ASTM C1292-00(2005)
(Test Method)Standard Test Method for Shear Strength of Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures
Standard Test Method for Shear Strength of Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures
SIGNIFICANCE AND USE
Continuous fiber-reinforced ceramic composites are candidate materials for structural applications requiring high degrees of wear and corrosion resistance, and damage tolerance at high temperatures.
Shear tests provide information on the strength and deformation of materials under shear stresses.
This test method may be used for material development, material comparison, quality assurance, characterization, and design data generation.
For quality control purposes, results derived from standardized shear test specimens may be considered indicative of the response of the material from which they were taken for given primary processing conditions and post-processing heat treatments.
SCOPE
1.1 This test method covers the determination of shear strength of continuous fiber-reinforced ceramic composites (CFCCs) at ambient temperature. The test methods addressed are (1) the compression of a double-notched specimen to determine interlaminar shear strength and (2) the Iosipescu test method to determine the shear strength in any one of the material planes of laminated composites. Specimen fabrication methods, testing modes (load or displacement control), testing rates (load rate or displacement rate), data collection, and reporting procedures are addressed.
1.2 This test method is used for testing advanced ceramic or glass matrix composites with continuous fiber reinforcement having uni-directional (1-D) or bi-directional (2-D) fiber architecture. This test method does not address composites with (3-D) fiber architecture or discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics.
1.3 The values stated in SI units are to be regarded as the standard and are in accordance with IEEE/ASTM SI 10.
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 and health practices and determine the applicability of regulatory limitations prior to use.Specific hazard statements are given in 8.1 and 8.2.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C1292–00(Reapproved 2005)
Standard Test Method for
Shear Strength of Continuous Fiber-Reinforced Advanced
Ceramics at Ambient Temperatures
This standard is issued under the fixed designation C1292; 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 D3846 Test Method for In-Plane Shear Strength of Rein-
forced Plastics
1.1 This test method covers the determination of shear
D3878 Terminology for Composite Materials
strength of continuous fiber-reinforced ceramic composites
D5379/D5379M Test Method for Shear Properties of Com-
(CFCCs) at ambient temperature. The test methods addressed
posite Materials by the V-Notched Beam Method
are (1) the compression of a double-notched specimen to
E4 Practices for Force Verification of Testing Machines
determine interlaminar shear strength and (2) the Iosipescu test
E6 TerminologyRelatingtoMethodsofMechanicalTesting
method to determine the shear strength in any one of the
E122 Practice for Calculating Sample Size to Estimate,
material planes of laminated composites. Specimen fabrication
With Specified Precision, the Average for a Characteristic
methods, testing modes (load or displacement control), testing
of a Lot or Process
rates (load rate or displacement rate), data collection, and
E177 Practice for Use of the Terms Precision and Bias in
reporting procedures are addressed.
ASTM Test Methods
1.2 This test method is used for testing advanced ceramic or
E337 Test Method for Measuring Humidity with a Psy-
glass matrix composites with continuous fiber reinforcement
chrometer (the Measurement of Wet- and Dry-Bulb Tem-
having uni-directional (1-D) or bi-directional (2-D) fiber archi-
peratures)
tecture. This test method does not address composites with
E691 Practice for Conducting an Interlaboratory Study to
(3-D) fiber architecture or discontinuous fiber-reinforced,
Determine the Precision of a Test Method
whisker-reinforced, or particulate-reinforced ceramics.
IEEE/ASTM SI 10 American National Standard for Use of
1.3 The values stated in SI units are to be regarded as the
the International System of Units (SI): The Modern Metric
standard and are in accordance with IEEE/ASTM SI 10.
System
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions—The definitions of terms relating to shear
priate safety and health practices and determine the applica-
strength testing appearing in Terminology E6 apply to the
bility of regulatory limitations prior to use. Specific hazard
terms used in this test method.The definitions of terms relating
statements are given in 8.1 and 8.2.
to advanced ceramics appearing in Terminology C1145 apply
2. Referenced Documents to the terms used in this test method. The definitions of terms
2 relating to fiber-reinforced composites appearing in Terminol-
2.1 ASTM Standards:
ogy D3878 apply to the terms used in this test method.
C1145 Terminology of Advanced Ceramics
Additional terms used in conjunction with this test method are
D695 Test Method for Compressive Properties of Rigid
defined in the following.
Plastics
3.1.1 advanced ceramic—engineered high-performance
predominately nonmetallic, inorganic, ceramic material having
This test method is under the jurisdiction of ASTM Committee C28 on
specific functional attributes.
Advanced Ceramics and is the direct responsibility of Subcommittee C28.07 on
3.1.2 continuous fiber-reinforced ceramic matrix composite
Ceramic Matrix Composites.
