ASTM_D_8255_-_19.pdf

Designation:D825519An American National StandardStandard Guide forWork of Fracture Measurements on Small Nuclear GraphiteSpecimens1This standard is issued under the fixed designation D8255;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 guide provides general tutorial information andbest practice for measuring the work of fracture on manufac-tured graphite and carbon specimens.Although applicable toall carbon and graphite materials,this guide is aimed specifi-cally at measurements required on nuclear graphites,wherethere may be constraints on the geometry and/or volume of thetest specimen.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses after SI units areprovided for information only and are not considered standard.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 ArticlesC651 Test Method for Flexural Strength of ManufacturedCarbon and GraphiteArticles Using Four-Point Loading atRoom TemperatureC695 Test Method for Compressive Strength of Carbon andGraphiteC747 Test Method for Moduli of Elasticity and FundamentalFrequencies of Carbon and Graphite Materials by SonicResonanceC749 Test Method for Tensile Stress-Strain of Carbon andGraphiteC769 Test Method for Sonic Velocity in ManufacturedCarbon and Graphite Materials for Use in Obtaining anApproximate Value of Youngs ModulusD7775 Guide for Measurements on Small Graphite Speci-mensD7779 Test Method for Determination of Fracture Tough-ness of Graphite at Ambient TemperatureD7972 Test Method for Flexural Strength of ManufacturedCarbon and Graphite Articles Using Three-Point Loadingat Room TemperatureE4 Practices for Force Verification of Testing MachinesE399 Test Method for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic Materials3.Terminology3.1 Definitions:3.1.1 work of fracture,f(J/m2),nthe total energy re-quired to produce a unit area of fracture surface.3.2 Definitions of Terms Specific to This Standard:3.2.1 absorbed energy,nthe plastic energy absorbed bythe system.3.2.1.1 DiscussionThis is primarily the work done toextend the crack but can also include other plastic strainsrelated to the specimen,such as microcracking,or the entiresystem,usually related to the stiffness of the loading frame.These cases are discussed in detail in Section 10.3.2.2 total(consumed)energy,nthe total energy calcu-lated by the load-displacement trace in this type of test.3.2.2.1 DiscussionThis is the sum of the elastic energythat leads to elastic deformation of the specimen and the plasticenergy,which is primarily the work done to extend the crack.4.Summary of Guide4.1 An introduction is provided on the characteristics ofnuclear graphite that restrict the number of test methods thatare applicable for measuring the Work of Fracture(WoF),especially with regard to testing of small irradiated specimens1This guide is under the jurisdiction of ASTM Committee D02 on PetroleumProducts,Liquid Fuels,and Lubricants and is the direct responsibility of Subcom-mittee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved May 1,2019.Published June 2019.DOI:10.1520/D8255-19.2For 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.1 in a shielded facility.This guide takes into account theserestrictions and proposes a method for measuring WoF.4.2 This guide provides the basic principles and experimen-tal setup for the proposed method.5.Significance and Use5.1 Structural integrity as