Ctod Procedure

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ECSS-Q-ST-70-45C31 July 2008

Space product

assuranceMechanical testing of metallicmaterials

ECSS SecretariatESA-ESTEC

Requirements & Standards DivisionNoordwijk, The Netherlands


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Foreword

This Standard is one of the series of ECSS Standards intended to be applied together for the

management, engineering and product assurance in space projects and applications. ECSS is a

cooperative effort of the European SpaceAgency, national space agencies and European industry

associationsforthepurposeofdevelopingandmaintainingcommonstandards.Requirementsinthis

Standardaredefinedintermsofwhatshallbeaccomplished,ratherthanintermsofhowtoorganize

andperform thenecessarywork.Thisallowsexistingorganizational structures andmethods tobe

appliedwheretheyareeffective,andforthestructuresandmethodstoevolveasnecessarywithout

rewritingthestandards.

ThisStandardhasbeenpreparedbytheECSSExecutiveSecretariat,endorsedbytheDocumentand

DisciplineFocalpoints,andapprovedbytheECSSTechnicalAuthority.

Disclaimer

ECSSdoesnotprovideanywarrantywhatsoever,whetherexpressed,implied,orstatutory,including,

butnotlimitedto,anywarrantyofmerchantabilityorfitnessforaparticularpurposeoranywarranty

that the contents of the item are errorfree. In no respect shall ECSS incur any liability for any

damages,including,butnotlimitedto,direct,indirect,special,orconsequentialdamagesarisingout

of,resulting from,or inanywayconnected to theuseof thisStandard,whetherornotbasedupon

warranty,businessagreement,tort,orotherwise;whetherornot injurywassustainedbypersonsor

propertyorotherwise;andwhetherornotlosswassustainedfrom,oraroseoutof,theresultsof,the

item,oranyservicesthatmaybeprovidedbyECSS.

Publishedby: ESARequirementsandStandardsDivisionESTEC, P.O. Box 299,2200 AG Noordwijk

The NetherlandsCopyright: 2008 by the European Space Agency for the members of ECSS

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Change log

ECSSQ7045A

7April2006

TransformationofESAPSS01745intoECSSformat

ECSSQ7045B Neverissued

ECSSQST7045C RedraftingofECSSQ7045AaccordingtonewECSStemplateandECSS

draftingrules.

Inparticular:

IntroductionofSection4 Principles tocollectdescriptivetext,

containedformerlyinrequirementssection.

CollectionofallrequirementsinoneSection5 Requirements

DeletionofAnnexA(informative)andmovingofrequirementsinto

bodytext.

Revisionofnormativeannexes(nowAnnexA,BandC)accordingto

newtemplateandadaptationoforderofappearance(AnnexA:DRDfor

testrequest,AnnexB:DRDfortestproposal,AnnexC:DRDfortest

report)

EditingoftexttocomplywithECSSdraftingrules

31July2008

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Table of contents

Change log .................................................................................................................3

1 Scope.......................................................................................................................7

2 Normative references .............................................................................................8

3 Terms, definitions and abbreviated terms..........................................................10

3.1 Terms defined in other standards.............................................................................10

3.2 Terms specific to the present standard ....................................................................10

3.3 Abbreviated terms ....................................................................................................11

3.4 Symbols....................................................................................................................12

4 Principles ..............................................................................................................13

4.1 Overview ..................................................................................................................13

4.2 Tensile test...............................................................................................................13

4.3 Fracture toughness test............................................................................................13

4.3.1 Overview.....................................................................................................13

4.3.2 Determination of fracture toughness using the KIc test method..................13

4.3.3 Determination of fracture toughness using the J Ic test method..................14

4.3.4 Characterization of fracture toughness using the R-curve test method......14

4.3.5 Characterization of fracture toughness using the CTOD test method........14

4.4 Fatigue test...............................................................................................................15

4.4.1 General.......................................................................................................15

4.4.2 Force controlled constant amplitude axial fatigue test................................15

4.4.3 Strain-controlled fatigue test.......................................................................15

4.5 Fatigue crack propagation test.................................................................................15

4.5.1 Stable crack growth rate.............................................................................15

4.5.2 Crack propagation threshold ......................................................................16

4.6 Fracture and fatigue test in special environment......................................................16

4.7 Stress corrosion cracking test ..................................................................................16

4.7.1 Overview.....................................................................................................16

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4.7.2 Stress corrosion cracking test using smooth specimens............................16

4.7.3 Stress corrosion cracking test using pre-cracked specimens.....................17

4.8 Creep test.................................................................................................................17

4.9 Test results presentation..........................................................................................17

5 Requirements........................................................................................................18

5.1 Customer agreement................................................................................................18

5.2 Tensile testing..........................................................................................................18

5.2.1 General.......................................................................................................18

5.2.2 Tensile testing of weldments ......................................................................18

5.3 Fracture toughness test............................................................................................19

5.3.1 KIc test method............................................................................................19

5.3.2 J Ic test method............................................................................................195.3.3 R-curve test method...................................................................................19

5.3.4 CTOD test method......................................................................................19

5.4 Fatigue test...............................................................................................................20

