ASTM E1823-2012a Standard Terminology Relating to Fatigue and Fracture Testing.pdf

1、Designation:E182312 Designation: E1823 12aStandard TerminologyRelating to Fatigue and Fracture Testing1This standard is issued under the fixed designation E1823; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi

2、sion. A number in 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 of terms specific to certain standards, symbols, and abbreviationsapproved f

3、or use in standards on fatigue and fracture testing. The definitions are preceded by two lists. The first is an alphabeticallisting of symbols used. (Greek symbols are listed in accordance with their spelling in English.) The second is an alphabeticallisting of relevant abbreviations.1.2 This termin

4、ology includes Annex A1 on Units and Annex A2 on Designation Codes for Specimen Configuration, AppliedLoading, and Crack or Notch Orientation.2. Referenced Documents2.1 ASTM Standards:2E6 Terminology Relating to Methods of Mechanical TestingE23 Test Methods for Notched Bar Impact Testing of Metallic

5、 MaterialsE28 Test Methods for Softening Point of Resins Derived from Naval Stores by Ring-and-Ball ApparatusE208 Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic SteelsE338 Test Method of Sharp-Notch Tension Testing of High-Strength Sheet Mat

6、erialsE399 Test Method for Linear-Elastic Plane-Strain Fracture Toughness KIcof Metallic MaterialsE436 Test Method for Drop-Weight Tear Tests of Ferritic SteelsE467 Practice for Verification of Constant Amplitude Dynamic Forces in an Axial Fatigue Testing SystemE468 Practice for Presentation of Cons

7、tant Amplitude Fatigue Test Results for Metallic MaterialsE561 Test Method for K-R Curve DeterminationE602 Test Method for Sharp-Notch Tension Testing with Cylindrical SpecimensE604 Test Method for Dynamic Tear Testing of Metallic MaterialsE606 Practice for Strain-Controlled Fatigue TestingE647 Test

8、 Method for Measurement of Fatigue Crack Growth RatesE739 Practice for Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain-Life (-N) Fatigue DataE740 Practice for Fracture Testing with Surface-Crack Tension SpecimensE813 Test Method for JIc, A Measure of Fracture ToughnessE992

9、Practice for Determination of Fracture Toughness of Steels Using Equivalent Energy MethodologyE1049 Practices for Cycle Counting in Fatigue AnalysisE1152 Test Method for Determining-J-R-CurvesE1221 Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, KIa, of Ferritic SteelsE1290

10、 Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness MeasurementE1304 Test Method for Plane-Strain (Chevron-Notch) Fracture Toughness of Metallic MaterialsE1457 Test Method for Measurement of Creep Crack Growth Times in MetalsE1681 Test Method for DeterminingThreshold Stress Int

11、ensity Factor for Environment-Assisted Cracking of Metallic MaterialsE1737 Test Method for J-Integral Characterization of Fracture ToughnessE1820 Test Method for Measurement of Fracture ToughnessE1921 Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition R

12、angeE1942 Guide for Evaluating Data Acquisition Systems Used in Cyclic Fatigue and Fracture Mechanics TestingE2207 Practice for Strain-Controlled Axial-Torsional Fatigue Testing with Thin-Walled Tubular Specimens1This terminology is under the jurisdiction of ASTM Committee E08 on Fatigue and Fractur

13、e and is the direct responsibility of Subcommittee E08.02 on Standards andTerminology.Current edition approved MarchMay 15, 2012. Published JanuaryFebruary 2013. Originally approved in 1996. Last previous edition approved in 20112012 as E1823 112.DOI: 10.1520/E1823-12A.2For referencedASTM standards,

14、 visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an ASTM s

15、tandard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by

16、ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E2208 Guide for Evaluating Non-Contacting Optical Strain Measurement SystemsE2298 Test Method for Instrumented Impact Testing of Metallic M

17、aterialsE2443 Guide for Verifying Computer-Generated Test Results Through The Use Of Standard Data SetsE2472 Test Method for Determination of Resistance to Stable Crack Extension under Low-Constraint ConditionsE2714 Test Method for Creep-Fatigue TestingE2760 Test Method for Creep-Fatigue Crack Growt

