ASTM D3479/D3479M-19(2023)
(Test Method)Standard Test Method for Tension-Tension Fatigue of Polymer Matrix Composite Materials
Standard Test Method for Tension-Tension Fatigue of Polymer Matrix Composite Materials
SIGNIFICANCE AND USE
5.1 This test method is designed to yield tensile fatigue data for material specifications, research and development, quality assurance, and structural design and analysis. The primary test result is the fatigue life of the test specimen under a specific loading and environmental condition. Replicate tests may be used to obtain a distribution of fatigue life for specific material types, laminate stacking sequences, environments, and loading conditions. Guidance in statistical analysis of fatigue life data, such as determination of linearized stress life (S-N) or strain-life (ε-N) curves, can be found in Practice E739.
5.2 This test method can be utilized in the study of fatigue damage in a polymer matrix composite such as the occurrence of microscopic cracks, fiber fractures, or delaminations.3 The specimen's residual strength or stiffness, or both, may change due to these damage mechanisms. The loss in stiffness may be quantified by discontinuing cyclic loading at selected cycle intervals to obtain the quasi-static axial stress-strain curve using modulus determination procedures found in Test Method D3039/D3039M. The loss in strength associated with fatigue damage may be determined by discontinuing cyclic loading to obtain the static strength using Test Method D3039/D3039M.
Note 1: This test method may be used as a guide to conduct tension-tension variable amplitude loading. This information can be useful in the understanding of fatigue behavior of composite structures under spectrum loading conditions, but is not covered in this test method.
SCOPE
1.1 This test method determines the fatigue behavior of polymer matrix composite materials subjected to tensile cyclic loading. The composite material forms are limited to continuous-fiber or discontinuous-fiber reinforced composites for which the elastic properties are specially orthotropic with respect to the test direction. This test method is limited to unnotched test specimens subjected to constant amplitude uniaxial in-plane loading where the loading is defined in terms of a test control parameter.
1.2 This test method presents two procedures where each defines a different test control parameter.
1.2.1 Procedure A—A system in which the test control parameter is the load (stress) and the machine is controlled so that the test specimen is subjected to repetitive constant amplitude load cycles. In this procedure, the test control parameter may be described using either engineering stress or applied load as a constant amplitude fatigue variable.
1.2.2 Procedure B—A system in which the test control parameter is the strain in the loading direction and the machine is controlled so that the test specimen is subjected to repetitive constant amplitude strain cycles. In this procedure, the test control parameter may be described using engineering strain in the loading direction as a constant amplitude fatigue variable.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.3.1 Within the text the inch-pound units are shown in brackets.
1.4 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 practices and determine the applicability of regulatory limitations prior to use.
1.5 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
Relations
Standards Content (Sample)
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.
Designation: D3479/D3479M − 19 (Reapproved 2023)
Standard Test Method for
Tension-Tension Fatigue of Polymer Matrix Composite
Materials
This standard is issued under the fixed designation D3479/D3479M; 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 responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 This test method determines the fatigue behavior of
mine the applicability of regulatory limitations prior to use.
polymer matrix composite materials subjected to tensile cyclic
1.5 This international standard was developed in accor-
loading. The composite material forms are limited to
dance with internationally recognized principles on standard-
continuous-fiber or discontinuous-fiber reinforced composites
ization established in the Decision on Principles for the
for which the elastic properties are specially orthotropic with
Development of International Standards, Guides and Recom-
respect to the test direction. This test method is limited to
mendations issued by the World Trade Organization Technical
unnotched test specimens subjected to constant amplitude
Barriers to Trade (TBT) Committee.
uniaxial in-plane loading where the loading is defined in terms
of a test control parameter.
2. Referenced Documents
1.2 This test method presents two procedures where each
2.1 ASTM Standards:
defines a different test control parameter.
D883 Terminology Relating to Plastics
1.2.1 Procedure A—A system in which the test control
D3039/D3039M Test Method for Tensile Properties of Poly-
parameter is the load (stress) and the machine is controlled so
mer Matrix Composite Materials
that the test specimen is subjected to repetitive constant
D3878 Terminology for Composite Materials
amplitude load cycles. In this procedure, the test control
D5229/D5229M Test Method for Moisture Absorption Prop-
parameter may be described using either engineering stress or
erties and Equilibrium Conditioning of Polymer Matrix
applied load as a constant amplitude fatigue variable.
Composite Materials
1.2.2 Procedure B—A system in which the test control
E4 Practices for Force Calibration and Verification of Test-
parameter is the strain in the loading direction and the machine
ing Machines
is controlled so that the test specimen is subjected to repetitive
E6 Terminology Relating to Methods of Mechanical Testing
constant amplitude strain cycles. In this procedure, the test
E83 Practice for Verification and Classification of Exten-
control parameter may be described using engineering strain in
someter Systems
the loading direction as a constant amplitude fatigue variable.
