ASTM_D_8356_-_20.pdf

Designation:D835620Standard Test Method forSonic Velocity in Manufactured Carbons and GraphiteMaterials for use in Obtaining Approximate ElasticConstants:Youngs Modulus,Shear Modulus,and PoissonsRatio1This standard is issued under the fixed designation D8356;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 a procedure for measuring thelongitudinal and transverse(shear)sonic velocities in manu-factured carbon and graphite which can be used to obtainapproximate values for the elastic constants:Youngs modulus(E),the shear modulus(G),and Poissons ratio(v).1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2C559 Test Method for Bulk Density by Physical Measure-ments of Manufactured Carbon and Graphite ArticlesC747 Test Method for Moduli of Elasticity and FundamentalFrequencies of Carbon and Graphite Materials by SonicResonanceD4175 Terminology Relating to Petroleum Products,LiquidFuels,and LubricantsD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products,Liquid Fuels,and LubricantsD7775 Guide for Measurements on Small Graphite Speci-mensE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodIEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units(SI)(the Modern Metric System)3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 end correction time(Te),na fixed correction timeassociated with the potential interaction of the couplant me-dium and the test material.3.1.2 longitudinal sonic pulse,na sonic pulse in which thedisplacements are in the direction of propagation of the pulse.3.1.3 pulse travel time,(Tt),nthe total time,measured inseconds,required for the sonic pulse to traverse the specimenbeing tested,and for the associated electronic signals totraverse the transducer coupling medium and electronic circuitsof the pulse-propagation system.3.1.4 shear or transverse sonic pulse,na sonic pulse inwhich the displacements are perpendicular to the direction ofpropagation of the pulse.3.1.5 time of flight(ToF),nthe total time,measured inseconds,required for the sonic pulse to traverse the specimenbeing tested(Tt T0).1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved Oct.1,2020.Published December 2020.DOI:10.1520/D8356-20.2For referenced ASTM standards,visit the ASTM website,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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.3.1.6 zero time,(T0),nthe travel time(correction factor),measured in seconds,associated with the transducer,couplingmedium and electronic circuits in the pulse-propagation sys-tem.4.Summary of Test Method4.1 The velocity of sound waves passing through the testspecimen is determined by measuring the distance through thespecimen and dividing by the time lapse,between the trans-mitted pulse and the received pulse.3,4Provided the wave-length of the transmitted pulse is a sufficiently small fraction ofthe samples lateral dimensions,a value of Youngs modulusfor isotropic graphite can then be obtained using Eq 1 and 2:E 5 CvVL2(1)where:E=Youngs modulus,Pa,=density,kg/m3,VL=longitudinal signal velocity,m/s,andCv=Poissons factor.4.2 The Poissons factor,Cv,is related to Poissons ratio,v,by the equation:Cv51 1 v!1 2 2 v!1 2 v(2)4.3 If the Poissons factor is unknown,it can be