ASTM D5467/D5467M-97(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D5467/D5467M – 97 (Reapproved 2004)
Standard Test Method for
Compressive Properties of Unidirectional Polymer Matrix
Composite Materials Using a Sandwich Beam
This standard is issued under the fixed designation D5467/D5467M; 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 D792 TestMethodsforDensityandSpecificGravity(Rela-
tive Density) of Plastics by Displacement
1.1 This test method covers the in-plane compressive prop-
D883 Terminology Relating to Plastics
erties of polymer matrix composite materials reinforced by
D2584 Test Method for Ignition Loss of Cured Reinforced
high-modulus fibers in a sandwich beam configuration. The
Resins
composite material forms are limited to continuous-fiber com-
D2734 Test Methods for Void Content of Reinforced Plas-
posites of unidirectional orientation. This test procedure intro-
tics
duces compressive load into a thin skin bonded to a thick
D3171 Test Methods for Constituent Content of Composite
honeycombcorewiththecompressiveloadtransmittedintothe
Materials
sample by subjecting the beam to four-point bending.
D3410/D3410M Test Method for Compressive Properties
1.2 This procedure is applicable primarily to laminates
ofPolymerMatrixCompositeMaterialswithUnsupported
made from prepreg or similar product forms. Other product
Gage Section by Shear Loading
forms may require deviations from the test method.
D3878 Terminology for Composite Materials
1.3 The values stated in either SI units or inch-pound units
D5229/D5229M Test Method for Moisture Absorption
are to be regarded separately as standard. Within the text the
Properties and Equilibrium Conditioning of Polymer Ma-
inch-pounds units are shown in brackets. The values stated in
trix Composite Materials
each system are not exact equivalents; therefore, each system
E4 Practices for Force Verification of Testing Machines
must be used independently of the other. Combining values
E6 TerminologyRelatingtoMethodsofMechanicalTesting
from the two systems may result in nonconformance with the
E111 Test Method forYoung’s Modulus,Tangent Modulus,
standard.
and Chord Modulus
NOTE 1—Additional procedures for determining compressive proper-
E122 Practice for Calculating Sample Size to Estimate,
ties of polymer matrix composites may be found in Test Methods
With Specified Precision, the Average for a Characteristic
D3410/D3410M and D695.
of a Lot or Process
1.4 This standard does not purport to address all of the
E177 Practice for Use of the Terms Precision and Bias in
safety concerns, if any, associated with its use. It is the
ASTM Test Methods
responsibility of the user of this standard to establish appro-
E251 Test Methods for Performance Characteristics of Me-
priate safety and health practices and determine the applica-
tallic Bonded Resistance Strain Gauges
bility of regulatory limitations prior to use.
E456 Terminology Relating to Quality and Statistics
E1237 GuideforInstallingBondedResistanceStrainGages
2. Referenced Documents
E1309 Guide for Identification of Fiber-Reinforced
2.1 ASTM Standards:
Polymer-Matrix Composite Materials in Databases
D695 Test Method for Compressive Properties of Rigid
E1434 Guide for Recording MechanicalTest Data of Fiber-
Plastics
Reinforced Composite Materials in Databases
E1471 Guide for Identification of Fibers, Fillers, and Core
Materials in Computerized Material Property Databases
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.
3. Terminology
Current edition approved Mar. 1, 2004. Published March 2004. Originally
3.1 Definitions—Terminology D3878 defines terms relating
approved in 1993. Last previous edition approved in 1997 as D5467/
´1
D5467M–97 . DOI: 10.1520/D5467_D5467M-97R04. to high-modulus fibers and their composites. Terminology
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
D883definestermsrelatingtoplastics.TerminologyE6defines
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
terms relating to mechanical testing. Terminology E456 and
Standards volume information, refer to the standard’s Document Summary page on
PracticeE177definetermsrelatingtostatistics.Intheeventof
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5467/D5467M – 97 (2004)
a conflict between terms, Terminology D3878 shall have (a transverse strain-longitudinal strain curve as used for deter-
precedence over the other terminology standards. mining Poisson’s ratio).
3.2 Definitions of Terms Specific to This Standard:
3.3 Symbols:
3.2.1 nominal value, n—a value, existing in name only,
3.3.1 a—distance between neutral axes of test and opposite
assigned to a measurable property for the purpose of conve-
facesheets.
nient designation. Tolerances may be applied to a nominal
3.3.2 A—cross-sectional area of test facesheet.
value to define an acceptable range for the property.
