ASTM_C_1819_-_15.pdf

Designation:C181915Standard 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 designation 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 determination 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 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 adefined 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 loading 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 pressure 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 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 reinforcement: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 compositions)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 methods 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 aredetermined 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 temperaturetesting.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 specimengeometries,test specimen methods,testing rates(force rate,induced pressure rate,displacement rate,or strain rate),anddata collection and reporting procedures in the followingsections.SectionScope1Referenced Documents2Terminology3Summary of Test Method4Significance and Use5Interferences6Apparatus7Hazards8Test Specimens9Test Procedure10Calculation of Results11Report12Precision and Bias13Keywords14AnnexesVerification Of Load Train AlignmentAppendix X11This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direct responsibility of Subcommittee 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 States1 SectionStress Factors For Calculation Of Maximum Hoop StressAppendix X2Axial Force To Internal PressureAppendix 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