x?A..J?-/67531/metadc54896/m2/1/high_res… · d % Ec Es Et e e= et ect Fe L M Me MO N h Rt s % S(j...
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‘i “ x? A..J?-.i ~A — /Q . NATIONALADVISORYCOMMITTEE FORAERONAUTICS TECHNICALNOTE No. 1105 STATICAND DYNAMIC CREEP PROPERTIES OF LAl!./mVATED PLASTICS FOR VARIOUS TYPES OF STRESS The By Joseph Pennsylvania ..-. .- ● I .-
Transcript of x?A..J?-/67531/metadc54896/m2/1/high_res… · d % Ec Es Et e e= et ect Fe L M Me MO N h Rt s % S(j...
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x?A..J?-.i~A
—
/Q .
NATIONALADVISORYCOMMITTEEFORAERONAUTICS
TECHNICALNOTE
No. 1105
STATICAND DYNAMIC CREEP PROPERTIES OF LAl!./mVATEDPLASTICS
FOR VARIOUS TYPES OF STRESS
TheBy Joseph
Pennsylvania
..-. .-
● I
.-
NATIONALADVXSORYCOMWITEEF(IRAERONAUTICS
m-es mTE No.
STATICANDDYNAMICCKEEPPROPERTIES
FORVARIOUSTY?ESOF
By JosephM,rin
1105.-
OFIAMINAT!EDPIAE?TICS
STRESS
Creep testis of fiveMmJ3na.tedplasticsweremadein thisinvestiga-tiontodeterminetheraLzti7ecreepymoyerti9sof thesematerialswhensub.lectedtovarioustypesof ste+.icELMdynszzlcstresses.C~ey defer-. __—mati.onsweremeasured%5determkwthevariationof thesedefomnatioaswithstress.Foreacht:% oftest,thestressvaluesinvestigated,coveredthestroesrangefromzswostressto theultimatestrengthofthematerial.Staticcreeptestswwe madefortension,bendingandtorsion,andthecreepbehaviorwe,sstudiedforfluctuatingaxislloadssuperimposedon statictensileloads.Ingeneral,‘hevariou~kindsofcreeptestsshowthatthecreepdeformationresfstan-everieswi~ theultimatetensilestrengthsofthelaminatesexceytforthetorsioncreep””testsof squarecrosssections.Attemptsweremadeto interpret thecreeptestresultsforthepurposeof oWai.ninga stress-creep ra’t re-lation.Thelog-log,logandkyprbolicsinemethodsof interpretationwereused. The ~reement%etweonthesemethodsof in’hmpmtationandthetentresultswasnotsatisfactoryso thattheresultsofthesein-terpretationsarenotincludedin thisreport.
In selectf~theloadstobe usedforthecreeptestsitwasffr~tnecessarytomakecontl*olstatictestsin tension,ccnnpression,bending,andtorsion.Forthesesimplestresstestsvaluesofyieldstrength,ultimatestrength,stiffnessemdductilityweredetermined,It WELSfoundthatthemechanicalpropertiesofa lsminateforonetypeof sim-plestres~exenotalwaysindicativeofwhatthepropertieswillbe foranotherkiniiof stress.Forexe.npie,itwasfoundthatthecottoabaselsminatatithalmostthelowesttensileultimatestrengthhasthehigh-esttorsionalultimatestrength.
An auxiliaryprogremofteetswasmadetodeterminetheinfluenceoi?repeatedstrem3ing,up toiOOcycles,on thestrength,stiffnessandductilityintensionendcompression.Threetyps ofrepeatedsbesstests weremade- repeatedtension followed by a testtoruptureintension,repeatedcompressionfollowedby a test to ru@mre in
a..
NACATNNo.1105
conqmession,andrepeatedtension-followedby a testtoruptureincom-pression.!Elereyeatedstresseswereup tolnm-thi.rd.sof theultimatestrengthsfcreachte:jt.Fra thetestresultsobtainednogeneralcon-clusioncanbemadeon theinfluence of prestressingon themechanicalproperties.
INTROUJCTION
Wkenmaterialssuchaslaminatedplasticsaresubjectedtoloads,thestz’ossesproducedareaccompaniedby deformationswhichincrease inmagnitudewithtimg.Thesedeforme.tions,calledcreepdefomnations,areinadditiontotheelasticdeformationsad mayOCCL-ati-lowstressvalues.Forsomematerialssubjectedto stresseskelcwtheyieldstress,creepdeformationsoccuronlyatelevatedtemperatures.Am Importantapplicationof steelatelevatedtemperatureisthesteamturbineforwhicha defiignstremmustbe eele:te~lmseii on a permissiblecreepde-formationthataliows oiiequateclearancebetweenthemoving~artsof’theturbine. Thedesigncrln”essesinal.rcrsftptitsusirgltinatedplnaticsmustalsobe Selectedsothatcreepdefo.rmaticriswillnotdistortthememberstoanundesirableextent. L
1Thepresenceofcreepinmaterialmsubjectedto stre~sinfluences
thetypeof stressdistributionandthemaximumstrsssvaluefor alltyyes of stressexceptsimpletensionandcompression.Forexszple,creeptestsinbendingshowthatthomszimumstresscalculatedusing
*
methodsdevelopedinthemechanicsofcreep(refereace1)w in somecasesbe abouttwo-thirdsof themaximumstress obtainedby theusual.elastictheoqy.It seemsdesirablethereforeto includeina comyleteinvesti~ationofc~eep,botha determinationandan interpretationofex~erimentaldataforvarioustyyesof stress.Itmaythenbe poqsibletoapplythesedatatotheforni’dationofa mechanicsofcreepqplica-bletotheyarticukz!materialinvesti~atud.
In theye.sijmostcreeptestsonplasticshavebeenmadeforsimpletension(rei’ereiwe2). Althmghtension-creeptestsmaygivea compari-sonofthecreeppropertiesforvarious plastics,thefactre~insthatotherkindsof streesesarepro~ucedinaircraftparts.Forthisreason,.theyresentinvestigationinclv.desa studyofthecreep-stressrelationsnotonlyforsimpletensionbutal-soforstatictorsion,static benu~jandstatictensioncombinedwithfluctuatingaxie.1stress.Testswerealsomadefordynemictorsioncombinedwithstatictensionbutarenotreportedsinceunreasonabletestresultswre ob+=ined.Specialequip-mentwasbuiltforthecreeptestsandiiimostcasescreepdefom??ationswereobsezwedforstressvaluescoveringthecoqleterangeof’stressesto theultimatestrength.
2
NACATNNO. H05
ControltestsweremA13on thefivelezdnatesin tension,compres-sion,torsicnandbendingtodeteminethemechanicalpropertiesofyieldstrength,Wtimatestrength,stiffnessendductility.Thepurposeofmakingthesetests~%sthree~old- (1)to selectstressvaluestobeusedforthecreeptests,(2)to comparepropertieswiththosewhenre-peatedstressiagwasused,end (3) ta provideamore [email protected]. .-
At thesug~estionoftheAirMaterielCommand,ArIWAirForces,testswerealsoconductedtodeterminetheinfluenceofrepeatedstress-ingin tensionandcompressiononthemechmicalpropertiesoftheVerioualaminatedplastics.
Thisinvestigationwasconductedby theSchoolofEngineeringofThe PennsylmniaState College underthesponsorshipandwiththefinan-cialassistemceof theNationalAdvisoryComitteforAeronautics.Mostof thetestswereccnductedin‘&ecreeplaboratoryof theDepartammtofEngineeringMechanics.Meaars.W. C.fi~hsndH.A,Albalawere,respec?tively,full-timeandpart-t=-researchassistantsforthisQvoject.Specialequi.pnents@.::~ecina~gWCO$emadeby.Massrs.S.S.Eclsley,E.Grove,andH. Johnson.FrofessorK. J. WJL2MSZ of theE.ngineerfngExperimentStationtisig-~dqecid- tension aid compre~sionStraingagesandgripsforthetensiontests.Professor F. G.Hechlergavevaluableadviceon severalproblemsimaluigtn.gthecontrolofhtidityforthetests. Dr.G. M.Kline,&ief oftheOrganicPlasticsSectionof theBureauofStandards,gavetechnicalassistanceonvariousphasesof theproject.TheadministrativeMrectiongivenby NationalAdviso~CommitteforAeronauticsandtheCollegeofEngLceeringendthetechnicelassistancegivenby theforegoingindividualsinmakingpossiblethisinvesii.gationwasgreatlyappreciated.
