomualBurfnceBtmssdiBtributiontcrmsofP Q耐unknowninapproximateBheargurmceBtrc8sdiBtributionintormBofP
H1,E2radiiorroUerBland2 」T=ElIW(E,+丘2)
2SnumberofBtraightmne8bywhichtheBtrCs8diBtributionBaToapproximcLted Bign()=+lifargumentiBpositivo,
=-lifargumentisnegativo T4tangentialdispIacement U=切位unommaldiBplacement
TNowabth⑧CentmfbrnlateriaL3Resem巴h,UniversityofBriti8hColumbia、037
1V
il l
凸0丘■■い■●L9.0■口00.●■■■■■5■已与■68■■S■P
I 638 R、H、BElvrALLandK.L・JoHKsoⅣ
V=tVq zdistancoBomcentroofcontact
X=年/a
Xm=伽ね,non-dm1en8ionaldistancetomthmatchingpoinLX向=〃/0,non・dim…ionaldiBtanceto柁thRor4ソdistancofTomlongitudhualcontreIinoorfreestrip,orfromtyTeinterfhce
a,りwandervariables
β-壷1,(筈)
&-2言lil/学殿一志
#轍顯、、 パー[(l+"3)(l-2iWEb-(l+",)(1-2,,)/Eu】[(1-増)/E3+(1-用)/Ej
coe価cientoffrictiom
Poisson,sratio
脾P
←¥,……。LINTRODUCTION
THJspallerdescribcsatheoreticalinvestigationofthestressesanddelhrnmtions producedinastriporsheetofelasticmaterialasitpassesthroughthenip
(a)
(鰊、
(b)
に) )
FIG・LBaSiCBtriI】con5gumtions.
betweenapairofrollers,TwodiBbrentarrangemel1t8havebeenstudied (Fig.1(a)and(b)).Inthenrstthestrippassesn℃elybetweenidenticalrolleIs lnthesecondarrangementthestripiBattachedtothesurfnceofonerollerlike atyre,acircumstancewhichiscommonlyfbumdinprocessingmachinery、I、
AnelasticBtripinplanerol1ingcontactO39
theIattercasetheanalysishasbeencon6nedtorollerswhicharerelativelV ⑪
rigidcomparedwiththeeIastictvre・ForbotharrangementsithasbeeluU
as8umedthatroIlingproceedswitholxtthetransmissionofanettractivefbrce, aIthoughthemethodofsolutionisnotrestrictedtothi8assumption
ThestripisnippedbetweentherollersbyanormalfbrceZValongtheline ofcentres、Therollersandstripareassumedtobewidesothatthedefbrmationmaybetakentobeplane,Wesetouttofindtheamountbywhichtherollers indentthestrip(`),thewidthoftheregionofcontactbetweentheroUersand thestrip(2α)andthedi8tributionofstressestranBmittedacrosstheinterfnce・WhenthestressesattheinterftLceareknown,thestressesanddelbrmation月
throughoutbothstripandroIIerscanbefbund、Finally,duetothecontactdefbrmation,thevelocityofthestripdiHbrs81ightIyfTomtheperipheralspeed oftheundefbrmedsurfbLceofthecontactingrollers・ThefractionaldiHbrel1ceinspeedi8callGdthe“oreepratio,,(:).Itsvaluei8ofinterestandmaybe fbundfi・omtheanalysis・
Theapproachfbllowsthatusualincontactstresstheoryinwhichthc contactwidthremainsBmallcomparedwiththeradiioftherollers、WithinthisapproximationthetyreproblemshowluinFigl(b)isequivalenttoanelastic stripofthicknes8battachedtoarigidplaneindentedbyarollerofradius 〃=E1IT2/(H1+庇2)(Fig.1(c)).Thesimilaritybetweenthetyreandthefreestripisnowapparent,Thecontactgeometryisidentical,but,whilstthe centralplaneofthefree8trip,bysymmetry,isfreefromshcarstress,thelower surfnceofthetyre,attachedtoitsrigidbase,haSzerodispIacement、
Itisclearthatthenom1alstress(pressure)transmittedacrossthecontact interfacemustbalancethecompressiveload、Sllcarstressesattheinterfncearisethroughfriction、Athinstrip,compressedbetweentheroUers,attemptstoeIongatewithinthenip・ItfbllowsfromtheHertztheorythattherollers,
ontheotherhmd,exhibitcircumfbrenti紐lcompression・Theseopposingtendenciesofthetwocontactingsurfncesareresistedbyfriction・However,ifatanyPointtheinterfncialshearstressreacIlesalimitingvaluegivenbythe productofthecoefHcientoffiPiction仏)andthenormalstress,then“micro‐
sIip,,willoccur、CmtactstressprobIemsinvolvingmicro-slipduringrollinghavereceivedconsiderableattentionrecentlyintlleliterature・lItmaybeaPPreciatedfromquaIitativeargumentsthat,whenthestripisthm,the stresseswithintheBtriparesensitivetoftictionalstressesactingovercontact、Itwas,therefbre,resolvedattheoutsettoattempttodeviseamethodof analysiswhichwouldenablefiPictionalstressestobeiIDcluded.(Pmviouswork ontheproblemhadnotexaminedslipandfrictionatthecontactinterfnce.)
IfthecontactcomprisesregionsofbotllB1ipandno-slip,theboundary conditionsintheseregionsaredifTbre1lt、IntheslipregionsthesurfnceshearstressisrelatedtothenormaIstressthroughthecoeIYicientofffiction;inthc no-slipregionstherelationshipbetweenthetangentialdisplacemcntsinthe twocontactingsurfncesisprescribed・Thesecondition8havebeendiscussedin
detailpreviously2andthere8uItsarereproducedinSection2below・TheprobleminelasticitycannowbedeIined,Aninfinitestripisloaded
overafiniteregionwllerethedisplacementsareprescribed;theremainderof
藍-07仏白び、■ⅢⅡ?⑪ⅡⅡいⅡ曰
。■0■引口-000■UaI0曰0■■■■Ⅱ■勺●口■■→凸。■■9I!■凸■UdpU9L■一二CDV■‐■■i■Q496pIq6qPIr●4DdrhPlblr△■|、!■。r|Ⅱ‐Ⅲ
■I|■q●0m〃00CGOいりoH4J即いら■■■■且■■■■、P1ケ■田■●■80・JDUSOⅡ■BPq6B■00勺1-.000日Ⅱ.94j・FD0-0●-0-0F・可‐・‐‐‐●il6p
I NI
640 R、Ⅱ.E庇NTATLmMlK.L・JomVBoN
thesurfnceofthestripisBtre8sftee・Withafreestrip,itscentre-p1aneisoneofsymmetryBothatthenorma1displacementBandthe8hemBtre88e8therearも
Zero、WithatyreattachedtoarigidroUerbothnorma1andtangentialdispIacementsmezeroatthelowerBurfhce、ItisrequiredtohndthestrcssesthroughouttheBtripand,inparticular,thoseactmgatthecontactmterface・
TheproblemcanbefbrmulatedeasilyintermBofFourierintegralB (Appendixl)fbllowingamethoddescribedbySneddC、3.110we▼er,obtaining numericalrcsultsfbractualca8e8hasledtorealdi価cultiesduetothemixed
natureoftheboundalycondition8andtheintractabnityoftheintegralswhich desoribethedefbrmation・Variousapproximateteohniqueshavebeentried・
WhentheBtripi8thiokcomparedwiththecontactwidth,the8olution
approache8thatlbrasemi-inlinite8oUdandapproximationsgeneraUygive rapidconvergence、Whenthestripisthin,itispossibletoapproximatethedefbrmationthroughthethicknessoftheBtripFeng4hasadaptedMindlin's second-orderpIatetheory5tothepresentProblem・
FormoregeneralvaluesofBtripthickneBse8theu8ualapproachhasbeento approximatethedistributionofstressatthemterfnceandtoBatiBfythe boundaIycondition8thereonlyat&numberofdiscretepomts、Hannah6,PariBh7andMillelsapproximatothedistributionofnormalstressbymodifying theHertzBolutionwithFouriercosinePerturbations,thus
Ⅳ
,(x)…[ルェ曇)w、…獺-1);刮wheretheA祁mFeRmknowncoefYicientsdeterminedbytheboundaェycondition8・Los8鉢αJ,DandConwayeUaJ.]ohaveapproximatedthesurfncestreBsdistribu-tionsbyelementsofunifbrm8trcssappIiedtoanumberofdiscreteintewalsof thecontactregionAgainthedispIacementboundaryconditionsa””tisned (ie・matchedbetweenroUerandstrip)atdi8cretepoint8attheinterfnce、1IOrerecentlyTulnhasobtamednumericalsolutionsfbrtheaxi8ymmetricproblems ofthefreestrip,whenthestripisnippedbetweentwosmoothspheres, prwiouslyconBideredbyTuandGazisn2and,morecompletely,byO,COnnorⅡ3. Tu'8fbrmofapproximatione8sentiaUycoincideswiththepresentmethodof solution・
InnoneoftheseBtudieswerotheboundaryconditionsoftangentialdiBplace‐ mentappropriatetoroUingcontactappliedtodeterminetheshearstI℃ssat theinterfnce,
Thetechniqueusedhere,whichisdiBcuB8edmreflandmdetailby Bentalll`,approximatesthe8urface8tressdistributionbyoverlappmgtri‐ angularelement8,charaCterizedbytheircentrcordinate8(Rn,Q伽)asshowninFig、2.TheBuperpositionOfalltheelementsresultsinapiecewise-】ineardistributionofBtressasBhownTheuseoftriangulareIementsgivesanorder ofimprovementuponunifbrmconstantBtresselementsmrepresentinga continuousdistribution・Alsoitsatisne8theconditionthatthecontactstIEsses
I繰鰯鰯、
‐1F1■0■0■BPlg00Ⅱ0凸■09109■I■■0I0l--L■FD-.ⅡⅡq・口
lIlll
I100IUdI0-90ⅡⅡK00l00b■■■曰■■■■■Ⅱ■■□■JⅡi05■■1‐■・■■■■10ⅡⅡ70■■■■口0‐‐11’011.‐
(綴,、.、
Ii1II-IIl1II1llIll1.11I
BhouldfnUtozeroattheedgesofthecontactregion、Thi8requirementiBnecessarysmce(a)atensUenormal8tres8isun8upportableand(b)interfbrence betweenthecontactingBurfnceBoutsidethecontactregionmustbeavoided.
