ASTM D2344/D2344M-00(2006)
(Test Method)Standard Test Method for Short-Beam Strength of Polymer Matrix Composite Materials and Their Laminates
Standard Test Method for Short-Beam Strength of Polymer Matrix Composite Materials and Their Laminates
SIGNIFICANCE AND USE
In most cases, because of the complexity of internal stresses and the variety of failure modes that can occur in this specimen, it is not generally possible to relate the short-beam strength to any one material property. However, failures are normally dominated by resin and interlaminar properties, and the test results have been found to be repeatable for a given specimen geometry, material system, and stacking sequence (4).
Short-beam strength determined by this test method can be used for quality control and process specification purposes. It can also be used for comparative testing of composite materials, provided that failures occur consistently in the same mode (5).
This test method is not limited to specimens within the range specified in Section 8, but is limited to the use of a loading span length-to-specimen thickness ratio of 4.0 and a minimum specimen thickness of 2.0 mm [0.08 in.].
SCOPE
1.1 This test method determines the short-beam strength of high-modulus fiber-reinforced composite materials. The specimen is a short beam machined from a curved or a flat laminate up to 6.00 mm [0.25 in.] thick. The beam is loaded in three-point bending.
1.2 Application of this test method is limited to continuous- or discontinuous-fiber-reinforced polymer matrix composites, for which the elastic properties are balanced and symmetric with respect to the longitudinal axis of the beam.
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.
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 may not be exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
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Designation:D2344/D2344M −00(Reapproved 2006)
Standard Test Method for
Short-Beam Strength of Polymer Matrix Composite Materials
and Their Laminates
This standard is issued under the fixed designation D2344/D2344M; 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 D3171Test Methods for Constituent Content of Composite
Materials
1.1 This test method determines the short-beam strength of
D3878Terminology for Composite Materials
high-modulus fiber-reinforced composite materials. The speci-
D5229/D5229MTestMethodforMoistureAbsorptionProp-
men is a short beam machined from a curved or a flat laminate
erties and Equilibrium Conditioning of Polymer Matrix
up to 6.00 mm [0.25 in.] thick. The beam is loaded in
Composite Materials
three-point bending.
D5687/D5687MGuide for Preparation of Flat Composite
1.2 Application of this test method is limited to continuous-
Panels with Processing Guidelines for Specimen Prepara-
or discontinuous-fiber-reinforced polymer matrix composites,
tion
for which the elastic properties are balanced and symmetric
E4Practices for Force Verification of Testing Machines
with respect to the longitudinal axis of the beam.
E6Terminology Relating to Methods of MechanicalTesting
1.3 This standard does not purport to address all of the E18Test Methods for Rockwell Hardness of Metallic Ma-
safety concerns, if any, associated with its use. It is the
terials
responsibility of the user of this standard to establish appro- E122PracticeforCalculatingSampleSizetoEstimate,With
priate safety and health practices and determine the applica-
Specified Precision, the Average for a Characteristic of a
bility of regulatory limitations prior to use. Lot or Process
1.4 The values stated in either SI units or inch-pound units
E177Practice for Use of the Terms Precision and Bias in
are to be regarded separately as standard. The values stated in ASTM Test Methods
each system may not be exact equivalents; therefore, each
E456Terminology Relating to Quality and Statistics
system must be used independently of the other. Combining E1309 Guide for Identification of Fiber-Reinforced
values from the two systems may result in nonconformance Polymer-Matrix Composite Materials in Databases
with the standard.
