ASTM D3479/D3479M-96
(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
SCOPE
1.1 These test methods cover the specimen, apparatus, and procedures for the determination of the constant-amplitude tension-tension fatigue properties of resin matrix composites reinforced by oriented continuous or discontinuous high modulus > 3 X 10 psi (> 20 GPa) fibers. This includes only the following:
1.1.1 Unidirectional -Continuous or discontinuous reinforcing fibers, 0° and 90° properties.
1.1.2 Laminates of Symmetric, Orthotropic Construction -Continuous or discontinuous reinforcing fibers.
1.2 The two methods are as follows:
1.2.1 Method A -A system in which the load is controlled so that the test specimen is subjected to a constant amplitude of load in each cycle.
1.2.2 Method B -A system in which the strain or deformation is controlled so that the test specimen is subjected to a constant amplitude of strain in each cycle.
1.3 The values stated in inch-pound units shall be regarded as the standard. The values in parentheses are for information only.
1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 3479/D 3479M – 96
Standard Test Method for
Tension-Tension Fatigue of Polymer Matrix Composite
Materials
This standard is issued under the fixed designation D 3479/D 3479M; 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.
1. Scope D 883 Terminology Relating to Plastics
D 3039/D 3039M Test Method for Tensile Properties of
1.1 This test method determines the fatigue behavior of
Polymer Matrix Composite Materials
polymer matrix composite materials subjected to tensile cyclic
D 3878 Terminology of High-Modulus Reinforcing Fibers
loading. The composite material forms are limited to
and Their Composites
continuous-fiber or discontinuous-fiber reinforced composites
D 5229/D 5229M Test Method for Moisture Absorption
for which the elastic properties are specially orthotropic with
Properties and Equilibrium Conditioning of Polymer Ma-
respect to the test direction. This test method is limited to
trix Composite Materials
unnotched test specimens subjected to constant amplitude
E 4 Practices for Force Verification of Testing Machines
uniaxial in-plane loading where the loading is defined in terms
E 6 Terminology Relating to Methods of Mechanical Test-
of a test control parameter.
ing
1.2 This test method presents two procedures where each
E 83 Practice for Verification and Classification of Exten-
defines a different test control parameter.
someters
1.2.1 Procedure A—A system in which the test control
E 122 Practice for Choice of Sample Size to Estimate a
parameter is the load (stress) and the machine is controlled so
Measure of Quality for a Lot or Process
that the test specimen is subjected to repetitive constant
E 177 Practice for Use of the Terms Precision and Bias in
amplitude load cycles. In this procedure, the test control
ASTM Test Methods
parameter may be described using either engineering stress or
E 456 Terminology Relating to Quality and Statistics
applied load as a constant amplitude fatigue variable.
E 467 Practice for Verification of Constant Amplitude Dy-
1.2.2 Procedure B—A system in which the test control
namic Loads on Displacements in an Axial Load Fatigue
parameter is the strain in the loading direction and the machine
Testing System
is controlled so that the test specimen is subjected to repetitive
E 739 Practice for Statistical Analysis of Linear or Linear-
constant amplitude strain cycles. In this procedure, the test
ized Stress-Life (S-N) and Strain-Life (e-N) Fatigue Data
control parameter may be described using engineering strain in
E 1012 Practice for Verification of Specimen Alignment
the loading direction as a constant amplitude fatigue variable.
Under Tensile Loading
1.3 This standard does not purport to address all of the
E 1049 Practices for Cycle Counting in Fatigue Analysis
safety concerns, if any, associated with its use. It is the
E 1150 Definitions of Terms Relating to Fatigue
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3. Terminology
bility of regulatory limitations prior to use.
3.1 Definitions—Terminology D 3878 defines terms relating
1.4 The values stated in either SI units or inch-pound units
to high-modulus fibers and their composites. Terminology
are to be regarded separately as standard. Within the text the
E 1150 defines terms relating to fatigue. Terminology D 883
inch-pound units are shown in brackets. The values stated in
defines terms relating to plastics. Terminology E 6 defines
each system are not exact equivalents; therefore, each system
terms relating to mechanical testing. Terminology E 456 and
must be used independently of the other. Combining values
Practice E 177 define terms relating to statistics. In the event of
from the two systems may result in non-conformance with this
a conflict between terms, Terminology D 3878 shall have
standard.
precedence over the other standards.
2. Referenced Documents 3.2 Definitions of Terms Specific to This Standard: The
following definitions shall have precedence over Terminology
2.1 ASTM Standards:
D 3878 and over other standards.
