ASTM E9-09(2018)

Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature

SIGNIFICANCE AND USE
5.1 Significance—The data obtained from a compression test may include the yield strength, the yield point, Young's modulus, the stress-strain curve, and the compressive strength (see Terminology E6). In the case of a material that does not fail in compression by a shattering fracture, compressive strength is a value that is dependent on total strain and specimen geometry.  
5.2 Use—Compressive properties are of interest in the analyses of structures subject to compressive or bending loads or both and in the analyses of metal working and fabrication processes that involve large compressive deformation such as forging and rolling. For brittle or nonductile metals that fracture in tension at stresses below the yield strength, compression tests offer the possibility of extending the strain range of the stress-strain data. While the compression test is not complicated by necking as is the tension test for certain metallic materials, buckling and barreling (see Section 3) can complicate results and should be minimized.
SCOPE
1.1 These test methods cover the apparatus, specimens, and procedure for axial-load compression testing of metallic materials at room temperature (Note 1). For additional requirements pertaining to cemented carbides, see Annex A1.
Note 1: For compression tests at elevated temperatures, see Practice E209.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
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, health, and environmental health practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 31-Dec-2017
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.04 - Uniaxial Testing

Standards Content (Sample)

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: E9 − 09 (Reapproved 2018)
Standard Test Methods of
Compression Testing of Metallic Materials at Room
Temperature
This standard is issued under the fixed designation E9; the number immediately following the designation indicates the year of original
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope E83Practice for Verification and Classification of Exten-
someter Systems
1.1 These test methods cover the apparatus, specimens, and
E111Test Method for Young’s Modulus, Tangent Modulus,
procedure for axial-load compression testing of metallic mate-
and Chord Modulus
rialsatroomtemperature(Note1).Foradditionalrequirements
E171/E171MPractice for Conditioning andTesting Flexible
pertaining to cemented carbides, see Annex A1.
Barrier Packaging
NOTE 1—For compression tests at elevated temperatures, see Practice
E177Practice for Use of the Terms Precision and Bias in
E209.
ASTM Test Methods
1.2 The values stated in inch-pound units are to be regarded
E209PracticeforCompressionTestsofMetallicMaterialsat
as standard. The values given in parentheses are mathematical
Elevated Temperatures with Conventional or Rapid Heat-
conversions to SI units that are provided for information only
ing Rates and Strain Rates
and are not considered standard.
E251Test Methods for Performance Characteristics of Me-
tallic Bonded Resistance Strain Gages
1.3 This standard does not purport to address all of the
E691Practice for Conducting an Interlaboratory Study to
safety concerns, if any, associated with its use. It is the
Determine the Precision of a Test Method
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental health practices and
3. Terminology
determine the applicability of regulatory limitations prior to
use.
3.1 Definitions: The definitions of terms relating to com-
1.4 This international standard was developed in accor-
pression testing and room temperature in Terminology E6 and
dance with internationally recognized principles on standard-
Practice E171/E171M, respectively, shall apply to these test
ization established in the Decision on Principles for the
methods.
Development of International Standards, Guides and Recom-
3.2 Definitions of Terms Specific to This Standard:
mendations issued by the World Trade Organization Technical
3.2.1 buckling—Inadditiontocompressivefailurebycrush-
Barriers to Trade (TBT) Committee.
ing of the material, compressive failure may occur by (1)
elastic instability over the length of a column specimen due to
2. Referenced Documents
nonaxiality of loading, (2) inelastic instability over the length
2.1 ASTM Standards:
of a column specimen, (3) a local instability, either elastic or
B557Test Methods for Tension Testing Wrought and Cast
inelastic, over a small portion of the gage length, or (4)a
Aluminum- and Magnesium-Alloy Products
twisting or torsional failure in which cross sections rotate over
E4Practices for Force Verification of Testing Machines
eachotheraboutthelongitudinalspecimenaxis.Thesetypesof
E6Terminology Relating to Methods of Mechanical Testing
failures are all termed buckling.
3.2.2 column—a compression member that is axially loaded
and that may fail by buckling.
