1、Designation: C1819 15Standard Test Method forHoop Tensile Strength of Continuous Fiber-ReinforcedAdvanced Ceramic Composite Tubular Test Specimens atAmbient Temperature Using Elastomeric Inserts1This standard is issued under the fixed designation C1819; the number immediately following the designati
2、on indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determi
3、nation of the hooptensile strength including stress-strain response of continuousfiber-reinforced advanced ceramic tubes subjected to an inter-nal pressure produced by the expansion of an elastomeric insertundergoing monotonic uniaxial loading at ambient tempera-ture. This type of test configuration
4、 is sometimes referred to asan overhung tube. This test method is specific to tubegeometries, because flaw populations, fiber architecture andspecimen geometry factors are often distinctly different incomposite tubes, as compared to flat plates.1.2 In the test method a composite tube/cylinder with a
5、defined gage section and a known wall thickness is loaded viainternal pressurization from the radial expansion of an elasto-meric insert (located midway inside the tube) that is longitu-dinally compressed from either end by pushrods. The elasto-meric insert expands under the uniaxial compressive loa
6、ding ofthe pushrods and exerts a uniform radial pressure on the insideof the tube. The resulting hoop stress-strain response of thecomposite tube is recorded until failure of the tube. The hooptensile strength and the hoop fracture strength are determinedfrom the resulting maximum pressure and the p
7、ressure atfracture, respectively. The hoop tensile strains, the hoopproportional limit stress, and the modulus of elasticity in thehoop direction are determined from the stress-strain data. Notethat hoop tensile strength as used in this test method refers tothe tensile strength in the hoop direction
8、 from the inducedpressure of a monotonic, uniaxially-loaded elastomeric insertwhere monotonic refers to a continuous nonstop test ratewithout reversals from test initiation to final fracture.1.3 This test method applies primarily to advanced ceramicmatrix composite tubes with continuous fiber reinfo
9、rcement:uni-directional (1-D, filament wound and tape lay-up), bidirec-tional (2-D, fabric/tape lay-up and weave), and tridirectional(3-D, braid and weave). These types of ceramic matrix com-posites can be composed of a wide range of ceramic fibers(oxide, graphite, carbide, nitride, and other compos
10、itions) in awide range of crystalline and amorphous ceramic matrixcompositions (oxide, carbide, nitride, carbon, graphite, andother compositions).1.4 This test method does not directly address discontinuousfiber-reinforced, whisker-reinforced or particulate-reinforcedceramics, although the test meth
11、ods detailed here may beequally applicable to these composites.1.5 The test method is applicable to a range of test specimentube geometries based on a non dimensional parameter thatincludes composite material property and tube radius. Lengthsof the composite tube, push rods and elastomeric insert ar
12、edetermined from this non dimensional parameter so as toprovide a gage length with uniform, internal, radial pressure.Awide range of combinations of material properties, tube radii,wall thicknesses, tube lengths and insert lengths are possible.1.5.1 This test method is specific to ambient temperatur
13、etesting. Elevated temperature testing requires high temperaturefurnaces and heating devices with temperature control andmeasurement systems and temperature-capable grips and load-ing fixtures, which are not addressed in this test standard.1.6 This test method addresses tubular test specimengeometri
14、es, test specimen methods, testing rates (force rate,induced pressure rate, displacement rate, or strain rate), anddata collection and reporting procedures in the followingsections.SectionScope 1Referenced Documents 2Terminology 3Summary of Test Method 4Significance and Use 5Interferences 6Apparatus
15、 7Hazards 8Test Specimens 9Test Procedure 10Calculation of Results 11Report 12Precision and Bias 13Keywords 14AnnexesVerification Of Load Train Alignment Appendix X11This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direct responsibility of Subcommittee
16、C28.07 onCeramic Matrix Composites.Current edition approved Aug. 1, 2015. Published September 2015. DOI:10.1520/C1819-15.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1SectionStress Factors For Calculation Of Maximum Hoop Stress Appe
17、ndix X2Axial Force To Internal Pressure Appendix X31.7 Values expressed in this test method are in accordancewith the International System of Units (SI).1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of th