SYMBOLS
A cross-sectionalareaof specimenj..squareinches
b widthof crosssectionforbendingsyecimensjinches
c creeprateforallcreey
Cb creeprateinbending
Cs creeprateintorsion,
Ct creepratein tension,
D dlsmberof roundtorsion
tests
de~eesperinchperhour
inchesperinchperhour
specimen,inches
3
d
%
Ec
Es
Et
e
e=
et
ect
Fe
L
M
Me
MO
N
h
Rt
s
%
S(j
NACATNNo.3.3.05
depthofcrosssection fur bendings+pecimen,inches
moduiusofelasticityin
modulusofelasticityin
motiv.lusofelasticityIn
mmlu.lusofelasticityin
bending, youndsyersquaretnch
cccap~esslon,poundspersquareinch
shear,,PCWZXISpersqua&einch
t9rx3ion,pcun%syersquareinch
.m@itudeofmotionofeccent~ic weightsfordynsmiccreeptests,iachGs
strain; inchesperinchatruptuz-eincompression
Btrain, inch.esperinchatn’uptuz”eintension
creepstrain, Inchesperirr.hintension
totalsxialtensiondyn.amj.oforce, pcunds
g-e ler~fihor Gpemlength, inches
bendingmoment,inch-potis
massofrotatingeccentricweights,youndspereecondpersecondperinch
totalexialmassappliedindynamictests,poundspersecondpersecondparinch
numberof stressrepetitionsinreyea%dstrasstests
loadin staticbendingtestatrupture,pounds
ratioof statictensiontomaxinmmtensilestressindynamictensfcntes”im
generalsymbolforstressforalltests,powndspersquare
ultimate strengthsquareinch
ultimatestrength
(modulusofrupture)forbending,pounds
forcompression,poundsper squareinch
inch
per
.
b.
.
.
4
8
“
Ss
ST”
SycSyt
%
S*
St
Ts
rd.timate strengthsquareinch
‘ultimate”strength
NA~ATN NO. =05
(lIIOdliLUS of rupture)fortorsion,pounds‘per~”‘.-
for‘knsion,poundspersquareinch
yieldstrengthforcom--ressioa,younds~ersquareinch
yieldstre~thfortension,pow.xlsyersquareinch
statictensilestressininch
shearstrqssfortorsion,. .,
@2amiccreegtest+,poundspersgmre.-
creeptests,poundsyersquareinch
tensionstressfortensicncreeptests,pounds
statictwi.stirg~T@rLt atrupture,inch-pounds
W. ‘[email protected]&nemrlctension
x~ deflectionin sta’~icbendi~te8tsa’%rupture,
.—
persquw~’inch “
teBtEl,golxde ,.
inches,,..-..—
e angleof $tistin statictorsiontests,degrees ..-
Lu frequencyofsecond
forcedvibrationin dynamiccreeptests,radiansper .—...-_
degrees —
DESCRIPTIONOFMAZERIALS—.,.
FivelE&natedplasticswereselectedforinvestigation:
1.2.3.4.5’.
Glaasfa_&ic.lam&atewithpolymerizingt~peresin(G)Hi~hstrengthpaperbaseplastic(P)
--.-.—.---——
Highstrengthraydhl~inatewithphenolicresin(R)GradeC phsnolicrecinWminato(C)CottonfabriclaminateasusedinGradeC butmolded~th
lowpressure(CL)
Forconvenienceinreferringtotheseplastics,thelettergivenh tiebracketsabovewill.be used..Informationregardingthemanw%ctureofthelmhates as suppliedby themanufacturerisgivenintable1. All~ .thematerialstested,excepttheglasslaminate(G),werecross-la.ridkted,
5
NACATN NO. 1109
Table1 givesvaluesofthickneesanddensityof thelaminatesandin.formationregardingtheresin,reinforcement,and.moldingcontlltions.
TEST2?RO(IEDURE
(a)Static‘Zests
Standardtension,co?gpresslon,andbendingtestswaremadeas out.linedir.theFe&ralSpecifications(reference3). ThedimensionscompliedwiththespecifiedvaluesexceptthatthebendingspecimenswaretestededgewisesinceItwasnecess~ to testthecreepbendingspecimensedgewise.Statictorsiontestsforbothsquareandroundspecimensweremadein,orderto determinetheloadstobeusedforthetorsioncreeptests.Foralltests,thespecimenswareheldat ~percentA 2 percent-relativehumiditysndthetemperaturewasmain-tainedat77’OA5°F’duringthetestand48hoursprevioustotesting.Thetensionandcompressiontestsweremda ina 50,000-poundUniversalOlsenmachine(fig.1). An enclosurewasconstructedaroundthetestingmachineas shownsotlaatairat ~0percentrelativehumiditycouldbemaintainedby a pipeconnectionfromthecreeplaborato~.Thisprovi-sionforcontrolledhumiditywasparticularlynecessaryfortherepeatedtensionandcompressiontestssincesow of theselattertestsrequired
t.
severalhoursforcompletion.
Forthetensionte~ts,syecialgripswereconstzwctiedwiths~hericalm
seatstoensureaxiallyappliedloads(fig.2),andthedeformationswaremsasuredby a speciallydesigned,,averagingtypestraingage(~lg.2)readingto 5 X 10-6inch perdisldivision.Thegagelengthusedwas2 inchesandthespecimsnswareabout3/8by 1/2inchincross-section.Load-strainreadingsweretakentoruptureforat leasttwospecimensofeachlambate,Whena largedifference”intheresultsoftwotestswas
—
obtained,marethantwotestsweremade. <
Forthecompressiontests,sphericalseatsanda syeciallydesigna~averagingtypestraingage(fig.3)wereused. Theaccuracyof thestraingageusedmeetstheFederalspecificationragprirementby readingto 4,8$Jx 10-4inch strainpargagedivision;Thegagelengthusedwas1 inchandthecross-sectionaldimensionsofthespacimanswareabout1/2by 1/2inch.Load-strainreadingsrarerecordedtoru@mreforatleasttwospecimensasforthetensiontests.
Forthebendingtests,specimensabout1/2~ch @de by 1: Inches— —-deepwer6loadad’at-midspan,Thespecimenswereloadedin theedgewiseyositionsincethecreeptestspacimensweresoloaded.Thesyan-dapthratiowasabout7. Daf’lactionsat themidspan~ra measuredwitha dial
●
6.
.-
NACATN No.1105
gageroattt~to 0.001inch.Readi~scf lbadandcord6d‘truptureforatleastthreespscimqnsof
deflectionsw~re.re-.each~terial.
Stattctorsioa+x2i3ti3were rimde so that torsionloa~valuescouldhe—selected t’Grth9 toraicncze9-ptcmts.ThetestswereA in thetor.sioncreepmachineshowninfigure9. 6~ecti-nsof?mthrov..t.mtEiASqUaZp. ._cross sectionswez*eteatelsincecreeptestsusi~ bothki@8 ofcrcmssectionsweremade. !l?heround. specimenswereab~~t1/2inchin&hmeter”ad thesq~a speci.m.easwereabout1/2by 1/2inch. Thea~le oftwis~wasrneasuxedto ().I.ofora gegeLeagthof 6 inchesfcm?mthtypesofspecimens. Lm3il-amgleof tznl.strea~~~sweretakentorupturefcratleastthreespacimnscfeachlaminate.
Forthetendon,compressionandbendingtests,thereadingswere.taken*’onthem“ andtherateof etraj,nusedwaswithinthevaluespecifiad’bytheFedezmlSpecifics.t~ous(reference3). Thesceleleadintervalcm ihe‘bstingmachineswas5 pmnds andthetosti~ m.chimwascalibrated.
(b)RepeatedStressTaats .;.
St~da..dsizetensionamiconqyessionspecimenswereusedto stu~theinfslaenceoiirepeated.stressesonthemechanicalpropertiesof.thelsminatesin tensionandcompression.Thetypfisof repeatedtests-dewere: repeatedtensilestressing,followedby testi.~toruptureintension,repeatedccmprossivestressin&followedby testingto ruptureticompress~.on,andrepea’~dtensilestressi~followedby testingtorupt@’ein compression.In alltests,thenumberof stressrepetitions(N)was100andthemagnitudeof themaximumstressd.ur:ngthaserepetitio~qofstresswastwo.-thirdstheQtimatsstress.Somatestsweremadeusingsmallernumbersof stresscyclesand.lowermaximumstressesbutthere-sultsof thesetestsarenotincludedsincetherewasnegligibleeffect.on thestress-strainrelations.&ly twotestswmremad~foreachtypeof testandniaterialwhentheultimatestrengthvalues checked,butcreeptestswererunin casesof discrepancy.For-thetestsinwhichrepgatedstjjgsf~intensionwasfouowedby a compre88iontest,aspecimenabout2 incheslongwascutfromthemiddlepartofthetensi~specimentopermittestingthematerialZncompression.Forthe~-pSated.tensiontests,load-strainrea~ngswereobtained,on thefirstreductionofloadfromtwo-thirdstileultimatestressto zerostresssothat~steresiscyclescouldbe plotted.
(c)CreepTests r—
All.creeptestsweremadeinq roominwh~chthetemperaturewas77°Z 5°F =d tiere.ktlvehumidity50percent~ 2 percent.The
7
NACATN NO. 1105
humiditywasmaintainedconstantby.mean~ofbotha humidifierenddehu-midifierhavi~ auixmaticcontrols.Statictension,staticbending,statictorsion,andi@naEcLccrsepte~tsweremadetodeterminethestress-creepdeformatlo~.relatimsforthesevdrioustypesof stress,
.