18、h TestingG15 Terminology Relating to Corrosion and Corrosion Testing3. Terminology3.1 Alphabetical Listing of Principal Symbols Used in This Terminology:Symbol Terma crack depth, crack length, crack size, estimated cracksizeaeeffective crack sizeannotch lengthaooriginal crack sizeapphysical crack si

19、zea/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/dN fatigue-crack-growth rate crack-tip o

20、pening displacement (CTOD)d specimen gage lengtha crack extension, estimated crack extensionK stress-intensity-factor rangeKthfatigue-crack-growth thresholdP force rangeastrain amplitudeininelastic strainmmean forceG crack-extension forceGRcrack-extension resistanceH* specimen center of pin hole dis

21、tance 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, KIIIstress-intensity factor (see mode)Kacrack-arrest fra

22、cture toughnessKcplane-stress fracture toughnessKEACstress intensity factor threshold for environment-assisted crackingKIaplane-strain crack-arrest fracture toughnessKIEACstress intensity factor threshold for plane strainenvironment-assisted crackingKIcplane-strain fracture toughnessKIvM, KIv, KIvjp

23、lane-strain (chevron-notch) fracture toughnessKmaxmaximum stress-intensity factorKminminimum stress-intensity factorKostress-intensity factor at crack initiationKRcrack-extension resistancen cycles enduredNffatigue lifeP forcePaforce amplitudePmmean forcePMprecrack forcePmaxmaximum forcePminminimum

24、forceq fatigue notch sensitivityr effective unloading slope ratioE1823 12a2Symbol Termrccritical slope ratioryplastic-zone adjustmentR force ratio (Pmin/Pmax)s sample standard deviations2sample varianceS specimen spanSaforce amplitudeSffatigue limitSmmean forceSNfatigue strength at N cyclesccrack st

25、rengthNnominal (net-section) stressrresidual strengthssharp-notch strengthTStensile strengthx, y, znormal stresses (refer to )Yeffective yield strengthYSyield strengthT specimen temperaturetTtransition timettotal cycle periodxy,yz, zxshear stresses (refer to Fig. 1)u displacement in x directionv dis

26、placement 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 Listing of Abbreviations Used:CMOD crack-mouth opening di

27、splacementCOD 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 crackingSZW stretch zone widthNOTESee definition of mode.F

28、IG. 1 Customary Coordinate System and Stress on a Small Volume Element Located on the x Axis Just Ahead of the Crack FrontE1823 12a33.3 DefinitionsEach definition is followed by the designation(s) of the standard(s) of origin. The listing of definitions isalphabetical.alternating forceSee loading am

29、plitude.acuracyThe quantitative difference between a test measurement and a reference value. E467, E2208applied-K curvea curve (a fixed-force or fixed-displacement crack-extension-force curve) obtained from a fracture mechanicsanalysis for a specific configuration. The curve relates the stress-inten

30、sity factor to crack size and either applied force ordisplacement.DISCUSSIONThe resulting analytical expression is sometimes called a K calibration and is frequently available in handbooks for stress-intensityfactors. E647blockin fatigue loading, a specified number of constant amplitude loading cycl

31、es applied consecutively, or a spectrum loadingsequence of finite length that is repeated identically. E1823blunting linein fracture testing, a line that approximates apparent crack advance due to crack-tip blunting in the absence of slowstable crack tearing. The line is defined based on the assumpt

32、ion that the crack advance is equal to one half of the crack-tipopening displacement.This estimate of pseudo-crack advance, aB, is based on the effective yield strength of the material tested.E813DaB5J/2sYE1823-12_1 (1)C*(t) integral, C*(t)FL1T1 a mathematical expression, a line or surface integral

33、that encloses the crack front from one cracksurface to the other, used to characterize the local stress-strain rate fields at any instant around the crack front in a body subjectedto extensive creep conditions. E1457, E2760DISCUSSION1 The C*(t) expression for a two-dimensional crack, in the x-z plan

34、e with the crack front parallel to the z-axis, is the line integral:C*t! 5 *GS W *t!dy 2 TuxdsD (1)E1823-12A_1where:W*(t) = instantaneous stress-power or energy rate per unit volume, = path of the integral, that encloses (that is,contains) the crack tip contour (see Fig. 2),ds = increment in the con