E1434Guide for Recording Mechanical Test Data of Fiber-
Reinforced Composite Materials in Databases
2. Referenced Documents
E1471Guide for Identification of Fibers, Fillers, and Core
2 Materials in Computerized Material Property Databases
2.1 ASTM Standards:
D792Test Methods for Density and Specific Gravity (Rela-
3. Terminology
tive Density) of Plastics by Displacement
D883Terminology Relating to Plastics
3.1 Definitions—Terminology D3878 defines the terms re-
D2584Test Method for Ignition Loss of Cured Reinforced
lating to high-modulus fibers and their composites. Terminol-
Resins
ogy D883 defines terms relating to plastics. Terminology E6
D2734TestMethodsforVoidContentofReinforcedPlastics
definestermsrelatingtomechanicaltesting.TerminologyE456
and Practice E177 define terms relating to statistics. In the
event of a conflict between definitions, Terminology D3878
1 shall have precedence over the other documents.
This test method is under the jurisdiction of ASTM Committee D30 on
Composite Materials and is the direct responsibility of Subcommittee D30.04 on
NOTE 1—If the term represents a physical quantity, its analytical
Lamina and Laminate Test Methods.
dimensionsarestatedimmediatelyfollowingtheterm(orlettersymbol)in
Current edition approved Jan. 15, 2006. Published January 2006. Originally
´1
fundamental dimension form, using the following ASTM standard sym-
approved in 1965. Last previous edition approved in 2000 as D2344–00 . DOI:
bology for fundamental dimensions, shown within square brackets: [M]
10.1520/D2344_D2344M-00R06.
formass,[L]forlength,[T]fortime,[Θ]forthermodynamictemperature,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and[ nd]fornondimensionalquantities.Useofthesesymbolsisrestricted
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 to analytical dimensions when used with square brackets, as the symbols
the ASTM website. may have other definitions when used without the brackets.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2344/D2344M−00 (2006)
3.2 Definitions of Terms Specific to This Standard:
3.2.1 balanced laminate, n—a continuous fiber-reinforced
laminateinwhicheach+θlamina,measuredwithrespecttothe
laminatereferenceaxis,isbalancedbya–θlaminaofthesame
material (for example, [0/+45/–45/+45/–45/0]).
3.2.2 short-beam strength, n—the shear stress as calculated
in Eq 1, developed at the specimen mid-plane at the failure
event specified in 11.6.
3.2.2.1 Discussion—Althoughshearisthedominantapplied
loading in this test method, the internal stresses are complex
andavarietyoffailuremodescanoccur.Elasticitysolutionsby
Berg et al (1) , Whitney (2), and Sullivan and Van Oene (3)
have all demonstrated inadequacies in classical beam theory in
defining the stress state in the short-beam configuration.These
solutions show that the parabolic shear-stress distribution as
predicted by Eq 1 only occurs, and then not exactly, on planes
midway between the loading nose and support points. Away
fromtheseplanes,thestressdistributionsbecomeskewed,with
peak stresses occurring near the loading nose and support
points. Of particular significance is the stress state local to the
loading nose in which the severe shear-stress concentration
combined with transverse and in-plane compressive stresses
has been shown to initiate failure. However, for the more
ductile matrices, plastic yielding may alleviate the situation
under the loading nose (1) and allow other failure modes to
occur such as bottom surface fiber tension (2). Consequently,
unless mid-plane interlaminar failure has been clearly
NOTE1—DrawinginterpretationperANSIY14.5-1982andANSI/ASM
observed, the short-beam strength determined from this test
B46.1-1986.
method cannot be attributed to a shear property, and the use of
NOTE 2—Ply orientation tolerance 60.5° relative to –B–.
Eq 1 will not yield an accurate value for shear strength.
FIG. 1Flat Specimen Configuration (SI)
3.2.3 symmetric laminate, n—a continuous fiber-reinforced
laminate in which each ply above the mid-plane is identically
specimen, it is not generally possible to relate the short-beam
matched (in terms of position, orientation, and mechanical
strength to any one material property. However, failures are
properties) with one below the mid-plane.
normally dominated by resin and interlaminar properties, and
3.3 Symbols:
the test results have been found to be repeatable for a given
b—specimen width.
specimen geometry, material system, and stacking sequence
CV—sample coefficient of variation (in percent).
