1、Designation:E101205 Designation: E1012 12Standard Practice forVerification of Testing Frame and Specimen AlignmentUnder Tensile and Compressive Axial Force Application1This standard is issued under the fixed designation E1012; the number immediately following the designation indicates the year ofori
2、ginal 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. Scope1.1Included in this practice are methods covering the determinatio
3、n of the amount of bending that occurs during the applicationof tensile and compressive forces to notched and unnotched test specimens in the elastic range and to plastic strains less than 0.002.These methods are particularly applicable to the force application rates normally used for tension testin
4、g, creep testing, anduniaxial fatigue testing. *1.1 Included in this practice are methods covering the determination of the amount of bending that occurs during the applicationof tensile and compressive forces to notched and unnotched test specimens during routine testing in the elastic range. These
5、methods are particularly applicable to the force levels normally used for tension testing, creep testing, and uniaxial fatigue testing.The principal objective of this practice is to assess the amount of bending exerted upon a test specimen by the ordinary componentsassembled into a materials testing
6、 machine, during routine tests.2. Referenced Documents2.1 ASTM Standards:2E6 Terminology Relating to Methods of Mechanical TestingE8 Test Methods for Tension Testing of Metallic MaterialsE9 Test Methods of Compression Testing of Metallic Materials at Room TemperatureE21 Test Methods for Elevated Tem
7、perature Tension Tests of Metallic MaterialsE83 Practice for Verification and Classification of Extensometer SystemsE251 Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain GaugesE466 Practice for Conducting Force Controlled Constant Amplitude Axial Fatigue Tests of Met
8、allic MaterialsE606 Practice for Strain-Controlled Fatigue TestingE1237 Guide for Installing Bonded Resistance Strain Gages2.2 Other Documents:VAMAS Guide 42 A Procedure for the Measurement of Machine Alignment in Axial Testing3. Terminology3.1 Definitions of Terms Common to Mechanical Testing:3.1.1
9、 For definitions of terms used in this practice that are common to mechanical testing of materials, see Terminology E6.3.1.2 notched sectionthe section perpendicular to the longitudinal axis of symmetry of the specimen where the cross-sectionalarea is intentionally at a minimum value in order to ser
10、ve as a stress raiser. alignment, nthe condition of a testing machine thatinfluences the introduction of bending moments into a specimen (or alignment transducer) during the application of tensile orcompressive forces.3.1.3 nominal percent bending in notched specimensthe percent bending in a hypothe
11、tical (unnotched) specimen of uniformcross sectionequal to the minimum cross section of the notched specimen, the eccentricity of the applied force in thehypothetical, and the notched specimens being the same. (See 11.1.5.) (This definition is not intended to define strain at the rootof the notch.)
12、eccentricity L, nthe distance between the line of action of the applied force and the axis of symmetry of thespecimen in a plane perpendicular to the longitudinal axis of the specimen.3.1.4 reduced sectionthe specimen length between the fillets. reduced section L, nsection in the central portion of
13、thespecimen which has a cross section smaller than the gripped ends.1This practice is under the jurisdiction of ASTM Committee E28 on Mechanical Testing and is the direct responsibility of Subcommittee E28.01 on Calibration ofMechanical Testing Machines and Apparatus.Current edition approved June 1,
14、 2005.2012. Published July 2005.June 2010. Originally approved in 1989. Last previous edition approved in 19992005 asE101299.E1012 05. DOI: 10.1520/E1012-05.10.1520/E1012-12.2For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For An
15、nual 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 changes have been made to the previous version. Becauseit may not
16、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 official document.*A Summary of Changes section appears at the end
17、of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2.1 alignmentthe condition of a testing machine and fixturing (including the test specimen) which can introduce bend
18、ingmoments into a specimen during the application of tensile or compressive forces. axial strain, a, nthe average of the longitudinalstrains measured by strain gages at the surface on opposite sides of the longitudinal axis of symmetry of the alignment transducerby multiple strain-sensing devices lo
19、cated at the same longitudinal position.3.2.1.1 DiscussionThis is the overall state of alignment comprising machine and specimen components.3.2.2apparatusthe components of the machine and fixturing to be used for testing. This includes all components that will beused repeatedly for multiple tests.3.