These test methods are under the jurisdiction of ASTM Committee E28 on
3.2.3 radius of gyration—the square root of the ratio of the
Mechanical Testing and are the direct responsibility of Subcommittee E28.04 on
Uniaxial Testing.
momentofinertiaofthecrosssectionaboutthecentroidalaxis
Current edition approved Jan. 1, 2018. Published January 2018. Originally
to the cross-sectional area:
published in 1924. Last previous edition approved in 2009 as E9-09. DOI:
1/2
10.1520/E0009-09R18.
ρ 5 ~I/A! (1)
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM where:
Standards volume information, refer to the standard’s Document Summary page on
ρ = radius of gyration,
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E9 − 09 (2018)
deformation as shown schematically and in the photograph in
I = moment of inertia of the cross section about centroidal
Fig. 2.Additional theoretical and experimental information on
axis (for specimens without lateral support, the smaller
barreling as illustrated in Fig. 2 is given in Ref (2).
value of I is the critical value), and
A = cross-sectional area.
4. Summary of Test Methods
3.2.4 critical stress—the axial uniform stress that causes a
4.1 The specimen is subjected to an increasing axial com-
column to be on the verge of buckling. The critical load is
pressive load; both load and strain may be monitored either
calculatedbymultiplyingthecriticalstressbythecross-section
continuously or in finite increments, and the mechanical
area.
properties in compression determined.
3.2.5 buckling equations—If the buckling stress is less than
or equal to the proportional limit of the material its value may
5. Significance and Use
be calculated using the Euler equation:
5.1 Significance—The data obtained from a compression
2 2
S 5 Cπ E/~L/ρ! (2)
cr
test may include the yield strength, the yield point, Young’s
If the buckling stress is greater than the proportional limit
modulus, the stress-strain curve, and the compressive strength
of the material its value may be calculated from the modi-
(see Terminology E6). In the case of a material that does not
fied Euler equation:
fail in compression by a shattering fracture, compressive
2 2
strength is a value that is dependent on total strain and
S 5 Cπ E /~L/ρ! (3)
cr t
specimen geometry.
where:
5.2 Use—Compressive properties are of interest in the
S = critical buckling stress,
cr
analyses of structures subject to compressive or bending loads
E = Young’s modulus,
or both and in the analyses of metal working and fabrication
E = tangent modulus at the buckling stress,
t
processes that involve large compressive deformation such as
L = column length, and
forging and rolling. For brittle or nonductile metals that
C = end-fixity coefficient.
fracture in tension at stresses below the yield strength, com-
Methods of calculating the critical stress using Eq 3 are
pression tests offer the possibility of extending the strain range
given in Ref (1).
of the stress-strain data. While the compression test is not
3.2.6 end-fixity coeffıcient—There are certain ideal speci-
complicated by necking as is the tension test for certain
men end-fixity conditions for which theory will define the
metallic materials, buckling and barreling (see Section 3) can
value of the constant C (see Fig. 1). These values are:
complicate results and should be minimized.
6. Apparatus
6.1 Testing Machines—Machinesusedforcompressiontest-
ing shall conform to the requirements of Practices E4. For
universalmachineswithacommontestspace,calibrationshall
be performed in compression.
6.1.1 The bearing surfaces of the heads of the testing
machine shall be parallel at all times with 0.0002 in./in. (m/m)
unlessanalignmentdeviceofthetypedescribedin6.3isused.
6.2 Bearing Blocks:
6.2.1 Both ends of the compression specimen shall bear on
blocks with surfaces flat and parallel within 0.0002 in./in.
(m/m). Lack of initial parallelism can be overcome by the use
ofadjustablebearingblocks(Note3).Theblocksshallbemade
of, or faced with, hard material. Current laboratory practice
FIG. 1 Diagrams Showing Fixity Conditions and Resulting Buck-
ling of Deformation suggests the use of tungsten carbide when testing steel and
hardened steel blocks (55 HRC or greater) and when testing
nonferrous materials such as aluminum, copper, etc. The
Freely rotating ends (pinned or hinged) C=1(a)
One end fixed, the other free to rotate C=2(b) specimen must be carefully centered with respect to the testing
Both ends fixed C=4(c)
machine heads or the subpress if used (see 6.3, Alignment
NOTE 2—For flat-end specimens tested between flat rigid anvils, it was Device/Subpress).
shown in Ref (1) that a value of C =3.75 is appropriate.