(4).
sbs
F —short-beam strength.
5.2 Short-beam strength determined by this test method can
h—specimen thickness.
be used for quality control and process specification purposes.
n—number of specimens.
It can also be used for comparative testing of composite
P —maximum load observed during the test.
m
materials, provided that failures occur consistently in the same
x—measuredorderivedpropertyforanindividualspecimen
i
mode (5).
from the sample population.
5.3 This test method is not limited to specimens within the
x¯—sample mean (average).
range specified in Section 8, but is limited to the use of a
4. Summary of Test Method
loading span length-to-specimen thickness ratio of 4.0 and a
minimum specimen thickness of 2.0 mm [0.08 in.].
4.1 The short-beam test specimens (Figs. 1-4) are center-
loaded as shown in Figs. 5 and 6. The specimen ends rest on
6. Interferences
two supports that allow lateral motion, the load being applied
6.1 Accurate reporting of observed failure modes is essen-
by means of a loading nose directly centered on the midpoint
tial for meaningful data interpretation, in particular, the detec-
of the test specimen.
tion of initial damage modes.
5. Significance and Use
7. Apparatus
5.1 In most cases, because of the complexity of internal
stresses and the variety of failure modes that can occur in this 7.1 Testing Machine, properly calibrated, which can be
operated at a constant rate of crosshead motion, and which the
error in the loading system shall not exceed 61%. The
Boldfacenumbersinparenthesesrefertothelistofreferencesattheendofthis
standard. load-indicating mechanism shall be essentially free of inertia
D2344/D2344M−00 (2006)
63%. Chamber conditions shall be monitored either on an
automated continuous basis or on a manual basis at regular
intervals.
7.5 Environmental Test Chamber, an environmental test
chamber is required for test environments other than ambient
testing laboratory conditions.This chamber shall be capable of
maintaining the test specimen at the required test environment
during the mechanical test method.
8. Sampling and Test Specimens
8.1 Sampling—Test at least five specimens per test condi-
tionunlessvalidresultscanbegainedthroughtheuseoffewer
specimens, as in the case of a designed experiment. For
statistically significant data, consult the procedures outlined in
Practice E122. Report the method of sampling.
8.2 Geometry:
8.2.1 Laminate Configurations—Both multidirectional and
pureunidirectionallaminatescanbetested,providedthatthere
are at least 10% 0° fibers in the span direction of the beam
(preferablywelldistributedthroughthethickness),andthatthe
laminates are both balanced and symmetric with respect to the
span direction of the beam.
8.2.2 Specimen Configurations—Typical configurations for
the flat and curved specimens are shown in Figs. 1-4. For
NOTE 1—Drawing interpretation per ANSI Y14.5-1982 and ANSI/
specimen thicknesses other than those shown, the following
ASME B46.1-1986.
geometries are recommended:
NOTE 2—Ply orientation tolerance 60.5° relative to –B–.
Specimen length = thickness × 6
FIG. 2Flat Specimen Configuration (Inch Pound)
Specimen width, b = thickness × 2.0
NOTE 2—Analysis reported by Lewis andAdams (6) has shown that a
lag at the crosshead rate used. Inertia lag may not exceed 1%
width-to-thickness ratio of greater than 2.0 can result in a significant
ofthemeasuredload.Theaccuracyofthetestingmachineshall width-wise shear-stress variation.
be verified in accordance with Practices E4.
8.2.2.1 For curved beam specimens, it is recommended that
7.2 Loading Nose and Supports, as shown in Figs. 5 and 6,
the arc should not exceed 30°. Also, for these specimens, the
shallbe6.00-mm(0.250-in.)and3.00-mm(0.125-in.)diameter
specimen length is defined as the minimum chord length.
cylinders, respectively, with a hardness of 60 to 62 HRC, as
8.3 Specimen Preparation—Guide D5687/D5687M pro-
specified in Test Methods E18, and shall have finely ground
videsrecommendedspecimenpreparationpracticesandshould
surfaces free of indentation and burrs with all sharp edges
be followed where practical.
relieved.