35、tour path,T = outward traction vector on ds,u= displacement rate vector at ds,x, y, z = rectangular coordinate system, andTuxds= rate of stress-power input into the area enclosed by across the elemental length, ds.DISCUSSION2 The value of C*(t) from this equation is path-independent for materials th

36、at deform according to a constitutive law that may beseparated into single-value time and stress functions or strain and stress functions of the forms:E1823-12A_4E1823-12A_5Where f1f4represent functions of elapsed time, t, strain, , and applied stress, , respectively; is the strain rate.DISCUSSION3

37、For materials exhibiting creep deformation for which the above equation is path independent, the C*(t)-integral is equal to the valueobtained from two, stressed, identical bodies with infinitesimally differing crack areas. This value is the difference in the stress-power per unitdifference in crack

38、area at a fixed value of time and displacement rate or at a fixed value of time and applied force.DISCUSSION4 The value of C*(t) corresponding to the steady-state conditions is called C*s. Steady-state is said to have been achieved when a fullydeveloped creep stress distribution has been produced ar

39、ound the crack tip. This occurs when secondary creep deformation characterized by theFIG. 2 J-Integral Crack Tip Contour and SymbolismE1823 12a4following equation dominates the behavior of the specimen.E1823-12A_6DISCUSSION5 This steady state in C* does not necessarily mean steady state crack growth

40、 rate. The latter occurs when steady state damage developsat the crack tip. For Test Method E1457 this behavior is observed as “tails” at the early stages of crack growth. Test Method E1457 deals with thisregion as the initial crack extension period defined as time t0.2, measured for an initial crac

41、k growth of 0.2 mm after first loading.Ctparameter, Ct, FL-1T-1parameter equal to the value obtained from two identical bodies with infinitesimally differing crackareas, each subjected to stress, as the difference in the stress-power per unit difference in crack area at a fixed value of time anddisp

42、lacement rate or at a fixed value of time and applied force for an arbitrary constitutive law. E1457, E2760DISCUSSIONThe value of Ctis path-independent and is identical to C*(t) for extensive creep conditions when the constitutive law described inDiscussion 2 of C*(t)-integral definition applies.DIS

43、CUSSIONUnder small-scale creep conditions, C*(t) is not path-independent and is related to the crack tip stress and strain fields only for pathslocal to the crack tip and well within the creep zone boundary. Under these circumstances, Ctis related uniquely to the rate of expansion of the creepzone s

44、ize . There is considerable experimental evidence that the Ctparameter which extends the C*(t)-integral concept into the small-scale creep andthe transition creep regime correlates uniquely with creep crack growth rate in the entire regime ranging from small-scale to extensive creep regime.DISCUSSIO

45、Nfor a specimen with a crack subject to constant force, Pandcirculation rate L3T1in fatigue testing, the volume rate of change of the environment chamber volume. E1823clippingin fatigue spectrum loading, the process of decreasing or increasing the magnitude of all loads (strains) that are,respective

46、ly, above or below a specified level, referred to as clipping level; the loads (strains) are decreased or increased to theclipping level (see Fig. 3). E1823compliance (LF1, n the ratio of displacement increment to force increment. E1820confidence intervalan interval estimate of a population paramete

47、r computed so that the statement the“the populationparameter included in this interval” will be true, on the average, in a stated proportion of the times such computations are madebased on different samples from the population. E1823confidence level (or coefficient)the stated proportion of the times

48、 the confidence interval is expected to include the populationparameter. E1823confidence limitsthe two statistics that define a confidence interval. E1823control force, Pm Fa calculated value of maximum force used in Test Method E1820 to stipulate allowable precracking limits.E1820, E1921FIG. 3 Clip

49、ping of Fatigue Spectrum LoadingE1823 12a5constant amplitude loading in fatigue loading, a loading (straining) in which all of the peak forces (strains) are equal and allof the valley forces (strains) are equal. E1049constant life diagram in fatigue, a plot (usually on rectangular coordinates) of a family of curves each of which is for a singlefatigue life, N, relating stress amplitude, Sa, to mean stress, Sm, or maximum stress, Smax, or both, to minimum stress, Smin. Theconstant life fati