18、is standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 8 and Note 1.2. Referenced Documents2.1 ASTM Standards:2C1145 Terminology of Advanced CeramicsC1239 Practice for R
19、eporting Uniaxial Strength Data andEstimating Weibull Distribution Parameters for AdvancedCeramicsD3878 Terminology for Composite MaterialsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE83 Practice for Verification and Classification o
20、f Exten-someter SystemsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE337 Test Method for Measuring Humidity with a Psy-chrometer (the Measurement of Wet- and Dry-Bulb Tem-peratures)E380 Practice for Use of the International System of Units(SI) (the Modernized Metric Syste
21、m) (Withdrawn 1997)3E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1012 Practice for Verification of Testing Frame and Speci-men Alignment Under Tensile and Compressive AxialForce ApplicationSI10-02 IEEE/ASTM SI 10 American National Standard forUse o
22、f the International System of Units (SI): The ModernMetric System3. Terminology3.1 Definitions:3.1.1 The definitions of terms relating to hoop tensilestrength testing appearing in Terminology E6 apply to theterms used in this test method. The definitions of terms relatingto advanced ceramics appeari
23、ng in Terminology C1145 applyto the terms used in this test method. The definitions of termsrelating to fiber reinforced composites appearing in Terminol-ogy D3878 apply to the terms used in this test method.Pertinent definitions as listed in Practice E1012, TerminologyC1145, Terminology D3878, and
24、Terminology E6 are shown inthe following with the appropriate source given in parentheses.Additional terms used in conjunction with this test method aredefined in the following:3.1.2 advanced ceramic, na highly engineered, high per-formance predominantly nonmetallic, inorganic, ceramic ma-terial hav
25、ing specific functional attributes. (See TerminologyC1145.)3.1.3 breaking force, nthe force at which fracture occurs.(See Terminology E6.)3.1.4 ceramic matrix composite (CMC), na material con-sisting of two or more materials (insoluble in one another), inwhich the major, continuous component (matrix
26、 component) isa ceramic, while the secondary component/s (reinforcingcomponent) may be ceramic, glass-ceramic, glass, metal ororganic in nature. These components are combined on amacroscale to form a useful engineering material possessingcertain properties or behavior not possessed by the individual
27、constituents.3.1.5 continuous fiber-reinforced ceramic matrix composite(CFCC), na ceramic matrix composite in which the reinforc-ing phase consists of a continuous fiber, continuous yarn, or awoven fabric.3.1.6 gage length, nthe original length of that portion ofthe specimen over which strain or cha
28、nge of length is deter-mined. (See Terminology E6.)3.1.7 hoop tensile strength, nthe maximum tensile com-ponent of hoop stress which a material is capable of sustaining.Hoop tensile strength is calculated from the maximum internalpressure induced in a tubular test specimen.3.1.8 matrix-cracking stre
29、ss, nthe applied tensile stress atwhich the matrix cracks into a series of roughly parallel blocksnormal to the tensile stress.3.1.8.1 DiscussionIn some cases, the matrix crackingstress may be indicated on the stress-strain curve by deviationfrom linearity (proportional limit) or incremental drops i
30、n thestress with increasing strain. In other cases, especially withmaterials which do not possess a linear region of the stress-strain curve, the matrix cracking stress may be indicated as thefirst stress at which a permanent offset strain is detected in theduring unloading (elastic limit).3.1.9 mod
31、ulus of elasticity, nthe ratio of stress to corre-sponding strain below the proportional limit. (See TerminologyE6.)3.1.10 modulus of resilience, nstrain energy per unitvolume required to elastically stress the material from zero tothe proportional limit indicating the ability of the material toabso
32、rb energy when deformed elastically and return it whenunloaded.3.1.11 modulus of toughness, nstrain energy per unitvolume required to stress the material from zero to finalfracture indicating the ability of the material to absorb energybeyond the elastic range (that is, damage tolerance of themateri
33、al).3.1.11.1 DiscussionThe modulus of toughness can also bereferred to as the cumulative damage energy and as such isregarded as an indication of the ability of the material to sustaindamage rather than as a material property. Fracture mechanics2For referenced ASTM standards, visit the ASTM website,
34、 www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.C1819 152methods for the charact
