1、Designation:E182312a Designation: E1823 12bStandard 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 rev
2、ision. 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
3、for 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 termi
4、nology 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 Metalli
5、c 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 Ma
6、terialsE399 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 Con
7、stant 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 Tes
8、t 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 SteelsE129
10、0 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 In
11、tensity 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
12、RangeE1942 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 Fractu
13、re and is the direct responsibility of Subcommittee E08.02 on Standards andTerminology.Current edition approved May 15,Aug. 1, 2012. Published February 2013. Originally approved in 1996. Last previous edition approved in 2012 as E1823 12A. DOI:10.1520/E1823-12AB.2For referencedASTM standards, visit
14、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 standard
15、 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 ASTM is
16、 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 Material
17、sE2443 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 Growth Testi
18、ngG15 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 sizea/W n
19、ormalized 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 opening
20、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 distance t
21、he 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 fracture t
22、oughnessKcplane-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-st
23、rain (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
24、fatigue notch sensitivityr effective unloading slope ratioE1823 12b2Symbol Termrccritical slope ratioryplastic-zone adjustmentR force ratio (Pmin/Pmax)s sample standard deviations2sample varianceS specimen spanSaforce amplitudeSffatigue limitSmmean forceSNfatigue strength at N cyclesccrack strengthN
25、nominal (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 displaceme
26、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
27、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 widthNOTESee definition of mode.FIG. 1 C
28、ustomary Coordinate System and Stress on a Small Volume Element Located on the x Axis Just Ahead of the Crack FrontE1823 12b33.3 DefinitionsEach definition is followed by the designation(s) of the standard(s) of origin. The listing of definitions isalphabetical.alternating forceSee loading amplitude
29、.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-intensity fa
30、ctor 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 cycles appl
31、ied consecutively, or a spectrum loadingsequence of finite length that is repeated identically. E1823C*(t) integral, C*(t)FL1T1 a mathematical expression, a line or surface integral that encloses the crack front from one cracksurface to the other, used to characterize the local stress-strain rate fi
32、elds 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 plane with the crack front parallel to the z-axis, is the line integral:C*t! 5 *GS W *t!dy 2 TuxdsD (1)E1823-12B_1where:W*
33、(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 contour path,T = outward traction vector on ds,u= displacement rate vector at ds,x, y, z = rectangular coordinate system,
34、 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 that deform according to a constitutive law that may beseparated into single-value time and stress functions or strain a
35、nd stress functions of the forms:E1823-12B_4E1823-12B_5Where f1f4represent functions of elapsed time, t, strain, , and applied stress, , respectively; is the strain rate.DISCUSSION3 For materials exhibiting creep deformation for which the above equation is path independent, the C*(t)-integral is equ
36、al 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 area at a fixed value of time and displacement rate or at a fixed value of time and applied force.DISCUSSION4 The valu
37、e 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 around the crack tip. This occurs when secondary creep deformation characterized by thefollowing equation dominates the
38、behavior of the specimen.E1823-12B_6DISCUSSION5 This steady state in C* does not necessarily mean steady state crack growth 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
39、Method E1457 deals with thisregion as the initial crack extension period defined as time t0.2, measured for an initial crack growth of 0.2 mm after first loading.FIG. 2 J-Integral Crack Tip Contour and SymbolismE1823 12b4Ctparameter, Ct, FL-1T-1parameter equal to the value obtained from two identica
40、l 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 anddisplacement rate or at a fixed value of time and applied force for an arbitrary constitutive law. E1457, E2760DISCUSSIONT
41、he 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.DISCUSSIONUnder small-scale creep conditions, C*(t) is not path-independent and is related to the crack tip stress and st
42、rain 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 size . There is considerable experimental evidence that the Ctparameter which extends the C*(t)-integral concept into t
43、he 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.DISCUSSIONfor a specimen with a crack subject to constant force, PE1823-12B_7andE1823-12B_8circulation rate L3T1in fatigue test
44、ing, 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,respectively, above or below a specified level, referred to as clipping level; the loads (strains) are dec
45、reased 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 parameter computed so that the statement “the population parameterincluded in this interval” will be tru
46、e, on the average, in a stated proportion of the times such computations are made based ondifferent samples from the population. E1823confidence level (or coefficient)the stated proportion of the times the confidence interval is expected to include the populationparameter. E1823confidence limitsthe
47、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, E1921constant amplitude loading in fatigue loading, a loading (straining) in which all of the peak forces (strains)
48、 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 m
49、inimum stress, Smin. TheFIG. 3 Clipping of Fatigue Spectrum LoadingE1823 12b5constant life fatigue diagram is usually derived from a family of S-N curves each of which represents a different stress ratio (Aor R) for a 50 % probability of survival. E1820control force, Pm Fa calculated value of maximum force used in Test Method E1820 to stipulate allowable precracking limits.E1820, E1921corrosion fatiguethe process by which fracture occurs prematurely under conditions of simultaneous corrosi
