1、Designation: E 1823 07aStandard 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 (e) 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 standard
3、s 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 Me
5、thods 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-ti
7、gue 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 Meas
8、urement 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 f
9、or 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 M
10、ethod 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
12、Test Method for Determination of Reference Tem-perature, To, for Ferritic Steels in the Transition RangeE 2472 Test Method for Determination of Resistance toStable Crack Extension under Low-Constraint Conditions1This terminology is under the jurisdiction ofASTM Committee E08 on Fatigueand Fracture a
13、nd is the direct responsibility of Subcommittee E08.02 on Standardsand Terminology.Current edition approved Aug. 1, 2007. Published August 2007. Originallyapproved in 1996. Last previous edition approved in 2007 as E 1823 07.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcon
14、tact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.G15 Termin
15、ology 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 lengthaooriginal crack sizeapphysical crack sizea/W normalized crac
16、k 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 rated crack-tip opening displacement
17、(CTOD)dd specimen gage lengthDa crack extension, estimated crack extensionDK stress-intensity-factor rangeDKthfatigue-crack-growth thresholdDP force rangeeastrain amplitudeeininelastic strainemmean forceG crack-extension forceGRcrack-extension resistanceH* specimen center of pin hole distanceG the p
18、ath 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 fracture tough
19、nessKcplane-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, KIvjplane-strain
20、 (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 forceq fati
21、gue notch sensitivityr effective unloading slope ratiorccritical slope ratioryplastic-zone adjustmentR force ratio (Pmin/Pmax)s sample standard deviations2sample varianceSymbol TermS specimen spanSaforce amplitudeSffatigue limitSmmean forceSNfatigue strength at N cyclessccrack strengthsNnominal (net
22、-section) stresssrresidual strengthsssharp-notch strengthsTStensile strengthsx, sy, sznormal stresses (refer to )sYeffective yield strengthsYSyield strengthT specimen temperaturetTtransition timetttotal cycle periodtxy,tyz, tzxshear stresses (refer to Fig. 1)u displacement in x directionv displaceme
23、nt 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 displacem
24、entCOD 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 width3.3 DefinitionsEach definition is f
25、ollowed 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 from afracture mechanics analysis for a specific configurati
26、on. 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-intensity factors. E 647blockin fatigue loading, a specified num
27、ber of constantamplitude loading cycles applied consecutively, or a spec-trum loading sequence of finite length that is repeatedidentically. E 1823blunting linein fracture testing, a line that approximatesapparent crack advance due to crack-tip blunting in theabsence of slow stable crack tearing. Th
28、e 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 strength of the material tested. E 813DaB5 J/2 sY(1)circulation rate L3T1in fatigue testing, the volume
29、rateof change of the environment chamber volume. E 1823E 1823 07a2clippingin fatigue spectrum loading, the process of decreas-ing or increasing the magnitude of all loads (strains) that are,respectively, above or below a specified level, referred to asclipping level; the loads (strains) are decrease
30、d 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 that the statement 88the populationparameter included in this interval” will be true, o
31、n 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 interval is expected to include thepopulation parameter. E 1823confidence limitsthe t
32、wo 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 loading in fatigue loading, a loading(straining) in which all of the peak forces (strain
33、s) 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, relating stress amplitude, Sa, to meanstress, Sm, or maximum stress, Smax, or both, t
34、o 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 force, Pm Fa calculated value of maximum forceused in Test Method E 1820 to stipulate al
35、lowable 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 fewer cyclesthan would be required in the absence of the corrosiveenvironment. G15countin
36、g 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, peakcount, mean crossing peak count, range count, range-paircount, rain-flow count, racet
37、rack 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 distance that achosen measurement point on the specimen displaces normal to thecrack plane.
38、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 thedifference between the crack size, either ap(physical crack size) or ae(effective cr
39、ack size), and ao(original crack size). E 561crack-extension 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 an
40、alytical model forwhich the stress-strain relations are regarded as elastic. The precedingdefinition of G applies to either static cracks or running cracks. FromNOTESee definition of mode.FIG. 1 Customary Coordinate System and Stress on a Small Volume Element Located on the x Axis Just Ahead of the
41、Crack FrontE 1823 07a3past 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, GRFL1orJRFL1a measure of the resistance of a material to crackextension expressed in terms
42、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 apreexisting macroscopic crack created in the specimen by astipulated procedure. E 1921crack le
43、ngth, 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 resulting from the total deformation (elasticplus plastic), measured under force at
44、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 cracklength. E 740crack-plane orientationan identification of the plane anddirection of fract
45、ure or crack growth 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(s) designat-ing the expected direction of crack propagation.DISCUSSIONSee also E 1823 An
46、nex 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 stress and dis-placement fields and is often also termed crack length ordepth.DISCUSSIO
47、NFor 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
48、size, ap, original crack size, ao, andeffective crack size, ae, as appropriate to the situation being considered.E 647crack strength, scFL2the maximum value of the nomi-nal stress that a cracked structure is capable of sustaining.DISCUSSION1 Crack strength is calculated on the basis of themaximum fo
49、rce and the original minimum cross-sectional area (netcross section or ligament). Thus, it takes into account the original sizeof the crack but ignores any crack extension that may occur during thetest.DISCUSSION2 Crack strength is analogous to the ultimate tensilestrength, as it is based on the ratio of the maximum force to theminimum cross-sectional area at the start of the test. E 338, E 602FIG. 2 Clipping of Fatigue Spectrum LoadingE 1823 07a4crack-tip opening displacement (CTOD), d, Lthe crackdisp