AnelasticStripinplaneroUmgcontact641
ThediBplacementboundaryconditionsarethen8atisfiedatthepointsonthe contactmterfncewhichcoincidewiththeapexofeachstrEsseIement.
。‐今‐h】。●て、□0『8同ざ■■|■ロ用aq4岾・■可!‐
STRESS 。
、0.2.ApproximationtoBtr℃ssd由tribution.
2.FORHULATIONOFrHEPROBLEM
(&)Bow1cdmVcooO(ZiUio1DB
ThocontacCdefbrmationcommontobothBtripproblemBiBBhowninFi9.3.Inthe BymmetricaMreeBtripproblem,thothickneB8ofth⑧Btrip由26.Thetyr℃problemhnsboenrcducedgeometricaUytocontactbetweenarollerandastrip,thiclmess6,Btucktoa hB1fLSpace・IhecontactiB8howneccentricwith、8pecttothorollercentre・lines,aUowingfbrtheaSymmetryassociatedwithBlip.
Ⅷ剛ⅧⅧⅧⅧⅧ緬螂州岬叩剛ⅧⅧ細川Ⅷ川棚剛洲”“”洲叩椰州Ⅷ靴馴馴岬Ⅶhhhトル孔Ⅲ小川
X
yOI LlNECF
CENTRES
rIC、3.Contactdefbrmation.
TheboundaryconditionsdOnnmgthedelbrmationimposodbyBtcadyroningcontact a8derivedinrcflapplycquaIlyweUtothoBtrippmblemsexceptthathomwGconBider djBPlacementB(凹,u)relativeto(0,0)andamthusabletodeterminethepenctrationoftheBtripbytheroller・
Fi函t,wehavethat
:lfl二:”'夢!山wherGp(X)and。(X)arethe8tressesactingonthe8urfnceorthestrip,andwhemX=勿/α・
mBidecontact,thenormaldiBplacements(U)arodet0rminedbythepenotrntionofthe roUer(。)anditsundefbrmedpronle,hence
H+昭一、+Xe;-x鈴 (2)
Sub8criPtSland2 whereH,JB=U,ノロ,tlg〃,、=。〃,and“由theeccentricityorcontact・rBfbrtotheBtripandroUerrCspectively.
642皿.H・BmmALLandK.L・JomqsoN
ABthetwo8urfncesmlltog⑧ther,thocontactiB,ingenerLl,dividcdintorcgionBof no・B1ipandmicro・Blip
lnno・BliprGgionB,thodiflbrCnceinBtIPainBofthetwosurlncesrcmaingataconBtant value(ど)detGrminedbytheirrelativevelooitiesJland尾.
Hence,fbrno・slip U1-U画=:X+0(3)
WhelもU,,U2=“、〃,叱位,f=(奥一喝)/FandOdenote8thocumulativOBliPfmmtheorigintothepomtinque8tion.
Inadditiontheshear8tr巳ssiB1imitedbythecoelYicientoffriction,thusJ1
(4) 19(X)|≦lLlp(X)1
Ifmicro-BlipoccurU,theBhearBtressattheBurfncewillm⑥chitB1imitingvalueina dircctionBuchthatthefrictionfbrCeopposesthGBlip・TheTclativevOIocity(〃)betweenthetwoBurmceBisgivenbythoequation
豐臺`+儂一叢)に’,撫爾、
Hence,inaBliPrCgionDworequim
Q(X)=Big、(〃)”(X)
whcreBign<△/)=+1,-lfbrムノpositive,negativere8pectively.
(6)
(b)DC7i…ioDLq'Zhemu8CJbi”eql“imo8 TheboundaryconditionsofdiBplacemente(equations(2)and(3))willbeBatis6ed(i、⑧.
mLLchedbetweenrollerandBtrip)atanumberofdi8cretepointsonthointerfbucc・Thoderivationofthemmtchingequationsfbrthefrco8tripproblemonlywmbeprcsented h0rG;thosefbrthetyrUproblemmaybeobtainedmthesameway・
ThegurfncediBplacementBofafYe⑧Btrip(rclativetoエ'=0,J=O)duetoevenapp1iedBurfncestr巴sgdistributionsP(⑰')GLndg(〃')haveb⑧enderivedinAppendiエピ1(equationB(A、6)-(A、9)).Withthe8ee。Epre8BionBwecandefinetheinfluenceofanindividualBtreBs eleme、tat垂=勿向ondi8placemeHutat⑰=Tm,Fig.2.ThuB,⑰'beingmeHLBuredlromaFn,thenormaldisplacemcntat⑰'is
oF-鶚IillF(.`:鶚塗J’1.1。…砦
-21鶚」川1-…('-,`)[蔬::毎l)小)…等(アIForatriangularstresselement(equation(A、14))ofbasewidth2c,p(α)isgivenby
p(α)-警。in圏(。./2)(8)Wenowdefinethenon-dimenBionalterm8;
β=麩6,B=&ぬs=./c,z=c/46=1/4SE(9)
wherCSchamcterizesthedegrceorrBfinementoftheapproximation・nneBtmssdistribu.
111 し
tioniBmddOupof2S1inearmcrements・ Notingthat年'=c(nD-”)wheremandooamintegeraweobtainthonormaldiBPlace-
mentB(岡IativetoO,O)atapointX=m/SduetoBtrcsselementsp薊andgnatX=,VSnB
vH-j・轍E鶚111[I』。+L,[…]……-鰯]]
‐,耐。[鶚211囮[…]+411竺器+ニニユ…[…]] (10)
AmelaBticstTipinplanemUingcontact 643
whoXも
叩一僻
噸叩一仔
訓蠅
調.m
叩一研》傘
》》》いが
幻I
‘"[噸-鯛1-1r・in…'…'壕=1m[1,]=l[(p+1>蟹1,(p+l)+(p-l)81,(p-l)-2jD21n(p>]
and
‘`…]-1F.、譽v・…-"17鶚=一万/2("8-机)≦-1
=0(、-レリーO
=+汀/2(,肥-,2)>+1
(11)
IARIm-"]andIE几[m-,0]rep…entthecomparablod垣p1acemontBofLhalr、Bpace,relativOto(工'=0,J=-6)andJA[伽_犯]andIE[、-,z]rCpI℃sentthemodincationtothatrelativediBplacementduetot】uennitethicknes8ofthestrip・LmrepresontBtheabsolutedeHOxionatZ`=0,J=-6.
TheintegmndsorI,0,J」[p】an〔lIE[j、]tqketheIbrmofo8cillationswithinadocayingenvOlope・Asthewidtho「thestI℃sselementcompamdwiththethicknes3ofthe8trip(z)increaseBpsodoestheIrequencyoftheoBcillation,worBoningtheconvergenceofthe integraLDimculticsofconvergencocanbeoverComebyemploymgatechniquodesc『ibedmAppendix3andintegmtionsprcsentfbwproblemstoLmodernhigh-Bpeedcomputer・ ReaBonableandconB鱈tentrcsuItshavebeenobtaineddowntotlIiclmc5sesofB=OOO1uBingS=20.