5.4.1 Force controlled constant amplitude axial fatigue test................................20

5.4.2 Strain-controlled fatigue test.......................................................................20

5.5 Fatigue crack propagation test.................................................................................21

5.5.1 Determination of fatigue crack growth rate.................................................21

5.5.2 Determination of a fatigue crack propagation threshold.............................215.6 Fracture and fatigue tests in special environments ..................................................22

5.7 Stress corrosion cracking test ..................................................................................22

5.7.1 Stress corrosion cracking test using smooth specimens............................22

5.7.2 Stress corrosion cracking test using pre-cracked specimens.....................22

5.8 Creep test.................................................................................................................22

5.9 Evaluation of test results ..........................................................................................22

5.10 Storage.....................................................................................................................23

5.11 Reporting..................................................................................................................235.12 Quality assurance.....................................................................................................23

5.12.1 General.......................................................................................................23

5.12.2 Calibration..................................................................................................23

5.12.3 Quality control of raw materials..................................................................24

5.12.4 Nonconformance........................................................................................24

5.12.5 Traceability and records .............................................................................24

Annex A (normative) Request for mechanical test ing of materials DRD.........25

Annex B (normat ive) Proposal for mechanical test ing of materials DRD........27

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Annex C (normative) Report of mechanical test ing of materials DRD.............29

Annex D (informat ive) References .........................................................................32

Bibliography.............................................................................................................33

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1Scope

This Standard specifies requirements for mechanical testing of metallic

materialstobeusedinthefabricationofspacecrafthardware.

This Standard establishes the requirements for most relevant test methods

carried out to assess the tensile, fatigue and fracture properties ofmetallic

materials.Itdoesnotgiveacompletereviewofalltheexistingtestmethodsfor

theevaluationofmechanicalpropertiesofmetallicmaterials.

Furthermore, this Standard specifies requirements for the evaluation,

presentationandreportingoftestresults.

Thisstandardmaybetailoredforthespecificcharacteristicandconstrainsofa

spaceprojectinconformancewithECSSSST00.

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2Normative references

The following normative documents contain provisions which, through

reference in this text, constitute provisions of thisECSS Standard. Fordated

references,subsequentamendmentsto,orrevisionofanyofthesepublicationsdonotapply,However,partiestoagreementsbasedonthisECSSStandardare

encouragedtoinvestigatethepossibilityofapplyingthemorerecenteditionsof

thenormativedocuments indicatedbelow. Forundated references, the latest

editionofthepublicationreferredtoapplies.

ECSSSST0001 ECSSsystemGlossaryofterms

ECSSQST1009 Nonconformancecontrolsystem

ECSSQST70 SpaceproductassuranceMaterials,mechanical

partsandprocesses

ECSSQST7037 SpaceproductassuranceDeterminationofthe

susceptibilityofmetalstostresscorrosioncracking

ECSSQST7046 SpaceproductassuranceRequirementsfor

manufacturingandprocurementofthreadedfasteners

ASTME139 Standardtestmethodsforconductingcreep,creep

rupture,andstressrupturetestsofmetallicmaterials

ASTME399 Standardtestmethodforplanestrainfracture

toughnessofmetallicmaterials

ASTME466 Standardpracticeforconducingforcecontrolled

constantamplitude

axial

fatigue

tests

of

metallic

materials

ASTME561 StandardpracticeforRcurvedetermination

ASTME606 Standardpracticeforstraincontrolledfatiguetesting

ASTME647 Standardtestmethodformeasurementoffatigue

crackgrowthrates

ASTME739 Standardpracticeforstatisticalanalysisoflinearor

linarizedstresslife(SN)andstrainlife(eN)fatigue

data

ASTME1290 Standardtestmethodforcracktipopeningdisplace

ment(CTOD)fracturetoughnessmeasurement

ASTME1820 Standardtestmethodformeasurementoffracture

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toughness

EN100021 MetallicmaterialsTensiletestingPart1:Method

oftestatambienttemperature

EN100022 MetallicmaterialsTensiletestingPart2:

Verificationoftheforcemeasuringsystemofthe

tensiletestingmachines

EN100024 MetallicmaterialsTensiletestingPart4:

Verificationoftheextensometersusedinuniaxial

testing

ESDU96013:1996 Fracturetoughness(KIc)valuesofsomealuminium

alloys

ISO75396:2003 CorrosionofmetalsandalloysStresscorrosion

testingPart6:Preparationanduseofprecracked

specimensfortestsunderconstantloadorconstant

displacement

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3Terms, definitions and abbreviated terms

3.1 Terms defined in other standards

For the purpose of this Standard, the terms and definitions fromECSSSST0001andECSSQST70apply.