8.3.1 Laminate Fabrication—Laminates may be hand-laid,
7.3 Micrometers—For width and thickness measurements,
filament-wound or tow-placed, and molded by any suitable
the micrometers shall use a 4- to 5-mm (0.16- to 0.2-in.)
laminating means, such as press, bag, autoclave, or resin
nominal diameter ball interface on an irregular surface such as
transfer molding.
thebagsideofalaminateandaflatanvilinterfaceonmachined
8.3.2 Machining Methods—Specimen preparation is impor-
edges or very smooth tooled surfaces.Amicrometer or caliper
tant for these specimens. Take precautions when cutting
with flat anvil faces shall be used to measure the length of the
specimen. The accuracy of the instrument(s) shall be suitable specimensfromtheringsorplatestoavoidnotches,undercuts,
rough or uneven surfaces, or delaminations as a result of
forreadingtowithin1%ofthesampledimensions.Fortypical
section geometries, an instrument with an accuracy of 60.002 inappropriate machining methods. Obtain final dimensions by
mm (60.0001 in.) is desirable for thickness and width water-lubricated precision sawing, milling, or grinding. The
measurement, while an instrument with an accuracy of 60.1
use of diamond tooling has been found to be extremely
mm (60.004 in.) is adequate for length measurement. effective for many material systems. Edges should be flat and
parallel within the specified tolerances.
7.4 Conditioning Chamber, when conditioning materials at
8.3.3 Labeling—Label the specimens so that they will be
nonlaboratory environments, a temperature/vapor-level-
controlledenvironmentalconditioningchamberisrequiredthat distinctfromeachotherandtraceablebacktotherawmaterial,
inamannerthatwillbothbeunaffectedbythetestmethodand
shall be capable of maintaining the required temperature to
within 63°C (65°F) and the required vapor level to within not influence the test method.
D2344/D2344M−00 (2006)
NOTE 1—Drawing interpretation per ANSI Y14.5-1982 and ANSI/ASM B46.1-1986.
NOTE 2—Ply orientation tolerance 60.5° relative to –A–.
FIG. 3Curved Specimen Configuration (SI)
9. Calibration 11.1.1 The specimen sampling method and coupon geom-
etry.
9.1 The accuracy of all measuring equipment shall have
11.1.2 The material properties and data-reporting format
certified calibrations that are current at the time of use of the
desired.
equipment.
NOTE 3—Determine specific material property, accuracy, and data-
10. Conditioning
reporting requirements before test for proper selection of instrumentation
and data-recording equipment. Estimate operating stress levels to aid in
10.1 Standard Conditioning Procedure—Unless a different
calibration of equipment and determination of equipment settings.
environment is specified as part of the test method, condition
11.1.3 The environmental conditioning test parameters.
the test specimens in accordance with Procedure C of Test
11.1.4 If performed, the sampling test method, coupon
Method D5229/D5229M, and store and test at standard labo-
geometry, and test parameters used to determine density and
ratory atmosphere (23 6 3°C (73 6 5°F) and 50 6 10%
reinforcement volume.
relative humidity).
11.2 General Instructions:
11. Procedure
11.2.1 Reportanydeviationsfromthistestmethod,whether
11.1 Parameters to Be Specified Before Test: intentional or inadvertent.
------------
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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.
´1
Designation:D 2344/D 2344M–00 Designation: D2344/D2344M – 00 (Reapproved 2006)
Standard Test Method for
Short-Beam Strength of Polymer Matrix Composite Materials
and Their Laminates
This standard is issued under the fixed designation D2344/D2344M; 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.
´ NOTE—The title has been editorially corrected in November 2000.