3.3.3 CV—sample coefficient of variation, in percent.
3.2.2 orthotropic material, n—a material with a property of
3.3.4 E —modulus of elasticity of the opposite facesheet in
interest that, at a given point, possesses three mutually perpen- o
the test direction.
dicular planes of symmetry defining the principal material
coordinate system for that property. 3.3.5 E—modulus of elasticity of the test facesheet in the
f
test direction.
3.2.3 principal material coordinate system, n—a coordinate
cu
systemwithaxesthatarenormaltotheplanesofsymmetrythat
3.3.6 F —ultimate compressive strength.
exist within the material.
3.3.7 G —through-thickness shear modulus of elasticity.
xz
3.2.4 reference coordinate system, n—a coordinate system
3.3.8 h —thickness of core.
c
for laminated composites used to define ply orientations. One
c
3.3.9 s —compressive normal stress.
of the reference coordinate system axes (normally the Carte-
sian x-axis) is designated the reference axis, assigned a
4. Summary of Test Method
position, and the ply principal axis of each ply in the laminate
is referenced relative to the reference axis to define the ply
4.1 Asandwichbeamcomposedoftwofacesheetsseparated
orientation for that ply. by a relatively deep honeycomb core, as shown in Fig. 1,is
3.2.5 specially orthotropic, adj—a description of an ortho-
loaded in four-point bending. The main component of the
tropic material as viewed in its principal material coordinate compression test specimen is the face sheet that is loaded in
system. In laminated composites, a specially orthotropic lami-
compression during flexure, with the material direction of
nate is a balanced and symmetric laminate of the (0/90) interest oriented along the length of the beam. The other
i j ns
family as viewed from the reference coordinate system, such
facesheetisofamaterialandsizecarefullyselectedtopreclude
that the membrane-bending coupling terms of the stress-strain its influence on the test results. The ultimate compressive
relation are zero.
strength of the material is determined from the load at which
transition
3.2.6 transition strain, ´ , n—the strain value at the the test facesheet of the sandwich beam fails in an acceptable
mid-range of the transition region between the two essentially compression failure mode. If the specimen strain is monitored
linear portions of a bilinear stress-strain or strain-strain curve with strain or deflection transducers then the stress-strain
FIG. 1 Longitudinal Compression Sandwich Beam Test Specimen
D5467/D5467M – 97 (2004)
responseofthematerialcanbedetermined,fromwhichcanbe thesteelplatensofthetestingmachine.Toavoidlocalcrushing
derived the compressive modulus of elasticity for this configu- or failure as a result of stress concentrations under the loading
ration. cylinders, the diameter of loading cylinders may be up to 1.5
timesthesandwichthickness,andloadingpadsmaybeneeded
5. Significance and Use under the loading cylinders (see 11.6).
7.3 Testing Machine—The testing machine shall be in
5.1 This test method is designed to produce membrane
conformance with Practices E4 and shall satisfy the following
compressive property data for material specifications, research
requirements:
and development, quality assurance, and structural design and
7.3.1 Testing Machine Heads—The testing machine shall
analysis. Factors that influence the compressive response and
have two loading heads, with at least one movable along the
should therefore be reported include the following: material,
testing axis.
methods of material and specimen preparation, specimen
7.3.2 Drive Mechanism—Thetestingmachinedrivemecha-
conditioning, environment of testing, specimen alignment,
nism shall be capable of imparting to the movable head a
speed of testing, time at reinforcement. Properties, in the test
controlled displacement rate with respect to the stationary
direction, that may be obtained from this test method include:
head. The displacement rate of the movable head shall be
5.1.1 Ultimate compressive strength,
capable of being regulated as specified in 11.3.