3.2 Terms specific to the present standard

3.2.1 crack tip plastic zone

plasticallydeformedregioninamaterialadjacenttoacracktip

3.2.2 creep

timedependentincreaseinstraininamaterialresultingfromforce

3.2.3 damage tolerance

inamaterialor structure, the capability towithstand stressesor loads in the

presenceofdefects

3.2.4 failure

conditiongenerallycausedbybreakorcollapsesothatastructuralelementcan

nolongerfulfilitspurpose

3.2.5 fatigueinamaterial,thefailurephenomenonwhichresultsfromrepeatedfluctuation

ofstress

3.2.6 fracture toughness

inherentresistanceofamaterialinthepresenceofacracklikedefect

3.2.7 fin ite life range

liferange,inwhichalltestpiecesbeforeapredeterminednumberofcyclesfail

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3.2.8 mechanical properties

those properties of amaterial that are associated with elastic and inelastic

reactionwhen force isapplied,or that involve therelationshipbetweenstress

andstrain

3.2.9 mechanical testing

determinationofmechanicalproperties

3.2.10 raw material

materialfromwhichspecimensaremanufactured

3.2.11 specimen

representative fraction ofmaterial tested or analysed in order to determine

mechanicalproperties

3.2.12 transit ion range

predeterminednumberof cyclesof stress cycles (typically 5 x 106 to 5 x 107

cycles),wherefailureaswellasnonfailureoccur.

3.2.13 threaded fastener

device composedby a cylindrical screwedbar providedwith a head and a

metal collar, screwed internally, to fit thecylindricalbar that is toholdparts

firmlytogetherinanassembly

3.2.14 weld heat affected zone (HAZ)

portionof

material

in

awelded

joint

whose

microstructure

and

physical

propertiesareaffectedbytheheatinputduringwelding

3.3 Abbreviated terms

ForthepurposeofthisStandard,theabbreviatedtermsfromECSSSST0001

andthefollowingapply:

Abbreviation Meaning

ASTM AmericanSocietyforTestingandMaterials

CEN EuropeanCommitteeforStandardization

CTOD cracktipopeningdisplacement

ESDU engineeringsciencesdataunit

HAZ heataffectedzone

ISO InternationalOrganizationforStandardization

NCR nonconformancereport

NDI nondestructiveinspection

RMC rawmaterialcertificate

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3.4 Symbols

Symbol Meaning

C(T) compacttensionspecimen

J Jintegral

JIc Jintegralplanestrainfracturetoughness

K stressintensityfactor

KIc stressintensityplanestrainfracturetoughness

Kmax maximumstressintensityfactor

ModeI openingmodeofloading

R stressratio

Rsx specimenstressratio

M(T) middletensionspecimen

da/dn crackgrowthrate

K stressintensityfactorrange

Kth fatiguecrackpropagationthreshold

KISCC thresholdstressintensityfactorforsusceptibilitytostresscorrosioncracking

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4Principles

4.1 Overview

ThisStandard specifies requirements to conduct tests inorder tocharacterizemechanicalbehaviourandpropertiesofmetallicmaterials.Selectioncriteriaof

mechanical tests arebased on the significance and use of each specified test

method.Testmethods,whicharecoveredinthisStandard,arecharacterizedin

thefollowingparagraphs.

4.2 Tensile test

Tensile tests provide information on the strength and ductility ofmaterials

underuniaxialtensilestresses.Testresultscanbeusedincomparingmaterials,

alloy development, design and quality control. The testmethod covers thetension testing ofmetallicmaterials in any form at room temperature, and

specifically the methods determine yield strength, yield point elongation,

tensilestrength,elongationandreductionofarea.

4.3 Fracture toughness test

4.3.1 Overview

Thistestreferstomethodstodeterminefracturetoughnessofmetallicmaterialsusingthefollowingparameters:stressintensityfactor(K),Jintegral(J),Rcurve

and crack tip opening displacement (CTOD). The fracture toughness

determined in accordancewith thismethod is foropeningmode (ModeI) of

loading.

4.3.2 Determination of fracture toughness usingthe KIc test method

Thismethod provides themeasurement of crackextension resistance at the

startof

acrack

extension

for

slow

rates

of

loading

and

when

the

crack

tip

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plastic zone is small compared toboth the crack size and to the specimen

dimensioninthedirectionoftheconstraint.

The method covers the determination of linear elastic planestrain fracture

toughness (KIc) of metallic materials by tests using a variety of fatigue

precrackedspecimens.

4.3.3 Determination of fracture toughness usingthe JIc test method

Thismethodprovides themeasurementofcrackextensionresistancenear the

onsetofstablecrackextensionforslowratesofloadingandsubstantialplastic

deformation.

Themethod covers the determination of the Jintegral planestrain fracture

toughness(JIc)ofmetallicmaterials.

4.3.4 Characterization of fracture toughnessusing the R-curve test method

Thismethodprovidesacharacterizationoftheresistancetofractureofmetallic

materials during incremental slow stable crack extension and result from

growthof theplasticzoneas thecrackextends fromasharpnotch.Materials

that can be tested for Rcurve development are not limited by strength,

thickness,ortoughnessprovidedthatspecimensareofsufficientsizetoremain

predominantlyelastic.

Themethod covers the determination of resistance to fracturing ofmetallic

materialsbyRcurvesobtainedby testingcompact tension specimensC(T)or

middletensionspecimensM(T).