1. Scope
1.1 This test method determines the short-beam strength of high-modulus fiber-reinforced composite materials. The specimen
is a short beam machined from a curved or a flat laminate up to 6.00 mm [0.25 in.] thick. The beam is loaded in three-point
bending.
1.2 Application of this test method is limited to continuous- or discontinuous-fiber-reinforced polymer matrix composites, for
which the elastic properties are balanced and symmetric with respect to the longitudinal axis of the beam.
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.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system must be used independently of the other. Combining values from the
two systems may result in nonconformance with the standard.
2. Referenced Documents
2.1 ASTM Standards:
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
D2584 Test Method for Ignition Loss of Cured Reinforced Resins
D2734 Test Methods for Void Content of Reinforced Plastics
D3171 Test Method for Fiber Content of Resin-Matrix Composites by Matrix Digestion Test Methods for Constituent Content
of Composite Materials
D3878 Terminology for High-Modulus Reinforcing Fibers and Their Composites Terminology for Composite Materials
D5229/D5229M Test Method for MoistureAbsorption Properties and Equilibrium Conditioning of Polymer Matrix Composite
Materials
D5687/D5687M Guide for Preparation of Flat Composite Panels with Processing Guidelines for Specimen Preparation
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E18 TestMethodsforRockwellHardnessandRockwellSuperficialHardnessofMetallicMaterials TestMethodsforRockwell
Hardness of Metallic Materials
E122 Practice for Choice of Sample Size to Estimate a Measure of Quality for a Lot or Process Practice for Calculating Sample
Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or Process
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E1309 Guide for Identification of Fiber-Reinforced Polymer-Matrix Composite Materials in Computerized Material Property
Databases
This test method is under the jurisdiction of ASTM Committee D-30 on Composite Materials and is the direct responsibility of Subcommittee D30.04 on Lamina and
Laminate Test Methods.
Current edition approved March 10, 2000. Published June 2000. Originally published as D 2344–65T. Last previous edition D 2344–84 (1995).
´1
Current edition approved Jan. 15, 2006. Published January 2006. Originally approved in 1965. Last previous edition approved in 2000 as D2344 – 00 . DOI:
10.1520/D2344_D2344M-00R06.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 08.01.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.
D2344/D2344M – 00 (2006)
E1434 Guide for Development of Standard Data Records for Computerization of Mechanical Test Data for High-Modulus
Fiber-Reinforced Composite Materials Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials
in Databases
E1471 Guide for Identification of Fibers, Fillers, and Core Materials in Computerized Material Property Databases
3. Terminology
3.1 Definitions—Terminology D 3878D3878 defines the terms relating to high-modulus fibers and their composites.
Terminology D 883D883 defines terms relating to plastics. Terminology E 6E6 defines terms relating to mechanical testing.
Terminology E 456E456 and Practice E 177E177 define terms relating to statistics. In the event of a conflict between definitions,
Terminology D 3878D3878 shall have precedence over the other documents.
NOTE 1—If the term represents a physical quantity, its analytical dimensions are stated immediately following the term (or letter symbol) in
fundamental dimension form, using the followingASTM standard symbology for fundamental dimensions, shown within square brackets: [M] for mass,
[L] for length, [T] for time, [Q] for thermodynamic temperature, and [nd] for nondimensional quantities. Use of these symbols is restricted to analytical
dimensions when used with square brackets, as the symbols may have other definitions when used without the brackets.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 balanced laminate, n—a continuous fiber-reinforced laminate in which each +u lamina, measured with respect to the
laminate reference axis, is balanced by a –u lamina of the same material (for example, [0/+45/–45/+45/–45/0]).
3.2.2 short-beam strength, n—the shear stress as calculated in Eq 1, developed at the specimen mid-plane at the failure event
specified in 11.6.