.
Thestatict~micgcreeptestswareUde usingthetwo-levertype—-,tensicmcreeptestir~machinesshowninfigures4 and5. By meansofthele-iez-loadl~.systemus9d,a constantstresswasmaintainedona~~ecimndw-lnga tsst:Thecree~tensions~echenshadthe,s~ -n--”sionsasths standardtencionspecimeasexcaptthata longerstraightsectionw-asyrovidedw%d.chgavea gagelerstlnof10.inches.Thiein-creaso~gagele~@lloneuredincreneedaccuracyInthe’creepstrainread-ings. Thecreepstrainsweremeamzzedhymeme of’a straing~e usingmicrometermicroscopesas showninfigure6. Target”’pointson thesyecimsnswereprovid.ed.byusingblackIndiainkdotsona whitepaint6dlmckground.!Knetotalcreepstwainswe~emeasuredto0.00002inch.
Staticbendlnqcreel?testsweremadeusingsyecimens1/2inchwideby l:~e inchesdesp.T& testswereco@uctedin themachinesho-wninfQure 7. A singlecreepbendingunitis showninfigure8, lll.uetcat-inghowthespecime,ni.~subjectedtoa pJre ?mzili~ momentfreefromtraneversoshearstremes. Crwp deflectionsweremeacuredovera 2-inchgagolengthby meansofdialgagesreadln~to0,0001inch.
~tatictorsioncreeptestsweremadeonlmnina~gR, ~ andG, usingbothround(1/2in.diameter)andsquare(1/2by 1/2in.)specimens.Al-thoughthexoundcrosssectionisthetypeusuallyusedinmat9rielstestin~,theitiluenceofthebindingmaterialinl,tiuatesis differentin squareandroundcrosssections.Fortiiisreasonbothtypesofcrosssectionswereused. Thetorsioncreeptmstsweremade,usingthefour-unitmachineinfigure9. Theloadingarmsmgemmtconsistsofa deadweightappliedtoa pulleywhichproducespuretorqueon thespecimenbymeansofadequatebearingsupports(fig.10).. Theangleoftwistwasmeasuredovera 6-inchgagelengthbymeansofa twistmeterwithavernierreadingtoO.1O,
btc’ tensioncreeptestsweremadeusinga hypocyclicoscillatortypedynamicmachineas showninfigure11enddescribedin reference 4.In thesetests,a statictensileIoadwasappliedtothespekimenbyweights(fig.11)anda superimposedfluctuatl~axialloadwasproducedon thesyectinby theoscillator.Thecreepelo~ationsweremeasuredfora 7-inchgagelengthusingmicrometer~tcroscopesasforthestatictensioncreeptests.Thecapacityoftheoscillatormadeitnecessarytousespecimensof smallcrosssectionsabout0.25by 0.10inch.Duringatest,hnatingof thespecimenwaspreventedby theuseofcirculatingairproducedby a fan.
In all creeptests,initialstrainreadingsof thecreepmeasuring
.
8
NACATNNo.1105
.
.
instrumentswererecordedbefo~ethespacixanwasleaded.Afterloadingthespeeimens,theirfitlaldefozvnattonwasrecorddia.ail.readingsofthecreepd.efcxrmatioaswelwnotedat sei9cteaintervalsct tim throu@outthelifeofthetegt.?HIOstatictension tests covered & periodof l@Ohours,thesta.tfcbendi~andtccrfiton1000hours,andthedynemictensicn200hours.Itwasnece~sarytousetheshcrterpsxiodoftimeof200hours~ortheLyec tensioutestssinceml.yonesuch‘%sLcmld be
--
runat cnetime. .L—’
Creeptestsalsoweremzdeon specimenssubjectedtofluctuatxtorsionS~yerimp@sedon statict@nt3iG~.TAoi’~~titsOf thesetOStSwereeYT:atiC,antiunreasorablovaluesforthedynamicshearstresswereobtaine~basel.on theu=asured~leQ of twist.It isprobablethattheerrorsintrmlucstwerein th3mafisureilan@es of twistresultingfromtheuseof s-pecimenswithsmallcrosssections.T% resultsof.thessdynsmiatorsioncreepunreliable.
had-deformationandtor~ic.nteetsare
testsareomittedfwu thisl*apox*tsincetheyare
!?3s72Iw3TmTs
relatiGnsforthetension,compression,bending,showninfi~Q.l?OS12,1.,14,15,and16,rSS@C-
tive~. FmM tkesegraphs,andwhereit;.ns~oseible~thefollowingmechanicalpropertiesweredetemirmd:(1)theyieldstrengthdefinedby 0.2perbentoffsetstrain,(2)theultimatestre,ngthormodulusofrupturs,(3)thestiffnessas definedby thesecantmodulusofelasti-cityend(4)theductilityas defiaedby thedeformationatrupture.
Th9valuesof thepropertiesfortensionandccmqnression,obtainedfromfigures12and13,arelisted.intables2 and3. ThesecantmGdu-lusvaluesgivenem basedontheslopeof thelinebetweenthepointsof Zei”osad70C0Foundspersquareinchstressvalues. —
Thevaluesof themechanicalpropertiesforbending,as obtainedfromfigure14,a~egivenin table4. In table4,theulti=testrength(modulusofruyture)andstlffrmsswerecalculatedonthebasisthatthematerialobeysEookers‘Lawin tensionandcomp~essionandthatth6mate-rialishccmgwneousanlelastic.Thatis,theultimatestrength(~)andstiffness(~) arerespectively . —
3~bL*=— (3)
2bd2
9
l’iACATNNo.1105.
.
(2)
whbre
load at ru~ture
loadcorxesyonding
spanlength
widthofspecimen
depthof specimen
Pb‘L3%=
4ybbd3
to a stress+ equalto’5CO0psi
deflectionconewponding
TM ductilityinbend3ngdeflectionatrupture.
to load Pbl
—
isgivenintable4 intezmeof thecenter .
ThemechanicalyroTertiesintcmsionas determinedf~omfigures159
and16forbothroundandsquaresyecimensareliitedin tables5 and6.Assumingforcomparativepurpo~esthattheultimatestrength(modulusofrupture)canbe determinedby thetiaeo~yofelasticity(reference5), .theultimatestrength(S~)forthesquareemdroundcrosssectionsarerespectively
m‘sSs =! (3)
O.208t3
5.08TSss.—
D3
where
T~ twistingmomentatru@_zre
t cross-sectionaldimensionsofthesquaresyecimens
D diameterof theroundspecimens
(4),
*
.
10
NACATNNo.1105
Thestiffness(Es)is determinedintables5 and6 basedon thesecantmodulusfora stressof 2500ysi. Assumingthetheoryofelastic-ity,thevaluesforthestiffnessforthe‘squaread roundcrosssectionsarerespectively
where
Ts~ twistingmomentequation(3)
Es =
Es =
correspondingor (4)
es angle of twist indegrees for
L gagelength
407LTsT(5)
t4 es
584LT~’
(6) _D4 @~ -...
toa stressequalto2500psiusing
torque(Te!)
Theductilityvaluesintables5 end6 are theenglesof ttistatrup-turefora 6-inchgsgelength. —
A cmparisonof themechanicalpropertiesof tileffvelaminatesi~givenintable7 basedon100percentforthehighestvalueof themechanicalpropertyconsidered.
4
(b) RepeatedStressTests
Theload-straindiagramsfortherepeatedstresstestsare@veninfigures12,13,and17. Infigures12and13,theload-straindia-gramsaregiven.Thesediagramssredesignatedfor R = lCO, where Nisthenumberof stressapplicationstotwo-thirdstheultimatestress.Thevaluesofthemechanicalpropertiesoryieldstrength,ultimatestrength,stiffness,endductilityas obtaineafrom the load-etraindia-grsmsaregivenin tables8,9, and10. Thevaluesof these~rqm?tiesweredeterminedinthesamemannerasforthestatictests.usingvaluesfrczutables2, 3,8, 9, and10,thepercentchsmgeinl?roPertiesproducedby repeatedstresswas calculatedan~listedintable11.Hysteresiscyclesintensionwereobtainedas showninfigure18. Theareaboundedby theload-strainlinesisproportionaltotheener~dissipatedper cycleof stressandis ofpracticalinterestsince this
—
11
.
I
energydeterminesthedampingyropertlesofthe’material.Thevaluesoftheseenergies,as obtainedfromfi~-e 18andexprsesed~ninch-youndspercubicincharegimn intable12.
(c) Creep Tests
Thestatictensioncreep-timerelationsareplottedinf@ures19to 23forthefivematerialstested.Thestrainsperinchofgagolengthwerecalculatedfromthemicrometer.microscoyereadings,a.zdthevaluesplottedincludedboththeelasticandcreepstrainsinccaupliancewiththeusualpractice,In thecreep-timeplots,theteststhatdonotcover theentirete~tingtimeasshownby a solidor dottedlinsinikt-catethatthespecimenruptured.
