ASTM_E_2207_-_15.pdf

Designation:E220715Standard Practice forStrain-Controlled Axial-Torsional Fatigue Testing with Thin-Walled Tubular Specimens1This standard is issued under the fixed designation E2207;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 The standard deals with strain-controlled,axial,torsional,and combined in-and out-of-phase axial torsionalfatigue testing with thin-walled,circular cross-section,tubularspecimens at isothermal,ambient and elevated temperatures.This standard is limited to symmetric,completely-reversedstrains(zero mean strains)and axial and torsional waveformswith the same frequency in combined axial-torsional fatiguetesting.This standard is also limited to characterization ofhomogeneous materials with thin-walled tubular specimensand does not cover testing of either large-scale components orstructural elements.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E3 Guide for Preparation of Metallographic SpecimensE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE8/E8M Test Methods for Tension Testing of Metallic Ma-terialsE9 Test Methods of Compression Testing of Metallic Mate-rials at Room TemperatureE83 Practice for Verification and Classification of Exten-someter SystemsE111 Test Method for Youngs Modulus,Tangent Modulus,and Chord ModulusE112 Test Methods for Determining Average Grain SizeE143 Test Method for Shear Modulus at Room TemperatureE209 Practice for Compression Tests of Metallic Materials atElevated Temperatures with Conventional or Rapid Heat-ing Rates and Strain RatesE467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemE606/E606M Test Method for Strain-Controlled FatigueTestingE1012 Practice for Verification of Testing Frame and Speci-men Alignment Under Tensile and Compressive AxialForce ApplicationE1417/E1417M Practice for Liquid Penetrant TestingE1444/E1444M Practice for Magnetic Particle TestingE1823 Terminology Relating to Fatigue and Fracture TestingE2624 Practice for Torque Calibration of Testing Machinesand Devices3.Terminology3.1 DefinitionsThe terms specific to this practice aredefined in this section.All other terms used in this practice arein accordance with Terminologies E6 and E1823.3.2 Definitions of Terms Specific to This Standard:3.2.1 axial strainrefers to engineering axial strain,andis defined as change in length divided by the original length(Lg/Lg).3.2.2 shear strainrefers to engineering shear strain,resulting from the application of a torsional moment to acylindrical specimen.Such a torsional shear strain is simpleshear and is defined similar to axial strain with the exceptionthat the shearing displacement,Lsis perpendicular to ratherthan parallel to the gage length,Lg,that is,=Ls/Lg(see Fig.1).3.2.2.1 Discussion=is related to the angles of twist,and as follows:=tan,where is the angle of twist along the gagelength of the cylindrical specimen.For small angles ex-pressed in radians,tan approaches and approaches.=(d/2)/Lg,where expressed in radians is the angle oftwist between the planes defining the gage length of thecylindrical specimen and d is the diameter of the cylindricalspecimen.1This practice is under the jurisdiction ofASTM Committee E08 on Fatigue andFracture and is the direct responsibility of Subcommittee E08.05 on CyclicDeformation and Fatigue Crack Formation.Current edition approved May 1,2015.Published July 2015.Originally approvedin 2002.Last previous edition approved in 2013 as E220708(2013)1.DOI:10.1520/E2207-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.2.2 DiscussionLsis measurable directly as displace-ment using specially calibrated torsional extensometers or asthe arc length Ls=(d/2),where is measured directly witha rotary variable differential transformer.3.2.2.3 DiscussionThe shear strain varies linearly throughthe thin wall of the specimen,with the smallest and largestvalues occurring at the inner and outer diameters of thespecimen,respectively.The value of shear strain on the outersurface,inner surface,and mean diameter of the specimen shallbe reported.The shear strain determined at the outer diameterof the tubul