4.3.5 Characterization of fracture toughnessusing the CTOD test method

This test method provides a characterization of the fracture toughness of

metallicmaterialsandisusedformaterialsthatexhibitachangefromductileto

brittlebehaviourwith decreasing temperature. Thismethod is also used to

characterizethe toughnessofmaterialsforwhichthepropertiesandthickness

of interestpreclude thedeterminationofKIc fracture toughness inaccordancewithASTME399.

The specimen dimensions can affect the values of CTOD. For this reason

specimensofsamedimensionsareusedwhencomparingtestresults.

Themethodcoversthedeterminationofcriticalcracktipopeningdisplacement

(CTOD)valuesatoneormoreofseveralcrackextensionevents.TheseCTODis

usedasmeasuresoffracturetoughnessformetallicmaterials.

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4.4 Fatigue test

4.4.1 General

Fatiguetest

refers

to

tests

methods

for

the

determination

of

fatigue

strength

of

metallicmaterialssubjectedtoconstantamplitudecyclingloading.

4.4.2 Force control led constant amplitude axialfatigue test

The force controlled axial fatigue test is used to determine the effect of

variations in stress,material, geometry and surface condition on the fatigue

resistanceofmaterialssubjectedtofatigueloading.Theresultscanalsobeused

asaguidelinefortheselectionofmetallicmaterialsforserviceunderconditions

ofrepeateddirectstress.

Themethod covers axial force controlled fatigue tests to obtain the fatigue

strengthofmaterialsinthefatigueregime,wherethestrainsarepredominately

elasticthroughoutthetest.

4.4.3 Strain-controlled fatigue test

Straincontrolled fatigue is important for situations inwhich components or

portions of components undergo either mechanically or thermally induced

cyclicplasticstrains thatcause failurewithinrelatively fewcycles (i.e. fatigue

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4.5.2 Crack propagation threshold

Although the fatiguecrack propagation threshold (Kth) is defined as the

asymptoticvalueofKatwhichda/dnapproacheszero,anoperational,though

arbitrary,definitionofKthisgivenformostmaterials.Thisvalueisdefinedas

K,which corresponds to a specified fatigue crackgrowth rate (typically for

crackgrowthratesof108m/cycleorless).

It is found that the propagation thresholdbehaviour of long cracks canbe

described in terms of stress ratio (R) aswell as in terms ofmaximum stress

intensityKmax,(seereferences[1],[2]and[3]inAnnexD).Fromapracticalpoint

ofview,testingatconstantKmaxallowstoproceedfastercomparedtotestingat

constantR,since loadhistoryeffectsaregenerallynegligible.Theapproach is

basedontheobservationthatformanyalloysKthvs.Kmaxrelationshipsshowa

quasilinear dependency above certain Kmax values. Similarly, Kmax vs. R

relationshipsatlowRvaluescanbeapproximatedbylinearrelations.

Under the assumption of linear dependence, Kth vs. Kmax or Kmax vs. R,

relationsforamaterialcanbedeterminedbyarelativelylownumberoftests.

Accordingly the requirement section covers two methods to determine the

fatiguecrackpropagationthresholdformetallicmaterials:

DeterminationofanoperationalvalueofKth)accordingtoASTME647.

Determinationof(Kth)bytestingatconstantKmax.

4.6 Fracture and fatigue test in special environment

Fatigueand

crack

propagation

behaviour

of

metallic

materials

exposed

to

gaseousorliquidenvironmentscandifferfromthatexhibitedinair.Testresults

obtained from fatigueand fracture tests inenvironmentsrepresentativeof the

serviceconditionsareused toevaluate the influenceofspecificenvironments

onthematerialbehaviour.

The method covers tests to determine the influence of environments

representative of service conditions on the fatigue and fracturebehaviour of

metallicmaterials.

4.7 Stress corrosion cracking test

4.7.1 Overview

Thetestreferstomethodsforthedeterminationofthesusceptibilityofmetallic

materialstostresscorrosioncracking.

4.7.2 Stress corrosion cracking test using smoothspecimens

Theresults

of

this

tests

are

used

to

classify

alloys,

weldments

and

their

individual heat treatment conditionswith respect to thematerial resistance

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against stress corrosion cracking.When sufficient stress corrosiondata exists

the alloy designation can be submitted for inclusion into relevant tables

containedinECSSQST7036.

The method covers the determination of the susceptibility of metals and

weldmentstostresscorrosioncrackingbyalternateimmersionin3,5%sodium

chloridewatersolutionunderconstantload.

4.7.3 Stress corrosion cracking test using pre-cracked specimens

This testmethod allows the determination of the threshold stress intensity

factor value for stress corrosion cracking KISCC, and the kinetics of crack

propagation.

Theuseofprecrackedspecimensacknowledgesthefactthatdefectsintroduced

during manufacturing and subsequent services are always present in real

structures.Furthermore,thepresenceofsuchdefectscancauseasusceptibility

tostresscorrosioncracking,whichinsomematerials(e.g.titaniumalloys)isnot

alwaysevidentfromtestsconductedonsmoothspecimens.

This testmethod covers preparing and testing of precracked specimens for

investigatingsusceptibilitytostresscorrosioncrackingofmetallicmaterials.