Thestaticbendingcreep-timediagramsplottedinfigures24to28areshownIntermsoftotalcreepdeflectionfora 2-inchgagelengthsincethecreepdeflectionwasmeamredfpra 2-inchgagelengthandthedeflectionIsnotproportionaltothagagelength.
Thestatictorsioncreep-timegra~hsaregiveninfigures@ to 35formaterialsR, l?,anCLGasrequested.Theserelationsaregivenforbothroundsndsquarespecimensintermsofcreepangleof twist~rinchgagelengthversustimeinhoum, Thestressesshownforeachcreeptimegraphinthebendi~andtorsioncreeptestswere ccmzputedusingequations(1),(3),and(4).
.
●
.
Forthedpamictensioncreeptests,theunitcreepstrain-timegraphsaregiveninfigures36to 40for various valuesof themeanorstaticstrees(~) a~plied.To determinethevalueofthe-c sxialforce,thefolloviagequationobtainedfromreferenoe4 wasused,
we c302cos q)
“Fe=MOL ;
1 -—00E.hA
where
Fs totalsxialdynamicforce
Me massof therotatingeccentricweights
(7)
P
.12
A
&
.
..
s
.
,,
amplitudeofmotionofstationary
NACATN NO, 1105
the eccentricweightswhentheoscillatoris
frequencyof thefoi>cedvibration
.ghasean@
static”“miialusofelimtf.cityin tension.,
‘total’massbppliedincludi~eccentricweights(We/g).,
,overtialllengthof specimen
The”maxizuomtensilestressthen,., ,. ..,,.’.-
,,.,’ ,,’
andthemeanstaticstress
,,
,,
azpliedby the‘stati”caiiddynamicforcesis
—
is
W.
%=— (9)A.,.
,,‘,
Thevaluesofthemsximumandme= stressesStt and ~ cd.thesttiess~“atiosRt = ~Stt aregivenin table”17foreachtest..Forcomparisonof%hedynamiccreeppropertiesof thefivelaminatesitwouldhavebeendesirable.tomaintainthestressratioRt constantforidltests.Becauseofthenumberofvariablesinfluencingthedynamic“forcevalue Fs (seeequation(7)).itwasnotyossiblet~fixthevalueof theratioRt. However,exceptfortheG material,thevaluesof Rtvariedo- a slightmount fromtheaverage“vdqeof0.64.Forthli”reasonthecreepdataforthelaminates qsn be compsxed. ....
Thetypesillustratedin
offractures‘producedinthestaticandcreept6stsWfigures41 to47,
13I
NACATNNo.1105
ANALYSISANDDISCUSSION .
. . .
An exsminati?onof thevaluesof themechanical‘propertiesinten-sion,compression,bending,andtorsion,asgivenintables2 to7,showsthatthepropertiesofa particularls.minatearenotequallyasgoodforalltypesofstress.Forexample,table7 showsthattheGlaminatehasthegreatesttensilestrengthandtheCLmaterialtheleast;whereasfortheCLmaterial.,theductilityisgreatestandfortheG leminateitisleast.Also,forbothcompressionandtending,althoughtheG materialhasthegreateststren@h,theCLmaterialhasthebestductility.In torsion,table7 showsthattheC leminakhasthegreatestultimate6tren@hwhiletheR materialhasthebestductil-ity. Apparentlythechoiceoflaminatedependsupontheparticulartypeofmembertobe designed,thetypeof stressinthemember,andthestrengthandductilityrequirementsthatareconsideredadequate,Itshouldbenotedthatthedeterminationof themechanicalpropertieswasasecondarypurposeinthisinvestigation,andanexactcomparisonwithprecisetestresultswasnote~ected.
Theinfluenceof’repeatedst~s%ng UIAUOcyclesonthetensionandc~resslonpropertiesis shownintable11, l?ositivepercent~evaluesgivenrepresentanimprovementin theparticularmechanicalprop-ertywhilea negativevaluerepr~sentsa decreasein themagnitudeof
.
theproperty.Froma comparisonofvaltiesintable11thefollowing ““analysiscanbemade: .
1.Fortensionstressingfollowedby a tensiontest.-Theinflu-enceonthetensilestre@h wasnegligibleforalllaminatesandtherewasa decreaseofalout 25percentinductilityandstiffnessforthe i
CL,C,andRlaminates,andan increaseinyieldstrengthforthesemate-rials,
2.ForcomwessionstressinR followedby a compressiontest..The.—influenceonthecompressivestrengthwasnegligibleforalllaminatesandtherewasem increaseinyieldstrengthfortheC,R, andp lami-nates.Thestiffnessofthe.CL,~and J?materialsdecreasedsndtheductilitydecreasedforalllemdnates.
3.Fortensionstressingfollowedbya compressiontest.-FortheCL,C,pndG laminatestherewasa ~creaseincompressivestrengthandductility,whilefortheP materialtherewasa slightincreas8.TheyieldstrengthoftheCL,C,andRmaterials,“increasedandthestiffnessof theselaminatesdecreased.It shouldbenotedthatinsomecasesthepercentagedifferencesgivenintableJ.1arewithinthedifferenceob-tainedfromtwostandg.rdtests.Limitedtimepreventeda morethorough ,studyoftheinfluenceofrepeatedstress.Thatis,itwouldbe desir-abletoconsiderintermediatevaluesof.numberof stresscyclesandotherr~es of stress, . . .
Ilk
NACATNNO.1105.
8.
.
“
.Thevaluesof’theener~ dissiya.tedpercycle&uringstressingintensionto two-thirdstheul.tinktestressaregivenintablel$?.TheTalues listedafiowthattheR and1?materte.hhavethebestdampingproperties.T@ G nterialhasthepoorestdampingvalue,havingonQabout17~rcentofthevaluefortheR itil~fite.
Valuesofthecreepdeformationsforthedurationof thetests,asobtainedfromfigures19 to ~, arelistedinthalastcolumnof tables13to17. Table18givesthecreepdeformationsforthevariouslami.natescorrespondingtoparticul~stressvalues.Thecreepdeformationsgivenintable18wereobtainedby plottingvaluesof thecreepversusstressasgivenin table~13to 17,ed repressntapproximatevaluesonly. Therelativecreepcharacteristicsforthevwiousmaterialsun~tensile,bending,torsion,anddynamic‘tensionareindicatedalsoappro~imatelyby thecurvesgiveninfigures~ to52. An exsminatioaofthecreey-stressrelations for varioustypesof stressshowsthatthecreepresistancevarieswiththeultimatetensilestrengthof thematerial ex-ceptfez”the torsioncreeptestson squareEpecimens.Thatis,thematerialcreep ratingisin thefollowingorder:G, P,R, C, andCL,withtheG laminateliavingthehighestresistancetocree~.The___tudesof thecreepdef’ormhtionshavea widerangeforthefivela@nate81Forexample,‘thecreepdeformationundera statictensilestressof 6000PS*,for.the,Gmaterialisabout5 percentof thatfortheCL.mterial.I?or.a’bendiagstressof 6000psi,thispercentageis about 10. “The-c creel? tensiondatashowthat,foramean stressOf hooopsi,thfi”creepdeformo,tionof theG materialisabout10percentof thatfortheCL laminate.
---
TheforeGo@ comparisonof c~eepboh~viorisbasedonperiod~oftime coveredby thetests.It isimportant,however,to detmmincamoansof extrapolationof thedatawhichtillgivem“approximationofwhatthecreepdeformationwillbe forperiodsof time~eaterthanthouecoveredby testsanda proachi.~theesttitedlifeAn service.Inpublishedinvestigations?reference2)onplasticsdoali~nti.thcreeptensiontests,m commonmethodhasbeentoslotthecreep-timedataon elog-logplotandtoassumea linearrelationbetweenthecreepdofo-- ..__tionsandtimewhenplottedinthis~. Thatis,At isassvmndthat~ora particularstressvaluethecreepis et z.=kt , where t isthotimeand k and n areqperinentalconstants.Withsucha ralati.on,thedataCarL he extrapolated. end th creep eb cm be dmterminod fortimevalues t not covered by thetest.
