ASTM C1341-00
(Test Method)Standard Test Method for Flexural Properties of Continuous Fiber-Reinforced Advanced Ceramic Composites
Standard Test Method for Flexural Properties of Continuous Fiber-Reinforced Advanced Ceramic Composites
SCOPE
1.1 This test method covers the determination of flexural properties of continuous fiber-reinforced ceramic composites in the form of rectangular bars formed directly or cut from sheets, plates, or molded shapes. Three test geometries are described as follows:
1.1.1 Test Geometry I—A three-point loading system utilizing center loading on a simply supported beam.
1.1.2 Test Geometry IIA—A four-point loading system utilizing two load points equally spaced from their adjacent support points with a distance between load points of one half of the support span.
1.1.3 Test Geometry IIB—A four-point loading system utilizing two load points equally spaced from their adjacent support points with a distance between load points of one third of the support span.
1.2 This test method applies primarily to all advanced ceramic matrix composites with continuous fiber reinforcement: uni-directional (1-D), bi-directional (2-D), tri-directional (3-D), and other continuous fiber architectures. In addition, this test method may also be used with glass (amorphous) matrix composites with continuous fiber reinforcement. However, flexural strength cannot be determined for those materials that do not break or fail by tension or compression in the outer fibers. This test method does not directly address discontinuous fiber-reinforced, whisker-reinforced, or particulate-reinforced ceramics. Those types of ceramic matrix composites are better tested in flexure using Test Methods C 1161 and C 1211.
1.3 Tests can be performed at ambient temperatures or at elevated temperatures. At elevated temperatures, a suitable furnace is necessary for heating and holding the specimens at the desired testing temperatures.
1.4 This test method includes the following:Section Scope1Referenced Documents2Terminology3Summary of Test Method4Significance and Use5Interferences6Apparatus 7Precautionary Statement8Specimens9Procedures10Calculation of Results11Report12Precision and Bias13Keywords14ReferencesCFCC Surface Condition and FinishingA1Conditions and Issues in Hot Loading of Specimens into FurnacesA2Toe Compensation on Stress-Strain CurvesA3Corrections for Thermal Expansion in Flexural EquationsA4Example of Test ReportX1
1.5 The values stated in SI units are to be regarded as the standard per Practice E 380.
1.6 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.
General Information
Relations
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: C 1341 – 00
Standard Test Method for
Flexural Properties of Continuous Fiber-Reinforced
Advanced Ceramic Composites
This standard is issued under the fixed designation C 1341; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope
Section
Scope 1
1.1 This test method covers the determination of flexural
Referenced Documents 2
properties of continuous fiber-reinforced ceramic composites
Terminology 3
Summary of Test Method 4
in the form of rectangular bars formed directly or cut from
Significance and Use 5
sheets, plates, or molded shapes. Three test geometries are
Interferences 6
described as follows:
Apparatus 7
Precautionary Statement 8
1.1.1 Test Geometry I—Athree-point loading system utiliz-
Specimens 9
ing center loading on a simply supported beam.
Procedures 10
1.1.2 Test Geometry IIA—A four-point loading system uti- Calculation of Results 11
Report 12
lizing two load points equally spaced from their adjacent
Precision and Bias 13
support points with a distance between load points of one half
Keywords 14
of the support span. References
CFCC Surface Condition and Finishing A1
1.1.3 Test Geometry IIB—A four-point loading system uti-
Conditions and Issues in Hot Loading of A2
lizing two load points equally spaced from their adjacent
Specimens into Furnaces
support points with a distance between load points of one third Toe Compensation on Stress-Strain A3
Curves
of the support span.