20、2.2.1DiscussionWhile the strain gaged specimen is not used for subsequent specimen testing it is included as part of theapparatus.3.2.3axial strainthe average of the longitudinal strains measured at the surface on opposite sides of the longitudinal axis ofsymmetry of the specimen by multiple strain-
21、sensing devices located at the same longitudinal position as the reduced section.3.2.3.1DiscussionThis definition is only applicable to this standard. The term is used in other contexts elsewhere inmechanical testing.3.2.4bending strain3.2.2 bending strain, b, nthe difference between the strain at t
22、he surface and the axial strain (see Fig. 1). In3.2.2.1 Discussionin general, the bending strain varies from point to point around and along the reduced section of thespecimen. Bending strain is calculated as shown in Section 1110.3.2.3 component (also known as force application component), nany of
23、the parts used in the attachment of the load cell orgrips to the testing frame, as well as any part, including the grips used in the application of force to the strain-gaged alignmenttransducer or the test specimen.3.2.4 grips, nthat part of the force application components that directly attach to t
24、he strain-gage alignment transducer or thetest specimen.3.2.5 eccentricitythe distance between the line of action of the applied force and the axis of symmetry of the specimen in aplane perpendicular to the longitudinal axis of the specimen. microstrain, nstrain expressed in micro-units per unit, su
25、ch asmicrometers/meter or microinches/in.3.2.6 machine alignmentthe condition of the testing machine and all rigid parts of the load train which can introduce bendingmoments into a specimen during subsequent force application. notched section L, nthe section perpendicular to the longitudinalNOTEA be
26、nding strain, 6B, is superimposed on the axial strain, a, for low-axial strain (or stress) in (a) and high-axial strain (or stress) in (b). Forthe same bending strain 6B, a high-percent bending is indicated in (a) and a low-percent bending is indicated in (b).FIG. 1 Schematic Representations of Bend
27、ing Strains (or Stresses) That May Accompany Uniaxial LoadingE1012 122axis of symmetry of the specimen where the cross-sectional area is intentionally at a minimum value in order to serve as a stressraiser.3.2.7 maximum bending strainthe largest value of bending strain at the position along the leng
28、th of the reduced section of astraight unnotched specimen at which bending is measured. (For notched specimens, see 4.9.) percent bending, PB, (also knownas percent bending strain), nthe ratio of the bending strain to the axial strain expressed as a percentage.3.2.8 percent bendingthe bending strain
29、 times 100 divided by the axial strain. strain-gaged alignment transducer, nthetransducer used to determine the state of bending and the percent bending of a testing frame.3.2.9 rated forcea force at which the alignment is being measured. Type 1 alignment, nthe condition of a testing machinetypicall
30、y used for static or quasi-static testing including the non-rigid components and the positioning of the specimen within thegrips which can introduce bending moments into the strain-gaged alignment transducer or test specimen during force application.3.2.10 specimen alignmentthe condition of the test
31、 specimen including the non-rigid parts of the fixturing and the positioningof the specimen within the grips which can introduce bending moments into the specimen during subsequent force application.Type 2 alignment, nthe condition of a testing machine typically used for dynamic testing and all rigi
32、d parts of the load trainwhich can introduce bending moments into the strain-gaged alignment transducer or test specimen force application.4. Significance and Use4.1It has been shown that bending stresses that inadvertently occur due to misalignment between the applied force and thespecimen axes dur
33、ing the application of tensile and compressive forces can affect the test results. In recognition of this effect, sometest methods include a statement limiting the misalignment that is permitted. The purpose of this practice is to provide a referencefor test methods and practices that require the ap
34、plication of tensile or compressive forces under conditions where alignment isimportant. The objective is to implement the use of common terminology and methods for verification of alignment of testmachines, associated fixtures and test specimens.4.2Unless otherwise specified, axiality requirements