This test method is under the jurisdiction of ASTM Committee D-30 on High
Modulus Fibers and Their Compositesand is the direct responsibility of Subcom- Annual Book of ASTM Standards, Vol 08.01.
mittee D30.04on Lamina and Laminate Test Methods. Annual Book of ASTM Standards, Vol 15.03.
Current edition approved June 10, 1996. Published August 1996. Originally Annual Book of ASTM Standards, Vol 03.01.
published as D 3479 – 76. Last previous edition D 3479 – 76. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3479/D 3479M
3.2.1 constant amplitude loading, n—in fatigue, a loading constant amplitude cycles to failure.
in which all of the peak values of the test control parameter are 3.3.6 a—Weibull fatigue life scale parameter.
equal and all of the valley values of the test control parameter 3.3.7 b—Weibull fatigue life shape parameter.
are equal.
4. Summary of Test Method
3.2.2 fatigue loading transition, n—in the beginning of
4.1 The tensile specimen described in Test Method D 3039/
fatigue loading, the number of cycles before the test control
D 3039M is mounted in the grips of the testing machine and is
parameter reaches the desired peak and valley values.
−1
tested as follows:
3.2.3 frequency, f [T ], n—in fatigue loading, the number
4.1.1 Procedure A—The specimen is cycled between mini-
of load (stress) or strain cycles completed in 1 s (Hz).
mum and maximum in-plane axial load (stress) at a specified
3.2.4 load (stress) ratio, R [nd], n—in fatigue loading, the
frequency. The number of load cycles at which failure occurs
ratio of the minimum applied load (stress) to the maximum
(or at which a predetermined change in specimen stiffness is
applied load (stress).
observed) can be determined for a specimen subjected to a
3.2.5 peak, n—in fatigue loading, the occurrence where the
specific load (stress) ratio and maximum stress. For some
first derivative of the test control parameter versus time
purposes it is useful to obtain the in-plane stiffness at selected
changes from positive to negative sign; the point of maximum
cycle intervals from static axial stress-strain curves using
load (stress) or strain in constant amplitude loading.
modulus determination procedures found in Test Method
3.2.6 replicate (repeat) tests, n—nominally identical tests
D 3039/D 3039M.
on different test specimens conducted at the same nominal
4.1.2 Procedure B—The specimen is cycled between mini-
value of the independent variable.
mum and maximum in-plane axial strain at a specified fre-
−2
3.2.7 residual stiffness, [FL ], n—the value of modulus of
quency. The number of strain cycles at which specimen failure
a specimen under quasi-static loading conditions after the
occurs (or at which a predetermined change in specimen
specimen is subjected to fatigue loading.
stiffness is observed) can be determined at a given strain ratio
−2
3.2.8 residual strength, [FL ], n—the value of load (stress)
and maximum strain. For some purposes it is useful to obtain
required to cause failure of a specimen under quasi-static
the in-plane stiffness at selected cycle intervals from static
loading conditions after the specimen is subjected to fatigue
axial stress-strain curves using modulus determination proce-
loading.
dures found in Test Method D 3039/D 3039M or continuously
3.2.9 spectrum loading, n—in fatigue, a loading in which
from dynamic axial stress-strain data using similar procedures
the peak values of the test control parameter are not equal or
as found in Test Method D 3039/D 3039M.
the valley values of the test control parameter are not equal
(also known as variable amplitude loading or irregular load- 5. Significance and Use
ing.)
5.1 This test method is designed to yield tensile fatigue data
3.2.10 strain ratio, R [nd], n—in fatigue loading, the ratio
e for material specifications, research and development, quality
of the minimum applied strain to the maximum applied strain.
assurance, and structural design and analysis. The primary test
3.2.11 test control parameter, n—the variable in constant
result is the fatigue life of the test specimen under a specific
amplitude loading whose maximum and minimum values
loading and environmental condition. Replicate tests may be
remain the same during cyclic loading, in other words, load
used to obtain a distribution of fatigue life for specific material
(stress) or strain.
types, laminate stacking sequences, environments, and loading
3.2.12 valley, n—in fatigue loading, the occurrence where
conditions. Guidance in statistical analysis of fatigue life data,
the first derivative of the test control parameter versus time
such as determination of linearized stress life (S-N) or strain-
changes from negative to positive; the point of minimum load
life (e-N) curves, can be found in Practice E 739.
(stress) or strain in constant amplitude loading.