3.2.2.1 Discussion—Although shear is the dominant applied loading in this test method, the internal stresses are complex and
a variety of failure modes can occur. Elasticity solutions by Berg et al (1) , Whitney (2), and Sullivan and Van Oene (3) have all
demonstrated inadequacies in classical beam theory in defining the stress state in the short-beam configuration. These solutions
show that the parabolic shear-stress distribution as predicted by Eq 1 only occurs, and then not exactly, on planes midway between
the loading nose and support points.Away from these planes, the stress distributions become skewed, with peak stresses occurring
near the loading nose and support points. Of particular significance is the stress state local to the loading nose in which the severe
shear-stressconcentrationcombinedwithtransverseandin-planecompressivestresseshasbeenshowntoinitiatefailure.However,
for the more ductile matrices, plastic yielding may alleviate the situation under the loading nose (1) and allow other failure modes
to occur such as bottom surface fiber tension (2). Consequently, unless mid-plane interlaminar failure has been clearly observed,
theshort-beamstrengthdeterminedfromthistestmethodcannotbeattributedtoashearproperty,andtheuseofEq1willnotyield
an accurate value for shear strength.
3.2.3 symmetric laminate, n—a continuous fiber-reinforced laminate in which each ply above the mid-plane is identically
matched (in terms of position, orientation, and mechanical properties) with one below the mid-plane.
3.3 Symbols:
b—specimen width.
CV—sample coefficient of variation (in percent).
sbs
F —short-beam strength.
h—specimen thickness.
n—number of specimens.
P —maximum load observed during the test.
m
x—measured or derived property for an individual specimen from the sample population.
i
x¯—sample mean (average).
4. Summary of Test Method
4.1 The short-beam test specimens (Figs. 1-4) are center-loaded as shown in Figs. 5 and 6. The specimen ends rest on two
supports that allow lateral motion, the load being applied by means of a loading nose directly centered on the midpoint of the test
specimen.
5. Significance and Use
5.1 Inmostcases,becauseofthecomplexityofinternalstressesandthevarietyoffailuremodesthatcanoccurinthisspecimen,
itisnotgenerallypossibletorelatetheshort-beamstrengthtoanyonematerialproperty.However,failuresarenormallydominated
by resin and interlaminar properties, and the test results have been found to be repeatable for a given specimen geometry, material
system, and stacking sequence (4).
5.2 Short-beam strength determined by this test method can be used for quality control and process specification purposes. It
can also be used for comparative testing of composite materials, provided that failures occur consistently in the same mode (5).
5.3 This test method is not limited to specimens within the range specified in Section 8, but is limited to the use of a loading
span length-to-specimen thickness ratio of 4.0 and a minimum specimen thickness of 2.0 mm [0.08 in.].
Annual Book of ASTM Standards, Vol 08.02.
Boldface numbers in parentheses refer to the list of references at the end of this standard.
D2344/D2344M – 00 (2006)
NOTE 1—Drawing interpretation per ANSI Y14.5-1982 and ANSI/
ASM B46.1-1986.
NOTE 2—Ply orientation tolerance 60.5° relative to –B–.
FIG. 1 Flat Specimen Configuration (SI)
6. Interferences
6.1 Accurate reporting of observed failure modes is essential for meaningful data interpretation, in particular, the detection of
initial damage modes.
7. Apparatus
7.1 Testing Machine, properly calibrated, which can be operated at a constant rate of crosshead motion, and which the error in
the loading system shall not exceed 61 %. The load-indicating mechanism shall be essentially free of inertia lag at the crosshead
rateused.Inertialagmaynotexceed1 %ofthemeasuredload.Theaccuracyofthetestingmachineshallbeverifiedinaccordance
with Practices E 4E4.
7.2 Loading Nose and Supports, as shown in Figs. 5 and 6, shall be 6.00-mm (0.250-in.) and 3.00-mm (0.125-in.) diameter
cylinders, respectively, with a hardness of 60 to 62 HRC, as specified in Test Methods E 18E18, and shall have finely ground
surfaces free of indentation and burrs with all sharp edges relieved.