5.1.2 Ultimate compressive strain,
7.3.3 Load Indicator—The testing machine load-sensing
5.1.3 Compressive (linear or chord) modulus of elasticity,
device shall be capable of indicating the total load being
and
carried by the test specimen. This device shall be essentially
5.1.4 Transition strain.
free from inertia lag at the specified rate of testing and shall
indicate the load with an accuracy over the load range(s) of
6. Interferences
interest of within 61% of the indicated value, as specified by
6.1 Test Method Sensitivities—Compressive strength for a
PracticesE4.Theloadrange(s)ofinterestmaybefairlylowfor
single material system has been shown to differ when deter-
modulus evaluation, much higher for strength evaluation, or
mined by different test methods. Such differences can be
both, as required.
attributed to specimen alignment effects, specimen geometry
NOTE 2—Obtaining precision load data over a large range of interest in
effects, and fixture effects even though efforts have been made
the same test, such as when both elastic modulus and ultimate load are
to minimize these effects.
being determined, place extreme requirements on the load cell and its
6.2 Material and Specimen Preparation—Compressive
calibration. For some equipment, a special calibration may be required.
modulus, and especially compressive strength, are sensitive to
For some combinations of material and load cell, simultaneous precision
poor material fabrication practices, damage induced by im-
measurement of both elastic modulus and ultimate strength may not be
proper coupon machining, and lack of control of fiber align-
possible, and measurement of modulus and strength may have to be
ment. Fiber alignment relative to the specimen coordinate axis performed in separate tests using a different load cell range for each test.
should be maintained as carefully as possible, although no
7.4 Strain-Indicating Device—Strain data, if required, shall
standard procedure to insure this alignment exists. Procedures
be determined by means of strain gages.
found satisfactory include the following: fracturing a cured
7.4.1 Bonded Resistance Strain Gages—Strain gage selec-
unidirectional laminate near one edge parallel to the fiber
tion is a compromise based on the procedure and the type of
direction to establish the [0] direction or laying in small
material to be tested. Strain gages should have an active grid
filamentcounttowsofcontrastingcolorfiber(aramidincarbon
length of 3 mm [0.125 in.] or less; (1.5 mm [0.06 in.] is
laminates and carbon in aramid or glass laminates) parallel to
preferable). Gage calibration certification shall comply with
the [0] direction either as part of the prepreg production or as
TestMethodsE251.Someguidelinesontheuseofstraingages
part of panel fabrication.
on composites are presented below, with a general discussion
6.3 Calculation—Stress equations are based on beam 3
on the subject in Footnote 8.
theory.
7.4.1.1 Surface preparation of fiber-reinforced composites
in accordance with Practice E1237 can penetrate the matrix
7. Apparatus
material and cause damage to the reinforcing fibers, resulting
7.1 Micrometers—The micrometer(s) shall use a suitable in improper coupon failures. Reinforcing fibers shall not be
size diameter ball-interface on irregular surfaces such as the exposed or damaged during the surface preparation process.
bag-side of a laminate, and a flat anvil interface on machined Consult the strain gage manufacturer regarding surface prepa-
edges or very smooth tooled surfaces. The accuracy of the ration guidelines and recommended bonding agents for com-
instruments shall be suitable for reading to within 1% of the posites.
sample width and thickness. For typical specimen geometries, 7.4.1.2 Select gages having larger resistances to reduce
an instrument with an accuracy of 62.5 µm [60.0001 in.] is heating effects on low-conductivity materials. Resistances of
desirable for thickness measurement, while an instrument with 350 Vorhigherarepreferred.Usetheminimumpossiblegage
an accuracy of 625 µm [60.001 in.] is desirable for width
measurement.
7.2 Compressive Fixture—A fixture of four loading cylin-
Pendleton, R. P. and Tuttle, M. E., Manual on Experimental Methods for
ders or cylindrical supports capable of loading the sandwich
Mechanical Testing of Composites, Society for Experimental Mechanics, Bethel,
beamasshowninFig.1.Thefixtureshallbeinstalledbetween CT, 1989.
D5467/D5467M – 97 (2004)
excitation voltage consistent with the desired accuracy (1 to 2 geometry and material specifications for carbon reinforced
V is recommended) to reduce further the power consumed by [0] and [90] test coupons are provided in Table 1. The
nT nT
the gage. Heating of the coupon by the gage may affect the facesheetsarebondedtothecoreusingastructuraladhesiveas
performance of the material directly, or it may affect the describedin8.3.1.Ifunacceptablefailuremodesforthecarbon
indicated strain as a result of a difference between the gage
reinforced coupons occur, or if alternate reinforcement fibers
temperaturecompensationfactorandthecoefficientofthermal are to be used (glass, aramid, boron, and so forth), then
expansion of the coupon material.
facesheet, beam core, and overall specimen geometry shall be
7.4.1.3 Temperature compensation is recommended when
...