ASTM D747-08
(Test Method)Standard Test Method for Apparent Bending Modulus of Plastics by Means of a Cantilever Beam
Standard Test Method for Apparent Bending Modulus of Plastics by Means of a Cantilever Beam
SIGNIFICANCE AND USE
This test method provides a means of deriving the apparent bending modulus of a material by measuring force and angle of bend of a cantilever beam. The mathematical derivation assumes small deflections and purely elastic behavior. Under actual test conditions, the deformation has both elastic and plastic components. This test method does not distinguish or separate these, and hence a true elastic modulus is not calculable. Instead, an apparent value is obtained and is defined as the apparent bending modulus of the material. The tangent modulus obtained by Test Methods D 790 is preferred, when the material can be tested by the Test Methods D 790 test procedure.
Because of deviations from purely elastic behavior, changes in span length, width, and depth of the specimen will affect the value of the apparent bending modulus obtained; therefore, values obtained from specimens of different dimensions are not necessarily comparable.
Rate of loading is controlled only to the extent that the rate of angular change of the rotating jaw is fixed at 58 to 66°/min. Actual rate of stressing will be affected by span length, width, depth of the specimen, and weight of the pendulum.
For many materials, there are specifications that require the use of this test method, but with some procedural modifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that material specification before using this test method. Table 1 of Classification System D 4000 lists the ASTM materials standards that currently exist.
Note 2—A discussion of the theory of obtaining a purely elastic bending modulus, using a cantilever beam testing apparatus, can be found in Appendix X1. The results obtained under actual test conditions will be the apparent bending modulus.
SCOPE
1.1 This test method covers the determination of the apparent bending modulus of plastics by means of a cantilever beam. It is well suited for determining relative flexibility of materials over a wide range. It is particularly useful for materials too flexible to be tested by Test Methods D 790.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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.
Note 1—There is no known ISO equivalent to this standard.
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Designation:D747–08
Standard Test Method for
Apparent Bending Modulus of Plastics by Means of a
1
Cantilever Beam
This standard is issued under the fixed designation D747; 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. Terminology
1.1 This test method covers the determination of the appar- 3.1 Definitions of Terms Specific to This Standard:
2
ent bending modulus of plastics by means of a cantilever 3.1.1 apparent bending modulus—an apparent modulus of
beam. It is well suited for determining relative flexibility of elasticity obtained in flexure, using a cantilever beam testing
materials over a wide range. It is particularly useful for apparatus, where the deformation involved is not purely elastic
materials too flexible to be tested by Test Methods D790. but contains both elastic and plastic components.
1.2 The values stated in SI units are to be regarded as the
4. Significance and Use
standard. The values given in parentheses are for information
4.1 This test method provides a means of deriving the
only.
1.3 This standard does not purport to address all of the apparent bending modulus of a material by measuring force
and angle of bend of a cantilever beam. The mathematical
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- derivation assumes small deflections and purely elastic behav-
ior. Under actual test conditions, the deformation has both
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. elastic and plastic components. This test method does not
distinguish or separate these, and hence a true elastic modulus
NOTE 1—There is no known ISO equivalent to this standard.
is not calculable. Instead, an apparent value is obtained and is
defined as the apparent bending modulus of the material. The
2. Referenced Documents
3 tangent modulus obtained by Test Methods D790 is preferred,
2.1 ASTM Standards:
when the material can be tested by the Test Methods D790 test
D618 Practice for Conditioning Plastics for Testing
procedure.
D790 Test Methods for Flexural Properties of Unreinforced
4.2 Because of deviations from purely elastic behavior,
and Reinforced Plastics and Electrical Insulating Materials
changes in span length, width, and depth of the specimen will
D4000 Classification System for Specifying Plastic Materi-
affect the value of the apparent bending modulus obtained;
als
therefore, values obtained from specimens of different dimen-
D4066 Classification System for Nylon Injection and Ex-
sions are not necessarily comparable.
trusion Materials (PA)
4.3 Rate of loading is controlled only to the extent that the
D5947 Test Methods for Physical Dimensions of Solid
rate of angular change of the rotating jaw is fixed at 58 to
Plastics Specimens
66°/min. Actual rate of stressing will be affected by span
E177 Practice for Use of the Terms Precision and Bias in
length, width, depth of the specimen, and weight of the
ASTM Test Methods
pendulum.
E691 Practice for Conducting an Interlaboratory Study to
4.4 For many materials, there are specifications that require
Determine the Precision of a Test Method
the use of this test method, but with some procedural modifi-
cations that take precedence when adhering to the specifica-
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
tion. Therefore, it is advisable to refer to that material speci-
and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.
fication before using this test method. Table 1 of Classification
Current edition approved Aug. 1, 2008. Published September 2008. Originally
System D4000 lists the ASTM materials standards that cur-
approved in 1943. Last previous edition approved in 2002 as D747 - 02. DOI:
10.1520/D0747-08. rently exist.
2
This property was designated stiffness in versions of this test method issued
NOTE 2—A discussion of the theory of obtaining a purely elastic
prior to 1984.
3
bending modulus, using a cantilever beam testing apparatus, can be found
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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
the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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D747–08
in Appendix X1. The
...
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:D747–02 Designation:D747–08
Standard Test Method for
Apparent Bending Modulus of Plastics by Means of a
1
Cantilever Beam
This standard is issued under the fixed designation D 747; 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 Department of Defense.
1. Scope*
2
1.1 This test method covers the determination of the apparent bending modulus of plastics by means of a cantilever beam. It
is well suited for determining relative flexibility of materials over a wide range. It is particularly useful for materials too flexible
to be tested by Test Methods D 790.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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.
NOTE 1—There is no known ISO equivalent forto this standard.
2. Referenced Documents
3
2.1 ASTM Standards: D374Test Methods for Thickness of Solid Electrical Insulation
D 618 Practice for Conditioning Plastics for Testing
D 790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials
D 4000 Classification System for Specifying Plastic Materials
5
D4066Classification System for Nylon Injection and Extrusion Materials 4066 Classification System for Nylon Injection and
Extrusion Materials (PA)
D 5947 Test Methods for Physical Dimensions of Solid Plastics Specimens
E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 apparent bending modulus—an apparent modulus of elasticity obtained in flexure, using a cantilever beam testing
apparatus, where the deformation involved is not purely elastic but contains both elastic and plastic components.
4. Significance and Use
4.1 This test method provides a means of deriving the apparent bending modulus of a material by measuring force and angle
of bend of a cantilever beam.The mathematical derivation assumes small deflections and purely elastic behavior. Under actual test
conditions, the deformation has both elastic and plastic components. This test method does not distinguish or separate these, and
hence a true elastic modulus is not calculable. Instead, an apparent value is obtained and is defined as the apparent bending
modulus of the material. The tangent modulus obtained by Test Methods D 790 is preferred, when the material can be tested by
the Test Methods D 790 test procedure.
4.2 Because of deviations from purely elastic behavior, changes in span length, width, and depth of the specimen will affect the
value of the apparent bending modulus obtained; therefore, values obtained from specimens of different dimensions mayare not
necessarily be comparable.
4.3 Rate of loading is controlled only to the extent that the rate of angular change of the rotating jaw is fixed at 58 to 66°/min.
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties .
Current edition approved April 10, 2002. Published June 2002. Originally published as D747–43T. Last previous edition D747–99.
Current edition approved Aug. 1, 2008. Published September 2008. Originally approved in 1943. Last previous edition approved in 2002 as D 747 - 02.
2
This property was designated stiffness in versions of this test method issued prior to 1984.
3
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 10.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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D747–08
Actual rate of stressing
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