Inasimilarwayweobtainthotang・mtiald由placementsatamatchingpointX=WSduotoa8tmsse】cmentatX='0/8.Relativeto(0,0)theseare
ひ`…膳i'1J`[''1-,W`[凧、+ 4(l+Pu)(1-2"】)
蓬umM"`-"]+恥廠[蝿])] ̄ ̄..L万必,。 ̄ヨーニーj,.斤囮,-,-jJnL…
+9阿B2(L二ピコ(('"["1-,0]-1⑩])+4z(I“[,"-"]-1』jw[,、]))7TEI who”
(12)
”[`鰯-鯛]-=r(1-誌辮)……-鰍'率:’1`)FollowingHertz,theroUerdisplacement8amtho8cofahalfspace・Theycanbo
obtainodeithorfromfi応tprinciples,”『.(1),orfromeqlMLtion8(10)and(12)asthestripthicknessB→CO.
Relativeto(0,-6>theroUer《li8placementBduotop励,9,mmre,Fig.2,
11
'…驫鶚尖('"[純一耐]-J"M1+,鳳些LL空』き('"[…]+虹"M)汀B2and
U曇-,銅(…ル2いき('厨、[噸-鑓]+恥鳳[総]1-,薊砦巽(j釧廠[,腿-”]-z"M)万E2
U41
Equationg(10),(12)and(14)givethodi8placementBduetosingICsn℃sselementB・Todcscribethedefbrmationa8awhole,thecontTibutionofeKLchelementintheBtrC8s
ヨ
n.H・BENTALLandK.L,JoImsox 644
地唾⑭dmtributionmmuョtboconsido唾。、ThomatChingequatjonBarBobtamedwhen孟鱗HiHi戯、h5hmJ5idinlgP…。…bsザPHlofPnP99B聖iRF(2)"。(3).
IftheBtripi8infinitolythick,thecontcLctwidth,2Cl四,泊givら、by
。:一半(等十署)-:…(等十署) (15)
wherePiBthemeanpressuuPBN/”. DemingA=αノロロ,thematchingequationfbrnomaldispIacemcnt8become8
。」翼L幽聡|圃膨(Ⅱ"+'』[,鰯-"])+き…-"]-匹"M1+:…-鰯]}‐燗」蔦Lm9(固…-“]一念(聡風[…]÷`"[輝ル鳥豐zE風[総]}
=幽劉+竿一等a
qndfbrtangentialdi8plaCementsinaregionofno-slip
oA鷺Lu展|…[瀬‐…回)-:(Ⅱ,…]+n厘mM1}
+鯛」覚LIP蝿I…[…]-ⅢDMI÷き(z"[…]-J"[風])}‐2鍔…・;』。
whem
(16)
'1鰯、、
(17)
L
脆'=丁干Z
雌‐署/署 (18)
臆-P'竺豊二2塗'-11生理豊二塾']/(豐十署)2,=ハノヮ,Q鰯=q凧ノグ
ToobtainaBolutionfbrthevaluesofBurfHce8tr巴sscs凪、andQnthematchingequation(16>muBbbesatiBHedthroughoutthecontactrogion,thatisat(2S+1)point8.Inano・BliprcgionthesecondmatchingeqUation(17)mugtbeBati86edBimultaneouBly,withthe 型ditionnlconditionthat
qDミノルRu(19)
nlaBlipregiontheaB8umeddimctionofBlipmustbecDnBistentwith
Q同=Big、(△/)lLB、(20)
,`總恩、
' AtboIdersbetweenBlipnndno、BlipregionB,equationB(19)and(20)ambo6happ1ied・
Finally,fbrequilibrium,thenormalprcBBurBmuBtbalancothe1oadowhenco (S-1I
ZIヨ、=-28 ,--(S-ユ》
(21)
ApplyingthematChmgeqUationB,andtheequnibriumequation,providesasetof 4S+3BimultaneouBeqUGLtionB・SolutionoftheseequationsprovidesvalueBfbr(28-1)B,,
 ̄
645 AncIasticstripinplnneroUingcontacb
(2S-1)on,、,e,A,どand0.IfmorctlMmoncno-BIipregioni8involvedinthedefbrmation,additionalunlmowns5'andC',ど"andc",etc・omuBtbointmduced,andasolutionmuBtbesoughtwhereピーゼ'=ど",etc.
(c)GouejPm打gpammcte7u/b『仇eルee8IアゴPExaminBtionofequations(16),(17),〈20)and(21)ghowBth醜the8olutionBdepend
upontheratioofBtripthicknesstocontactwidthanduponthenon・dimensionalmaterial pammeter8比,KandP1・InadditiontheextentoftheBIipregionBdependBuponthecoefYicientof金ictionlL.
ItmaybeshowT1thattheBtressdiBtributionBaredepondenton〃,KandlLLonly;theabsolutevalueo「"nonlyinnuencesthevalueoftheindentationD・rnrther,P,onlyappeaエ洵aBanindependantpammeterinthetermiIwolvingQ伽inequation(16),andnotatallinequation(17).Theinnu⑧nceoftheshear8trBssQ回uponthenomma1stms8BQisnotverygreat,aBBuner,sworkl5indicGLtes・ILaBiscommonincontactBt唾8theory,weneglectit,theterminquestiondiBappeBIB・WOmcLyBtatethat,therefbre,tocLclosGapproximation Che801uCionstothematChingoquationsarefimction8offburindOpendentpGLrfLmeterBD B,ル,虻and脾.
3.RESULTSOFTHECOnlPUTATIONS(noSlip)
ThemethodofanalyBi8developedinthepmvious8ectioniB,Bomr,perfbctlygenemU・ ThecoexistenceofBlipandno-B1ipmguonBcanbehandled;theinterfnco…ytrnnBmita tractivefbrUevaryingfiomlimitingfrictionwhencomp1eteBIipoccmBinonGdirもctiontocomplete81ipintheother・
Howwer,thecomputationBpr℃sentcdinthiBpaperamrG3trictedtoooIteeroUing,,,i、e・whonthe”iBnorcsultamttangentialfb配etranBmittedbythecontact・Intheseclrcum‐BtancesitiggenercUIlytruethaMbrpracticalvalue8ofthecce団cientoffrictiontheextentoftho81iprcgion8isnotverygmat.Forthi8rea8onthecomputationhaBconc⑧ntⅡmedon solutionsfbrnoBlipanywh…(lL÷CO).Thetmldencyto8Uipcanthenbesppreciatedby examiningtheratioofBheartonormalBtI℃SSQ(X)/p(X)Boobtained・Theinfluencoofs1ip垣conRid⑨【℃dinthenextBectiolL
Cmnputationshavebeencarriedoutoverarangeofstripthicknes8eB(B).Whenthe stripisthick(B→。。)iCbecome8anelastichalfgp“ofbrwhichBolutionsinclosedfbrm exist・ForvBrythinBtripB(B→O>approximateBimpIeBolutionsmaybefbundinthemanneriⅡndicatedmAppendix2・Thocomputedm8ultBmUbetweenthesebwoextmmes.
llll
IiI,11111
:卜’1111,111‐1-。‐
(&)me介cc8ケ中pmblem
(1)E9umJclaBliCco加8m"68.ルー1,K=0.(1,,=0.3)
Ifstripandrollerhavethesameela8ticcom3tants,thelimitingSolutionfbraninfinitely thickstripbecomesthatofHertz;
p(X)=ルイ(l-Xg)
9(X)=0
2,②=-2N/汀α-
.選-.:=竿儒+響)dルー。。
鼻-.=鼻一=0
0
(22)
11
IⅡ
IntheotheTlimitingBolutionoraninnnite8imaUythinBtrip,althoughBhearBtresses amdevelopedduetoami8matchintangentialdisplacement8,theya“vani8hingly BmaII,BothattheBurfn幻econmct8tTCssesaro昭alnessontiaUydOfinedbytheHertzBOlution・Th画thinBtripsolutionisdevelopedinAppendix2、
42
R、H・EEwTAZLandK.L・JoIKJIsoN 646
ThIn民
鱒Ix1臺弐命{u-x圏’
@(x1-觜【…'十剛鎧X
Ju-x2)
α圏=竺匹l二二;7TEB (23)
。ルーBa/亟
息-。=0.457[ん+K(l+化)]。/E
4_。=[ん+K(1+化)]b化庇
●。
ThenumericalresultBgivSninFi9.4BhowthevariationoftheBurfncocontactstⅢも目已esG
wiChstmpthiCImess,PlottedintermBofPの。WeBeethat,⑩rnormalBtzもsseB,themaUorpartoftmnBitionbetweenthickandthin8tripbehcwiourliesintherange2>B>0.1, whenthestripthiclmes8iBtheBameorderormagnitudoaBthecontactwidth・TheBhear BtrcsBes,however,appm⑥chtheirlowerlimibmoreB1owly,bemgmoBtdevOlopedata th6nLmP2写ofaboutB=0.3.
