ASTM_D_1774_-_94_scan.pdf

ASTM DL774 94 0759510 055b593 638(Tb Designation:D 1774-94 AMERICAN SOCIEN FOR TESTING AND MATERIALS 1916 Race St.Philadelphia,Pa 19103 Reprinted from the Annual Book of ASTM Standards Copyright ASTM If not listed in the current combined index,will appear in the next ediiion Standard Test Methods for Elastic Properties of Textile Fibers This standard is issued under the fixed designation D 1774;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope 1.i These test methods cover measurement of the elastic behavior of fibers by assessing their ability to recover strain-induced energy,and to recover their original dimen-sions following a known extension.Since the crimp in a fiber alters the initial shape of the stress-strain curve,separate procedures are described for uncrimped and crimped fibers.NOTE I-For the determination of the elastic properties of elastomeric yarns,refer to Test Method D 273 I,Test Method for Elastic Properties of Elastomeric Yams(Constant-Rate-of-Extension Ma-chines).2 1.2 This standard does not purport to address all o f the safety concerns,if any,associated with its use.It is the responsibility ofthe user o f this standard to establish appro-priate safety and health practices and determine the applica-bility o f regulatory limitations prior to use.2.Referenced Documents 2.i ASTM Sandards:D 76 Specification for Tensile Testing Machines for D 123 Terminology Relating to Textiles D 1776 Practice for Conditioning Textiles for Testing D 2258 Practice for Sampling Yarn for Testing D 3333 Practice for Sampling Man-Made Staple Fibers,D 4848 Terminology of Force,Deformation and Related Textiles2 Sliver,or Tow for Testing3 Properties of Textiles3 3.Terminology 3.1 DeJinitions:3.1.1 dt.formation,permanent,n-the net long-term change in a dimension of a specimen after deformation and relaxation under specified conditions.(Syn.permanent set,nonrecoverable deformation,and nonrecoverable stretch.3.I.1.I Discussion-Permanent deformation is usually expressed as a percentage of the original dimension.3.1.2 elongation,n-the ratio of the extension of a mate-rial to the length of the material prior to stretching,expressed as a percent.3.1.2.1 Discussion-Elongation may be measured at any specified force or at rupture.3.i.3 tensile strain recvery,n-the percent of recoverable I These test methods are under the jurisdiction of ASTM Committee D-13 on Textiles and are the direct responsibility of Subcommitice D13.57 on Fiber Tcs Methods,General.Current edition approved Dec.15,1994.Published February 1995.Originally published as D 1774-60 T.Last previous edition D 1774-93.Annirul Book ofASTM Slrrnddi,Vol 07.01.3 Annirul Roo!,o/AS7M Slutid(rt(/$,Vol 07.02.extension to the total extension impressed on a fiber under specified conditions.3.1.3.1 Discussion-The tensile strain recovery includes both immediate elastic recovery and delayed recovery and is equivalent to the quantity 100-percent permanent defor-mation.3,1.4 work recovery,n-the percent of recoverable work to the total work required to strain a fiber a specified amount under specified conditions.3.1.5 For definitions of other terms related to force and deformation in textiles,refer to Terminology D 4848.For definitions of other textile terms used in this test method,refer to Terminology D 123.4.Summary of Test Methods 4.i The elastic properties of fibers are measured by(I)determining the amount of recoverable energy exhibited by a fiber when it is stretched to a predetermined extension at a specific rate of strain,held at this extension for a specified length of time,and finally relaxed at the same rate at which it was extended;and(2)determining the dimensional recovery of the fiber following the strain history described in Item(1).5.Significance and Use 5.1 Elastic properties are related to a fibers ability to recover from a tensile deformation.These properties are important in the selection of fibers for specific end-use application and in determining processing characteristics.5.2 This test method specifies that the fiber is to be tested at each of three levels of extension(2.0%,5.0%,and 10.0%)to describe the elastic behavior of the fiber at both small and large deformations.5.3 This method of testing the elastic properties of fibers is not recommended for acceptance testing of commercial shipments of fibers because the between-laboratory precision has not been established.In some cases the purchaser and the seller may have to test a commercial shipment of one or more specific materials by the best available method,even though the method has not been recommended for accep-tance testing of commercial shipments.In such a case,if there is a disagreement arising from differences in values reported by the purchaser a