Corrections for Thermal Expansion in A4
1.2 This test method applies primarily to all advanced
Flexural Equations
ceramic matrix composites with continuous fiber reinforce- Example of Test Report X1
ment:uni-directional(1-D),bi-directional(2-D),tri-directional
1.5 The values stated in SI units are to be regarded as the
(3-D),andothercontinuousfiberarchitectures.Inaddition,this
standard per Practice E380.
test method may also be used with glass (amorphous) matrix
1.6 This standard does not purport to address all of the
composites with continuous fiber reinforcement. However,
safety concerns, if any, associated with its use. It is the
flexural strength cannot be determined for those materials that
responsibility of the user of this standard to establish appro-
do not break or fail by tension or compression in the outer
priate safety and health practices and determine the applica-
fibers.Thistestmethoddoesnotdirectlyaddressdiscontinuous
bility of regulatory limitations prior to use.
fiber-reinforced, whisker-reinforced, or particulate-reinforced
ceramics. Those types of ceramic matrix composites are better
2. Referenced Documents
tested in flexure using Test Methods C1161 and C1211.
2.1 ASTM Standards:
1.3 Tests can be performed at ambient temperatures or at 2
C1145 Terminology of Advanced Ceramics
elevated temperatures. At elevated temperatures, a suitable
C1161 Test Method for Flexural Strength of Advanced
furnace is necessary for heating and holding the specimens at 2
Ceramics at Ambient Temperature
the desired testing temperatures.
C1211 Test Method for Flexural Strength of Advanced
1.4 This test method includes the following: 2
Ceramics at Elevated Temperatures
C1239 Practice for Reporting Uniaxial Data and Estimat-
ing Weibull Distribution Parameters forAdvanced Ceram-
ics
This test method is under the jurisdiction of ASTM Committee C-28 on
Advanced Ceramics and is the direct responsibility of Subcommittee C28.07 on
Ceramic Matrix Composites.
Current edition approved April 10, 2000. Published July 2000. Originally
published as C1341–96. Last previous edition C1341–97. Annual Book of ASTM Standards, Vol 15.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1341 – 00
C1292 Test Method for Shear Strength of Continuous form a useful engineering material possessing certain proper-
Fiber-Reinforced Advanced Ceramics at Ambient Tem- ties or behavior not possessed by the individual constituents.
peratures
3.1.4 continuous fiber-reinforced ceramic composite
D790 TestMethodsforFlexuralPropertiesofUnreinforced (CFCC),n—aceramicmatrixcompositeinwhichthereinforc-
and Reinforced Plastics and Electrical Insulating Materi-
ing phase consists of a continuous fiber, continuous yarn, or a
als woven fabric.
−2
D 2344 Test Method for Apparent Interlaminar Shear
3.1.5 flexural strength, n [FL ]—a measure of the ultimate
Strength of Parallel Fiber Composites by Short Beam strength of a specified beam in bending. [C 1161]
Method
3.1.6 four-point- ⁄3 point flexure, n—a configuration of
D3878 Terminology for High-Modulus Reinforcing Fibers
flexural strength testing where a specimen is symmetrically
and Their Composites
loadedattwolocationsthataresituatedonethirdoftheoverall
E4 Practices for Force Verification of Testing Machines
span away from the outer two support bearings.
E6 Terminology Relating to Methods of Mechanical Test-
3.1.7 four-point- ⁄4 point flexure, n—a configuration of
ing
flexural strength testing where a specimen is symmetrically
E177 Practice for Use of the Terms Precision and Bias in
loaded at two locations that are situated one quarter of the
ASTM Test Methods
overall span away from the outer two support bearings.
E220 Test Method for Calibration of Thermocouples by
[C 1161]
−2
Comparison Techniques
3.1.8 fracture strength, n [FL ]—the calculated flexural
E337 TestMethodforMeasuredHumiditywithPsychrom-
stress at the breaking load.
−2
eter (the Measurement of Wet- and Dry-Bulb Tempera-
3.1.9 modulus of elasticity, n [FL ]—the ratio of stress to
tures)
corresponding strain below the proportional limit. [E 6]
−2
E380 PracticeforUseofInternationalSystemofUnits(SI)
3.1.10 proportional limit stress, n [FL ]—the greatest
(The Modernized Metric System)
stress that a material is capable of sustaining without any
E691 Practice for Conducting an Interlaboratory Study to
deviation from proportionality of stress to strain (Hooke’s
Determine the Precision of a Test Method
law).