.—Unfortunately,thiscreep-t.trm
relationisnotadequateforthedataoltainedinthtsreportexceptforthestatictensi~CreepTesfits.For thisreason,,md in Ortirtodeterminea creep-stressrelation,thelog-log,lcgand ~perbolfcsinemethods[reference1) of interpretationwereappliedtothetesttiti.___.__Allthree~thodsof intcmpretaticmassumea constantoreeprateso that,wherenecessaq,straightlineswereassumed.torepresentapproximately
NACATNNO.11.05
thecreep.t& datainfigures19to 40forperiodqoftimebeyondtheinitialcreep.An irmyecticmofthesefiguresshowsthattheap~roxima-tionof thedataby-straightlinesformgstofthelowerstressvaluesisgoadexceptforthetensioncreepdata.Forthehigherstressvaluesthereisa,divergencofroma straightline,It ,shouldbenoted.,how-ever,thatthesehi@er stressesarebeyondworking~tiessvalues,Theslopesoftheass~edstraightlinesInfigures19to @ arecalledthe
,’ crecrpratesandtheirvaluesado~imn intables13 to18. Thethreemethodsofinterpretationwwe appliedtothefivematerialsandfourtypesof creeptests.Creeprate-stressrelationsobtahedshowedthatno oneofthesemethodscouldle consideredtole mfficientl.yaccurateto interpretthetestdata.Forthisreason,theseresultsarenotin-cludedinthisreport.
CONCLUSIONS
1.Therelativovaluesof themeohanlcalpropertiesofthelami-natesintension,compression,lending,aridtorsionarenotinthesameorderforalltypesoftests.
2. The effectofreTeatedstressingto100cyclesintensionandcompressiononthemechanicalpropertiesvaried.Formosttests,how.ever,therewasa decreaseinductilityandstiffness,andan Increaseinyleld.strength.
3. Thecreepresistanceofthelaminateswasfound’tovarywiththeultlmatetensilestrengthforalltestsexceptthetorsion-creeptestson squarespecim9ns.
.
EngineeringExperimentStation,ThePennsylvaniaStateCollege,
StateCollege,Pa.,April1946.
16.
.—
NACATNXO.110~
1. Marin,Joseph:Mechanicall?ropert~.esoflta~trialsandDesign.McGrww..iIillBcokCo.,Inc.j 19;+2.
2.FindLey,W. N.: CreepCharacteristicsofPlastics.SympcsiumonPlastics,puhliskedby theA.S.’l.M,,194L,-pp.118-134.
3.FederalSpecificationsforPLastics,Or~anic;GeneralSpecifications(MsthodsofTests)- L-P-~iC6,Jan.24,1934.
4.Lazan,B. J.: SomeMechanicalPropertiesofPlasticsandMetals ,.UnderSiitaimdVibrations.Trans.A.S.M.E.,TOI.65,no.2,Feb.1943,pp,87-98,
5.Timoshmlco,S.: TheoryofElasticity.NCGTaW-Hill BookCo.jInc.,1934.
BIBIZOGRAEIY —
.PlasticsforAircraft.ANC-17,Arqy-Navy-CivilCorn.onAircraftDesign
Criteria,July23,1943. .—
. Nadai,A.: TheInfluenceofTimeuponCreep- TheHy_perholicSineCreepLaw. P. 155ofStephenZ!imoahenko60thAnniversaryVolume.Theht3CtilklZlCo.,1938.
-.
17
.
i.
.
.
NACATN No.1105
TABLE1 -DESCRIPTIONOFLAMINATES
Laminate CL c R P G
Cons.WatezManufacturer Synthane Synthane Formica
Corp.Power& Pa., ---
Corp. Ins.Oo, perCoe
Thiokness(ln~) 0.536 0●l+.76 0.491 0.509 0.505
Densi.ty(gm/cm3) 1.29 1.36 1.37 1042 1.87
Type Phenollc Phenolic PhenolicPhenolto UnsaturatedPolyester
5 Identifica. Bakelitem Bakellte 91-L Bakelite Plaskontion BV-16.887 BV-111.2 NO.16526
2900
Con:~ntby $+$ 51 47 37-90(no%al)
43
KindofFab. May Army Rayon.aot- Paper Glassfabriz rac Duok Duck tonf’abri.c Heattreatel8~ PlyArrange. Crossed Crossed Crossed Crossed Parallelment2h: FabrlaWeave --- ..- 3/1Twill --- ---2 .
Fabrh t.-Y 10.38 10.38OZ/yd 1.2.5 --- -“-
MoldingPres- 180 1800 1100 250 40sure(pos.l.)
3 ‘O1?%?‘emp”320 320 320 310* 10 180-220
32 TimeofCyole~ (rein)for
50 50 --- Faatas 2hrs.atpossible 160°F
g heating 2hrs.at180°F
g 2hre.at~ 200°F
2hrs.ats 220@FTimeofCycle --- ---(ln~n;r
20 Cooledin -s-till airat75°F
18 .- .
.
.“
.
*
.
.
NACATNNo.1105
TABLE2 - MECHANICALPROPERTIESIN STATICTENSION
-.
Yield Ultimatelat. Spec. Area Strength Strength Stiffnee
8’Euotll%ty
Ho. A;Kl 2
Etx10- 100eTsq.in. %
1::;;k k;:: ~~~ ~
c):~8 5*5CL 2 5*5
Aver. 5,100 0.6 5*5
0.177 5,100 11,300 :::4 3*3c i 0.177 5S700 11,300
z3.7
Aver● 5,m 11,300 009 3~5
0.180 7s700 2 ,000 1.48 304R 2 0.184
k b7,00 2,00 1.45 3.4
AveP. 7,00 , 00 I*47 3.4
00190 1 ,300 25,200 2.58 1.4P 2 0.190 2i
800 25,200 $:% 1.5
Aver. 21:00 25,200 1.5
0.188 ;7:~:: 3 ,3002 ii
k$:91.5
G 0.189ii
3 ,2005
1.5Aver. 3 ,300 3 J3°0 2.5 1.5
TABLE3 - MECHANICALPROPERTIESINSTATICCOMPRESSION
Yield UltimateMat. Spec. Area Strength Strength Stlffnes
tIhlcti.lity
No. A%
Sc Ec X 10- 1009Csq.in. p? pet psi %
0.279 0.682 19
, 00 21,002
1.4CL 0.277 , 00
?21,00 0.5
11.2
Aver. 7,00 21,600 0.6 1.3
0.236 8,500 21,200 “ 0.77 1.0c $ 0.238 8,100 21,1+oo 0.7z
Aver. 8,300 21,300 ;:% 0.90
0.254 8,400 19,200 107 0.40R : 0.252 8,200 19,600 zh 4 0..44
Aver. 8,300 19,400 1.71 0.42
Us$ 10,600 19,800 2.39 0.47P : 9,800 19,900 2.71 0.45
Aver. 10,200 19,900 2.55 0.46
1 0.258 40,800 40,800 2.97
ii
0.1G 2 0.264 41,000 41,000
40,9002.81 0.
Aver. 40,900 2.89 0.
19
NACATNNo.1105w- MECHANICALPROPERTIESINSTATICBENDING
UltimateStrength
‘fPa
Mat. Spec.No-
Widthbin.
Depthdim.
StiffnesEb X 10-~
psi
Ductility
12
O*5470.5420.545
0-473004730*473
0.4810.4810.478
0.5050.500.50i?
0.506::;*;
16,700
k16,0016,0016,600
;3Ave??.
:3Aver.
:3Aver.
23Aver.
23Aver.
1.I.221.1.210I2?
1.151.d1.15i
i:E;1.121
1.1.27;:gz
1.1171.1631.*
0.79009$007
0.82
0.43009J?003
Oe@
CL
c
R
P
G
00930.930.930093
0.310.3003i?o.%
k31,0029,0031,90031,000
1.581.581*51058
O*JJL00370.39O*39
31,1003.2,10031,10031,~oo
0.160.10.1ii0.17
H3,004?;6%49,200
2.392,52.iz2. 3
O*210.20O*2O0.20
~Valuegivenis averageof6 testscmspeeimena1/2Wx 1/2”x 6nspan* w
9ELiui.- MECHANICALPROPERTIESINSTATICTCRSIONSquareCross-Sections
StiffnessEs x 10-6psi
UlttiateStrength
‘fpa
Duotllityes
de&?eesMat. Spee.
No.Dimen.tIne
O*110.130.130.12
:3
Aver.
;3AveP.123
Aver.
:3Aver.
23
Aver.
0.5210.28?o.21
0.480.48T0.487
0.4913
0.400.44
0.5060.5060.507
0.5020.5010.508
CL
o
R
P
G
0.20.2!?0.280.260.250.230.190.22
0.360.360.360.36
5,9005,00‘i5,00
5#700
.
.04.600510.560.51
60606261
7$300i,100,2007850020
NACATNNo.1105
TABLE6 - MECHANICALPROPERTIESIN STATICTCRSIOl?RoundCross-Seoti.ons
T31tlmateStrength
‘fps
Dia.
i:.
Sti.ffnes!!!Es X 10- .
psi
Ductility&
degrees
Mat. Spec.No.
~ 80;
4,8004,800
8,400
i
7,007,007,00
180170:
3Aver.
:3AveP.
23Aver.
;3Aver.
;3Aver.
0.5020.5000.501
0.4.440.430.46i
0.4760.470.47t
io.010.800.485
0.00?3::42
0.;:0.260.26
0.350.310.260.31
0.190.200.210.20
0.400.380;360.38
CL
c
R
P
G
175
110115112112
60&38;38
.
.