NOTE 3—The purpose of an adjustable bearing block is to give the
3.2.7 barreling—restricted deformation of the end regions
specimen as even a distribution of initial load as possible. An adjustable
ofatestspecimenundercompressiveloadduetofrictionatthe
bearing block cannot be relied on to compensate for any tilting of the
heads that may occur during the test.
specimen end sections and the resulting nonuniform transverse
6.2.2 The bearing faces of adjustable bearing blocks that
contact the specimen shall be made parallel before the load is
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
this standard. applied to the specimen. One type of adjustable bearing block
E9 − 09 (2018)
NOTE 1—A cylindrical specimen of AISI 4340 steel (HRC=40) was compressed 57% (see upper diagram). The photo macrograph was made of a
polished and etched cross section of the tested specimen. The highly distorted flow lines are the result of friction between the specimen ends and the
loading fixture. Note the triangular regions of restricted deformation at the ends and the cross-shaped zone of severe shear.
FIG. 2 Illustration of Barreling
that has proven satisfactory is illustrated in Fig. 3. Another blockthathasbeenfoundsatisfactoryfortestingmaterialother
arrangement involving the use of a spherical-seated bearing than in sheet form is shown in Fig. 4. It is desirable that the
spherical-seated bearing block be at the upper end of the test
specimen(forspecimenstestedwiththeloadaxisvertical).The
spherical surface of the block shall be defined by a radius
having its point of origin in the flat surface that bears on the
specimen.
FIG. 3 Adjustable Bearing Block for Compression Testing FIG. 4 Spherical-Seated Bearing Block
E9 − 09 (2018)
6.3 Alignment Device/Subpress: ofthesevariablesshouldbeestablishedduringthequalification
6.3.1 It is usually necessary to use an alignment device, of the equipment (see 6.6).
unless the testing machine has been designed specifically for 6.4.1 It is not the intent of these methods to designate
axial alignment. The design of the device or subpress depends specific jigs for testing sheet materials, but merely to provide a
on the size and strength of the specimen. It must be designed few illustrations and references to jigs that have been used
so that the ram (or other moving parts) does not jam or tilt the successfully, some of which are cited in Table 1. Other jigs are
device or the frame of the machine as a result of loading. The acceptable provided they prevent buckling and pass the quali-
bearing blocks of the device shall have the same requirements ficationtestsetforthin6.6.Compressionjigsgenerallyrequire
for parallelism and flatness as given in 6.2.1. that the specimen be lubricated on the supported sides to
6.3.2 Theprimaryrequirementsofallalignmentdevicesare preventextraneousfrictionforcesfromoccurringatthesupport
that the load is applied axially, uniformly, and with negligible points.
“slip-stick” friction. An alignment device that has been found
6.5 Strain Measurements:
suitable is shown in Fig. 5 and described in Ref. (3). Other
6.5.1 Mechanical or electromechanical devices used for
devices of the subpress type have also been used successfully.
measuring strain shall comply with the requirements for the
6.4 Compression Testing Jigs—In testing thin specimens, applicable class described in Practice E83. The device shall be
such as sheet material, some means should be adopted to verified in compression.
prevent the specimen from buckling during loading. This may 6.5.2 Electrical-resistance strain gages (or other single-use
be accomplished by using a jig containing side-support plates devices) may be used provided the measuring system has been
that bear against the wide sides of the specimen. The jig must verified and found to be accurate to the degree specified in
afford a suitable combination of lateral-support pressure and Practice E83. The characteristics of electrical resistance strain
spring constant to prevent buckling, but without interfering gages have been determined from Test Methods E251.
with axial deformation of the specimen. Although suitable
6.6 Qualification of Test Apparatus—The complete
combinations vary somewhat with variations in specimen
compression-test apparatus, which consists of the testing ma-
material and thickness, testing temperatures, and accuracy of
chine and when applicable, one or more of the following; the
alignment, acceptable results can be obtained with rather wide
alignment device, the jig and the strain-measurement system,
ranges of lateral-support pressure and spring constant.
shall be qualified as follows:
Generally, the higher the spring constant of the jig, the lower
6.6.1 Conduct tests to establish the elastic modulus of five
thelateral-supportpressurethatisrequired.Properadjustments
replicate specimens of 2024-T3 aluminum alloy sheet or
2024-T4 aluminum alloy bar in accordance with Test Method
E111. These qualification specimens shall be machined from
sheet or bar in the location specified in Test Methods B557.