(錦顯、
や「、曵一 -..2. 2..
熱
二ljfTJimiJ
が幻
洲一% -..15
’し
夢夢鵠-゜'。1..
一観盲'19扇;§ラミ〃’〃.
、(綴mmM、
ノ
-005
ざツざ2◎・'0
0.12
0.08
..04
。
忠~
蛎一
,’2参釜。身:;諺二2 25
§夢
州一%
0b■
Z二霊奎城
〆B@
百垂
{』
B・2-02-0 。 ◎
。 。・5~B□。.・・I。。 O5
X
1-.
XX
(a)(b)
FIC、4.StripandroI1erofequalela8ticconstant8ルー1,K=0.(&)Stressdi8tributiong;(b)Stressratio・
Ap1otoftheratioofBheartonomnalBurlnceBtress,Fig.4(bLteBteChetendencyfbr B1iptooccur・Iheratioapproache8amaximumclosetotheedgeofcontactandadiHiculty arisesfromtheinGUbnityofthenuⅡnericaltechniquBtoresolvethevarmtionBinBtr℃ssratio
-●CG~ --
■□‐□Ⅱ日山Ob0PJ
Ane】nsticstripinpIanemUingcontuctO47
iluthc唾giono「highstI℃ssgradicntclosetothecdge・ItiBnotclearfmmthenumerical
anmysifBwhetherthestre&ヨratiofmUstozoToorriBeBtoinnnityatX=±1.Toanswerthis qucstionwoconsidertheBingulariWattheedgGofcontact・Whatcvertheactualthickness o「thestrip,itwillappeartobethickwhenconBideringthoBtateof8tressontheBurfnceBulYicientlyclosetotheedgeofcontact・Weconclude,the”fb麺,thattheBinglllarityatjY=±lwillbetlhosamea81brathickBtripDi.e・IbranelaBtichalfLBpnca
Withequalel四ticconBtant8,thehalfspacesolutiongivesm8etonoshearBtI℃&ョ.Inthisca8eweexPoctthoBtres8ratiotolnlltozeroattheedge四indicatedinFig、4(b).エtigthusnotunrCnBonabletoI℃gardthevalueoftheBtresSmtiogivenbythenumerical methodinthelastintorvala81LroughapproximationtothetruenMLximumvaluethroughout th⑧contact、ThusDfmmthOcurvefbrB=0.75,themaximumvalueofq(X)/p(X)=0.09,sothatavalueo「lLgTcaterthanthiswouldpreventBlipentircly・
Thecms8eBinFig、4(&)Bhowth⑧shearstrEssegpIもdictedbythinstriptheory(equation(23))fbrB=0.025.TheseBtresseSagmewellwiththenum0ricalIもsultBoverthecentrallxwtofcontact,butnottowardBtheedgewheI℃thinBtTipaBsumptionBbecomeless aPWop「iBte、
ThevariqtionBofmllingcI℃ep0contactwidthandin〔1entGLtionwithBtlpipthickneBBa唾BhowninFig5.
!ⅧiⅧ!ⅢIⅧIiIliI1
ロー□
かぐ
I
輯■
A伽
D§ い=-)
LI M
FIC、5. tStripandrollerofequale】asticconBtants・ルー1,K=0,シ,=0.3.VaFiHLLionof5,DandAwithstripthickness.
(2)UDWuJ“eku8zjCcmwmoね.ルー3.0,K=-0.286.(〃u=0.3)Thematerialpammotc耐cho8cmfbrthi8examplorcpJ℃sentcontactbetwccn8teel
roller臼andaluminium8trip・The配sultsaIもdisplayedintheBamewayinFigB・Oand7・SincothoeIasticconstantBarediflcrentinrollerandBlip,theshearBtrCsBattheBurfkLce
nolongerwhnisheswhenthestripisvorythick・InBteadthestuでssesapproachasolutionduetoBuIlorl5fbrdiBsimiIqrelaBticro1leIB.
ThuswhenB→CO
2pのJu-x2)
(β1,1苔|)
(β1,1砦|)
p(X) COS
(l+4β2M4-K国)
-2アーイ(I-X2) 9(X)
1 81,
麺、 ̄’(1+4β魁)《(4-ks)…
α=。./《(I+4僻)
dルーCO
鼻_.=0.457Kα/丘
4-.-急1,(聟)=÷。/歴
(24)
uPUI1bl00tpaごLロ』■シロロ000口■000■00,011叩口11
IC.H・BENrALLandK.L・JOHNSON648
Pb「-ご ̄巴
●
四%
,侭鰕顯、
州一%
〈a)(b)FIG、6.Stripandmll⑧rofunequalelaBticco噸tants・ルー3,K=-0.286.
(&)StresBdiBtTibutions;(b)Strcssratio.
~二二二二三?T。綴 I・o
OO
OG
OT
E:。。◎5
,号。‘叫已 ̄)。3
.2
0.0
.
0,0
0.2
/L1M1TFOREASB-O I似pol
||,
A“
I
 ̄
程cロ)
上 胆・Cl
[い=-】 ̄
:51:3s LIMITFCREASB一一一''5 1.. ◎5 。
[二。こ=二|鰯…。一FIG、7.StripandrollerofunequalelasticconstantB・ルー30K=-0.286.
VariatiOnorf,DandAwithstripthickn…
L
will 649 Auuelasticstripinplanorollingcontact
whem
β-鳶'、(譜)“dwhemu四and必arogivOninequation<22).
TheotherlimitingBolutiom,fbrinnnitesimallythinstrips,isgivenbyequation(23). BGcGLusoK(equuLtion(22))isnegative,theBheGLrBtT℃ssactingontheBnrfnceoftheBtrip
change8dhもctiona8thoBtripthicknessdecreases・ThiBi8clearlydemonBtratedinFi9.6,whemwe8eethattheBhearstreBsn画tchangesBigmatthecentrBofcontact・ThehalfBpacosolutionfbrbodieswhosoelasticconstantearelmequalgiveBaratioofq(X)to p(X)whichbecomesinlmiteaCtheedgOofcontact,Wemayexpect,thorDfbrもthattheplotoftheBtrc8Bratio,Fig.6(b),willalBoh&vOasingu1arityGLtX=±1,andthat8omesUp iBinovitablewhateverthethiclme8softhestrip・
Thovariationsofcontactwidth,indentationandcreopwithBtripthicknessare8hown
inFi9.7.
(3)AdゼノbPwOub妙Zripb卸…Pure”i鯵cJy殉jUroUUCmThiBBituationiBcommonintheproces8ingindustuPioBwhoretheexistenceofBhear
Btrcssandnnicro-BIipexistingwithinthenipareessentialtotheBurfEcennighoftheproduct, refl6・ItiBconvenientto8ubdividetheproblemintotwocategories,dependimgonthe compI℃ssibilityofthe8trip.
(i”<0.5:IfthBBtripiBverythick,thesurfncestrBssesaregivenbycquMion(24鵬theBhear8trCssesactoutwaⅡdBontheBurfm心eofthestrip・Atdecrea且ingvaluesoTthe
Btripthiclmess,thenormal8tmBsbecomesmorcconcentrated・The8hearBtr℃sschanges direction,EⅡ召tabtheccntI②ofcontact,Bothat,fbrverythinBtTips,itisprcdominantlyinwardacting(CfFig.6).IfcoInpleteroUerrigidityiBas8umedHLthinBtripsolutioni8then appro“hedwhichisbnsedonapq「abolicdistributionofnormalBtress。
p(Xyp=-3(l-X2)
,Ix1ノガー豊国璽
ガー急島
.~…子ルーα/2況
鼻-.=-0"台論ソⅡα
鼻--=---2(l-yI)BIF
(25)
However,ifthestripiBverythinitbecomesuntenGbblotonBsumothatthemUers 西mminumdefbrmed・Inthelimit,whateverthemtioofelasticmoduli,thedefbrmatiom
oftherollerm四tprGdominateoverthatoftheBtripThenormalBtrcssdistributionwiⅡthenbecomoHoTtzianandCheBolutionwillbetlMLtgivenbyequations(23).
ThismiBesthequestionofthepointatwhichtl1eagsumptionorrigidrollerBBhouldbe abandoncd、Simpleanaly8iBofmLthinBtripbetweenela8ticrolle函(E忠勇〃、)givesthcratiobetweenBtripandmuerdeflexionBa8
:一等&‘['-可き而鬮] (20)
ThesecondterminthebmcketarisesfromtheshearBtrEBsandvani8l1eswhenlL=0.
