ASTM_D_7269_-_D_7269M_-_11.pdf

Designation:D7269/D7269M11Standard Test Methods forTensile Testing of Aramid Yarns1This standard is issued under the fixed designation D7269/D7269M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the tensile testing of aramidyarns,cords twisted from such yarns,and fabrics woven fromsuch cords.The yarn or cord may be wound on cones,tubes,bobbins,spools,or beams;may be woven into fabric;or maybe in some other form.The methods include testing procedureonly and include no specifications or tolerances.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard includes the following test methods:SectionBreaking Strength(Force)11Breaking Tenacity12Breaking Toughness17Elongation at Break13Force at Specified Elongation(FASE)14Linear Density10Modulus15Work-to-Break161.4 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD1907 Test Method for Linear Density of Yarn(Yarn Num-ber)by the Skein MethodD1909 Standard Tables of Commercial Moisture Regainsand Commercial Allowances for Textile FibersD2258 Practice for Sampling Yarn for TestingD4848 Terminology Related to Force,Deformation andRelated Properties of TextilesD6587 Test Method for Yarn Number Using AutomaticTester3.Terminology3.1 Definitions:3.1.1 slippage,nwith tensile testing,insufficient quality ofclamping,resulting in movement of the test material throughthe total clamping surface.This can be visualized by themovement of markers at the clamp exit,or by sudden changesin the strain-modulus curves(1st derivative of the strain-stresscurve).3.1.2 zero twist,ntwistless,devoid of twist.3.2 The following terms are relevant to this standard:industrial yarn,moisture equilibrium for testing,aramid,zerotwist,standard atmosphere for testing textiles.3.3 For definitions of terms related to force and deformationin textiles,refer to Terminology D4848.3.4 The following terms are relevant to this standard:breaking force,breaking strength,breaking tenacity,breakingtoughness,chord modulus in a stress-strain curve,elongation,force at specified elongation(FASE),initial modulus,tensilestrength,and work-to-break.3.5 For definitions of other terms related to textiles,refer toTerminology D123.4.Summary of Test Method4.1 These test methods are used to determine the tensileproperties of aramid yarns or cords.4.2 Aconditioned or oven-dried specimen of aramid yarn orcord is clamped in a tensile testing machine and then stretchedor loaded until broken.Breaking force,elongation,and force atspecified elongation(FASE)are determined directly.Modulusand work-to-break are calculated from the force-elongationcurve.The output of a constant-rate-of-extension(CRE)tensiletesting machine can be connected with electronic recording and1These test methods are under the jurisdiction of ASTM Committee D13 onTextiles and are the direct responsibility of Subcommittee D13.19 on IndustrialFibers and Metallic Reinforcements.Current edition approved May 1,2011.Published June 2011.Originallyapproved in 2006.Last previous edition approved in 2010 as D7269/D7269M10.DOI:10.1520/D7269_D7269M-11.2For 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 States1 computing equipment,which may be programmed to calculateand print the test results of tensile properties of interest.5.Significance and Use5.1 The levels of tensile properties obtained when testingaramid yarns and cords are dependent on the age and history ofthe specimen and on the specific conditions used during thetest.Among these conditions are rate of stretching,type ofclamps,gage length of specimen,temperature and humidity ofthe atmosphere,rate of airflow across the specimen,andtemperature and moisture content of the specimen.Testingconditions accordingly are specified precisely to obtain repro-ducible test results on a specific sample.5.2