Standard Practice for Verification of Test Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application

SIGNIFICANCE AND USE
It has been shown that bending stresses that inadvertently occur due to misalignment between the applied force and the specimen axes during the application of tensile and compressive forces can affect the test results. In recognition of this effect, some test methods include a statement limiting the misalignment that is permitted. The purpose of this practice is to provide a reference for test methods and practices that require the application of tensile or compressive forces under conditions where alignment is important. The objective is to implement the use of common terminology and methods for verification of alignment of test machines, associated fixtures and test specimens.
Unless otherwise specified, axiality requirements and verifications should be optional when testing is performed for acceptance of materials for minimum strength and ductility requirements. This is because any effects especially from excessive bending, would be expected to reduce strength and ductility properties and give conservative results. There may be no benefit from improved axiality when testing high ductility materials to determine conformance with minimum properties. Whether or not to improve axiality should be a matter of negotiation between the material producer and the user.
SCOPE
1.1 Included in this practice are methods covering the determination of the amount of bending that occurs during the application of 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 testing, creep testing, and uniaxial fatigue testing.

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Publication Date
31-May-2005
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ASTM E1012-05 - Standard Practice for Verification of Test Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E1012 – 05
Standard Practice for
Verification of Test Frame and Specimen Alignment Under
1
Tensile and Compressive Axial Force Application
This standard is issued under the fixed designation E1012; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.3 nominal percent bending in notched specimens—the
percent bending in a hypothetical (unnotched) specimen of
1.1 Included in this practice are methods covering the
uniform cross section—equal to the minimum cross section of
determination of the amount of bending that occurs during the
the notched specimen, the eccentricity of the applied force in
application of tensile and compressive forces to notched and
the hypothetical, and the notched specimens being the same.
unnotched test specimens in the elastic range and to plastic
(See 11.1.5.) (This definition is not intended to define strain at
strains less than 0.002. These methods are particularly appli-
the root of the notch.)
cable to the force application rates normally used for tension
3.1.4 reduced section—the specimen length between the
testing, creep testing, and uniaxial fatigue testing.
fillets.
2. Referenced Documents 3.2 Definitions of Terms Specific to This Standard:
2
3.2.1 alignment—the condition of a testing machine and
2.1 ASTM Standards:
fixturing (including the test specimen) which can introduce
E6 TerminologyRelatingtoMethodsofMechanicalTesting
bending moments into a specimen during the application of
E8 Test Methods for Tension Testing of Metallic Materials
tensile or compressive forces.
E83 Practice for Verification and Classification of Exten-
3.2.1.1 Discussion—This is the overall state of alignment
someter Systems
comprising machine and specimen components.
E251 Test Methods for Performance Characteristics of Me-
3.2.2 apparatus—the components of the machine and fix-
tallic Bonded Resistance Strain Gauges
turing to be used for testing. This includes all components that
E466 Practice for Conducting Force Controlled Constant
will be used repeatedly for multiple tests.
Amplitude Axial Fatigue Tests of Metallic Materials
3.2.2.1 Discussion—While the strain gaged specimen is not
E1237 GuideforInstallingBondedResistanceStrainGages
used for subsequent specimen testing it is included as part of
3. Terminology
the apparatus.
3.2.3 axial strain—the average of the longitudinal strains
3.1 Definitions of Terms Common to Mechanical Testing:
measured at the surface on opposite sides of the longitudinal
3.1.1 For definitions of terms used in this practice that are
axis of symmetry of the specimen by multiple strain-sensing
common to mechanical testing of materials, see Terminology
deviceslocatedatthesamelongitudinalpositionasthereduced
E6.
section.
3.1.2 notched section—the section perpendicular to the
3.2.3.1 Discussion—This definition is only applicable to
longitudinal axis of symmetry of the specimen where the
this standard. The term is used in other contexts elsewhere in
cross-sectional area is intentionally at a minimum value in
mechanical testing.
order to serve as a stress raiser.
3.2.4 bending strain—the difference between the strain at
the surface and the axial strain (see Fig. 1). In general, the
1
This practice is under the jurisdiction ofASTM Committee E28 on Mechanical
bending strain varies from point to point around and along the
Testing and is the direct responsibility of Subcommittee E28.01 on Calibration of
reduced section of the specimen. Bending strain is calculated
Mechanical Testing Machines and Apparatus.
as shown in Section 11.
CurrenteditionapprovedJune1,2005.PublishedJuly2005.Originallyapproved
in 1989. Last previous edition approved in 1999 as E1012 – 99. DOI: 10.1520/
3.2.5 eccentricity—the distance between the line of action
E1012-05.
of the applied force and the axis of symmetry of the specimen
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
in a plane perpendicular to the longitudinal axis of the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on specimen.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E1012 – 05
NOTE 1—Abending 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). For
the same bending strain 6B, a high-percent bending is indicated in (a) and a low-percent bending is indicated in (b).
FIG. 1
...

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