ASTM E1823-2009a Standard Terminology Relating to Fatigue and Fracture Testing.pdf

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1、Designation: E 1823 09aStandard TerminologyRelating to Fatigue and Fracture Testing1This standard is issued under the fixed designation E 1823; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in

2、parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This terminology contains definitions, definitions ofterms specific to certain standards, symbols, and abbreviationsapproved for use in standards

3、 on fatigue and fracture testing.The definitions are preceded by two lists. The first is analphabetical listing of symbols used. (Greek symbols are listedin accordance with their spelling in English.) The second is analphabetical listing of relevant abbreviations.1.2 This terminology includes Annex

4、A1 on Units andAnnex A2 on Designation Codes for Specimen Configuration,Applied Loading, and Crack or Notch Orientation.2. Referenced Documents2.1 ASTM Standards:2E6 Terminology Relating to Methods of Mechanical Test-ingE23 Test Methods for Notched Bar Impact Testing ofMetallic MaterialsE28 Test Met

5、hods for Softening Point of Resins Derivedfrom Naval Stores by Ring-and-Ball ApparatusE 208 Test Method for Conducting Drop-Weight Test toDetermine Nil-Ductility Transition Temperature of FerriticSteelsE 338 Test Method of Sharp-Notch Tension Testing ofHigh-Strength Sheet MaterialsE 399 Test Method

6、for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE 436 Test Method for Drop-Weight Tear Tests of FerriticSteelsE 467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemE 468 Practice for Presentation of Constant Amplitude Fa-tig

7、ue Test Results for Metallic MaterialsE 561 Test Method for K-R Curve DeterminationE 602 Test Method for Sharp-Notch Tension Testing withCylindrical SpecimensE 604 Test Method for Dynamic Tear Testing of MetallicMaterialsE 606 Practice for Strain-Controlled Fatigue TestingE 647 Test Method for Measu

8、rement of Fatigue CrackGrowth RatesE 739 Practice for Statistical Analysis of Linear or Linear-ized Stress-Life ( S-N) and Strain-Life (e-N) Fatigue DataE 740 Practice for Fracture Testing with Surface-CrackTension SpecimensE 813 Test Method for JIc, A Measure of Fracture Tough-nessE 992 Practice fo

9、r Determination of Fracture Toughness ofSteels Using Equivalent Energy MethodologyE 1049 Practices for Cycle Counting in Fatigue AnalysisE 1152 Test Method for Determining-J-R-CurvesE 1221 Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, KIa, of Ferritic SteelsE 1290 Test Me

10、thod for Crack-Tip Opening Displacement(CTOD) Fracture Toughness MeasurementE 1291 Test Method for Conducting a Saturated VaporInhalation Study with RatsE 1304 Test Method for Plane-Strain (Chevron-Notch)Fracture Toughness of Metallic MaterialsE 1457 Test Method for Measurement of Creep CrackGrowth

11、Times in MetalsE 1681 Test Method for Determining Threshold Stress In-tensity Factor for Environment-Assisted Cracking of Me-tallic MaterialsE 1737 Test Method for J-Integral Characterization of Frac-ture Toughness (Discontinued 1998)3E 1820 Test Method for Measurement of Fracture Tough-nessE 1921 T

12、est Method for Determination of Reference Tem-perature, To, for Ferritic Steels in the Transition RangeE 1942 Guide for Evaluating Data Acquisition SystemsUsed in Cyclic Fatigue and Fracture Mechanics TestingE 2208 Guide for Evaluating Non-Contacting Optical StrainMeasurement SystemsE 2443 Guide for

13、 Verifying Computer-Generated Test Re-sults Through The Use Of Standard Data Sets1This terminology is under the jurisdiction ofASTM Committee E08 on Fatigueand Fracture and is the direct responsibility of Subcommittee E08.02 on Standardsand Terminology.Current edition approved Feb. 15, 2009. Publish

14、ed March 2009. Originallyapproved in 1996. Last previous edition approved in 2009 as E 1823 09.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Documen

15、t Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E 2472 Test Method for Determination of Resistance toSta

16、ble Crack Extension under Low-Constraint ConditionsG15 Terminology Relating to Corrosion and CorrosionTesting3. Terminology3.1 Alphabetical Listing of Principal Symbols Used in ThisTerminology:Symbol Terma crack depth, crack length, crack size, estimated cracksizeaeeffective crack sizeannotch length

17、aooriginal crack sizeapphysical crack sizea/W normalized crack sizeA force ratio (Pa/Pm)ANnet-section areab remaining ligamentbooriginal uncracked ligamentB specimen thicknessBeeffective thicknessBNnet thickness2c surface-crack lengthC normalized K-gradientD cycle ratio (n/Nf)C*(t) C*(t) Integralda/