3.1.10.1 Discussion—Many experiments have shown that
3. Terminology
valuesobservedfortheproportionallimitvarygreatlywiththe
3.1 Definitions—The definitions of terms relating to flexure
sensitivity and accuracy of the testing equipment, eccentricity
testingappearinginTerminologyE6applytothetermsusedin
of loading, the scale to which the stress-strain diagram is
this test method. The definitions of terms relating to advanced
plotted, and other factors. When determination of proportional
ceramics appearing in Terminology C1145 apply to the terms
limit is required, the procedure and sensitivity of the test
used in this test method. The definitions of terms relating to
equipment shall be specified. [E 6]
fiber-reinforced composites appearing in Terminology D3878
3.1.11 slow crack growth, n—subcritical crack growth (ex-
applytothetermsusedinthistestmethod.Pertinentdefinitions
tension) that may result from, but is not restricted to, such
as listed in Test Method C1161, Test Method D790, Termi-
mechanisms as environmentally assisted stress corrosion or
nologyC1145,TerminologyD3878,andTerminologyE6are
diffusive crack growth.
shown in the following with the appropriate source given in
3.1.12 span-to-depth ratio, n [nd]—for a particular speci-
brackets. Additional terms used in conjunction with this test
men geometry and flexure test configuration, the ratio (L/d)of
method are also defined in the following.
theoutersupportspanlength(L)oftheflexuretestspecimento
3.1.1 advanced ceramic, n—a highly engineered, high-
the thickness/depth (d) of specimen. (As used and described in
performance, predominately nonmetallic, inorganic, ceramic
Test Method D790.)
material having specific functional attributes. [C 1145]
3.1.13 three-point flexure, n—a configuration of flexural
3.1.2 breaking load, n [F]—the load at which fracture
strength testing where a specimen is loaded at a location
occurs.(Inthistestmethod,fractureconsistsofbreakageofthe
midway between two support bearings. [C 1161]
testbarintotwoormorepiecesoralossofatleast20%ofthe
maximum load carrying capacity.) [E 6]
4. Summary of Test Method
3.1.3 ceramic matrix composite, n—amaterialconsistingof
4.1 Abar of rectangular cross section is tested in flexure as
two or more materials (insoluble in one another) in which the
a beam as in one of the following three load geometries:
major,continuouscomponent(matrixcomponent)isaceramic,
4.1.1 Test Geometry I—Thebarrestsontwosupportsandis
while the secondary component(s) (reinforcing component)
loaded by means of a loading roller midway between the
may be ceramic, glass-ceramic, glass, metal, or organic in
supports (see Fig. 1.)
nature. These components are combined on a macroscale to
4.1.2 TestGeometryIIA—Thebarrestsontwosupportsand
is loaded at two points (by means of two loading rollers), each
an equal distance from the adjacent support point. The inner
Annual Book of ASTM Standards, Vol 08.01.
Annual Book of ASTM Standards, Vol 15.03.
loadingpointsaresituatedonequarteroftheoverallspanaway
Annual Book of ASTM Standards, Vol 03.01.
from the outer two support bearings. The distance between the
Annual Book of ASTM Standards, Vol 14.02.
loadingrollers(thatis,theloadspan)isonehalfofthesupport
Annual Book of ASTM Standards, Vol 14.03.
Annual Book of ASTM Standards, Vol 11.03. span (see Fig. 1).
C 1341 – 00
experience “graceful” fracture from a cumulative damage
process. Therefore, the volume of material subjected to a
uniform flexural stress may not be as significant a factor in
determiningtheflexuralstrengthofCFCCs.However,theneed
to test a statistically significant number of flexure specimens is
not eliminated. Because of the probabilistic nature of the
strength of the brittle matrices and of the ceramic fiber in
CFCCs, a sufficient number of specimens at each testing
conditionisrequiredforstatisticalanalysis,withguidelinesfor
sufficient numbers provided in 9.7. Studies to determine the
exact influence of specimen volume on strength distributions
for CFCCs are not currently available.