4.8 Creep test

Theresultsofthistestmethodareusedtoassessthe loadcarryingabilityofa

materialat

high

temperatures

for

limited

deformations

and

as

afunction

of

time.Thetestprovidesinformationtoassessthesuitabilityofmaterialsforhigh

temperaturestructuralapplications.

The method covers the determination of the amount of deformation as a

functionoftime(creeptest)andofthetimeforfracturetooccur(rupturetest)in

materialssubjectedtoconstanttensileforcesatconstanttemperature.

4.9 Test resul ts presentation

Beforeresultsobtained frommechanical testscanbeappliedwithconfidence,

allowable values are statistically determined. The applicability of statistical

methodstotheevaluationofnumericalresultsdependson:

thenumberoftestsperformedonaspecificmaterialandtestconditions,

which should be large enough to constitute a statistically significant

sample;

the assumption that test data constitute a random sample of (or

representationof)thepopulationofthematerialunderinvestigation.

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5Requirements

5.1 Customer agreement

a.

a.

b.

a.

b.

c.

Testmethodsandproceduresshallbeagreedwiththecustomerpriortotesting.

5.2 Tensi le testing

5.2.1 GeneralTestapparatus,specimens,testprocedures,precisionandbiasshallbein

conformancewithEN100021.

Aminimumnumber of three tests shallbe carried out for each set ofmaterialandtestconditions.

5.2.2 Tensile testing of weldmentsSpecimenswithatransverseweldshallbemanufacturedwith theweld

jointlineonthecentreofthespecimengaugelength.

Specimenswithalongitudinalweldshallbemanufacturedwiththeweld

jointlineonthespecimenlongitudinalaxis.

For specimenswitha transverseweld, thespecimengauge length shall

beequal

or

greater

than

the

weld

heat

affected

zone

(HAZ).

NOTE1 When testing specimenswith a transverseweld,

note that the strain distributionwithin theHAZ

variesasa functionofthedistance fromtheweld

centreline.Thisimpliesthatelongationvariesasa

functionofthegaugelength.

NOTE2 Weldmentsarecharacterizedbynonuniformityin

tensileproperties.

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5.3 Fracture toughness test

5.3.1 KIc test methoda.

b.

c.

d.

a.

b.

a.

b.

a.

b.

Testapparatus,specimens,testprocedures,precisionandbiasshallbein

conformancewithASTME399.

The crackplane orientation code for rectangular sections, forbars and

hollow cylinders in conformance with ASTME399 shall be used

throughouttestingandreporting.

Aminimum number of threeKIc valid tests, in conformancewith the

validity criteria of ASTME399, shall be carried out for each set of

materialandtestcondition.

If any dimension of the available stock of amaterial is insufficient to

provideaspecimenoftherequiredsizetoproduceavalidKIcresult,the

specimen strength ratio (Rsx) shall be used to provide a comparative

measureofthetoughnesswhenthespecimensareofthesameformandsize.

NOTE In certain materials (e.g. some structural grade

steels)theplanestraintoughnessissensitivetothe

loadingrate.In thesecasesthe testloadingrate is

selectedwithrespect to thespecificapplicationof

thetestresults.

5.3.2 JIc test methodTestapparatus,specimens,testprocedures,precisionandbiasshallbein


Aminimum number of threeJIc valid tests, in conformancewith the

validity criteria of ASTME1820, shall be carried out for each set of

materialandtestcondition.

5.3.3 R-curve test methodTestapparatus,specimens,testprocedures,precisionandbiasshallbein


Aminimumnumberofthreevalidtests,inconformancewiththevalidity

criteriaofASTME561,shallbecarriedout foreachsetofmaterialandtestcondition.

5.3.4 CTOD test methodTestapparatus,specimens,testprocedures,precisionandbiasshallbein


Aminimumnumberofthreevalidtests,inconformancewiththevalidity

criteriaofASTME1290,shallbecarriedoutforeachsetofmaterialand

testcondition.

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5.4 Fatigue test

5.4.1 Force control led constant amplitude axialfatigue test

a.

b.

c.

d.

e.

f.

g.

h.

i.

a.

b.

c.



Fatiguestrengthvaluesshallbedeterminedinthefiniteliferangeandin

thetransitionrange.

Theminimum number of tests and load levels shallbe established in

relationtothetypeoftestprogrammeconducted.

NOTE For example: exploratory research and

development tests, design allowables data,

reliabilitydata.

Forthefiniteliferange,thefollowingminimumsshallapply:

1. aminimumofsixtestsperselectedstresslevel;

2. aminimumofthreestresslevels.

Inthetransitionrange(infiniteliferange),theselectionoftheteststress

levelsshallbeaccordingtothestaircasemethod,theboundarymethodor

thearcsinemethod.

NOTE A review of these methods can be found in

ISO3800

Fatigue test stress levels shallbe selected in order to obtain constant

stressratio(R)stresslifedatasets.

Statisticalanalysis

of

test

results

shall

be

carried

out

in

conformance

with

ASTME739.

When testing a nominally homogeneous material, specimens with

continuousradiusbetweenendsshallbeused.