E122 Practice for Calculating Sample Size to Estimate, With
1.3 The values stated in either SI units or inch-pound units Specified Precision, the Average for a Characteristic of a
Lot or Process
are to be regarded separately as standard. The values stated in
each system are not necessarily exact equivalents; therefore, to E177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
ensure conformance with the standard, each system shall be
used independently of the other, and values from the two E456 Terminology Relating to Quality and Statistics
E467 Practice for Verification of Constant Amplitude Dy-
systems shall not be combined.
1.3.1 Within the text the inch-pound units are shown in namic Forces in an Axial Fatigue Testing System
E739 Guide for Statistical Analysis of Linear or Linearized
brackets.
Stress-Life (S-N) and Strain-Life (ε-N) Fatigue Data
1.4 This standard does not purport to address all of the
E1012 Practice for Verification of Testing Frame and Speci-
safety concerns, if any, associated with its use. It is the
men Alignment Under Tensile and Compressive Axial
Force Application
This test method is under the jurisdiction of ASTM Committee D30 on
Composite Materials and is the direct responsibility of Subcommittee D30.04 on
Lamina and Laminate Test Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Sept. 1, 2023. Published September 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1976. Last previous edition approved in 2019 as D3479/D3479M – 19. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D3479_D3479M-19R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3479/D3479M − 19 (2023)
E1823 Terminology Relating to Fatigue and Fracture Testing 3.2.13 wave form, n—the shape of the peak-to-peak varia-
tion of the test control parameter as a function of time.
3. Terminology
3.3 Symbols:
3.1 Definitions—Terminology D3878 defines terms relating 3.3.1 S (or ε )—the value of stress (or strain) corre-
max max
to high-modulus fibers and their composites. Terminology sponding to the peak value of the test control parameter in a
E1823 defines terms relating to fatigue. Terminology D883 constant amplitude loading.
defines terms relating to plastics. Terminology E6 defines terms
3.3.2 S (or ε )—the value of stress (or strain) corre-
min min
relating to mechanical testing. Terminology E456 and Practice
sponding to the valley value of the test control parameter in a
E177 define terms relating to statistics. In the event of a
constant amplitude loading.
conflict between terms, Terminology D3878 shall have prece-
3.3.3 S (or ε )—the mean value of stress (or strain) as
mn mn
dence over the other standards.
given by S = (S + S )/2 or ε = (ε + ε )/2.
mn max min mn max min
3.2 Definitions of Terms Specific to This Standard: The
3.3.4 S (or ε )—the difference between the mean value of
following definitions shall have precedence over Terminology a a
stress (or strain) and the maximum and minimum stress (or
D3878 and over other standards.
strain) as given by S = (S − S )/2 or ε = (ε − ε )/2.
3.2.1 constant amplitude loading, n—in fatigue, a loading in a max min a max min
which all of the peak values of the test control parameter are
3.3.5 N —the scalar value of fatigue life or number of
f
equal and all of the valley values of the test control parameter
constant amplitude cycles to failure.
are equal.
3.3.6 α—Weibull fatigue life scale parameter.
3.2.2 fatigue loading transition, n—in the beginning of
3.3.7 β—Weibull fatigue life shape parameter.
fatigue loading, the number of cycles before the test control
parameter reaches the desired peak and valley values.
4. Summary of Test Method
−1
3.2.3 frequency, f [T ], n—in fatigue loading, the number
4.1 The tensile specimen described in Test Method D3039/
of load (stress) or strain cycles completed in 1 s (Hz).
D3039M is mounted in the grips of the testing machine and is
3.2.4 load (stress) ratio, R [nd], n—in fatigue loading, the tested as follows:
ratio of the minimum applied load (stress) to the maximum
4.1.1 Procedure A—The specimen is cycled between mini-
applied load (stress). mum and maximum in-plane axial load (stress) at a specified
frequency. The number of load cycles at which failure occurs
3.2.5 peak, n—in fatigue loading, the occurrence where the
(or at which a predetermined change in specimen stiffness is
first derivative of the test control parameter versus time
observed) can be determined for a specimen subjected to a
changes from positive to negative sign; the point of maximum
specific load (stress) ratio and maximum stress. For some
load (stress) or strain in constant amplitude loading.
purposes it is useful to obtain the in-plane stiffness at selected
3.2.6 replicate (repeat) tests, n—nominally identical tests on
cycle intervals from static axial stress-strain curves using
different test specimens conducted at the same nominal value
modulus determination procedures found in Test Method
of the independent variable.
D3039/D3039M.
−2
3.2.7 residual stiffness, [FL ], n—the value of modulus of
4.1.2 Procedure B—The specimen is cycled between mini-
a specimen under quasi-static loading conditions after the
mum and maximum in-plane axial strain at a specified fre-
specimen is subjected to fatigue loading.
quency. The number of strain cycles at which specimen failure
−2
occurs (or at which a predetermined change in specimen
3.2.8 residual strength, [FL ], n—the value of load (stress)
stiffness is observed) can be determined at a given strain ratio
required to cause failure of a specimen under quasi-static
and maximum strain. For some purposes it is useful to obtain
loading conditions after the specimen is subjected to fatigue
the in-plane stiffness at selected cycle intervals from static
loading.
axial stress-strain curves using modulus determination proce-
3.2.9 spectrum loading, n—in fatigue, a loading in which
dures found in Test Method D3039/D3039M or continuously
the peak values of the test control parameter are not equal or
from dynamic axial stress-strain data using similar procedures
the valley values of the test control parameter are not equal
as found in Test Method D3039/D3039M.