5.4 The four-point loading geometries (Geometries IIAand
IIB) are preferred over the three-point loading geometry
(Geometry I). In four-point loading, a larger portion of the test
FIG. 1 Flexural Test Geometries specimenissubjectedtothemaximumtensileandcompressive
stresses, as compared to the three-point geometry. If there is a
statistical/Weibull character failure in the particular composite
4.1.3 TestGeometryIIB—Thebarrestsontwosupportsand
systembeingtested,thesizeofthemaximumstressregionwill
is loaded at two points (by means of two loading rollers),
play a role in determining the mechanical properties. The
situated one third of the overall span away from the outer two
four-point geometry may then produce more reliable statistical
supportbearings.Thedistancebetweentheloadingrollers(that
data.
is, the load span) is one third of the support span (see Fig. 1).
5.5 Flexure tests provide information on the strength and
4.2 The specimen is deflected until rupture occurs in the
deformation of materials under complex flexural stress condi-
outer fibers or until there is a 20% decrease from the peak
tions. In CFCCs nonlinear stress-strain behavior may develop
load.
as the result of cumulative damage processes (for example,
4.3 The flexural properties of the specimen (flexural
matrixcracking,matrix/fiberdebonding,fiberfracture,delami-
strength and strain, fracture strength and strain, modulus of
nation, etc.) which may be influenced by testing mode, testing
elasticity, and stress-strain curves) are calculated from the load
rate, processing effects, or environmental influences. Some of
and deflection using elastic beam equations.
these effects may be consequences of stress corrosion or
subcritical (slow) crack growth which can be minimized by
5. Significance and Use
testing at sufficiently rapid rates as outlined in 10.3 of this test
5.1 This test method is used for material development,
method.
quality control, and material flexural specifications. Although
5.6 Because of geometry effects, the results of flexure tests
flexural test methods are commonly used to determine design
ofspecimensfabricatedtostandardizedtestdimensionsfroma
strengths of monolithic advanced ceramics, the use of flexure
particular material or selected portions of a component, or
test data for determining tensile or compressive properties of
both, cannot be categorically used to define the strength and
CFCC materials is strongly discouraged. The nonuniform
deformationpropertiesoftheentire,full-sizeendproductorits
stress distributions in the flexure specimen, the dissimilar
in-service behavior in different environments. The effects of
mechanical behavior in tension and compression for CFCCs,
size and geometry shall be carefully considered in extrapolat-
low shear strengths of CFCCs, and anisotropy in fiber archi-
ing the test results to other configurations and performance
tecture all lead to ambiguity in using flexure results for CFCC
conditions.
material design data (1-4). Rather, uniaxial-loaded tensile and
5.7 For quality control purposes, results from standardized
compressive tests are recommended for developing CFCC
flexure test specimens may be considered indicative of the
material design data based on a uniformly stressed test condi-
response of the material lot from which they were taken with
tion.
the given primary processing conditions and post-processing
5.2 In this test method, the flexure stress is computed from
heat treatments.
elastic beam theory with the simplifying assumptions that the
5.8 The flexure behavior and strength of a CFCC are
material is homogeneous and linearly elastic. This is valid for
dependentonitsinherentresistancetofracture,thepresenceof
composites where the principal fiber direction is coincident/
fracture sources, or damage accumulation processes or combi-
transverse with the axis of the beam. These assumptions are
nation thereof. Analysis of fracture surfaces and fractography,
necessary to calculate a flexural strength value, but limit the
though beyond the scope of this test method, is highly
application to comparative type testing such as used for
recommended.
material development, quality control, and flexure specifica-
6. Interferences
tions. Such comparative testing requires consistent and stan-
dardized test conditions, that is, specimen geometry/thickness, 6.1 ACFCC material tested in flexure may fail in a variety
strain rates, and atmospheric/test conditions. of distinct fracture modes, depending on the interaction of the
5.3 Unl
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.