Axial load fatigue testing of threaded fasteners shallbe carried out in

conformancewithclauseFatiguetestofECSSQST7046.

NOTE Fatiguestrengthofweldedcomponentsistypically

influencedbyweldresidualstress.Forthisreason,

fatigue testing of weld coupons is not

representativeoftheeffectsofweldresidualstress

onthefatiguestrengthofrealcomponents.

5.4.2 Strain-controlled fatigue testTestapparatus,specimens,testprocedures,precisionandbiasshallbein


Fatiguestrengthvaluesshallbedeterminedinthefiniteliferangeuptoa

predeterminednumberofstresscycles.

NOTE Thenumberofpredeterminedstresscyclesforthe

finiteliferangeistypically105straincycles

Test requirements as specified in 5.4.1c, 5.4.1d, 5.4.1e and 5.4.1f shall

apply.

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5.5 Fatigue crack propagation test

5.5.1 Determination of fatigue crack growth ratea.

b.

c.

d.

e.

f.

a.

a.



NOTE C(T)specimensshouldbeusedfortestscarriedout

at positive stress ratios, andM(T) specimens for

testscarriedoutatnegativestressratios.Specimen

configurations other thanC(T) andM(T)maybe

used providing that well established stress

intensity factor solutions are available and that

specimens are of sufficient planar size to remain

predominantlyelasticduringtesting.

A minimum of three valid tests shall be carried out for each set of

materialsand

test

conditions.

NOTE ForvaliditycriteriaseeASTME647.

Accuracyandresolutionofselectedcrack lengthmeasurementmethods

shallbeassessedbeforetesting.

NOTE Measurementmethods are optical, direct current

potentialdroptechniqueandcompliancemethods.

Thefilmreplicatechniqueshouldbeusedtomeasurethelengthofshort

cracks.

At the end of the test crack length values obtainedwith the selected

measurementmethodshallbecorrelatedtothephysicalcracklengthby

fractographicexamination.Tests to characterize the crack propagationbehaviour in the threshold

regimeshallbecarriedouttomeetcrackgrowthratesasspecifiedbythe

customer.

NOTE Typical growth rates of the threshold regime are

lessthan108m/cycles.

5.5.2 Determination of a fatigue crackpropagation threshold

5.5.2.1 Operational value ofKthDetermination of operational values of Kth shall be carried out

accordingtothetestprocedureofASTME647,clause9.4.

5.5.2.2 Alternative determination ofKth values by testingat constant Kmax

Crackpropagation tests shallbe carried out under constantmaximum

stressintensityfactorKmaxandinconformancewithclause5.5.1.

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5.6 Fracture and fatigue tests in special environments

a.

b.

c.

a.

a.

b.c.

d.

e.

a.

b.

a.

Test apparatus, specimens, testprocedures,precision andbias shallbe

agreedwiththecustomerpriortotesting.

Transportation,handlinganddisposalofhazardoussubstancesshallbe

inagreementwiththeapplicablehealthandsafetyrules.NOTE Forexample:material safetydata sheets,national

healthandsafetyrules.

Compositionandpurityofthetestenvironmentshallbemonitoredand

controlledthroughoutthetest.

5.7 Stress corrosion cracking test

5.7.1 Stress corrosion cracking test using smoothspecimens


conformancewithECSSQST7037.

5.7.2 Stress corrosion cracking test using pre-cracked specimens


conformancewithISO75396:2003.

Testsshallbecarriedoutunderconstantload.Thenumberof tests tobe carriedout for each setofmaterial and test

conditionsshallbeagreedwiththecustomer.

Specimensshallbestressedafterbeingbroughtintocontactwiththetest

environment,

Alternatively thespecimensshallbeexposedto thetestenvironmentas

soonaspossibleafterstressing.

5.8 Creep test



Theminimumofnumberofteststobecarriedoutforeachsetofmaterial

andtestconditionshallbeagreedwiththecustomer.

5.9 Evaluation of test results

Arithmeticmeanvalueandstandarddeviationshallbecalculated from

eachsetofnumericalresultsobtainedbytestingaspecificmaterialunder

sametest

conditions.

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b.

c.

d.

a.

a.

b.

c.

a.

b.

c.

a.

b.

c.

Statistical analysis of numerical results of toughness tests shall be

conductedinconformancewithclause4ofESDU96013.

Statisticalanalysisofnumericalresultsoffatiguetestsshallbeconducted

inconformancewithclause5.4.1g.

Data reduction of numerical results of fatigue crack propagation tests

shallbeconductedinconformancewithASTME647,AppendixX1.

5.10 Storage

Storageofmaterialsandspecimensshallbeagreedwiththecustomer.

5.11 Reporting

The Request formechanical testingofmaterials shallbe issuedby the

customerinconformancewiththeDRDofAnnexA.

The Proposalformechanicaltestingofmaterials shallbeissuedbythe

supplierinconformancewiththeDRDofAnnexBandsubmittedtothe

customerforreviewandapproval.

The Report ofmechanical testing ofmaterials shallbe issuedby the

supplierinconformancewiththeDRDofAnnexCandsubmittedtothe

customerforreviewandapproval.

