ASTM E132-97
(Test Method)Standard Test Method for Poisson's Ratio at Room Temperature
Standard Test Method for Poisson's Ratio at Room Temperature
SCOPE
1.1 This test method covers the determination of Poisson's ratio from tension tests of structural materials at room temperature. This test method is limited to specimens of rectangular section and to materials in which and stresses at which creep is negligible compared to the strain produced immediately upon loading.
1.2 The values stated in inch-pound units are to be regarded as the 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E 132 – 97
Standard Test Method for
Poisson’s Ratio at Room Temperature
This standard is issued under the fixed designation E 132; 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 (e) 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 hence, should not be regarded as Poisson’s ratio. If this ratio is
reported, nevertheless, as a value of “Poisson’s ratio” for
1.1 This test method covers the determination of Poisson’s
stresses beyond the proportional limit, the range of stress
ratio from tension tests of structural materials at room tem-
should be stated.
perature. This test method is limited to specimens of rectan-
3.1.3 Discussion—Poisson’s ratio will have more than one
gular section and to materials in which and stresses at which
value if the material is not isotropic. Deviations from isotropy
creep is negligible compared to the strain produced immedi-
should be suspected if the Poisson’s ratio, μ, determined by the
ately upon loading.
method described below differs significantly from that deter-
1.2 The values stated in inch-pound units are to be regarded
mined when the ratio E/G of Young’s modulus, E, to shear
as the standard.
modulus, G, is substituted in the following equation:
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the μ 5 ~E/2G! 2 1 (1)
responsibility of the user of this standard to establish appro-
where E and G must be measured with greater precision than
priate safety and health practices and determine the applica-
the precision desired in the measurement of μ.
bility of regulatory limitations prior to use.
4. Significance and Use
2. Referenced Documents
4.1 When uniaxial force is applied to a solid, it deforms in
2.1 ASTM Standards:
the direction of the applied force, but also expands or contracts
E 4 Practices for Force Verification of Testing Machines
laterally depending on whether the force is tensile or compres-
E 8 Test Methods for Tension Testing of Metallic Materials
sive. If the solid is homogeneous and isotropic, and the
E 83 Practice for Verification and Classification of Exten-
material remains elastic under the action of the applied force,
someters
the lateral strain bears a constant relationship to the axial strain.
E 111 Test Method for Young’s Modulus, Tangent Modulus,
This constant, called Poisson’s ratio, after a French scientist
and Chord Modulus
that developed the concept, is a definite material property just
E 1012 Practice for Verification of Specimen Alignment
like Young’s modulus and Shear modulus.
Under Tensile Loading
4.2 Poisson’s ratio is used for design of structures where all
dimensional changes resulting from application of force need
3. Terminology
to be taken into account, and in the application of the
3.1 Definitions:
generalized theory of elasticity to structural analysis.
3.1.1 Poisson’s ratio—the absolute value of the ratio of
4.3 In this test method, the value of Poisson’s ratio is
transverse strain to the corresponding axial strain resulting
obtained from strains resulting from uniaxial stress only.
from uniformly distributed axial stress below the proportional
limit of the material.
5. General Considerations
3.1.2 Discussion—Above the proportional limit, the ratio of
5.1 The accuracy of the determination of Poisson’s ratio is
transverse strain to axial strain will depend on the average
usually limited by the accuracy of the transverse strain mea-
stress and on the stress range for which it is measured and,
surements because the percentage errors in these measurements
are usually greater than in the axial strain measurements. Since
a ratio rather than an absolute quantity is measured, it is only
This test method is under the jurisdiction of ASTM Committee E-28 on
necessary to know accurately the relative value of the calibra-
Mechanical Testing and is the direct responsibility of Subcommittee E28.03 on
Elastic Properties and Definitions on Mechanical Testing.
tion factors of the extensometers. Also, in general, the values of
Current edition approved Apr. 10, 1997. Published November 1997. Originally
the applied loads need not be accurately known. It is frequently
published as E 132 – 58 T. Last previous edition E 132 – 86 (1992).
Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E 132
expedient to make the determination of Poisson’s ratio concur- 6.3 Alignment Devices—Grips and other devices for obtain-
rently with determinations of Young’s modulus and the pro- ing and maintaining axial alignment are shown in Test Methods
portional limit. E8.
7. Test Specimens
7.1 Selection and Preparation of Specimens—In the selec-
tion and preparation of test specimens, special care shall be
taken to assure obtaining representative specimens that are
straight and uniform in thickness.
7.2 Dimensions—In general, it is recommended that the
length of the portion of the specimen that is of constant width
be at least five times the width, and that the length of the
specimen between grips be at least seven times the width. The
width itself should be at least equal to the thickness. If fillets
are used near the ends of the specimen as in the standard
rectangular tension test specimen (see Figs. 6 and Figs. 7 of
Methods E 8), these fillets should have a radius not less than
the minimum width of the specimen. The width shall be
constant throughout the entire length over which the extensom-
NOTE 1—Each symbol indicates the location of a pair of extensometers
eters are placed and for an additional distance at each end and
on opposite sides of the specimen.
equal to at least this width, unless otherwise provided in the
FIG. 1 Three Possible Arrangements of Extensometers
product specifications.
7.3 Stress Relief—This test method is intended to produce
intrinsic materials properties. Therefore, the specimen needs to
6. Apparatus
be free of residual stresses, which may require a heat treatment
6.1 Load—Loads shall be applied either by calibrated dead
to relieve the stresses in the material. The heat treatment
weights or in a testing machine that has been calibrated in
procedure consists of annealing the specimen at Tm/3 for 30
accordance with Practices E 4.
min (Tm is the melting point of the material in °K). The
6.2 Extensometers—Class B-1 extensometers, as described
procedure must be mentioned in the report section. However, if
in Practice E 83, shall be used except as otherwise provided in
the intent of the test is to verify the performance of a product,
the product specifications.
the heat treatment procedure may be omitted. This must be
NOTE 1—If exceptions are provided in the product specification so that
mentioned explicitly in the report section.
extensometers of types other than those covered in Practice E 83 are used,
it may be necessary to apply corrections, for example, the correction for
8. Procedure
the transverse sensitivity of bonded resistance gages.
8.1 Measurement of Specimens—All surfa
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