1、Designation: E1823 11Standard 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 revision. A number in par
2、entheses 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 on
3、 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 A1
4、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 MechanicalTestingE23 Test Methods for Notched Bar Impact Testing ofMetallic MaterialsE28 Test Methods
5、for Softening Point of Resins Derivedfrom Naval Stores by Ring-and-Ball ApparatusE208 Test Method for Conducting Drop-Weight Test toDetermine Nil-Ductility Transition Temperature of FerriticSteelsE338 Test Method of Sharp-Notch Tension Testing of High-Strength Sheet Materials3E399 Test Method for Li
6、near-Elastic Plane-Strain FractureToughness KIcof Metallic MaterialsE436 Test Method for Drop-Weight Tear Tests of FerriticSteelsE467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemE468 Practice for Presentation of Constant Amplitude Fa-tigue Test R
7、esults for Metallic MaterialsE561 Test Method for K-R Curve DeterminationE602 Test Method for Sharp-Notch Tension Testing withCylindrical Specimens3E604 Test Method for Dynamic Tear Testing of MetallicMaterialsE606 Practice for Strain-Controlled Fatigue TestingE647 Test Method for Measurement of Fat
8、igue CrackGrowth RatesE739 Practice for Statistical Analysis of Linear or Linear-ized Stress-Life (S-N) and Strain-Life (e-N) Fatigue DataE740 Practice for Fracture Testing with Surface-Crack Ten-sion SpecimensE813 Test Method for JIc,AMeasure of FractureToughnessE992 Practice for Determination of F
9、racture Toughness ofSteels 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 Test Method for Crack-Tip Openi
10、ng Displacement(CTOD) Fracture Toughness MeasurementE1304 Test Method for Plane-Strain (Chevron-Notch) Frac-ture Toughness of Metallic MaterialsE1457 Test Method for Measurement of Creep CrackGrowth Times in MetalsE1681 Test Method for Determining Threshold Stress In-tensity Factor for Environment-A
11、ssisted Cracking of Me-tallic MaterialsE1737 Test Method for J-Integral Characterization of Frac-ture Toughness (Discontinued 1998)3E1820 Test Method for Measurement of Fracture Tough-nessE1921 Test Method for Determination of Reference Tem-perature, To, for Ferritic Steels in the Transition RangeE1
12、942 Guide for Evaluating Data Acquisition SystemsUsed in Cyclic Fatigue and Fracture Mechanics TestingE2207 Practice for Strain-Controlled Axial-Torsional Fa-tigue Testing with Thin-Walled Tubular SpecimensE2208 Guide for Evaluating Non-Contacting Optical StrainMeasurement Systems1This terminology i
13、s under the jurisdiction ofASTM Committee E08 on Fatigueand Fracture and is the direct responsibility of Subcommittee E08.02 on Standardsand Terminology.Current edition approved June 1, 2011. Published December 2011. Originallyapproved in 1996. Last previous edition approved in 2010 as E1823 10a. DO
14、I:10.1520/E1823-11.2For 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 Document Summary page onthe ASTM website.3Withdrawn. The last approved version of t
15、his historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E2298 Test Method for Instrumented Impact Testing ofMetallic MaterialsE2443 Guide for Verifying Computer-Generated Test Re-sults Thr
16、ough The Use Of Standard Data SetsE2472 Test Method for Determination of Resistance toStable Crack Extension under Low-Constraint ConditionsE2714 Test Method for Creep-Fatigue TestingE2760 Test Method for Creep-Fatigue Crack Growth Test-ingG15 Terminology Relating to Corrosion and CorrosionTesting33
17、. 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 crack sizeA force ratio (Pa/Pm)ANnet-section areab re
18、maining 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 (CTOD)dd specimen gage lengthDa crack extension,
19、estimated crack extensionDK stress-intensity-factor rangeDKthfatigue-crack-growth thresholdDP force rangeastrain amplitudeininelastic strainmmean forceG crack-extension forceGRcrack-extension resistanceH* specimen center of pin hole distanceG the path of the J-integralJJ-integralJIcplane-strain frac
20、ture 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 toughnessKcplane-stress fracture toughnessKEACstress inte
21、nsity 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 (chevron-notch) fracture toughnessKmaxmaximum stres
22、s-intensity factorKminminimum stress-intensity factorKostress-intensity factor at crack initiationKRcrack-extension resistancen cycles enduredNffatigue lifeP forceSymbol TermPaforce amplitudePmmean forcePMprecrack forcePmaxmaximum forcePminminimum forceq fatigue notch sensitivityr effective unloadin
23、g slope ratiorccritical slope ratioryplastic-zone adjustmentR force ratio (Pmin/Pmax)s sample standard deviations2sample varianceS specimen spanSaforce amplitudeSffatigue limitSmmean forceSNfatigue strength at N cyclessccrack strengthsNnominal (net-section) stresssrresidual strengthsssharp-notch str
24、engthsTStensile 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 displacement in y direction2vmcrack-mouth opening displacement
25、Vcforce-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 displacementCOD see CTODCTOD crack-tip opening displacementDT
26、 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 followed by the desig-nation(s) of the standard(s) of
27、 origin. The listing of definitionsis alphabetical.alternating forceSee loading amplitude.acuracyThe quantitative difference between a test measure-ment and a reference value. E467, E2208applied-K curvea curve (a fixed-force or fixed-displacement crack-extension-force curve) obtained from afracture
28、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-intensity factors.