(CFCC)—ceramic matrix composite in which the reinforcing
Current edition approved June 1, 2005. Published June 2005. Originally
approved in 1995. Last previous edition approved in 2000 as C1292 – 00. DOI:
phase consists of a continuous fiber, continuous yarn, or a
10.1520/C1292-00R05.
woven fabric.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.1.3 shear failure load—maximum load required to frac-
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 ture a shear loaded test specimen.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1292–00 (2005)
FIG. 1 Schematic of Test Fixture for the Double-Notched
Compression Specimen
3.1.4 shear strength—maximum shear stress that a material
is capable of sustaining. Shear strength is calculated from the
shear fracture load and the shear loaded area.
4. Summary of Test Method
4.1 This test method addresses two methods to determine
the shear strength of CFCCs: (1) the compression of a
double-notched specimen test method to determine interlami-
nar shear strength, and (2) the Iosipescu test method to
determine the shear strength in any one of the material planes
of laminated CFCCs.
4.1.1 Shear Test by Compression Loading of Double-
NOTE 1—All tolerances are in millimetres.
Notched Specimens—The interlaminar shear strength of
FIG. 2 Schematic of Double-Notched Compression Specimen
CFCCs, as determined by this method is measured by loading
in compression a double-notched specimen of uniform width.
5. Significance and Use
Failure of the specimen occurs by shear between two centrally
located notches machined halfway through the thickness and
5.1 Continuous fiber-reinforced ceramic composites are
spaced a fixed distance apart on opposing faces. Schematics of candidate materials for structural applications requiring high
the test setup and the specimen are shown in Fig. 1 and Fig. 2.
degrees of wear and corrosion resistance, and damage toler-
4.1.2 Shear Test By the Iosipescu Method—The shear ance at high temperatures.
strength of one of the different material shear planes of
5.2 Shear tests provide information on the strength and
laminated CFCCs may be determined by loading a coupon in deformation of materials under shear stresses.
the form of a rectangular flat strip with symmetric centrally
5.3 This test method may be used for material development,
located V-notches using a mechanical testing machine and a material comparison, quality assurance, characterization, and
four-point asymmetric fixture. The loading can be idealized as
design data generation.
asymmetric flexure by the shear and bending diagrams in Fig. 5.4 For quality control purposes, results derived from stan-
3. Failure of the specimen occurs by shear between the
dardized shear test specimens may be considered indicative of
V-notches. Different specimen configurations are addressed for the response of the material from which they were taken for
this test method. Schematics of the test setup and specimen are
given primary processing conditions and post-processing heat
shown in Fig. 4 and Fig. 5. The determination of shear treatments.
properties of polymer matrix composites by the Iosipescu
6. Interferences
method has been presented in Test Method D5379/D5379M.
6.1 Test environment (vacuum, inert gas, ambient air, etc.)
including moisture content (for example, relative humidity)
Whitney, J., M., “Stress Analysis of the Double Notch Shear Specimen,”
may have an influence on the measured shear strength. In
Proceedings of the American Society for Composites, 4th Technical Conference,
particular, the behavior of materials susceptible to slow crack
Blacksburg Virginia, Oct. 3–5, 1989, Technomic Publishing Co, pp. 325.
growthfracturewillbestronglyinfluencedbytestenvironment
Iosipescu, N., “NewAccurate Procedure for Shear Testing of Metals,” Journal
of Materials, 2, 3, Sept. 1967, pp. 537–566. and testing rate. Testing to evaluate the maximum strength
C1292–00 (2005)
NOTE 1—The loads are depicted as being concentrated, whereas they
are actually distributed over an area.
FIG. 3 Idealized Force, Shear, and Moment Diagrams for
Asymmetric Four-Point Loading
NOTE 1—All tolerances are in millimetres.
FIG. 5 Schematic of the Iosipescu Specimen
under those conditions. When testing is conducted in uncon-
trolled ambient air with the intent of evaluating maximum
strength potential, relative humidity and temperature must be
monitored and reported. Testing at humidity levels >65 % RH
is not recommended and any deviations from this recommen-
dation must be reported.
6.2 Preparation of test specimens, although normally not
considered a major concern with CFCCs, can introduce fabri-
cation flaws which may have pronounced effects on the
mechanical properties and behavior (for example, shape and
level of the resulting load-displacement curve and shear
strength). Machining damage introduced during specimen
preparation can be either a random interfering factor in the
determination of shear strength of pristine material, or an
inherent part of the strength characteristics to be measured.
Universal or standardized test methods of surface preparation
do not exist. Final machining steps may, or may not negate
machining damage introduced during the initial machining.