35、and verifications should be optional when testing is performed foracceptance of materials for minimum strength and ductility requirements. This is because any effects especially from excessivebending, would be expected to reduce strength and ductility properties and give conservative results. There
36、may be no benefit fromimproved axiality when testing high ductility materials to determine conformance with minimum properties. Whether or not toimprove axiality should be a matter of negotiation between the material producer and the user.4.1 It has been shown that bending stresses that inadvertentl
37、y occur due to misalignment between the applied force and thespecimen axes during the application of tensile and compressive forces can affect the test results. In recognition of this effect, sometest methods include a statement limiting the misalignment that is permitted. The purpose of this practi
38、ce is to provide a referencefor test methods and practices that require the application of tensile or compressive forces under conditions where alignment isimportant. The objective is to implement the use of common terminology and methods for verification of alignment of testingmachines, associated
39、components and test specimens.4.2 Alignment verification intervals when required are specified in the methods or practices that require the alignmentverification. Certain types of testing can provide an indication of the current alignment condition of a testing frame with eachspecimen tested. If a t
40、est method requires alignment verification, the frequency of the alignment verification should capture all theconsiderations i.e. time interval, changes to the testing frame and when applicable, current indicators of the alignment conditionthrough test results.4.3 Whether or not to improve axiality
41、should be a matter of negotiation between the material producer and the user.5. Verification of Alignment5.1For ease of reference in other practices, test methods, and product specifications, the most commonly used methods forverifying alignment are listed in Section 6.5.2A numerical requirement for
42、 alignment should specify the force, specimen dimensions, and temperature at which themeasurement is to be made. An alternate method employed when strain levels are of particular importance may be used asdescribed in Practice E466. When this method is used, the numerical requirement should specify t
43、he strain levels, specimendimensions and temperature at which the measurement is to be made.5.2.1The force at which the bending strain is specified may be stated in terms of a yield strength or other nominal specimenstress.5.1 A numerical requirement for alignment should specify the force, strain-ga
44、ged alignment transducer dimensions, andtemperature at which the measurement is to be made. Alternate methods employed when strain levels are of particular importancemay be used as described in Practices E466 or E606. When these methods are used, the numerical requirement should specify thestrain le
45、vels, strain-gaged alignment transducer dimensions and temperature at which the measurement is to be made.NOTE 1For a misaligned load train, the percent bending usually decreases with increasing applied force. (See CurvesA, B, and C in Fig. 2.) However,in some severe instances, percent bending may i
46、ncrease with increasing applied force. (See Curve D in Fig. 2.)5.3Alignment requirements and results can refer to either an overall test machine capability or to a specific test. This distinctionshould be noted in the results.5.3.1Verifications of overall test machine capability should be made using
47、 a specimen and apparatus made to a similar designand of similar materials as those that will be used during testing, except that any specimen notches may be eliminated. The sameE1012 123specimen may be used for successive verifications. The materials and design should be such that only elastic stra
48、ins occur at therated force. In cases where the expected test specimen material is not yet known, use good engineering judgement to select aspecimen made of a commonly used material for verification.5.2 For a verification of alignment to be reported in compliance with the current revision of E1012 a
49、 strain-gaged alignmenttransducer shall be used. This applies to both Type 1 and Type 2 levels of alignment verification.5.2.1 This standard defines two types of classified testing machine alignment per the classification criteria. The type ofalignment shall be noted on the report.5.2.2 When performing an alignment of a testing machine for the first time or if normally fixed components have been adjustedor repaired, a mechanical alignment of the testing machine should be performed. For tensile and fatigue equipment, this step canbe accomplis