PmvidedthisrLtioiBappreciablygreaterthanunity(1)L/UB=10,Bay)thcnitwoul《I
 ̄
650 R、H・BmvmLLamdK.L・JoHw息ON
appearrも⑧sonabletoneglectthodefbrmationoftheroUerentirD1y・Ifthi8conditionisBat由fiedequationB(25)canbeappliodtothinBtripprovidedツiB1essthqnaboutO・45.
(ii川÷0.5:ForrCIativelyincompmBBiblethinstrips,ther℃stmintimpogedbyno‐B1ipdovelop8BhearstmsBeswhichgrcaUymodifythenmm2lBtrcBB,andequationB(25) and(26)onlyapp1yifl4=0.RoUingcontactbetweenahardrubberBtripandfbrTDu8 roUe麺iBmpI℃8entedbythemsultBghowninFig8.8and9whemitwuBaa8umedシュー0.5,吃=0.3and亙愈/E,=1000(ん=824,K=4.92xlO-0).TheBtms8diBtribution8inFi9.8
曇 P△■■■■■■■■■■■10■▽01■■■■00000!■■■■■』■IiIBlII□111.;01・IJI,‐‐I
繩
-1.
qIxl  ̄
P仁I
-..
1.1’
巳、
X
J■|■■〃7.01卜0-9‐01-1ローl1BPLr■■Ⅱ196,■0■9人00-■■■■■■■・ill0q901-0TIl〃0-6010ⅡQI-jl0■q■I‐pBiI67I・Ir△■■■■■■50■j1II1
(`鰯,、 十
(a)(b) FIC、8.EmBticstripbetween“lativelyrigidroUeIB.(a)Str巴ssdiBtributio噸(----,ツ、=0.5,〃&=0.3,回z/Eu=1000;----,ツ、=0.5,回h/Eu=。。;-.-.-.-,1imitingHertz8olution);
(b)StI℃B8ratio. % 〆
…plottedintermsofj5,theavemgecontactpI宅ssu届,Bincetheiractualmagnitudes●
mcr己aBeconsidembblywithdecrca8mgBtripthickne8g・TheyBhowthevBriationfromthenear・HertzBolutionofarubberplGLneindemtedbyGLBteslrollertotheHertzBolutionof contactbetweentwDidenticalBteo1rone画whenthoBLripboCweenthemigvaniBhinglythin.AlBo且hownamcurvesofnormalBt1℃8sfbrB=O・OOlandO・O25derivedonthe…umptionthatthemUe”amrigid・NotGthatUu/t'2=l0whOnB=0.1.
ThevariationofcreepDcontactwidthandindentationwith8tripthicknessiBBhownm Fig、9.
(b)zThely7E
ThOmatchingequationBfbrthetymamobtainedintheBamowayaBtho8efbrthefrce strip・Inthero8ultBpr℃sentedhem,ith四beonBssumedthatthOmlle”amrigidcompaI℃。
AnelaBticBtripinplamerDUingcontact651
witlutheBtrip,thusavoidingtheaIgebraicinconv⑧menceoflnllconBiderationofanelastic
Bub8trate・ItBhouldbeappreciated,however,thatthiBBimplincationisnotvalidfbrvery thinBtripBBinceth⑥ntheroUerdiBplacementBbecomecompamb1ewiththoseorthe Btmp・ThiBpointwaBdiBcuBsedintholBBtBection.
lUM1TOFE必.。ASB-..377%
レモル。
U2
UMIToFAASB-po
-L----l 10
二三菫ニニヅニー
8642。
R万
十こ
。、:
/:
/一二巧聯似
ICA
'
、
1二::ミ::菖竺L-- ̄ ̄■■■----
。 05
旧(□
0.5 2℃
LIMIToFA
ASB-O LlMITnOFE ASB-。①
FⅡG、9.Ela8CioBtripbetwcenmlativelyrigidrollOrau'、=0.5,1,2=0.3, EJE,=1000.Vn画iationof5,DandAwithBtripthicknesS.-,
Re8ultfbrlL=CO;------,reBultfbr脾=0.:’ '’ '’ '’
''’ 1冊
イ'’ 11
lftherolleZBarDrigid,thedofbrmation由influencedbyonematerialparnmeteronly,thOPoi88on,BrntioofthoBtripし,、AgainfbrathickBtriptheBolutiontendstowardsthatgivenbyequatio、(24).ForathinBtripwehgwe
(i”u<0.5:
p(Xyp=-;(l-Xg)
9(X)ノア=0
-@国E1u-ソ、)
p=面面T7(l+ヅu)(1-21,m)■~S▽
。(I+''1)(1-2〃、) (27)
'’ '1 111
,M
αg=;BⅣE
dルーα/212
EKl-Pl)
(1-4〃,)Ba
乱-。=身-。=-『T=Z711頭
Thi8rU8ulCdemand8thattheBtripmaterialinBidetheoontacbremmmconmued,and ●
Unde田図oeBBomecomprUBBion・Foranincompres8ible8tripthiBmBcleBェIyimposBibleandfbrツーO6aBeparateBolutionemmgeB.
652 R、n.BENTALLandK.L・JomvsoN
111‐1111
(iiwl=0.58 j,(X)炉=-子(l-X2)2*
Q(Xyp=一等EX(l-X2)
-E1C p=壷万百万
。:=2竺墾2回1
.ルーay6R*
乱-.=-0.19WBH
馳一=-0.2“/BE
(28)
ThecomputationBhBverBveq1edthatthebehaviouuPiBverysensitivetOPoiB8on,B mtiofbrvalueSwhicharcclosotoO5・ThiBiBclearfromacompamsonofChomsultBfbr P,=0.49and】'1=O50giveninFigB、12,13and14.Althoughtherもisnodiscontinuityinbehaviour,theapproximateeqmtionBfbrthinBtripB(equmbtionB(23)andequationB(28)) aⅡDdiHCIもnblbrp<0.5andツー0.5mgpectively・ItiBBuggeBtedthGLtequationB(27)mightbeusedfbr沙<0.45andequationB(28)fbr〃>0.48.TheintermodiatemngoiBlikelytobeveIyinaccurate.
「IillIlII
(繩、,、
ll ll l`、、、
-..2
. ユニジー
15:〈
一雨ルー
11;
、、1。 十0.1
洲一二P qM  ̄
PM
-0.5 +0.2
。 +0.コ
qM -
P
-oqIo
(a)
FXG、10.ElastictyrBonrigidmUer.(b)St罐襲
(b)
ツー0.3.(&)StI℃B8distributionB;mtio.
Again,becGLusOofthehigh8trCs8e8achievedwiththinBtrips,itiBconvenienttoprCsent theBurfncecontactBtresBeBintemmofthcaveragecontactpI℃BBure,P・FigB・10(a)andll(a)show8h℃B8diBtributionBfbrレー0.3andツー0.5fbrvariouB8tripthiclmeBBes・Note,inFigB、11(a),themverBecurwLturcthatoccmもinthenormalBtrCggdistributionfbrverythinstrip8.
* TheseⅡ泊sultBhcwe aL3obeenobtainedbynleje昭17
iB
653 AnelaBtic8t,ripinplanorollingcontact
2.0
5
21二1-
P
07
◎6
OS 0
一○ヨ
qIzI
Phl
-O3
’ 0.5
-.-2
l iL
◎ 州一一P』
◎ 0 。 。。 O・s
X- X--八一一一
(&)(b)
FIC・lLElaBtictymoInrigidroller・ツー0.5.($し)Strcssdigtributions;(b)Sn℃ssmtio.
111
2。
-づ0.8 莚』U二
C
O
RlQ
dlo
--
U雲Q当2C・4
7百55
0.2
。
0.50..IS
B・÷ FIG、12.EIastictyrconrigidroller・VariationofindentGLtionwithstriP
thiclm函sandPoiBson'Bmtio.