18、dN fatigue-crack-growth rated crack-tip opening displacement (CTOD)dd specimen gage lengthDa crack extension, estimated crack extensionDK stress-intensity-factor rangeDKthfatigue-crack-growth thresholdDP force rangeastrain amplitudeininelastic strainmmean forceG crack-extension forceGRcrack-extensio

19、n resistanceH* specimen center of pin hole distanceG the path of the J-integralJJ-integralJIcplane-strain fracture toughnessJRcrack-extension resistancekffatigue notch factorkttheoretical stress concentration factor (sometimes ab-breviated stress concentration factor)K, K1, K2, K3,KI, KII, KIIIstres

20、s-intensity factor (see mode)Kacrack-arrest fracture toughnessKcplane-stress fracture toughnessKEACstress intensity factor threshold for environment-assisted crackingKIaplane-strain crack-arrest fracture toughnessKIEACstress intensity factor threshold for plane strainenvironment-assisted crackingKIc

21、plane-strain fracture toughnessKIvM, KIv, KIvjplane-strain (chevron-notch) fracture toughnessKmaxmaximum stress-intensity factorKminminimum stress-intensity factorKostress-intensity factor at crack initiationKRcrack-extension resistancen cycles enduredNffatigue lifeP forcePaforce amplitudePmmean for

22、cePMprecrack forcePmaxmaximum forcePminminimum forceq fatigue notch sensitivityr effective unloading slope ratiorccritical slope ratioryplastic-zone adjustmentSymbol TermR force ratio (Pmin/Pmax)s sample standard deviations2sample varianceS specimen spanSaforce amplitudeSffatigue limitSmmean forceSN

23、fatigue strength at N cyclessccrack strengthsNnominal (net-section) stresssrresidual strengthsssharp-notch strengthsTStensile strengthsx, sy, sznormal stresses (refer to )sYeffective yield strengthsYSyield strengthT specimen temperaturetTtransition timetttotal cycle periodtxy,tyz, tzxshear stresses

24、(refer to Fig. 1)u displacement in x directionv displacement in y direction2vmcrack-mouth opening displacementVcforce-line displacement due to creepw displacement in z directionW specimen widthY* stress-intensity factor coefficientY*mminimum stress-intensity factor coefficient3.2 Alphabetical Listin

25、g of Abbreviations Used:CMOD crack-mouth opening displacementCOD see CTODCTOD crack-tip opening displacementDT dynamic tearDWTT drop-weight tear testEAC environment-assisted crackingK-EE equivalent-energy fracture toughnessNTS notch tensile strengthPS part-through surfaceSCC stress corrosion crackin

26、gSZW stretch zone width3.3 DefinitionsEach definition is followed by the desig-nation(s) of the standard(s) of origin. The listing of definitionsis alphabetical.alternating forceSee loading amplitude.applied-K curvea curve (a fixed-force or fixed-displacement crack-extension-force curve) obtained fr

27、om afracture mechanics analysis for a specific configuration. Thecurve relates the stress-intensity factor to crack size andeither applied force or displacement.DISCUSSIONThe resulting analytical expression is sometimes calleda K calibration and is frequently available in handbooks for stress-intens

28、ity factors. E 647basic datathe sampled value of a sensor taken at fixed orvariable time intervals. Each sample represents the valuemeasured by the sensor at that instant of time.DISCUSSIONin Test Method E 2208, for optical, non-contactingmethods, a two dimensional array of image intensity data is g

29、enerallythe basic data. E 1942, E 2208, E 2443blockin fatigue loading, a specified number of constantamplitude loading cycles applied consecutively, or a spec-trum loading sequence of finite length that is repeatedidentically. E 1823E 1823 09a2blunting linein fracture testing, a line that approximat

30、esapparent crack advance due to crack-tip blunting in theabsence of slow stable crack tearing. The line is definedbased on the assumption that the crack advance is equal toone half of the crack-tip opening displacement.This estimateof pseudo-crack advance, DaB, is based on the effectiveyield strengt

31、h of the material tested. E 813DaB5 J/2 sY(1)circulation rate L3T1in fatigue testing, the volume rateof change of the environment chamber volume. E 1823clippingin fatigue spectrum loading, the process of decreas-ing or increasing the magnitude of all loads (strains) that are,respectively, above or b

32、elow a specified level, referred to asclipping level; the loads (strains) are decreased or increasedto the clipping level (see Fig. 2). E 1823compliance (LF1, n the ratio of displacement increment toforce increment. E 1820confidence intervalan interval estimate of a populationparameter computed so t

33、hat the statement 88the populationparameter included in this interval” will be true, on theaverage, in a stated proportion of the times such computa-tions are made based on different samples from the popula-tion. E 1823confidence level (or coefficient)the stated proportion of thetimes the confidence