29、E647blockin fatigue loading, a specified number of constantamplitude loading cycles applied consecutively, or a spec-trum loading sequence of finite length that is repeatedE1823 112identically. E1823blunting linein fracture testing, a line that approximatesapparent crack advance due to crack-tip blu
30、nting 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 strength of the material tested. E813DaB5 J/2 sY(1)C
31、*(t) integral, C*(t)FL1T1a mathematical expression,a line or surface integral that encloses the crack front fromone crack surface to the other, used to characterize the localstress-strain rate fields at any instant around the crack frontin a body subjected to extensive creep conditions. E1457,E2760D
32、ISCUSSION1 The C*(t) expression for a two-dimensional crack, inthe x-z plane with the crack front parallel to the z-axis, is the lineintegral:C*t! 5 *GSW *t!dy 2 TuxdsD (2)where:W*(t) = instantaneous stress-power or energy rate perunit volume,G = path of the integral, that encloses (that is,contains
33、) the crack tip contour (see Fig. 2),ds = increment in the contour 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 en-closed by G across the elemental length, ds.DISCUSSION2 The value
34、 of C*(t) from this equation is path-independent for materials that deform according to a constitutive lawthat may be separated into single-value time and stress functions orstrain and stress functions of the forms:5 f1t!f2s! or,5 f3!f4s!Where f1f4represent functions of elapsed time, t, strain, , an
35、dapplied stress, s, respectively; is the strain rate.DISCUSSION3 For materials exhibiting creep deformation for whichthe above equation is path independent, the C*(t)-integral is equal tothe value obtained from two, stressed, identical bodies with infinitesi-mally differing crack areas. This value i
36、s the difference in thestress-power per unit difference in crack area at a fixed value of timeand displacement rate or at a fixed value of time and applied force.DISCUSSION4 The value of C*(t) corresponding to the steady-stateconditions is called C*s. Steady-state is said to have been achievedwhen a
37、 fully developed creep stress distribution has been producedaround the crack tip. This occurs when secondary creep deformationcharacterized by the following equation dominates the behavior of thespecimen.ss5 AsnNOTESee definition of mode.FIG. 1 Customary Coordinate System and Stress on a Small Volum
38、e Element Located on the x Axis Just Ahead of the Crack FrontFIG. 2 J-Integral Contour and SymbolismE1823 113DISCUSSION5 This steady state in C* does not necessarily meansteady state crack growth rate. The latter occurs when steady statedamage develops at the crack tip. For Test Method E1457 this be
39、havioris observed as “tails” at the early stages of crack growth. Test MethodE1457 deals with this region as the initial crack extension perioddefined as time t0.2, measured for an initial crack growth of 0.2 mmafter first loading.circulation rate L3T1in fatigue testing, the volume rateof change of
40、the environment chamber volume. E1823clippingin 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 decreased or increasedto the clipping
41、 level (see Fig. 3). E1823compliance (LF1, n the ratio of displacement increment toforce increment. E1820confidence intervalan interval estimate of a populationparameter computed so that the statement 88the populationparameter included in this interval” will be true, on theaverage, in a stated propo
42、rtion of the times such computa-tions are made based on different samples from the popula-tion. E1823confidence level (or coefficient)the stated proportion of thetimes the confidence interval is expected to include thepopulation parameter. E1823confidence limitsthe two statistics that define a confi
43、denceinterval. E1823control force, Pm Fa calculated value of maximum forceused in Test Method E1820 to stipulate allowable precrack-ing limits. E1820, E1921constant amplitude loading in fatigue loading, a loading(straining) in which all of the peak forces (strains) are equaland all of the valley for
44、ces (strains) are equal. E1049constant 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, to minimumstress, Smin. The constant li
45、fe 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. E1820control force, Pm Fa calculated value of maximum forceused in Test Method E1820 to stipulate allowable precrack-ing limits. E1820, E192
46、1corrosion 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. G15counting methodin fatigue spectrum loading, a method ofc
47、ounting 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, racetrack count). E1049crack displacement Lthe force-i
48、nduced separation vectorbetween two points (on the facing surfaces of a crack) thatwere initially coincident.DISCUSSIONIn Practice E561, displacement is the distance that aFIG. 3 Clipping of Fatigue Spectrum LoadingE1823 114chosen measurement point on the specimen displaces normal to thecrack plane.
49、 Measurement points on the C(W) and C(T) specimenconfigurations are identified as locations V0, V1, and V2. E561crack extension, Da Lan increase in crack size.DISCUSSIONFor example, in Practice E561, Dapor Daeis thedifference between the crack size, either ap(physical crack size) or ae(effective crack size), and ao(original crack size). E561crack-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