11:I‐11
654 R、H・BENTAzLandK.L・JomusoN
了藝111
..一一自国・ロ§一・白已圓§且。z己冒。言一参二§・迂星一一・』
」C旨。菅一目』・由の一一2で薗一』目の具令昌図一国・守【・冨呂
。
9。oOOOrhD症
(`《mmm9、
uli 四【可、
正1c
d▲’
~r
[1
。。』.菖出囚・三c爵旨良
一』巨己莇域C巨二色』【宅二一』一切二曽彦二一一』冨戸ぞこ自今ECC」c目C室
・星』ご←。怠――。』一》一m一』三C2溢孕○一曽己一日・里。自虐
ミロ・色
U0句
(綴鰄、、
11
01
<
。。-P。-‐1‐1●■■l0Ijq-4■■■▽000■・凸■■■已召凸ご■『、■BqG■▽且P卜壹●■□IOD‐
I61-0--1
0ロ,-‐+‐I‐口6句-●0-●■】0■Ⅱ8■P0q■●0t+bPUp‐0‐し.C・けり104‐l■0Pu
AnelaBticstripinplaneTollingcontactO55
Thev巴riationswithstripthicknessandPoisson,BratioofindentationDcontactwidthandcreeparBshowninFigs、l2jl3andl4・The⑧碇ctofBurlEcoBh“ronthereBultBiB
gonerallyBmaⅡ(brindontationandcontactwidth,exceptfbrthinBtripsorhighPoisso、'8 凪tio・Inthisuもgion,however,aswehavealmadynoted,theBolutionbecomeslG8svaIidaBthe“BumpCionofroUerrigiditybrBakBdown・Inthe8einBtances,reaultBareBhownonlylbrlo=CO・Onthem℃SF,however,theBurfnceshearstI℃gBhaB$markedeHbct,andrcsultBa”al9oshownfbrmUingwithum℃strictcdslil〕,orIL=0.
4.THEINFLUENCEOFSLIP
ThemsultBprcsented8ofnrhavebeenobtainedontheaBsumptionthattherもiBnoBupbetw⑧enthemlle”andthe8brip・ThevalidityofChiBaBBumPtioncanbete8tedby examiningthomtioofBurlnceshearBtr℃sS9(X)tonormal8tX℃SSP(X)inFig8.4(b),6(b), etc.,andcomparingitBvaluewiththOcoe6Hciemtoflimitingfriction伜
Whenthematerialof8tTipamdroI10rgamtheBamePorwhenPn=p2=0.5,BliPcanbo eHutimlyp”ventedifthevalu⑥oflLi88uHiciemtlyhigh・ThecriticaWalue,dePendingonthe stripthickn…,canbeestimatedfromFig、4(bルwhereitwi]lbeBeenthatthinBtriPSaremomlikelyto81ipthana応thickBtrip8・
WhentheO1aBticconBtantBortheBtripandroUersarcunequalitfbllowsthatBome micro・B1ipiBinevitablo・ThepGLtternofB1ipdependBuponthOmaterialBPammeterk・IfK>0,whichiBnormallythecnBewhentherolleri8momnoxiblethantheBtriP,thesurfncG BhearBtr巴ssesactinwnrdBontheBtripfbrallvaluesofitBthiclmeBs,BeeFig.4(b).If氏<0,thoBhear8t函88蝿acbinwLrdBonthin8tripsandoutwardBonthickBtrips,Ieadingtoachang⑥inmicm-81ipbeh8wiourwithBtripthickne&3.
(a)K>O
Inthi8caBethepattemofBIip画theBameaBthaMbundwithtworollerBhavingdifIb定ntclaBticconBtantB(mfl).ABanoxampleDcomp1ete8olution8withmicro・B1iPhLvebeen 化undfbrBrollerLnd8tripofBimilarmaterial8に=O)whenlL=O・LTheBurfEceBtrcsses…plottedinFig、15(a)fbraBtripthicknesBgivenbyB=0.1.ThemarethⅡ℃eB1iPregion且;onoateachedgeorthecontactandonetoward8tho応armwhiohthedirCctionofsliPismwrsed・Thedi定ctionormicm-slipfbllowBfmmthe81ipvelccity△fcalculatedfmmequation(5),andiBalBoplottedinFig、15(a).NocomputationBhavebeonporfbrmedfbr othervaluesofIuL,butwocanu8etheanalogywiththetwo-mllCrpmblem,diBcomsaedin detailinrcfl,todescribequalitativelywhathappens・AslLLiBrCducedPthecent凪lBliPrcg1ongrow8inSizeand8prcadsfbrward“m頭thointerfnceuntilDwhenlL→0,thethrceBlipmgionB…symmetricaUydi8posedacmsBth⑧enti”interfEcoas8howninFig,15(b).
TheBtateofafYbLirUwhenlL→Oi8capablooflnirly8impleanalysis,Bincethecontribu・ tiontotheOIDstic8tmin8madebythevani8hingly8mau8urfnceBhearBtlUsse8maybe ncglected・Thevariationinglipvelocitythmughthecontact,calculBtodinthiBway,旧BhowninFig、15(b).ThepoBitionsofthetwopoint8ofno-Blip,AcLndB,aronxedbythe twocondition8:(a)thatthedircctionofthe8urfnce8hearBtmssBhouldopposethaLofthe 8Upvelocity(equation(O))mnd(b)thattheBhoar8trE顕shouldhavezeroI℃BultantinhEemlling・
OthercaBcsofK=OarspmvidedbyanincompIEs8ibl⑥strippaBsingbctweenmlatively r噂droll・rg,Fig.8,Bndanincompn℃ssibletym,Fig.11.CompariBonofFigB、4(b),8(b)and1l(b)BhowsthatthevLriationBorBtrcgsmtio9(XW(X)withstripthickneBB… BmmlarinfbrmeventhoughthemagnitudesdiIYbr・ItmI℃aBonablotoexpect,themfbreo thatthepaCternsofmicTo・BlipanddistributiongofBhearBtⅡ巴gBwiUbeBimilartothoseBhowmi,lFig.15.AroughestimateoftheextentoftheB1ipmguonBcanbemadefromthe
C
valucorthe8tI℃ssratiolbrno←glipandtheopemtivevaluKoofthccoofYicientorfPiction.
■●J|■■▽ⅢBU1Bu■FF01c印・OB・‐90FひPFljq・0■r・Ilj5I‐■J・B1qもr■
(b〉K<0
Thecomljlexmicro・BlippattemBwhichcanoccurwhenKnBnegativehavenobbeen anaIyBedindctail・Wecan,howovor,obtainEomoqualitativeingightbyconsideringthelimitingBUppatternscorr℃spondingtolL→0,uBingthemgumentBwhichledtoFig、15(b).
唖neV師iationm8tmindifYbroncebetweenroUerandstripthroughhalfthecontacbiBplottedinFi9.16(a)fbrdiHErEntstripthiclmesses・ThemiBachangDofBignfmmthickto
--P付
百。.I
-1
| 」F
SLIP の●
NOSLlP
-1
I (鰄關、 l
alF ローI□
(等~期:△f
F
(a)(b)
FIC・15.StripandrollerofequalelasticconBtantS・ルー1パー0.F”eroUingwithslip.(a)-----,粋=01,partial81ip;-.-.-,,
Juトーcc,noslip5(bルー0,qmmestricted81ip.
DIRECTION OFSLlP oFRoLLER oVERSTRIp IbjTHICKSTRIP
△ 】
/’1,MP、
□ IG)MEDIUM THICkNE霊STRIPB■1.. [ ソR
とq
llIjJ
弧|、 118■Ⅲ、□
脚
他jTHlNSTRIp
(olSURFACESTRAINDIFFERENCE
FIc、16.StripandrollerorunequaIelaBticconBtauuts・ルー3,パー-0.286.Variationofunrもstrictedslippattemい=O)withstripthickn….
AnelasticstTipinplalIorolliIugcontact657
thinstrips・WithvoTythickoIPvorythimBtriptheslilDvelocitychangesdirectiontwice withinthecontact,msu1tinginthreeslipregionB・ThereiBnrangeofintermedintestripthickn…Cs,however,whemthevariationinstraindifYbmnceshomuinFi9.16(a)leadsto
liveBliPregiOnS・ WiththinBtrips(Bsmall)theBtrCssratiosBhowninFigs、6(b)and4(b)ammottoo
diBsimUar、AlsothelimitingBtⅡもssdistributionBaslL→OshowninFigs、16(d)andl5(b)a”simiIur・Atpracticalvalueso「'4,themfb”,wemightexpectaBIip]patternaU1dBhearBtI⑱ssdistributionsimilarinmrmtothatcalculatedindetailnndshowninFig、15(a).