~- CCMPARISONOF MECHANICALPROPERTIES
FCRFIVE
1RatTypeofTest
Tension
Compres.aion
Bending
Torsion(round)
Torsion(Square)
-7—Kat. Mat.
— —
UltimateStr-.GYieldStr. GStiffnessIGDuotilitiy CL
100100100100
CLCLCLP
RCLCLG
::P
RRP
RCLP
UlttmateStr”.GYieldStr.StiffnessI:Ductility CL
UltimateStr.GStiffnessDuotiility
I;L
100100100100
100100100.
.
UltimateStr”.CStiffnessDuctilityI :
100100100
UltimateStr.C
~
100100100
— —
NACATNNo. 1105
TABLE8 - MECHANICALPROPERTIESINT@LSIONAFTER
100STRESSREPETITIONSINTENSION
TO 2/3UL5’IMATESTRENGTHYieldStrength
%2P
UltimateStrength
Stpsi
Eiona:
0.58005&
0.40d00 7
00480.47z
0,5100.513
0.5020.506
Speo.No.
Stif’fnef3EtX 10-t
psi
Mat.
CL
c
R
P
G
6,2006,3006,300
0047
Bo* -0.
0.650.770.71
c)::;
1,01
2.27
%$8
::;z
2.69
pot4*42,2.22.6
2.62.82.71.1,t1.6
1.21.41*3
D.3760.377
2O*37O*33
0.3720.372
O*34z0.31
0.3660.366
z,000,9009,000
10,50011,20010,900
24,6002 ,0002’?,800
27,30027,20027,300
35s9008
35#0035000
:Aver.
:Aver.
;Aver.
;Aver.
:Aver.
z7,007,007$90022,50021,90022,200
23,10022,00
ii22,00
35,90058q,oo3,00
.
.TAME ~- MECHANICALPROPERTIESINCOMPRESSIONAFTER
100STRESSREPETITIONSINOOMPRESSION
TO2/3ULTIl@%TESTRENGTH
HeldStrength
%!P
UltlmateStrengthsopa3
Mat. Dime]
1:.
ions~
Sw.ffnesE* x lo-gpsl
Duotillty
$
00490.498
0.4820.478
0.4800.482
oo4990.501
0.5010.500
005490.550
00490.49i
c):goJ
0.5000.504
0052900500
20,80020,80020,800
21,20022,00
321,0019,10019,20019,200
19,700
?;j%
36,50038,000379300
1Aver.
7,000
2,200,100
?I!, 00
110;6%14,00
!?ii?,0013,300
15,00015,40015,200
36,50038,000379300
22
0.55O*50.5z
0.87005?!0.1
0.981.361.17
1.431.311.37
3.353.3.1?
0.30.80.7z
CL
c
R
P
G
:Aver.
o●&0.’70052
2Aver.
;Aver.
0040,z0.&
.
.2Aver●
0.110.110.11
.
.
.
.
.
Mat .
OL
a
R
P
G
NACATli~0. 1105
TABIE10- MECHANICALPROPERTIESIN COMPRESSIONAFTER
200STRESSREPETITIOI?SIN TENSION
TO 2/3 UIWIMATESTRENGTH
Speo.No.
Tenston-Tenslon
Comp.-Comp.
Tenaion-Comp.
0.3760.378
~00340037
0.3840*373
0.37z0037
k00390.36
0.5380.550
0.45i0.49
0.04z0.05
00509O*51O
::gg
12,600
“E:;%It,3~o
a9:0013,100
if’10, 011,00
8,700
:;8::
36,80035,000358900
UltimateStr~ngth
pa?
18,30017,00
317,00
$8:;%19,50017,60017,60017,600
19,40019,40019~400
36,80035,00035s900
Stiff’nesE~ x lo-i?pal
0.410,9i0.0
o* 1i!0.20.57
2.682.382.53
2.93*d3.05
TABLE11 - INF-CE OFREPEATEDSTRESSINGON
THEMECHANICALPROPERTIES
Material
CL
:
CLc
G
c
30+8-6
-17-8-6+9-12
0.610.560.58
0.620.640.63
0.360.340.35
0.47
30.40.4
0.130.130.13
%w5--Strength
+22+45
1+: 3
-18+27+60+49-9
+67+17+51-1-12
-1.2+10-2-?6+21
-37.23.62+24+5
-55;~o+2-13
NACATNNo. 1105TABLE12 - ENERGYDISSIPATEDPERCYCLEFORSTRESSING
INTENSIONTO TWO-THIRDTHEULTIMATESTRESS
Ultimate EnergyDissipatedMat. Tensile Spec.No, perCyale
Strength (in*lb.perou.in.)psi
9CL 25.7CL 9200 10CL 25.
Aver. 25.i2Ck
18.2c ll,~oo 2 20.7
Aver. 20005 .5
R 24$700 % i5 .5Aver. 54.02P
P 25,200 82P g:;Aver.
LG 9.8
G 38,300 ~9.5Aver. ●
TABIE12- STATICTENSIONCREEPTESTDATA
Mat. Speo.Area Load Stress CreepRate CheepetNo. sq~in. lb.
‘tps in.\in.}&.X 106at 400 hr.in.x 500
C&;; 8 8Z! $::%
O*5O0.202
1010 k
i:;917 $:3$
CL 0.2001.0
1,037 210.0
1.0 11.02
0.208 1,230 29,20 26.00.207 1,359 ,570 ;::: 26.70.174
:k
35; ?;~:g ?o.0
0.173.8
z
1.00.17 917
zJ7
1.90c 0.16
81,077
6;k~~2.00
%J
1?0.11 1,20
3 2.20 1 :2
0.175 1,37 79950 .00 --
0.181 838$ &h,60 1.00
0.178 1,16z
4::
?
,520 1.600.178
21.90 z
R 0.178 ~’95~s80:$$$0.1782.30 10:
2 ?2.30 ii
0.178 2:1511.2,10
80.17
13:::
2,53214,260 $!0.17 2s55049310 2.10 32 .10.10
; ?1,110 5,80
30.5
O*11 32.8
tNJ; 1?;;2:
0.90.182
P1.3.
z2:;
0.13i
2;82914,6705
1.00,17 2,83015,120
9.01.36 10.5
0.168 8382 Hi
, 80 0.051,491 00
1*12
?:::Tt
0020 2.222,26513:100
G 0.14L
0.262,93 17,3008
3.67
2 :::71 $;44?:2;;::0.60
i!.50
0.400.25 6:!?
-.
.
.
—
.
.
.
.
—
,
.
.
.
NA(JATN No. 1105
auu4- STATICBENDINGCREEPTESTDATA
Mat● SpeeO, DimensionsMoment Stress CreepRake CreepDef.No. M
5at 1000hr.
in. in. in.lb. P8 in./h2 x 5X105in.x 1000(211gagelength)
0.540 1.125 468 4,120;
::$% z~~ $:% !%
7.500.540
CL2
0●543
::??l ::3 X38 7;;$$;:
10185 1.2 25Z!o
1g ;:3 ~q $:$
0●480 Oo11.1 9.200.47 0.23
i ~4
9*7Oc 0.47 le125
z I0.7
:: 78 1.Iz?
77 7: 00 00h $:~~~ 1.12 917 9,235 0093
0s474 1.124 932 9s350 0.91 -.
810.4 1.127
2?,260 0.28
i 478; z
4.500.4 1.127 0.20
6~~9i ?7. 0
::47 1.la 771?
0.31 9*oR L 3.26 O*5
J12.70
~ ~$g ::ig g!jij $!$1.0 1 ●1O ._0.91 J1 .10
z *2%1.30 26.00
0.482 1.100 1519 1.93 32.00
O*5O ~e:9 478 4,50: z i? 2
0.23 2.60.0? 8 Jz: ‘JS50 0.23
kz
P?
o.02 1.07 1 ?750 0.50 :$0.504 1.011
J!J; 11,300 0.6
5 ?17.00
0.504 1.001 17,050 I.6 .-
9 0.034
“ ~ I; iii # J& ;:;T; g0.023():)1
?
25
blat.
R
P
G
Mat.
c
R
P
G
HAOATNNo. 1105
~- STATICTORSIONCREEPTESTDATA- ROUNDCROSS-SECTIONS
Spec.No.
Dia.in.
o.&60.475O*45J00 3
Lo.h952 0.50’0
io.02z0.93
1? 09499o.~oo
7 0.500
0.501: 0.04
J?i::4;2
T;:::stg
h. lb.
3~:6257;::
33*4500758.270.79.?!531 1:2
54*579.292.0105●o
ShearStressSsrmli1,90
32,503,1083.90
1,4002,00
b2,33,0003,260
2,870,5502.2103;150
t,810s370
Cree@Rate.
deglin~ x 10~
1.171.823.67Failed
0.3i!
007o*71071.912.00Failed
0.670.83Failed2.67
ZpeepAngleat 1000hrtdeg/in.
2.5z.0
1 .5.-
--“.
-9-.