(also known as variable amplitude loading or irregular load-
ing.)
5. Significance and Use
3.2.10 strain ratio, R [nd], n—in fatigue loading, the ratio
ε
5.1 This test method is designed to yield tensile fatigue data
of the minimum applied strain to the maximum applied strain.
for material specifications, research and development, quality
3.2.11 test control parameter, n—the variable in constant
assurance, and structural design and analysis. The primary test
amplitude loading whose maximum and minimum values
result is the fatigue life of the test specimen under a specific
remain the same during cyclic loading, in other words, load
loading and environmental condition. Replicate tests may be
(stress) or strain.
used to obtain a distribution of fatigue life for specific material
3.2.12 valley, n—in fatigue loading, the occurrence where types, laminate stacking sequences, environments, and loading
the first derivative of the test control parameter versus time conditions. Guidance in statistical analysis of fatigue life data,
changes from negative to positive; the point of minimum load such as determination of linearized stress life (S-N) or strain-
(stress) or strain in constant amplitude loading. life (ε-N) curves, can be found in Practice E739.
D3479/D3479M − 19 (2023)
5.2 This test method can be utilized in the study of fatigue cations to the Test Method D3039/D3039M geometry to
damage in a polymer matrix composite such as the occurrence promote fatigue failures in the gauge section of the specimen.
of microscopic cracks, fiber fractures, or delaminations. The
7. Apparatus
specimen’s residual strength or stiffness, or both, may change
due to these damage mechanisms. The loss in stiffness may be
7.1 Micrometers—As described in Test Method D3039/
quantified by discontinuing cyclic loading at selected cycle
D3039M.
intervals to obtain the quasi-static axial stress-strain curve
7.2 Testing Machine—The testing machine shall be in con-
using modulus determination procedures found in Test Method
formance with Practices E4 and E467, and shall satisfy the
D3039/D3039M. The loss in strength associated with fatigue
following requirements:
damage may be determined by discontinuing cyclic loading to
7.2.1 Testing Machine Heads—The testing machine shall
obtain the static strength using Test Method D3039/D3039M.
have both an essentially stationary head and a movable head.
NOTE 1—This test method may be used as a guide to conduct 7.2.2 Drive Mechanism and Controller—The testing ma-
tension-tension variable amplitude loading. This information can be useful
chine shall be capable of imparting to the movable head a
in the understanding of fatigue behavior of composite structures under
controlled velocity with respect to the stationary head. The
spectrum loading conditions, but is not covered in this test method.
velocity of the movable head shall be capable of being
regulated under cyclic load (stress) or strain conditions. The
6. Interferences
drive mechanism and controller shall be in compliance with
6.1 Material and Specimen Preparation—Poor material fab-
Practice E467 and shall be capable of imparting a continuous
rication practices, lack of control of fiber alignment, and
loading wave form to the specimen. It is important to minimize
damage induced by improper coupon machining are known
drift of the fatigue loading away from the maximum and
causes of a large degree scatter in composite fatigue data.
minimum values. Achieving such accuracy is critical in the
development of reliable fatigue life data since small errors in
6.2 System Alignment—Excessive bending will cause pre-
loading may result in significant errors in fatigue life.
mature failure. Every effort should be made to eliminate excess
7.2.3 Load Indicator—As described in Test Method D3039/
bending from the test system. Bending may occur due to
D3039M. The load indicator shall be in compliance with
misaligned grips, or from specimens themselves if improperly
Practice E4. The fatigue rating of the load indicator shall
installed in the grips, or from out-of-tolerance due to poor
exceed the loads at which testing will take place. Additionally
specimen preparation. If there is any doubt as to the alignment
this test method recommends compliance with Practice E467
inherent in a given test machine then the alignment should be
for the development of a system dynamic conversion for the
checked as discussed in 7.2.6.
verification of specimen loads to within 1 % of true loads.
6.3 Tab Failure—Premature failure of the specimen in the
7.2.4 Strain Indicator—It is recommended that an exten-
tab region is common in tension-tension fatigue testing as a
someter be used for strain determination for strain control in
result of stress concentrations in the vicinity of tab region. A set
Procedure B, or to obtain strain data for Procedure A. For
of preliminary fatigue tests are recommended to find the
specimens to be tested per Procedure A and to be checked for
combination of tab material, tab length, and adhesive that
initial stiffness only, a bonded strain gauge (or gauges) may be
minimizes tab failures. Using an optical microscope to view
used for static s
...
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