Withthickstrip8,onthoothorhan(】,thecomp1etesolutionwiIlapproachthatfbrrolle園ofdissimilareI鴎ticconstantB,giveninrefl・Themicm-BlippattornandBhearstr℃ssdiBtributionisagainnotunlikethatBhowninFi9.15(a)withthedimctiomsofBlip andBhearBtr℃ssroverBed・IfthovaluOoflLi38umcientlylow,Btripsofintermediate thiclmeBs(B=l)giveriBo,intlueory,toBcomplexmicm-Blipl〕atteminvolvingfive8⑧pamtoslipmgionsBeparatedbyfburno-81ipmgions・NodetailedcaIculationshavebecnmadeofthiBcomplicatedBituatiom,butitiBumlikelytooccurwitlupTactbicalwLlueso「14,Bincothestr℃ssratio9(X)/p(X)(BeeFigs.O(b)andlO(b))iBincvitablyBmHLⅡ、
MicTo,81iphasamarkedinnuenceonthestateofgtmminthestripwhichismani化stbythoc…pratio:、Valuesor:h8webeencomputodfbrnosIipい=。◎ハun”strictedBlip中->O)and,intheparticuIarexample,quotedfbrl4=0.1.Rca8onableinteTpolationBbouldbepoBBibleinFig8.5,7,9andl4notingthatpIncticalcircumstancesamlikelyto lieclossrtocompleteadhe8ionthGLntocomploteBlip・
Micro-sliponlyinfluence8theBizeofthecontactarEa(A)andthepenetHntion(D)toa BecondordelP・AJ1exceptiomtothiBBtqtementoccurBwhemathinincompressiblOstrip pa日Be8b⑧twecnIdativelyrigidmⅡemB,BeeFig.0.Inthiscascthe唾is&ImgcintemFLctionbetweonthesheaTstIもssandnormalstmssattheintermce.
5.CONCLUSION
ThestressesallddefbrmationsinanelastioBheetasitpasse8throughthenip betweenelasticrollershavebeenstudiedinthispaper・Thepresentinvestiga‐
tiondiHbrsfiPompreviousworkinthatproperaccounthasbeentakenofthe shearstressesdevelopedbyfi「ictionattheinte㎡ncebetweenthestripandtherolIe頤.
Inthemajorityofcasestheshearstressesdollotgreatlyinfluencetlle contactareaorindentationofthestripbytherollersOntheotherhand,
particularlylbrthinstrips,thestresseswithinthestripsandtherateatwhich thestripfbedsthroughtherolIs,i、e・the‘`creep,,,arecriticalIvaIYbctedbythe ̄
臼'】「filceshear・
DependingupontheelasticpropertiesoftheroIIerandstripmaterialsand thecoe缶cientoffiPiction,somemicro-slipmaytakeplaceattheinterfnoe・If
themIlerandstripmaにriaIsarethesame,asufYicientIyhighcoeHicientofftictionwouldprevent81ipemtirely,butwithdifYbrentmaterials,K≠0,some 8】ipisinevitable・Tllepattemofslipissimilarinmostcases;tl1rees】ipregionsexist,oneateachedgeofthecontactandathird,inwhichtheslipdirectionis rever8ed,placedtowardstherearofthecontact・ForllighvaluesoflLthemicm-slipregionsaresmalIandclosetotheedges・AslLisreduccdthecentre
81ipregIonsprCadsacrossthecontactuntilasvmmetricalpatternofth頤e●1
1℃gionsisfbrmedasshowninFi9.15(b). WithmetalstripsincontactwithmetalrolIs,underconditionsofboundary
lubricatio、,thevalueof脾willbeabout0.1.Theextentofmicro-slipinthiscaBei88howninFi9.15(a).Itisapprecinblebutnotsolargethatanestimateof thestrcssesbaseduponnoslip(i、e、infinitefriction)wouldbegreatlyinerror.
b■且■■■0凸■|■■■■■■■■V0■ⅡPOB■BBOⅡⅡ■■■!■■I0bI00I01.-6-11‐
658 R、H・BENTALLandlE.L・JollNsoN
}'Iiiili蕊lii鱗i繍讓iiiiili篝iiiiiil輔iii蝋ii灘蕊|職ii曇iijiiiijiil繍蝿撚鮒#i菱iMii蕊;蝿’
■■B■■汀■■■■■U■□■■■Ⅱ■BBE■P00Ii●●lトリ‐-1-1■0・b40Lf■74
(側藏、AC陣ot4jUed’cme〃J5-Theautho函gratOfhllyacknowledgethehelptheyobtainedintheearlyBtage8ofthi8workthroughdiscuBsionBwithProfbssorJDuflyandDr.』.』.O,Comlor.
REFERENOES
LR,11.BmvmエェandK.L、JoH蕊BON,ルoC.‘.??OBCハ.Sci、9,389(1967).2.;EP-v…製、P…鋤mpEb"”cb1…汐雄魎祇-節・…E鱈…,
A、ごLerd画凹(1962).
3.LN.S爵EDDoN,五W雄r乃也'1q/bmoaMcGraw-HilI,NewYork(1951).4.G.OrENG,mesis,Unive曙iGyofMinne8ota(1964).5.R、D・nmmmNandM.A、nIEDICx,J・CZjqpZ.」lfech.26,561(1959).6.M.HAm7AH,0.JZjuCcハ.。Z,pZ、JInZハ.4,94(1951). 7.G.』・PAnIsH,Br.‘・qppZ.Pハ顔.12,333(1961)8.R,,.W・MImgEn,Br.』.[W,2.F)W8.15,1423(1964).9.F.』・Loss,A、S,WE噸smmandC.F・ZoRowsxI,』.’加0.JIB肱陀92,104(1964).10.画D・ComvwAY,S・M・VoGEL,K、A・FAILmlAⅡ,andS、so,I〃Z.‘.c加,腕gSci,4,343
(1966).
11.YIII-om,J・ajDpZ・jMccハ.34,283(1967).12.YIH-OTuandD.C・GAzls,J・cWlJ・jlfech.31,659(1964).13.J.』、0℃omvo皿,J,qjlpJ、J1recハ.33,377(1966).14.n.H・BENmhLL,Thesi8,UniversityofCambridgo(1966).15.H・BUrL画'6,1129.-Aγc几27,137(1959).16.J・nPEEL,PapeアPBC几Dool、7,460(1966).17.P・MEJERS,A”・Sci.Re8.18,353(1968>・’8.11.PoRmSxY,J・qnpZ.」MCCルー17,191(1950).19.s・TI。IosHnNxonndJ.N、GooDIEn,me0秒q/遍必aZicf妙,pp8詮91.McGmw-Hil],
NewYork(1951).
20.TablesofSine,CoBinoandExponentiallntegTals.P”parcdbytheFedemlWorks Agency,WorksPmjectsAdministration,NcwYork(1940).
APPENDIXl
〃hedq/bmmDio,Lq/a8zγわα世ezozppJ趣馳がbce8j7es8“we…hereconcemcdtodovelopoxpression8fbrthOBtressesandsurfncOdisplacements
熈kl9BjH妙jPvYhioh、酉loadod6vorlP…f喚團u滅囿さ囹了玉露5誌邑臘筒冒藤striploadedBymエu己t両国llyonoppositefEcesand(b>astrip(tyre)withoneBurfncerigidlynxed、TheapproachfbI1owgthatofSneddon3towhomthereaderisrefbIPTedfbrfmrtherdetails.
<鰍、;、、
L0
P‐r‐。。■90;.|■■I9U2U■■■ⅡU□095■00日■07l0fBR0E0d0uBI0『◆j■■YPI6ⅡⅣ■■■■18‘LB5IlPBB■■Ⅱ■00口■0■8■ⅡP9qLq8■IF■リーャヮ●。、f■76■D0P0YpB‐句。■901口・凸■巳■PBl00dFBB■】い、PC■Ⅱ■hBJ7JX0,P‐‐’,。.‐:07F。040,冊40964p0p杉沮70■・0.F090-.0910.段・巾。■‐,
AnolasticBtripinplaneroningcontact 659
InpIainstrainthootressesmaybeexp正ssedintormsoftheAiエystressfimctionゆby
・雲-掌,。鋤-窯…--識(A」)wheIもJsatisfiesthebihmmonicequati。n
▽や=0(A、2)
IfthedefbrmationiBevenabout⑰=0,thepmblemreducegtothesolutionoftheequation
G=P4+Bay]coghw+[C+Dy]Binhay(A,3)
whemA,B,OandDamunlmownfimctionsofozandwhereGIisther℃uriercosine
tran国Ibrmof↓
゜-17…….仏4)IftheboundaryconditionB錘enowstatedintemnBofG,theunlmownBA,B,CandDcanbedeteImined.
’ (a)FreeBtrip
Considerastriploadedbyanomnausurlbwestressp(〃>atitesurmceBy=overエー±c・
Thebounda可conditionBam
r:二;i小………Thesi厚lconventionisgiv0ninFi9.A.I.
±6,0mending
FIG.A・LSignconventionlbrBurfnceBtresses;positivedirectionshown
USoofequations(A、l),(A、3)and(A、4)BhowBthatB=O=O(sincethedefmmationiB evenabouty=O)andthat
p(α)oubcosha6+Binhab
α
4
αb+sinhcubco8hab
Bmhab
and 空罐一一
、
αBab+sinhabcoshab
whereP(α)istheFouriercoginetransfbrmoftheapp1iedBtI℃8s〃は).
17,(露)。.…“p(α)= (A、5)
ThroughHooke'8law,wCmaynowderivethedisplacementBcLttheBurlbLcey=-bdue toanevendiBtributionofnormalBtress,p(⑰).
