ASTM_D_7774_-_22.pdf

Designation:D777422Standard Test Method forFlexural Fatigue Properties of Plastics1This standard is issued under the fixed designation D7774;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.Scope*1.1 This test method covers the determination of dynamicfatigue properties of plastics in flexure.This method is appli-cable to rigid and semi-rigid plastics.Stress and strain levelsare below the proportional limit of the material where thestrains and stresses are relatively elastic.Three-point or four-point bending systems are used to determine these properties.1.2 This test method can be used with two procedures:1.2.1 Procedure A,designed for materials that use three-point loading systems to determine flexural strength.Three-point loading system is used for this procedure.1.2.2 Procedure B,designed for materials that use four-point loading systems to determine flexural strength.Four-point loading system is used for this procedure.1.3 Comparative tests can be run in accordance with eitherprocedure,provided that the procedure is found satisfactory forthe material being tested.1.4 The values stated in SI units are to be regarded as thestandard.The values provided in parentheses are for informa-tion only.1.5 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.NOTE1This standard and ISO 13003 address the same subject matter,but differ in technical content and results cannot be directly comparedbetween the two test methods.1.6 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:2D618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materi-alsD792 Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by DisplacementD883 Terminology Relating to PlasticsD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD2839 Practice for Use of a Melt Index Strand for Deter-mining Density of PolyethyleneD3479/D3479M Test Method for Tension-Tension Fatigueof Polymer Matrix Composite MaterialsD4883 Test Method for Density of Polyethylene by theUltrasound TechniqueD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensD6272 Test Method for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materi-als by Four-Point BendingE4 Practices for Force Calibration and Verification of Test-ing MachinesE83 Practice for Verification and Classification of Exten-someter SystemsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1942 Guide for Evaluating Data Acquisition Systems Usedin Cyclic Fatigue and Fracture Mechanics Testing2.2 ISO Standard:ISO 13003Fibre-Reinforced PlasticsDetermination ofFatigue Properties Under Cyclic Loading Conditions31This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved July 1,2022.Published July 2022.Last previousedition approved in 2017 as D7774-17.DOI:10.1520/D7774-22.2For 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright 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.13.Terminology3.1 DefinitionsDefinitions applying to this test methodappear in Terminology D883.3.2 mean strain,nthe algebraic average of the maximumand minimum strains in