34、 interval is expected to include thepopulation parameter. E 1823confidence limitsthe two statistics that define a confidenceinterval. E 1823control force, Pm Fa calculated value of maximum forceused in Test Method E 1820 to stipulate allowable precrack-ing limits. E 1820, E 1921constant amplitude lo

35、ading in fatigue loading, a loading(straining) in which all of the peak forces (strains) are equaland all of the valley forces (strains) are equal. E 1049constant life diagram in fatigue, a plot (usually on rectan-gular coordinates) of a family of curves each of which is fora single fatigue life, N,

36、 relating stress amplitude, Sa, to meanstress, Sm, or maximum stress, Smax, or both, to minimumstress, Smin. The constant life fatigue diagram is usuallyderived from a family of S-N curves each of which repre-sents a different stress ratio (A or R) for a 50 % probabilityof survival. E 1823control fo

37、rce, Pm Fa calculated value of maximum forceused in Test Method E1820 to stipulate allowable precrack-ing limits. source E 1820, E 1921corrosion fatiguethe process by which fracture occursprematurely under conditions of simultaneous corrosion andrepeated cyclic loading at lower stress levels or fewe

38、r cyclesthan would be required in the absence of the corrosiveenvironment. G15counting methodin fatigue spectrum loading, a method ofcounting the occurrences and defining the magnitude ofvarious loading parameters from a load-time history; (someof the counting methods are: level crossing count, peak

39、count, mean crossing peak count, range count, range-paircount, rain-flow count, racetrack count). E 1049crack displacement Lthe force-induced separation vectorbetween two points (on the facing surfaces of a crack) thatwere initially coincident.DISCUSSIONIn Practice E 561, displacement is the distanc

40、e that achosen measurement point on the specimen displaces normal to thecrack plane. Measurement points on the C(W) and C(T) specimenconfigurations are identified as locations V0, V1, and V2. E 561crack extension, Da Lan increase in crack size.DISCUSSIONFor example, in Practice E 561, Dapor Daeis th

41、eNOTESee definition of mode.FIG. 1 Customary Coordinate System and Stress on a Small Volume Element Located on the x Axis Just Ahead of the Crack FrontE 1823 09a3difference between the crack size, either ap(physical crack size) or ae(effective crack size), and ao(original crack size). E 561crack-ext

42、ension force, G FL1or FLL2the elastic en-ergy per unit of new separation area that is made available atthe front of an ideal crack in an elastic solid during a virtualincrement of forward crack extension.DISCUSSIONThis force concept implies an analytical model forwhich the stress-strain relations ar

43、e regarded as elastic. The precedingdefinition of G applies to either static cracks or running cracks. Frompast usage, G is commonly associated with linear-elastic methods ofanalysis, although the J (see J-integral) also may be used for suchanalyses. E 1823crack-extension resistance, KRFL3/2, GRFL1o

44、rJRFL1a measure of the resistance of a material to crackextension expressed in terms of the stress-intensity factor, K;crack-extension force, G; or values of J derived using theJ-integral concept.DISCUSSIONSee definition of R-curve. E 561crack initiationthe onset of crack propagation from apreexisti

45、ng macroscopic crack created in the specimen by astipulated procedure. E 1921crack length, a LSee crack size and surface cracklength. Also see crack length in the Description of Terms.E 647crack-mouth opening displacement (CMOD),2vmLtheMode 1 (also called opening-mode) component of crackdisplacement

46、 resulting from the total deformation (elasticplus plastic), measured under force at the location on a cracksurface that has the greatest elastic displacement per unitforce.DISCUSSIONIn part-through surface-crack (PS) specimens, CMODis measured on the specimen surface at the midpoint of the cracklen

47、gth. E 740crack-plane orientationan identification of the plane anddirection of fracture or crack extension in relation to productconfiguration. This identification is designated by a hyphen-ated code with the first letter(s) representing the directionnormal to the crack plane and the second letter(

48、s) designat-ing the expected direction of crack propagation.DISCUSSIONSee also E 1823 Annex A2,(A2.4 on crack or notchorientation). E 399, E 1457crack size, a La lineal measure of a principal planardimension of a crack. This measure is commonly used in thecalculation of quantities descriptive of the

49、 stress and dis-placement fields and is often also termed crack length ordepth.DISCUSSIONFor example, in the C(T) specimen a is measured fromthe line connecting the bearing points of force application; in the M(T)specimen, a is measured from the perpendicular bisector of the centralcrack.DISCUSSIONIn practice, the value of a is obtained from proceduresfor measurement of physical crack size, ap, original crack size, ao, andeffective crack size, ae, as appropriate to the situation being considered.E 647FIG. 2