1.833,00
TABLE16- STATICTQRSIOl?CREEPTESTDATA- SQUARECROSS-SECTION
Dlm.t(aver)
o.h80.4830.4860.486
0.4880.494o.~920.490
0.50100500.5030.505
0.510o*10
io.000.96
66.099.1132.2165.0
33.170.5192:3
66.098.0120.5152.0
ShearStress
p:!
2,7704,1005$5006,900
2,30
Zz?o
: 305,220
Cree Rate&
deg/in/hr.x 103
063300501.081.83
0.I.20.300.‘0.W
lreepAngleat1000hrdeg/in.
i
.00●67●75
ls.21j
1.833.005*37.6
0.831.802.03394
*
.
.
.
.
.
26
.,
.
.
.
.
NAOATNNo. 1105
TABLE17- D?I!I’JAMICTENSIONCREEPTESTDATA
.
.
.
NACATNNO.1105
TABLE18 - COMPARISONOFCREEPDEFCFLMATIONS
Typeof’ Strea8 OreepDeformationol?Material;reeptest psi CL c R P (3gd M 2,000 2.5 1.6 007
!/8.2
008 004:*m* ,000 5.8” 1.6 1.0
2!J 20.3 13.6
8$%t? 2.4 1.5
H@ .- --0SAA% ii:! &
2.010,000 -- -.W1.1-l0+ 2.6
u.a~ 12,000 “- -- 17.1
k1 ,000 3
97 3.;
s%55-. --
1 ,00025,5 ●5
i.*
-- -. -- 11.7* ●yl
Ih
2,000,000
+ ,000j$OOO II-- -..- ---- -.-- --I c,
I 2,000 I -- 10“1 .- 1I ?___,000
_ ,000 t I9
J?:;5!
2.5 1.0 0.62.%2 k
1,01.5
V*3 ;:2 2.?
2.713.4*-- 4--6.7 2.b
.-p
9-..- :7*2.4 1.64.g 2.8
fj.1-- I 11.4*[ U*5*mIi!,000 I -- b.:
.: ,000 .- 1006 ] -- I 3.0-.. I
) I -- I -- I b-b I ,
0.61.11*72.z~.,I10,000 I “- I .- 116.5*
IL
12,000 -- -- -- 5“2* I 2“!---
* ExtrapolatedValues
b
.
*
.
.
.
28
NACA TN No. 1105 rig.1
Figurel.-Universaltestingmachineshowingenclosureforhumiditycontrol.
* , .
[email protected] 8pecimenassemblyfortensiontei3ts.
Figure3.- Specimen assembly forcompressiontests.
v J .
,J, ,
Figure 5.- Nine unit atatio tension
-
Figure 4..
creep maohine.
Four unit static teneioncreep machine.
●
1
I
,,1,
i’i
i’:,.!;
I
,.
>
‘1
F~~t3 13.- Straingagefor rneaauringtensioncTeeP6tralna,
4
i
NACA TN.
.
.
Figure8.-Staticcreepbendingunitshowingmethodof loading.
8,9
Figure9.-Static creep torsionknachine.
, 4 ,
method of loading.
1,
Figure 11.- Dynamicoreeptensionmachine
#
I
I
rig. MNACATNw. 1105
UnitStrain- in.~w inMATERIACL
Unit Stra[n—In.porIn.MATERIALR
8
7
6‘&MS I2-4 —I-:32
z0.006s5
IIn pwln.
o [
UnitStrain- in.pu inMATERIALO
5
4
3
2
I
o
UnitStrah-hpw In.MATERIALp
FIG.12-
STATIC TEWION
LOAD- STRAIN DIAQRAUS
UnitStrain- in.perin.MATERIAL 6
.Fig.13a NAu TNNo. llos
UNITSTRAIN- in.parin
.
.
.
—
.UNIT STRAIN - h. perIn.
FIG. 13a- STATIC COMPRESSION LOAD-STRAIN DIAGRAMS
NAOATN NO. 1105 3W& 13b
4
70 ?J
Kg
‘22cJ
I
oUNITSTRAIN- III.parin.
6
I
4
7
;2 - Id
/ ./MATERIALP
1 &0.00978
B
?
/In. parinJ
o +. I
UNIT STRAIN - In. par[n. .-
FIG. 13b-
STATIC COMPRESSION
LOAD-STRAIN DIAGRAMS
UNITSTRAIN-in.perIn.
Defleatlon- In.MATERIALOL
Daflmt[ en- InMATERIAL R
10
8
2
0
NAaATN No.1105.
Dafleotion- in.MATERIALC
Daflcotlon- II!MATERIALP
FIG.14-
STATIC SENDING
WAD- DEFLECTIONLSIAGtWMS
L
.
.
.
.
Deflection-in.MATERIAL O
N&2&TNNo.1105 rig.15
.
.
i-0a
22
20 d
18
16~
S14 1 ‘/ 1 ‘1 /
t
7+J12 ~If /{ // ‘
g-10—
0●
:6s+
4
2
0Angle of Twist - D:grees
MATERIAL
20
Ie
16 II / 14~g
414,
i_oQ 12a
* 10
usWE:+
6
2
0 t /Angls of Twist-Degraa8
I MATERIAL P
FIG. 15-
STATIC TORSION
TORQUE-TWIST DIAGRAMS
ROUNDGROSS-SECTIONS
—-.
NAOATN No. 110S.rig. 16
32~
?7kFiFtw-i4
0AN6LEOF TWIST- degree-
MATERIAL CL20
16
g14
&I 12
7= Q Qgm
.58
~6
4
2 -
0AM&E OF TWIST - degrees
MATERIAL R
AWLS OF TWIST=- degreesMATERIAL C
ANGLE OF TWl= - dqmcs
MATERIAL P
FIG. i6-
STATIC TORSION
TORQUE- TWIST DIAGRAMS
SQUARE WOSS- SECTIONS
.
.
.
.
ANGLE OF TWIST. degreee
NAOATNNo.1105 rig.17
4
3.5
3m‘Q*2.5
I
0.5
0
v
/ {1 ?{f(
{
0.02445
in. parin.
Unit Strain- In. p.r in.
MATERIAL CL4
3.3
3 1. ~1 1
722.5 /
v
M:-2I
‘u: 1.3 t /J
I / [
050.02445
t
in. par[mo I I
UnitStrain- In.perin.MATERIAL R
e-
7 I
6 { i
90-5 / (x
~ 4I
:3
: ~ J’2 1
.
f0.004s9
h perim
oUnit Strain- In. porln.
4
3.5
3m‘g- 2.s
:!?
Iw: 1.5d
I
0.3
0
4
3.6
3
I
0.3
0
Unii Strain— In. per in.
MATERIAL c
f [
aoo97s
th per in.
I IUnit Strain—h.per hr.
MATER14L P
FIG. 17-
STATIC COMPRESSION
LOAD-STRAIN DIAGRAMS
(100 Tenelon Stress Repetitions)
MATERIAL G
Fig.IS .
cd‘Q
50
40
30
20
10 t
STRAIN - In. PO! in.MATERIAL G
Is
12 A /
9[- “
s
i
. 1
●
30.0025In.perin.
STRAIN - h perIn.MATERIAL O
NACA‘mNo.lloit!
50
40N‘g
; 30 —.. —
nz 20-1
10 / /
0.0025Irhpcrln.
STRAIN - in.p~r In.MATERIAL P
STRAIN - hbperln.MATERIAL R
FIG.lE-
STRESS- STRAIN
HYSTERESIS LOOPS
IN
TENSION
NotwMaximumload=~ltlmalo load.
STRAIN - h. par h.
MATERIAL CL
b b
EP
;
g- 6f 6:m~~~ _ _ ----- ------ ~
--- --.
!+m6230@ --—-
-● . . ●
.* I --+xb>~hr- --:: _____--- --— -- --●
s+. Wopd. — —-- _--— ---- ----
— — —
s:P6U@hl● —-—— ——
/ ..
) 200 3m 400 500 600 700 Boo 900 1000 I 100 1200 I 3m I 400
Time - Hours-1K
FIG.19-STATIC TENSION CREEP TIME RELATIONS- MAT.CL..P.
29 I
P4
23
Is
12I
8
4
0
Time-Hours
FiG.20-sTATic TENSION CREEP TIME RELATIONS - MAT G
-T--
-t1
I.
m0
I
● !“. , .
* *
28
24.
10
0
LenE 12 — —
. ●.
I - ~ .
&
g ●
ma ● — —
●●
o00 200 100 4W IWO (
.
Tim. - Hours
FIG.21-STATIC TENSION CREEP TIME RELATIONS - MATc R :mP
i’-
M S.=1611Ops.i.r
-
-9 . .
.● .
I 3
I
● D*
I 4
● ☛
●
●
●
—*. 9
) ,
-
● ✜.0
●
●
-r
T● ● e*
‘****’
I
1) 700 a
*
● ● e.
●
---L
~15120P9J.
S+=14670P.~i.