。`一二鶚ブテ2,1r(諒鶚…)……空α and
.、-聖帯」r[(』-2職)-2(1-噺)(…為塗小)。i…空a Whereuuisrelativoto(⑰=0,V=O)andw,iBrelativeto(勿=0,ヅー-6).
(A、6)
(A,7)
660R、H・BENTALLandK.L・JoInusoⅣ
ThOdiSplacementeduetoanevend垣tributionofBuエfhceBhear,9(幻)(anodddefbrmMion)canbeobtainedmtheBamewayandare
-2(l+シ,) tJ1=
汀El lr[('-2町1-2('→,唯`+`論難洲)。…等("’and
-4(1-端)
)7t`÷鶚…) ?(α)に。…-1)空a
(A、9) 141= 万四1
(b)z1gIPe
TheBu」Pfncedkp1acement8duetoevendLstributionsofsurfncenomlalandshear
BtreBBescanbefbundintheBamewayasfbrtheft℃eBtripproblem・ SincetheinnerboundaryofthetyrGiBattachedtoarigidroUer,thebounda可
conditio皿are
:三:ルー・
鷺:二潟ルー。‐…<十.Fmmthean&lyBisweobtainthefbUowingsurf面cedisplacementB;duetop(⑪);
'鰯1mm、
4U一端〉UⅡ=-
7TEL 17 函一A(3-4〃,)Binh2a6
]pla)。.…等(A・'01(α6)愈十(l-2ソ,)3+(3-4ツ,)cosh3db
慨`‐二鶚』型Llr[(α6)B+(3-4ツ,)(1-2Jx)(l-cosh2ab) p<α)sin亟竺(A、,,)
a (αb)g+(l-2u',)窪+(3-4P,)cogh筥α6
duetoq低>;
.、-鶚部[(αb)2+(3-4u'1)(l-2PL)(l-cosh2a6) 。α
q(α)sinan9- a
(A,12) (αb)2+(1-2ツユ)g+(3-4Ⅲ,)CoSHZ5R5
…二鶚;〒』ilr(“)+&(3-4ツ,)Sinh2o[6
岬1.。…苧(Al31
11「
(αb)3+(l-2u,,)g+(3-4ツ】)coSh2cub
lneqUationB(A,6)-(A、13),thestrcssdiBtributionsca頤ingthedefbrmationshGweremninedundefined・
Atriangularstmss⑧lementatエーOofwidth2cisdeEnedby
しわ副■B■■9●1010‐Ⅲ‐ムリⅡβ■P■Ⅱ50‐凸Ⅱ79-人■■■■■平07日69.-00IIB■ⅡI6l0z9BPBp-L00Ⅱ006-■■■■■■-■80,6P,トー
'顯驍、p'露)=p(1-ヨ,'鯵'鬘.=0,I⑰|>c
PIa1-lrp(霧)。。…〃
一等…;
for帝hich
{ (A・'4)
APPENDIX2
amiU”BoZc4J"oo8jbrイハ向08t,.`pU
LimitingsolutionBfbrinnniteBimaUythiIlBtripsmaybeobtainedfromsimplemodels ofthinBtripbehBviourassuming,lbTexample,thatplanesectionsremainplane・A1teInatively,assummgZD(X)tobeevenandq(X)odd,wecanaUow6tobecomevery
●
smauinequationB(A、6)-(A,13).
Ⅱ40-▲■▽
P
lりうりゆj竹V〃,
p1lI110J
AnelaBticstripmplanerolliIlgcontacb
ForafhBe8trip,duetop(X)
661
●‐○・‐I‐1‐1141;
0DPrI。jlCf0-‐‐
。=二」'二壁l6p(x)Eu
塾一一ヅ'(l+'1)罰,愛,
and
p(勿)鉱E1
and,duetoq(X) (▲15〉
詩型型,(露)Eユ
窯一旦蓋i';,(露)and
I Foratym,stucktoarigidbaBqtheyam8duetop(X)
-.--(l+ツュ)(1-2シ,)1-,_、正62,(⑩)if8,1<0.5 U=
(1-8',)Eu or
。-論竺警'1,' ツュー0.5
and
-(l+ツュ)(1-⑬,)626(3D(⑰))処== (A、16) 四,<l-P,)2鉱
一(1+P,)(l-4yj626(p(毎>)
and,duetoq(X)
U==
E,(1-〃,)2鉱and
…二'蒼堕'2…)
Z1hi?L8z7fp〃ieo1Ryjbo・介ee86”
ABtheBtripbecomesverythin,itsnormaldi且placememBbecomeinsignincantcompBⅡBdwiththoBeoftheroller,BDthatthonmmalBtres臼distributionbecomesllertzian;
,Ix1-蓋覺処翼ッ仏』,)TheBhearBtr℃ssandtherollingcreeparefbundfmmequation(5)Porits町n8gives
thero1lertangential8tminduetoanappliedellipticalnormalBtTBsB,Bothat
鶚--笥鎧Ju-x愚)+癖('1xnwhemF(9(X))isthetang0ntialBtraincausOdbythe,asyetunknown,shearBtⅡ℃sB di8tribution,q(X).
Thu8,uBingequations(A、15),equation(5)becomes
鶚-`-【…+卿]金作x愚)十箸:lIx1…(,Ix11(A18)whemKBndkaredeHnedbyequationB(18).
IflL=0,BothabtherBiBunrestrictedS1ip,?(X)=Oandtherea”twono-slippoints wh…AノーOatX=±0.404.
IIence
鼻_.=0.457[ん+K(l+化)]α/丘(A、19)43
662R、H=nTnwATLand
lfI4=cc,ムノiszeTothroughoutcontact.
。‐…+鰯)]而豊可孟十等;`(x'十厩1,(x))nowif
XX
q(x)=m「=うて可whereKisaconstantitfbUow3*that
-2K(1-増)
FMx))==- 8,.
F'Mx))=o
BothatequBution(A20)iBBatiBfiedif
,(x1-島[…+聡)]衾而当両fmmwhiCheqUation(A,18)giveB
(A、20)
(A,21)
11無職、
[〃+Ku+化)]'6貼豆+conBt4-。=〈A22)
whe”theconstantrefbrBtotheBtminintheBtTipasitemterscontacb・TobeconBistent withthebaBicaBsumptionofplaneBectionBremamingplanewemuBtassumethatthe BtripiBungtrninedjuBtoutBidethemp,BothabtheconBtantiBzero,IIowever,aBsumptionB ofthinBtripbehaviourbreakdownattheedgeofcontaCt(seeSection3)Bothatthe mnalysisi8unabletop"dict鼻一accuZately・
OtherlimitingsoluCionBamfbundinmuchtheBameway.
111.
1;III1111II
APPENDIX3
ZVi4n1criCqZf汎tegmzioTO
integmll4O(equation(11)) CO、⑨iderthe
Ⅲ。(蓋:;調…鵲
ワニz
l- o
心
ByitselLtheintegralconvergesslowly・However,theBituationcanbeeasedbymeuns ofthelbUowmgdevice・
ThehyperbolicfimctioninBidethBparenthesesconvergesatitsupperlimitto-l, henceweBp1ituptheintegralthus:
エュ。-:11$〒:;謡)…詫に['十ヒヨ:鍔)]…鵲-:111.…鶚Whero6issomeemaUvaluoofβasyetunspecined・
TheintegralnowconBiBtsofthreeparts;thenr己tiBcalculatedoveritBlimitedrange,theBecondpartconvergesrapidlyandiBeasilyevaluated,andthethirdpartcanbe mpresentedbyatabul&tedfimction(ref20).
Inte2“bingtwicebyparts,weobtain
r…鵲一等+鬘辮-遷圖…’where
…)-j;:露、竿。,
i#1mm:、
*nhtegrationofPoinbloadBolutionDTimoshenkoandGoodiern9
11,1
Anelasticstripinplanerollingcontact 603
α(8)istabulatedinintewBlsofOofO・2.6i8the鹿fbrDcoIwenientlychoBenBothatthealuoof2z6coincideBwithanexacCmultipleof0.2. ThoothcrintegralBmaybehandledinaBimnarway・ SincetheintegmlBdependon】yonthewUlueofz,orontheratioc/6,theycanbeused
lcalculationBfbrmorothanoneBtripthiclme餌.Forexample,ifaproblemisBolvedfbrairipofthiclm…B1withS=Si,thenthesameintegmlBcanbeusedinthoBolutionfbra iripofthidmesSB2,prm7idedthat
B B
s S (A、23)
CaIculation8werSperfbrmedontheUniverBityofCambridge Departmento8At1ascomputer.
Mathematical
l llI lI