The thickness of the sheet or diameter of the bar may be
machined to the desired thickness or diameter. It is essential
that the extensometer be properly seated on the specimens
when this test is performed. When the qualification specimens
each provide a modulus value of 10.7×10 psi (73.8 GPa)
65%, the apparatus qualifies.
6.6.2 The qualification procedure shall be performed using
the thinnest rectangular specimen or smallest diameter round
specimen to be tested in the apparatus.
7. Test Specimens
7.1 Specimens in Solid Cylindrical Form—It is recom-
mended that, where feasible, compression test specimens be in
the form of solid circular cylinders. Three forms of solid
cylindrical test specimens for metallic materials are
recognized, and designated as short, medium-length, and long
(Note 4). Suggested dimensions for solid compression test
specimens for general use are given in Table 2.
NOTE 4—Short specimens typically are used for compression tests of
such materials as bearing metals, which in service are used in the form of
thin plates to carry load perpendicular to the surface. Medium-length
specimens typically are used for determining the general compressive
strengthpropertiesofmetallicmaterials.Longspecimensarebestadapted
for determining the modulus of elasticity in compressio
...

This 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. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: E9 − 09 E9 − 09 (Reapproved 2018)
Standard Test Methods of
Compression Testing of Metallic Materials at Room
Temperature
This standard is issued under the fixed designation E9; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 These test methods cover the apparatus, specimens, and procedure for axial-load compression testing of metallic materials
at room temperature (Note 1). For additional requirements pertaining to cemented carbides, see Annex A1.
NOTE 1—For compression tests at elevated temperatures, see Practice E209.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
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 safety, health, and environmental health practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B557 Test Methods for Tension Testing Wrought and Cast Aluminum- and Magnesium-Alloy Products
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E83 Practice for Verification and Classification of Extensometer Systems
E111 Test Method for Young’s Modulus, Tangent Modulus, and Chord Modulus
E171E171/E171M Practice for Conditioning and Testing Flexible Barrier Packaging
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E209 Practice for Compression Tests of Metallic Materials at Elevated Temperatures with Conventional or Rapid Heating Rates
and Strain Rates
E251 Test Methods for Performance Characteristics of Metallic Bonded Resistance Strain Gages
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions: The definitions of terms relating to compression testing and room temperature in Terminology E6 and
SpecificationPractice E171E171/E171M, respectively, shall apply to these test methods.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 buckling—In addition to compressive failure by crushing of the material, compressive failure may occur by (1) elastic
instability over the length of a column specimen due to nonaxiality of loading, (2) inelastic instability over the length of a column
These test methods are under the jurisdiction of ASTM Committee E28 on Mechanical Testing and are the direct responsibility of Subcommittee E28.04 on Uniaxial
Testing.
Current edition approved Nov. 1, 2009Jan. 1, 2018. Published December 2009January 2018. Originally published in 1924. Last previous edition approved in 2000 as E9
-89a(2000) which was withdrawn March 2009 and2009 as E9reinstated in November 2009. DOI: 10.1520/E0009-09. -09. DOI: 10.1520/E0009-09R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E9 − 09 (2018)
specimen, (3) a local instability, either elastic or inelastic, over a small portion of the gage length, or (4) a twisting or torsional
failure in which cross sections rotate over each other about the longitudinal specimen axis. These types of failures are all termed
buckling.
3.2.2 column—a compression member that is axially loaded and that may fail by buckling.
3.2.3 radius of gyration—the square root of the ratio of the moment of inertia of the cross section about the centroidal axis to
the cross-sectional area:
1/2
ρ5 I/A (1)
~ !
where:
ρ = radius of gyration,
I = moment of inertia of the cross section about centroidal axis (for specimens without lateral support, the smaller value of I
is the critical value), and
A = cross-sectional area.