35、erization of CMCs have not beendeveloped. The determination of the modulus of toughness asprovided in this test method for the characterization of thecumulative damage process in CMCs may become obsoletewhen fracture mechanics methods for CMCs become available.3.1.12 proportional limit stress, nthe
36、greatest stress that amaterial is capable of sustaining without any deviation fromproportionality of stress to strain (Hookes law).3.1.12.1 DiscussionMany experiments have shown thatvalues observed for the proportional limit vary greatly with thesensitivity and accuracy of the testing equipment, ecc
37、entricityof loading, the scale to which the stress-strain diagram isplotted, and other factors. When determination of proportionallimit is required, the procedure and sensitivity of the testequipment should be specified. (See Terminology E6.)3.1.13 slow crack growth, nsubcritical crack growth (ex-te
38、nsion) which may result from, but is not restricted to, suchmechanisms as environmentally-assisted stress corrosion ordiffusive crack growth.4. Summary of Test Method4.1 In the test method a composite tube/cylinder with adefined gage section and a known wall thickness is loaded bythe radial expansio
39、n an elastomeric insert (located midwayinside the tube) that is compressed longitudinally betweenpushrods. The elastomericinsert expands under the uniaxialcompressive loading of the pushrods and exerts a uniformradial pressure on the inside of the tube. The resulting hoopstress-strain response of th
40、e composite tube is recorded untilfailure of the tube. The hoop tensile strength and the hoopfracture strength are determined from the resulting maximumpressure and the pressure at fracture. The hoop tensile strains,the hoop proportional limit stress, and the modulus of elasticityin the hoop directi
41、on are determined from the stress-strain data.4.2 Hoop tensile strength as used in this test method refersto the tensile strength in the hoop direction from the inducedpressure of a monotonic, uniaxially-loaded elastomeric insertwhere monotonic refers to a continuous test rate with noreversals.4.3 T
42、he test method is applicable to a range of test specimentube geometries based on a non dimensional parameter thatincludes composite material property and tube radius. Lengthsof the composite tube, push rods and elastomericinsert aredetermined from this non dimensional parameter so as toprovide a gag
43、e length with uniform, internal, radial pressure.Awide range of combinations of material properties, tube radii,wall thicknesses, tube lengths and insert lengths are possible.5. Significance and Use5.1 This test method (a.k.a., overhung tube method) may beused for material development, material comp
44、arison, materialscreening, material down selection and quality assurance. Thistest method is not recommended for material characterization,design data generation and/or material model verification/validation.5.2 Continuous fiber-reinforced ceramic composites(CFCC) are composed of continuous ceramic-
45、fiber directional(1-D, 2-D, and 3-D) reinforcements in a fine grain-sized (65% relative humidity (RH) is not recommended and anydeviations from this recommendation must be reported.6.2 Surface preparation of test specimens, although nor-mally not considered a major concern in CMCs, can introducefabr
46、ication flaws that may have pronounced effects on hooptensile stress mechanical properties and behavior (for example,shape and level of the resulting stress-strain curve, hoop tensilestrength and strain, proportional limit stress and strain, etc.).Machining damage introduced during test specimen pre
47、para-tion can be either a random interfering factor in the determi-nation of ultimate strength of pristine material (i.e., increasedfrequency of surface initiated fractures compared to volumeinitiated fractures), or an inherent part of the strength charac-teristics to be measured. Surface preparatio
48、n can also lead tothe introduction of residual stresses. Universal or standardizedtest methods of surface preparation do not exist. It should beunderstood that final machining steps may, or may not negatemachining damage introduced during the initial machining.Thus, test specimen fabrication history
49、 may play an importantrole in the measured strength distributions and should bereported. In addition, the nature of fabrication used for certaincomposites (for example, chemical vapor infiltration or hotpressing) may require the testing of test specimens in theas-processed condition (that is, it may not be possible tomachine the test specimen faces).6.3 Internally-pressurized tests of CMC tubes can producebiaxial and triaxial stress distributions with maximum andminimum stresses occurring at the test specimen surfaceleading to fractures originating at surfaces or near