5.2 This test method can be utilized in the study of fatigue
3.2.13 wave form, n—the shape of the peak-to-peak varia-
damage in a polymer matrix composite such as the occurrence
tion of the test control parameter as a function of time.
of microscopic cracks, fiber fractures, or delaminations. The
3.3 Symbols: specimen’s residual strength or stiffness, or both, may change
3.3.1 S (or e )—the value of stress (or strain) corre- due to these damage mechanisms. The loss in stiffness may be
max max
sponding to the peak value of the test control parameter in a quantified by discontinuing cyclic loading at selected cycle
constant amplitude loading. intervals to obtain the quasi-static axial stress-strain curve
using modulus determination procedures found in Test Method
3.3.2 S (or e )—the value of stress (or strain) corre-
min min
D 3039/D 3039M. The loss in strength associated with fatigue
sponding to the valley value of the test control parameter in a
damage may be determined by discontinuing cyclic loading to
constant amplitude loading.
obtain the static strength using Test Method D 3039/D 3039M.
3.3.3 S (or e )—the mean value of stress (or strain) as
mn mn
illustrated in Fig. 1 and given by S 5 (S + S )/2 or
mn max min
NOTE 1—This test method may be used as a guide to conduct
e 5 (e + e )/2.
mn max min tension-tension variable amplitude loading. This information can be useful
3.3.4 S (or e )—the difference between the mean value of in the understanding of fatigue behavior of composite structures under
a a
spectrum loading conditions, but is not covered in this standard.
stress (or strain) and the maximum and minimum stress (or
strain) as illustrated in Figure 1 and given by
S 5 (S − S )/2 or e 5 (e − e )/2. 6
a max min a max min
Reifsnider, K. L., 1991, “Damage and Damage Mechanics,” Composite
3.3.5 N —the scalar value of fatigue life or number of Materials Series: Fatigue of Composites, Vol 4, pp. 11–75.
f
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3479/D 3479M
6. Interferences initial stiffness only, a bonded strain gage (or gages) may be
used for static strain measurements. This test method follows
6.1 Material and Specimen Preparation—Poor material
extensometer requirements as found in Test Method D 3039/
fabrication practices, lack of control of fiber alignment, and
D 3039M. Verification of data acquisition and extensometer
damage induced by improper coupon machining are known
accuracy shall be completed in accordance with Practice E 83.
causes of a large degree scatter in composite fatigue data.
However, a static verification is insufficient for dynamic
6.2 System Alignment—Excessive bending will cause pre-
loading, and it is recommended as a minimum to conduct a
mature failure. Every effort should be made to eliminate excess
dynamic verification using Appendix X3 of Practice E 83.
bending from the test system. Bending may occur due to
Practice E 83 discusses dynamic calibration of the extensom-
misaligned grips, or from specimens themselves if improperly
eter by comparing extensometer strain to those from strain
installed in the grips, or from out-of-tolerance due to poor
gages during cyclic loading. Practice E 83 discusses the
specimen preparation. If there is any doubt as to the alignment
assessment of the vibrational sensitivity of the extensometer
inherent in a given test machine then the alignment should be
using a single moving anvil.
checked as discussed in 7.2.6.
6.3 Tab Failure—Premature failure of the specimen in the
NOTE 2—The user is also cautioned that the effect of temperature
tab region is common in tension-tension fatigue testing as a variation on strain reading by extensometers may result in erroneous
fatigue data as is discussed in Practice E 83.
result of stress concentrations in the vicinity of tab region. A set
of preliminary fatigue tests are recommended to find the
7.2.5 Grips—As described in Test Method D 3039/
combination of tab material, tab length, and adhesive that
D 3039M. The grips shall also have sufficient fatigue rating for
minimizes tab failures. Using an optical microscope to view
loads at which testing will take place.
the edge of the specimen, it can be determined if similar states
7.2.6 System Alignment—Poor system alignment can be a
of damage occur in the tab region and the gage region.
significant contributor to premature fatigue failure and fatigue
6.4 Load History—Variations in testing frequency, and
life data scatter. Practice E 1012 describes alignment guide-
stress (or strain) ratio from test to test will result in variations lines for the determination of out of plane loading during static
in fatigue life data. Every effort should be made to evaluate the
tensile testing. In addition to Practice E 1012, the system shall
fatigue performance of composite laminates using the same
be aligned using static tension procedures outlined in Test
testing frequencies and load (or stress) ratios.
Method D 3039/D 3039M.
7.3 Thermocouple and Temperature Recording Devices—
7. Apparatus
Capable of reading specimen temperature to 60.5°C [61.0°F].
7.1 Micrometers—As described in Test Method D 3039/
8. Sampling and Test Specimens
D
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.