3.2.4 critical stress—the axial uniform stress that causes a column to be on the verge of buckling. The critical load is calculated
by multiplying the critical stress by the cross-section area.
3.2.5 buckling equations—If the buckling stress is less than or equal to the proportional limit of the material its value may be
calculated using the Euler equation:
2 2
S 5 Cπ E/~L/ρ! (2)
cr
If the buckling stress is greater than the proportional limit of the material its value may be calculated from the modified
Euler equation:
2 2
S 5 Cπ E / L/ρ (3)
~ !
cr t
where:
S = critical buckling stress,
cr
E = Young’s modulus,
E = tangent modulus at the buckling stress,
t
L = column length, and
C = end-fixity coefficient.
Methods of calculating the critical stress using Eq 3 are given in Ref (1).
3.2.6 end-fixity coeffıcient—There are certain ideal specimen end-fixity conditions for which theory will define the value of the
constant C (see Fig. 1). These values are:
FIG. 1 Diagrams Showing Fixity Conditions and Resulting Buckling of Deformation
Freely rotating ends (pinned or hinged) C = 1 (a)
One end fixed, the other free to rotate C = 2 (b)
Both ends fixed C = 4 (c)
NOTE 2—For flat-end specimens tested between flat rigid anvils, it was shown in Ref (1) that a value of C = 3.75 is appropriate.
The boldface numbers in parentheses refer to the list of references at the end of this standard.
E9 − 09 (2018)
3.2.7 barreling—restricted deformation of the end regions of a test specimen under compressive load due to friction at the
specimen end sections and the resulting nonuniform transverse deformation as shown schematically and in the photograph in Fig.
2. Additional theoretical and experimental information on barreling as illustrated in Fig. 2 is given in Ref (2).
4. Summary of Test Methods
4.1 The specimen is subjected to an increasing axial compressive load; both load and strain may be monitored either
continuously or in finite increments, and the mechanical properties in compression determined.
5. Significance and Use
5.1 Significance—The data obtained from a compression test may include the yield strength, the yield point, Young’s modulus,
the stress-strain curve, and the compressive strength (see Terminology E6). In the case of a material that does not fail in
compression by a shattering fracture, compressive strength is a value that is dependent on total strain and specimen geometry.
5.2 Use—Compressive properties are of interest in the analyses of structures subject to compressive or bending loads or both
and in the analyses of metal working and fabrication processes that involve large compressive deformation such as forging and
rolling. For brittle or nonductile metals that fracture in tension at stresses below the yield strength, compression tests offer the
possibility of extending the strain range of the stress-strain data. While the compression test is not complicated by necking as is
the tension test for certain metallic materials, buckling and barreling (see Section 3) can complicate results and should be
minimized.
NOTE 1—A cylindrical specimen of AISI 4340 steel (HRC = 40) was compressed 57 % (see upper diagram). The photo macrograph was made of a
polished and etched cross section of the tested specimen. The highly distorted flow lines are the result of friction between the specimen ends and the
loading fixture. Note the triangular regions of restricted deformation at the ends and the cross-shaped zone of severe shear.
FIG. 2 Illustration of Barreling
E9 − 09 (2018)
6. Apparatus
6.1 Testing Machines—Machines used for compression testing shall conform to the requirements of Practices E4. For universal
machines with a common test space, calibration shall be performed in compression.
6.1.1 The bearing surfaces of the heads of the testing machine shall be parallel at all times with 0.0002 in./in. (m/m) unless an
alignment device of the type described in 6.3 is used.
6.2 Bearing Blocks:
6.2.1 Both ends of the compression specimen shall bear on blocks with surfaces flat and parallel within 0.0002 in./in. (m/m).
Lack of initial parallelism can be overcome by the use of adjustable bearing blocks (Note 3). The blocks shall be made of, or faced
with, hard material. Current laboratory practice suggests the use of tungsten carbide when testing steel and hardened steel blocks
(55 HRC or greater) and when testing nonferrous materials such as aluminum, copper, etc. The specimen must be carefully
centered with respect to the testing machine heads or the subpress if used (see 6.3, Alignment Device/Subpress).
