1、Designation:E182312d Designation: E1823 12eStandard 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 MaterialsE1450 Test Method for Tension Testing of Structural Alloys in Liquid HeliumE1457 Test Method for Measurement of Creep Crack
11、 Growth Times in MetalsE1681 Test Method for DeterminingThreshold Stress Intensity 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 Determi
12、nation of Reference Temperature, To, for Ferritic Steels in the Transition RangeE1942 Guide for Evaluating Data Acquisition Systems Used in Cyclic Fatigue and Fracture Mechanics Testing1This terminology is under the jurisdiction of ASTM Committee E08 on Fatigue and Fracture and is the direct respons
13、ibility of Subcommittee E08.02 on Standards andTerminology.Current edition approved Nov.Dec. 15, 2012. Published February 2013. Originally approved in 1996. Last previous edition approved in 2012 as E1823 12cd. DOI:10.1520/E1823-12DE.2For referencedASTM standards, visit theASTM website, www.astm.org
14、, 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 an indication of what change
15、s 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 to be considered the officia
16、l document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E2207 Practice for Strain-Controlled Axial-Torsional Fatigue Testing with Thin-Walled Tubular SpecimensE2208 Guide for Evaluating Non-Contacting Optical Strain Measurement Sys
17、temsE2298 Test Method for Instrumented Impact Testing of Metallic MaterialsE2443 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 C
18、reep-Fatigue TestingE2760 Test Method for Creep-Fatigue Crack Growth 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 cracksizeaeeffecti
19、ve crack sizeannotch lengthaooriginal 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
20、/Nf)C*(t) C*(t) Integralda/dN fatigue-crack-growth rate crack-tip opening 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
21、forceGRcrack-extension resistanceH* specimen center of pin hole distance 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, K
22、3,KI, KII, KIIIstress-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-
23、assisted crackingKIcplane-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
24、 amplitudePmmean forcePMprecrack forcePmaxmaximum forcePminminimum forceE1823 12e2Symbol Termq fatigue notch sensitivityr effective unloading slope ratiorccritical slope ratioryplastic-zone adjustmentR force ratio (Pmin/Pmax)s sample standard deviations2sample varianceS specimen spanSaforce amplitud
25、eSffatigue limitSmmean forceSNfatigue strength at N cyclesccrack strengthNnominal (net-section) stressrresidual strengthssharp-notch strengthTStensile strengthx, y, znormal stresses (refer to )Yeffective yield strengthYSyield strengthT specimen temperaturetTtransition timettotal cycle periodxy,yz, z
26、xshear stresses (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 Alp
27、habetical Listing of Abbreviations Used:NOTESee 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 FrontE1823 12e3CMOD crack-mouth opening displacementCOD see CTODCTOD crack-tip opening displacementDT dynamic tearD
28、WTT 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 designation(s) of the standard(s) of origin. The li
29、sting of definitions isalphabetical.alternating forceSee loading amplitude.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 mechanicsanalys
30、is for a specific configuration. The curve relates the stress-intensity 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 fat
31、igue loading, a specified number of constant amplitude loading cycles applied 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 crack
32、surface 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 plane with the crack front parallel to the z-axi
33、s, is the line integral:C*t! 5 *GS W *t!dy 2 TuxdsD (1)E1823-12E_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 contour path,T = outward traction vector on ds,
34、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 that deform according to a constitutive law th
35、at may beseparated into single-value time and stress functions or strain and stress functions of the forms:E1823-12E_4E1823-12E_5FIG. 2 Contour and Symbolism for Path-Independent Crack TipIntegralsE1823 12e4Where f1f4represent functions of elapsed time, t, strain, , and applied stress, , respectivel
36、y; is the strain rate.DISCUSSION3 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-
37、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 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
38、 distribution has been produced around the crack tip. This occurs when secondary creep deformation characterized by thefollowing equation dominates the behavior of the specimen.E1823-12E_8DISCUSSION5 This steady state in C* does not necessarily mean steady state crack growth rate. The latter occurs
39、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 crack growth of 0.2 mm after
40、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 anddisplacement rate or at a fix
41、ed 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.DISCUSSIONUnder small-scale
42、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 size . There is considerab
43、le 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.DISCUSSIONfor a specimen with a cr
44、ack subject to constant force, PE1823-12E_9andE1823-12E_10circulation 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,respectively
45、, 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. E1820FIG. 3 Clipping of Fatigue Spectrum LoadingE1823 12e5confidence in
46、tervalan interval estimate of a population parameter computed so that the statement “the population parameterincluded in this interval” will be true, on the average, in a stated proportion of the times such computations are made based ondifferent samples from the population. E1823confidence level (o
47、r coefficient)the stated proportion of the times 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 allo
48、wable precracking limits.E1820, E1921constant 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 famil
49、y 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 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 fa