5.12 Quality assurance

5.12.1 General

The supplier shall implementquality assurance, inspectionandquality

controlproceduresbeforeanytestactivity.

Theimplementationoftheproceduresshallbemaintainedfortheentire

durationofthetestactivity.

The supplier shall establish and implementquality control actions and

inspectionstoprovideevidenceofconformitytotestrequirements.

NOTE

Qualitycontrol

actions

and

inspections

for

test

activities carried out by subcontracted

laboratories are under the responsibility of the

supplier.

5.12.2 CalibrationCalibration of test equipment shall be carried out and maintained

throughoutthetestactivity.

Calibrationoftensiletestingmachinesandextensometersshallbecarried

outinconformancetoEN100022andEN100024,respectively.

Calibration records shall be readily accessible and retrievable on

customerrequestfortheentiredurationofthebusinessagreement.

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5.12.3 Quality control of raw materialsa.

b.

a.

b.

a.

b.

c.

d.

The supplier shallprovidedocumentedevidence thatonlymaterials in

conformancewiththecustomerspecificationsareusedinthetestactivity.

The supplier of rawmaterials shall include a rawmaterial certificate

(RMC)ineachtestreportinconformancewiththeDRDofAnnexC.

5.12.4 NonconformanceNonconformanceofmaterials,specimenpreparation, testing,evaluation

and reporting shall be documented in a nonconformance report in

conformancewith theNCRDRD ofECSSQST1009, and reported to

thecustomer.

Upon customer request, results affected by nonconformities shall be

invalidatedandtestsrepeated.

5.12.5 Traceability and recordsMaterialsshallbedurablymarkedtounivocallyidentifymanufacturers

code,batchnumber,materialstandarddesignationandgrainorientation.

Specimens shall be durablymarked to univocally identify individual

specimensandgrainorientation.

Testrecordsshallbemaintainedandoncustomerrequestaccessibleand

retrievablefortheentiredurationofthebusinessagreement.

Thecustomershallauthorizedisposalofmaterialsandspecimens.

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Annex A (normative)Request for mechanical testing of

materials DRD

A.1 DRD identification

A.1.1 Requirement ident if ication and source document

ThisDRDiscalledfromECSSQST7045,requirement5.11a.

A.1.2 Purpose and objec tive

Thedocument Request formechanical testingofmaterials specifies the test

activityrequestedbythecustomerformechanicaltestingofmetallicmaterials.

Therequestformechanicaltestingisbasisforthesuppliertosubmitaproposalfortherelevanttestactivity.

A.2 Expected response

A.2.1 Scope and content

Backgroundinformation

a.

a.

a.

Informationtothetechnical,businessagreementandprojectbackgroundofthetestactivityshallbedescribed.

Objectiveoftestactivity

Theobjectiveoftherequestedtestactivityshallbedescribed.

Materialidentification

Material, designation, heat treatment, form and configuration,

procurementsourceshallbeidentified.

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Testdefinition

a.

b.

a.

a.

a.

b.

Environment, number of tests and measurement techniques shall be

identified.

Referencetoapplicablestandardsshallbegiven.

Testoutput

Therequestedtestoutputshallbespecified.

NOTE Forexample:Numberofcycles,determinedcrack

lengthandcrackgrowthrates.

Additionalrequest

Anyotherspecificcustomerrequestshallbespecified.

A.2.2 Special remarks to document tit leThedocumentshallbetitled[insertadescriptivemodifier]Requestfor

mechanicaltestingofmaterials.

The descriptive modifier shall be selected to clearly identify the

applicableproduct.

NOTE1 Forexample:Measurementoffracturetoughness

ofAA7175T7351plateRequest formechanical

testingofmaterials.

NOTE2 For example: Fatigue crack propagation

behaviour of Ti6Al4V STA sheet at different

stress ratios Request formechanical testing of

materials.

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Annex B (normative)Proposal for mechanical testing of

materials DRD

B.1 DRD identification

B.1.1 Requirement identification and source document

ThisDRDiscalledfromECSSQST7045,requirement5.11b.

B.1.2 Purpose and objective

Thedocument Proposal formechanical testing ofmaterials defines the test

activity formechanical testingofmetallicmaterialsproposedby the supplier.

Thesupplierpreparesthedocumentandsubmitsittothecustomerforreviewandapproval.

B.2 Expected response

B.2.1 Scope and content

Descriptionofwork

a. Theproposedtestactivityshallbedescribedintheformofastatementofworkincluding:

1. Descriptionoftheobjectiveofthetestactivity.

2. Description of proposed test method including reference to

applicablestandards

3. Identificationofthematerialtobetested.

4. Definition and confirmation of test conditions (i.e. environment,

specimen geometry and orientation, number of specimens and

measurementtechniques)

5. Description of expected test output (i.e. crack length,number of

cycles,crackgrowthrates).

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Testprocedures

a.

a.

a.

b.

Proposed test procedures shall be described and deviations from

standardtestproceduresidentified.