NOTE 3—The purpose of an adjustable bearing block is to give the specimen as even a distribution of initial load as possible. An adjustable bearing
block cannot be relied on to compensate for any tilting of the heads that may occur during the test.
6.2.2 The bearing faces of adjustable bearing blocks that contact the specimen shall be made parallel before the load is applied
to the specimen. One type of adjustable bearing block that has proven satisfactory is illustrated in Fig. 3. Another arrangement
involving the use of a spherical-seated bearing block that has been found satisfactory for testing material other than in sheet form
is shown in Fig. 4. It is desirable that the spherical-seated bearing block be at the upper end of the test specimen (for specimens
tested with the load axis vertical). The spherical surface of the block shall be defined by a radius having its point of origin in the
flat surface that bears on the specimen.
6.3 Alignment Device/Subpress:
6.3.1 It is usually necessary to use an alignment device, unless the testing machine has been designed specifically for axial
alignment. The design of the device or subpress depends on the size and strength of the specimen. It must be designed so that the
ram (or other moving parts) does not jam or tilt the device or the frame of the machine as a result of loading. The bearing blocks
of the device shall have the same requirements for parallelism and flatness as given in 6.2.1.
6.3.2 The primary requirements of all alignment devices are that the load is applied axially, uniformly, and with negligible
“slip-stick” friction. An alignment device that has been found suitable is shown in Fig. 5 and described in Ref. (3). Other devices
of the subpress type have also been used successfully.
6.4 Compression Testing Jigs—In testing thin specimens, such as sheet material, some means should be adopted to prevent the
specimen from buckling during loading. This may be accomplished by using a jig containing side-support plates that bear against
the wide sides of the specimen. The jig must afford a suitable combination of lateral-support pressure and spring constant to prevent
buckling, but without interfering with axial deformation of the specimen. Although suitable combinations vary somewhat with
variations in specimen material and thickness, testing temperatures, and accuracy of alignment, acceptable results can be obtained
with rather wide ranges of lateral-support pressure and spring constant. Generally, the higher the spring constant of the jig, the
lower the lateral-support pressure that is required. Proper adjustments of these variables should be established during the
qualification of the equipment (see 6.6).
6.4.1 It is not the intent of these methods to designate specific jigs for testing sheet materials, but merely to provide a few
illustrations and references to jigs that have been used successfully, some of which are cited in Table 1. Other jigs are acceptable
provided they prevent buckling and pass the qualification test set forth in 6.6. Compression jigs generally require that the specimen
be lubricated on the supported sides to prevent extraneous friction forces from occurring at the support points.
FIG. 3 Adjustable Bearing Block for Compression Testing
E9 − 09 (2018)
FIG. 4 Spherical-Seated Bearing Block
FIG. 5 Example of Compression Testing Apparatus
6.5 Strain Measurements:
6.5.1 Mechanical or electromechanical devices used for measuring strain shall comply with the requirements for the applicable
class described in Practice E83. The device shall be verified in compression.
6.5.2 Electrical-resistance strain gages (or other single-use devices) may be used provided the measuring system has been
verified and found to be accurate to the degree specified in Practice E83. The characteristics of electrical resistance strain gages
have been determined from Test Methods E251.
6.6 Qualification of Test Apparatus—The complete compression-test apparatus, which consists of the testing machine and when
applicable, one or more of the following; the alignment device, the jig and the strain-measurement system, shall be qualified as
follows:
6.6.1 Conduct tests to establish the elastic modulus of five replicate specimens of 2024-T3 aluminum alloy sheet or 2024-T4
aluminum alloy bar in accordance with Test Method E111. These qualification specimens shall be machined from sheet or bar in
the location specified in Test Methods B557. The thickness of the sheet or diameter of the bar may be machined to the desired
thickness or diameter. It is essential that the extensometer be properly seated on the specimens when this test is performed. When
the qualification specimens each provide a modulus value of 10.7 × 10 psi (73.8 GPa) 65 %, the apparatus qualifies.
6.6.2 The qualification procedure shall be performed using the thinnest rectangular specimen or smallest diameter round
specimen to be tested in the apparatus.
E9
...