ASTM E83-10
(Practice)Standard Practice for Verification and Classification of Extensometer Systems
Standard Practice for Verification and Classification of Extensometer Systems
ABSTRACT
This practice covers procedures for the verification and classification of extensometer systems, but it is not intended to be a complete purchase specification. The practice is applicable only to instruments that indicate or record values that are proportional to changes in length corresponding to either tensile or compressive strain. Extensometer systems are classified on the basis of the magnitude of their errors. The apparatus for verifying extensometer systems shall provide a means for applying controlled displacements to a simulated specimen and for measuring these displacements accurately. Extensometer systems shall be classified in accordance with the requirements as to maximum error of strain indicated: Class A; Class B-1; Class B-2; Class C; Class D; and Class E. Extensometer systems shall be categorized in three types according to gage length: Type 1; Type 2; and Type 3. A verification procedure for extensometer systems shall be done in accordance with the specified requirements.
SCOPE
1.1 This practice covers procedures for the verification and classification of extensometer systems, but it is not intended to be a complete purchase specification. The practice is applicable only to instruments that indicate or record values that are proportional to changes in length corresponding to either tensile or compressive strain. Extensometer systems are classified on the basis of the magnitude of their errors.
1.2 Because strain is a dimensionless quantity, this document can be used for extensometers based on either SI or US customary units of displacement.
Note 1—Bonded resistance strain gauges directly bonded to a specimen cannot be calibrated or verified with the apparatus described in this practice for the verification of extensometers having definite gauge points. (See procedures as described in Test Methods E251.)
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: E83 – 10
Standard Practice for
1
Verification and Classification of Extensometer Systems
This standard is issued under the fixed designation E83; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3.1.1 calibration—a determination of the calibration factor
for a system using established procedures.
1.1 This practice covers procedures for the verification and
3.1.2 calibration factor—the factor by which the change in
classification of extensometer systems, but it is not intended to
extensometer reading must be multiplied to obtain the equiva-
beacompletepurchasespecification.Thepracticeisapplicable
lent strain.
only to instruments that indicate or record values that are
3.1.2.1 Discussion—For any extensometer, the calibration
proportional to changes in length corresponding to either
factor is equal to the ratio of change in length to the product of
tensile or compressive strain. Extensometer systems are clas-
the gauge length and the change in the extensometer reading.
sified on the basis of the magnitude of their errors.
For direct-reading extensometers the calibration factor is unity.
1.2 Because strain is a dimensionless quantity, this docu-
3.1.3 compressometer—a specialized extensometer used for
ment can be used for extensometers based on either SI or US
sensing negative or compressive strain.
customary units of displacement.
3.1.4 deflectometer—a specialized extensometer used for
NOTE 1—Bonded resistance strain gauges directly bonded to a speci-
sensing of extension or motion, usually without reference to a
men cannot be calibrated or verified with the apparatus described in this
specific gauge length.
practicefortheverificationofextensometershavingdefinitegaugepoints.
3.1.5 error, in extensometer systems—the value obtained by
(See procedures as described in Test Methods E251.)
subtracting the correct value of the strain from the indicated
1.3 This standard does not purport to address all of the
value given by the extensometer system.
safety concerns, if any, associated with its use. It is the
3.1.6 extensometer, n—a device for sensing strain.
responsibility of the user of this standard to establish appro-
3.1.7 extensometer systems—a system for sensing and indi-
priate safety and health practices and determine the applica-
cating strain.
bility of regulatory limitations prior to use.
3.1.7.1 Discussion—The system will normally include an
extensometer, conditioning electronics and auxiliary device
2. Referenced Documents
(recorder, digital readout, computer, etc.). However, com-
2
2.1 ASTM Standards:
pletely self-contained mechanical devices are permitted. An
E6 TerminologyRelatingtoMethodsofMechanicalTesting
extensometer system may be one of three types.
E21 Test Methods for Elevated Temperature Tension Tests
3.1.8 Type 1 extensometer system, n—an extensometer sys-
of Metallic Materials
tem which both defines gauge length and senses extension, for
E251 Test Methods for Performance Characteristics of Me-
example, a clip-on strain gauge type with conditioning elec-
tallic Bonded Resistance Strain Gauges
tronics.
3.1.9 Type 2 extensometer system, n—an extensometer
3. Terminology
which senses extension and the gauge length is defined by
3.1 Definitions: In addition to the terms listed, see Termi-
specimen geometry or specimen features such as ridges or
nology E6.
notches.
3.1.9.1 Discussion—A Type 2 extensometer is used where
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the extensometer gauge length is determined by features on the
This practice is under the jurisdiction ofASTM Committee E28 on Mechanical
Testing and is the direct responsibility of Subcommittee E28.01 on Calibration of
specimen, for example, ridges, notches, or overall height (in
Mechanical Testing Machines and Apparatus.
case of compression test piece). The precision associated with
Current edition approved Jan. 1, 2010. Published February 2010. Originally
gauge length setting for a Type 2 extensometer should be
approved in 1950. Last previous edition approved in 2006 as E83 – 06. DOI:
10.1520/E0083-10. specified in relevant test method or product standard. The
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
position readout on a testing machine is not recommended for
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
use in a Type 2 extensometer system.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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