7.3 Micrometers—For width and thickness measurements, the micrometers shall use a 4- to 5-mm (0.16- to 0.2-in.) nominal
diameter ball interface on an irregular surface such as the bag side of a laminate and a flat anvil interface on machined edges or
very smooth tooled surfaces.Amicrometer or caliper with flat anvil faces shall be used to measure the length of the specimen.The
accuracy of the instrument(s) shall be suitable for reading to within 1 % of the sample dimensions. For typical section geometries,
an instrument with an accuracy of 60.002 mm (60.0001 in.) is desirable for thickness and width measurement, while an
instrument with an accuracy of 60.1 mm (60.004 in.) is adequate for length measurement.
7.4 Conditioning Chamber, when conditioning materials at nonlaboratory environments, a temperature/vapor-level-controlled
environmental conditioning chamber is required that shall be capable of maintaining the required temperature to within 63°C
(65°F) and the required vapor level to within 63 %. Chamber conditions shall be monitored either on an automated continuous
basis or on a manual basis at regular intervals.
7.5 Environmental Test Chamber, an environmental test chamber is required for test environments other than ambient testing
laboratory conditions. This chamber shall be capable of maintaining the test specimen at the required test environment during the
mechanical test method.
D2344/D2344M – 00 (2006)
NOTE 1—Drawing interpretation per ANSI Y14.5-1982 and ANSI/
ASME B46.1-1986.
NOTE 2—Ply orientation tolerance 60.5° relative to –B–.
FIG. 2 Flat Specimen Configuration (Inch Pound)
8. Sampling and Test Specimens
8.1 Sampling—Test at least five specimens per test condition unless valid results can be gained through the use of fewer
specimens, as in the case of a designed experiment. For statistically significant data, consult the procedures outlined in Practice
E 122E122. Report the method of sampling.
8.2 Geometry:
8.2.1 Laminate Configurations—Both multidirectional and pure unidirectional laminates can be tested, provided that there are
at least 10 % 0° fibers in the span direction of the beam (preferably well distributed through the thickness), and that the laminates
are both balanced and symmetric with respect to the span direction of the beam.
8.2.2 Specimen Configurations—Typical configurations for the flat and curved specimens are shown in Figs. 1-4. For specimen
thicknesses other than those shown, the following geometries are recommended:
Specimen length = thickness 3 6
Specimen width, b = thickness 3 2.0
NOTE 2—Analysis reported by Lewis andAdams (6) has shown that a width-to-thickness ratio of greater than 2.0 can result in a significant width-wise
shear-stress variation.
8.2.2.1 For curved beam specimens, it is recommended that the arc should not exceed 30°. Also, for these specimens, the
specimen length is defined as the minimum chord length.
8.3 Specimen Preparation—Guide D 5687/D 5687MD 5687/D 5687M —Guide D5687/D5687M provides recommended
specimen preparation practices and should be followed where practical.
8.3.1 Laminate Fabrication—Laminates may be hand-laid, filament-wound or tow-placed, and molded by any suitable
laminating means, such as press, bag, autoclave, or resin transfer molding.
8.3.2 Machining Methods—Specimen preparation is important for these specimens. Take precautions when cutting specimens
from the rings or plates to avoid notches, undercuts, rough or uneven surfaces, or delaminations as a result of inappropriate
machining methods. Obtain final dimensions by water-lubricated precision sawing, milling, or grinding. The use of diamond
tooling has been found to be extremely effective for many material systems. Edges should be flat and parallel within the specified
tolerances.
8.3.3 Labeling—Label the specimens so that they will be distinct from each other and traceable back to the raw material, in a
manner that will both be unaffected by the test method and not influence the test method.
D2344/D2344M – 00 (2006)
NOTE 1—Drawing interpretation per ANSI Y14.5-1982 an
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