●● .** .*
9
s,=s7aOp.s.i.
● . .** woe
S,=5WJ
1100 I2(24J ,:
FIG.22-STATIG TENSION CREEP TIME RELATIONS - MAT P
.
) 14
.-
* b I . *
~ 26300 Pd. ●
●9. D
6f3yoo@ ●
. ~.
. mood . .●
.D. . .
●.13100kbl
●, .
., .
!
g 6600phL.$ B ●
●* ●
q 6ooom.L ● 9
,
Wo low Ilw IZQo Iwo 14
FIG.23-STATIC TENSION CREEP TIME RELATIONS- MAT G
I
14
,962 O**’12 6%
.
la
n
6
.
4 *
sf4120pd.
o
0 Iw mo 300 400 Sao (
,, .
I
---- ,-------- -------
+-t-l-+-----”---—
-------
0 700 bm mo Kno
Time - Ii ours
FIG.24-STATIC BE NDING CREEP TIME RELATIONS - MAT CL
. ? .
100 2ca 300 400
. 235 Rd. ~ - ----- -
~~ ~ —
, 935( R&l. --- ---------- ------ - --
●
Qmm p,d.
v“? *’.,
=628( I *S.I.● -------
9 9
~: 526C P.s.l.
800 7m mo 900 1000 I
Time - Hours
FIG25- STATIC BENDING CREEP TIME RELATIONS- MAT. C
I
c
.
w
ion K.R
17.5
I M
I 2.5--------
0
% 10.& ----------
1eo 76zoez
; M —-- -------
$25
m. F
~
Time- Hours 2g.,
FIG.26-STATIC BENDING CREEP TIME RELATIONS- MAT. R :
. r ,,
* ●
_—— .—— -——— ———
———— - —————- -
● ❆
✎
☛ Ilworml —.—● .
*q. la700@
.
(
~= 4750 Pti
)-8
I1 100 P.oo 300 W 500 000 700 Ooo MO Iwo I
Time - Hours
FIG27.- STATIC BENDING CREEP TIME=i
RELATIONS - MAT. P ~
I
‘r
8
5
4
a
?.
I
c
I
T..
●.“
I
-=t---
.
●
“ ~ z3500W~
. ● * ● .
~=20mcw.1.--—. — —----
*I18BOPA-— —.—— — --—— -
~=148C4pcl.-- —— -- —. ——.—-S
~7000p8.1.-- ----- - --—. -
●
* Ioosorgl. --- ------= 4200 pd.
—- ——-—— _——.
aoo 400 500
Time- Hours
FIG.213STATIC BENDING CREEP TIME
600 700 Soo 900 1000 1100 ,
RELATIONS - MAT. G
. . *
120
I 00
c.-
UI
c 80.-
* , , *
=L=L*
1 1 I 1 I
100 200 3CQ 400 600 690 700 s
Time-Hours
●
-------
I
FIG.29-STATIC TORSION CREEP TIME RELATIONS MAT. R- ROUND CROSS-SECTION
40
3C
2(
la
c
~
T100 2
4●
—.— -.
● ●
✎
. ● ●
;g.14mFLd.
●
✎ ✎
FIG.30-STATIC TORSION CREEP TIME RELATIoNS ‘. MAT. P-ROUND
, .
I I
CROSS-SECTION
I
r *
,s/5450p&~
I_——--
——----—--—..
0 Iw 200 300 400 300 6 Ou (00 800 moo 1’
Time-Hours
FIG.31-sTATIC TORSION CREEP TIME RELATIONS - MAT. G - ROUND CROSS-SECT
I
= SC.-
1
+0
6(
4[
2(
a
s’. :900 PR.J
● ● ● ●.
● ● ● =●
;m.8280m.i x
f&5500w.b,
5 .* .
7
s;4100w.i.●
I 00 200 3C9 400 500 600 700 800 900 la
Time-Hours
FIG32-STATIC TORSION CREEP TIME RELATIONS- MAX C-SQUARE CROSS-SECTION
. ,
i.-
I 20
!00
80
6a
u
2(
c
//
/
.
I
I
*I
eoo 3
FIG/33-STATIC TORSION
* ● ?
1) ● OO SOo 600 700 800 900 Icno
Time-Hours
CREEP TIME RELATIONS -MAT. R- SQUARE CROSS- SECTIONwE.ucd
28
24
2C
+
1
+
..
-F● .”
100
● ☛ ●9 .
-
r+n67f50@i
.s 7mpd.● ● *
— —. ●
.**. “*. ” ● ●
33_---*----___
● w
S+S 4250P$I -.● . a .
● .*.. *
—
s“.2000P.&L *---- -* . ● ● ● .
.
I 300 400 !300 600 700 800 900 Iwo ~
Time - Hours ~2!
FIG. 34-STATIC TORSION CREEP TIME RELATIONS- MAT- P- SQUARE CROSS-SECTIONg“u
h 1,,
5
c.-
1
{ ●
----
●
●
9
,---
●
— — — — — — — _____ . .--—
100 200 300 4000[
0
Time - Houre
FIG 35-STATIC TORSION CREEP TIME RELATIONS - MAT,G - SQUARE CROSS-SECTION
●I?
.
36, 37.
NAOATNNo.1105
‘TTTrTTTrrr10 !
●
8 s =3740P.s.l.
9
6
m4 4 ~
I2 Sm=[950p.s.l
●
o0 20 40 60 80 I00 I20 140 160 180 1
nmc - Hours
F[G.36 - DYNAMIC TENSION CREEP- TIME RELATIONS- MAT CL
14
12—
10 :mI,~In 9
8
●
9
6 II
-- -
. ~ —●
●
4
2.
0.0 20 ,40 60 so 100 120 140 I60 leo 2
Time-Hours
.
)0
)0
.
.
FIG.37-DYNAMIC TENSION CREEP’-TIME RELATIONS- MAT.C
TNNo.llos Figs.38,20
18 .a● ● *
1.
16S* 9 Soop.s.i.
● .
9
14
12
10
4s
@,
00 Eo
Time- Hours
FIG.3S-DYNAMICTENSION CREEP-TIME RELATI(X4S— MAT.R
Time-Hours
39
FI(33SOYNAMIC TENSION CREEP -TIME RELATIONS-MAT.P
,
‘ Figs. 40,40 NAOAm No. 11o6
ISm=17,500p L1.
sm=14,300p r.1.
Sm=13,400 p.s.l● 9
/ -“●
I●
Su= 9,980p.s.l.● --- ---- .- —- ---- -—. -.--- I
20 40 60 80‘ 100 120 140 I60 180 200 220
●
Time- hours.
FIG.40-DYNAMICTENSIONCREEP-TIME RELATIONS— MAT (3
w N o
●
a
a
JI X ‘l’sed_S@OJJS.
Figure 41. - 8tatic tensionspecimensshowingtype of fracture; left to right,
materials CL, C, R, P and G.
Figure42.- Staticcompressionspecimensshowingtype of fracture;left to right,
materialsCL,C,R, P andG.
Figure43.- Sltaticbendingspecimensshowing typeof fracture; topto bottom, materials
CL,C, R, P andG.
# . * b
FigureM .- Statlctoreionf3pecimeneshowingtype of fracture,
squarecross-sections,leftto right,materialsCL, C, R, P and G.
Figure 45.- Statictorsionepecimens
round cross-~~;%s~~~f~ft?%j%~’materialsCL, O, R, P and G.
9!c!
.
. “ v I
Fi~e 46. - Static ten~ion creep specmneneehowingtype of fracturesleft
to right,materialsCL, C, R, P and 13.
Figure 47,- Dynamicteneionspecimens—showingt?eleftto right,materias
Of fTaCtUrejOL,C, R,PandG
, + * -. .
c
●
✏
4.4 &
+
9,
/
●
/
.
0 Mat, o● Mat. P● klat. R● Mat. c
● MaLCL
‘“l
Fl&49-COMPARBON OF STATIC SCNOlkGRIIEP WLECTH I
Dathotl.n at 1000 h---l.l !JOO
/ // ,/
/“ ,Y’/
.
/’*
o Mat.e
● Mat, P
.- ..0 5 w ,= ~
ARgio of Twl ti at 1000 haars - Dog. Pcr h:.
F 10.50-COMPARISON OF STAT[G TORSIONOREEP $.
ANGLES OF TWIST-ROUND GROSS- SECTION g
,>0
.
—m~
I....Z=J
o 2 4 6
P
0 Mat a
● Mat.P● Mot. R
Angle of twist at 1000 hours - deg. pm In.
FI13. 51 -OOMPARISDN OF STATIC TORSION CRfEP ANGLES ~ TWIST
SQUARE CROSS- SECTION
●
o Mti. B● mat. P● U at. Re Mat. C● MO?. a
&
—-
10 12 14 la
21rnhat tY30tmura-rn.puk xl& 1-
EFIG. 52- COUPARISN OF DYNAMIC TENSION cREEP SnAINS a
● ✎✌