Financial

and

administrative

proposal

Afinancialandadministrativeproposalshallbepresentedincluding:

1. Identificationofresponsiblepersonfortheactivity;

2. List of deliverable items including test records with tabulated

values of crack length, number of cycles, growth rates, stress

intensityandrespectiveunitsofmeasure;

3. Workbreakdownstructuredefiningresponsibilitiesfor:

(a) procurementofrawmaterial,

(b) preparationofspecimens,

(c) heattreatment,

(d) testing,

(e) evaluationofresults,

(f) reporting.

4. Timeschedule;

5. Travelandsubsistenceplan;

6. Itemizedcostlist;

7. Milestonepayment

plan.

B.2.2 Special remarks to document title

Thedocumentshallbe titled[insertadescriptivemodifier]Proposal

formechanicaltestingofmaterials.


applicableproduct.

NOTE1 Forexample: Measurementoffracturetoughness

ofAA7175T7351plate Request formechanical

testingof

materials.

NOTE2 Forexample: Fatigue crack propagation

behaviour of Ti6Al4VSTA sheet at different


materials.

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Annex C (normative)Report of mechanical testing of materials

DRD

C.1 DRD identification

C.1.1 Requirement identification and source document

ThisDRDiscalledfromECSSQST7045,requirement5.11cand5.12.3b.

C.1.2 Purpose and objective

The document Report of mechanical testing of materials describes and

discussestestproceduresandresultsofmechanicaltestingofmetallicmaterials.

The document contains the elements and information relevant to the

understandingandcorrectinterpretationofthetestactivityandtestresults.

Thesupplierpreparesthedocumentandsubmitsittothecustomerforreview

andapproval.

C.2 Expected response

C.2.1 Scope and contents

Abstract

a.

a.

Theabstract shall summarize the testprocedureand themost relevant

findingsofthetestactivity.

Introduction

The introduction shall provide background information to the test

including:

1. Reasonsforcarryingoutthetestactivity;

2. Reference to any previous relevant test activities and technical

reports;

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3. Useandapplicabilityoftheresults;

4. Identification of other organizations that contributed to the test

activity;

5. Objectivesofthetestactivity.

Informationonrawmaterial

a.

b.

c.

d.

a.

b.

c.

d.

a.

b.

Thedocument shall includea rawmaterialcertificate (RMC) issuedby

thesupplieroftherawmaterial.

TheRMCshallbedeliveredtogetherwiththerawmaterial,

TheRMCshallinclude:

1. batchsuppliersnameandcode,

2. materialstandarddesignationandheattreatment,

3. dateofbatchmanufacturing,

4. specifiedchemicalcomposition,

5. materialandheattreatmentspecifications,

6. productform,quantity,dimensionsandgrainorientation,

7. surfacetreatment,

8. descriptionofmanufacturingprocesses.

NOTE Forexample:welding,cuttingandmilling.

9. nondestructiveinspection.

Thedocument

shall

indicate

the

raw

material

tensile

properties

with

respecttothegrainorientationandhardness.

NOTE1 Tensile properties include elasticmodulus, 0,2%

proofstress,tensilestrengthandelongation

NOTE2 ThesepropertiesareeitherspecifiedintheRMCor

obtainedbytestingtherawmaterialupondelivery

Descriptionoftestprocedures

Thedocumentshallprovideanunivocalandcompletedescriptionofthe

specimenpreparation,testequipmentandtestprocedure.

Theinformationprovidedshallbeinconformancewiththerequirements

specifiedintherelativesectionsoftheapplicableteststandards.

Estimated values of precision and bias for the test results shall be

indicated.

Anomaliesanddeviationsfromstandardproceduresshallbereported.

Testresults

Testresultsshallbepresentedinanappropriateformatusingdrawings,

plots,diagramsandphotos.

Test results shall be described and conformance to requirementsdiscussed.

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c.

a.

b.

Unitsofmeasureandscalesshallbeconsistentandinagreementwiththe

customerspecifications.

C.2.2 Special remarks to document title

Thedocumentshallbe titled[insertadescriptivemodifier]Proposalformechanicaltestingofmaterials.


applicableproduct.

NOTE1 Forexample:Measurementoffracturetoughness

ofAA7175T7351plate Request formechanical

testingofmaterials.

NOTE2 For example: Fatigue crack propagation

behaviour of Ti6Al4V STA sheet at different


materials.

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Annex D (informative)References

[1] H.Doeker,Y.BachmannandG.Marci,Acomparisonofdifferentmethodsof

determination of the threshold for fatigue crack propagation, Fatigue

Thresholds,16June1981,Stockholm.

[2] H. Doeker and M. Peters, Fatigue threshold dependence on materialenvironment and microstructure, Fatigue 84, 37 September 1984,

Birmingham,UK.

[3] H.Doeker,Fatiguecrackgrowth threshold: implications,determinationand

data evaluation, International Conf. on Fatigue Damage in Structural

Materials,EngineeringFoundation,1996,Massachusetts,US.

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Bibliography

ECSSSST00 ECSSsystemDescription,implementationand

generalrequirements

ECSSQST7036 SpaceproductassuranceMaterialselectionfor

controllingstresscorrosioncracking

ISO3800 ThreadedfastenersAxialloadfatiguetesting

Test

methods

and

evaluation

of

results.

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