Thus, specimen fabrication history may play an important role
FIG. 4 Schematic of Test Fixture for the Iosipescu Test
in the measured strength distributions and shall be reported.
6.3 Bending in uniaxially loaded shear tests can cause or
potential of a material shall be conducted in inert environments promote nonuniform stress distributions that may alter the
or at sufficiently rapid testing rates, or both, so as to minimize desired uniform state of stress during the test.
slow crack growth effects. Conversely, testing can be con- 6.4 Fractures that initiate outside the uniformly stressed
ducted in environments and testing modes and rates represen- gage section of a specimen may be due to factors such as
tative of service conditions to evaluate material performance localized stress concentrations, extraneous stresses introduced
C1292–00 (2005)
TABLE 1 Recommended Dimensions for Double-Notched
by improper loading configurations, or strength-limiting fea-
Compression Specimen
tures in the microstructure of the specimen. Such non-gage
section fractures will normally constitute invalid tests.
Dimension Description Value, mm
6.5 For the conduction of the Iosipescu test, thin test
L Specimen length 30.00
specimens (width to thickness ratio of more than ten) may
h Distance between notches 6.00
suffer from splitting and instabilities rendering in turn invalid W Specimen width 15.00
d Notch width 0.50
test results.
t Specimen thickness . . .
6.6 For the evaluation of the interlaminar shear strength by
the compression of a double-notched specimen, the distance
between the notches in the specimen has an effect on the 5
description of the test fixture is shown in Fig. 1. Asupporting
maximum load and therefore on the shear strength. It has been
jig conforming to the geometry of that shown in Fig. 1 of Test
foundthatthestressdistributioninthespecimenisindependent
Method D3846 or Fig. 4 of Test Method D695 may also be
of the distance between the notches when the notches are far
used.
apart. However, when the distance between the notches is such
7.4.2 Iosipescu Specimen—The fixture shall be a four-point
that the stress fields around the notches interact, the measured
asymmetricflexurefixtureshownschematicallyinFig.4. This
interlaminar shear strength increases. Because of the complex-
fixture consists of a stationary element mounted on a base
ity of the stress field around each notch and its dependence on
plate, and a movable element capable of vertical translation
the properties and homogeneity of the material, it is recom-
guided by a stiff post. The movable element attaches to the
mended to conduct a series of tests on specimens with different
cross-head of the testing machine. Each element clamps half of
spacing between the notches to determine their effect on the
the test specimen into position with a wedge action grip able to
measured interlaminar shear strength.
compensate for minor specimen width variations.Aspan of 13
6.7 For the evaluation of the interlaminar shear strength by
mm is left unsupported between fixture halves. An alignment
the compression of a double-notched specimen, excessive
tool is recommended to ensure that the specimen notch is
clamping force with the jaws will reduce the stress concentra-
aligned with the line-of-action of the loading fixture.
tion around the notches and therefore artificially increase the
measured interlaminar shear strength. Because the purpose of
8. Hazards
the jaws is to maintain the specimen in place and to prevent
8.1 Duringtheconduct of thistest method, the possibilityof
buckling, avoid overtightening the jaws.
flying fragments of broken test material may be high. The
6.8 Most fixtures incorporate an alignment mechanism in
brittle nature of advanced ceramics and the release of strain
the form of a guide rod and a linear roller bearing. Excessive
energy contribute to the potential release of uncontrolled
freeplayorexcessivefrictioninthismechanismmayintroduce
fragments upon fracture. Means for containment and retention
spurious moments that will alter the ideal loading conditions.
of these fragments for later fractographic reconstruction and
analysis is highly recommended.
7. Apparatus
8.2 Exposed fibers at the edges of CFCC specimens present
a hazard due to the sharpness and brittleness of the ceramic
7.1 Testing Machines—The testing machine shall be in
fiber. All persons required to handle these materials shall be
conformance with Practices E4. The loads used in determining
well informed of these conditions and the proper handling
shearstrengthshallbeaccuratewithin 61 %atanyloadwithin
techniques.
the selected load range of the testing machine as defined in
Practices E4.
9. Test Specimens
7.2 Data Acquisition—At the minimum, autographic
9.1 Test Specimen Geometry:
records of applied load and cross-head displacement versus
9.1.1 Double-Notched Compression Specimen—The test
time shall be obtained. Either analog chart recorders or digital
specimens shall conform to the shape and tolerances shown in
data acquisition systems may be used for this purpose although
Fig. 2. The specimen consists of a rectangular plate with
a digital record is recommended for ease of later data analysis.
notches machined on both sides.The depth of the notches shall
Ideally, an analog chart recorder or plotter shall be used in
be at least equal to one half of the specimen thickness, and the
conjunction with t
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