ASTM_D_4476_-_D_4476M_-_14.pdf

Designation:D4476/D4476M14Standard Test Method forFlexural Properties of Fiber Reinforced Pultruded PlasticRods1This standard is issued under the fixed designation D4476/D4476M;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.Scope*1.1 This test method covers the determination of the flexuralproperties of fiber-reinforced pultruded plastic rods.The speci-men is a rod with a semicircular cross section,molded or cutfrom lengths of pultruded rods(see Fig.1).This test method isdesigned for rods with a diameter of12in.or greater.NOTE1There is no known ISO equivalent to this standard.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 nonconformancewith the 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD3918 Terminology Relating to Reinforced Plastic Pul-truded ProductsE4 Practices for Force Verification of Testing MachinesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 For definitions of terms used in this test method,seeTerminology D883 or Definitions D3918.4.Summary of Test Method4.1 A rod of semicircular construction is tested in flexure asa simple beam.The specimen rests on two supports and isloaded by means of a loading nose midway between thesupports(see Fig.3).4.2 The specimen is deflected until rupture occurs in theouter fibers,or until the maximum fiber strain of 5%isreached,whichever occurs first.5.Significance and Use5.1 Flexural properties determined by this test method areespecially useful for quality control and specification purposes.5.2 The maximum axial fiber stresses occur on a line underthe loading nose.The use of the semicircular cross sectioneliminates premature compression shear that has been noted inthree-point flexure tests on full-round rods.5.3 Flexural properties may vary with specimen depth,temperature,atmospheric conditions,and differences in rate ofstraining.5.4 Before proceeding with this test method,referenceshould be made to the specification of the material being tested.Any test specimen preparation,conditioning,dimensions,ortesting parameters,or combination thereof,covered in thematerials specification shall take precedence over those men-tioned in this test method.If there are no materialspecifications,then the default conditions apply.6.Apparatus6.1 Testing MachineAproperly calibrated testing machinethat can be operated at constant rates of crosshead motion overthe range indicated,and in which the error in the load-measuring system shall not exceed 61%of the maximum loadexpected to be measured.It shall be equipped with adeflection-measuring device.The stiffness of the testing ma-chine shall be such that the total elastic deformation of thesystem does not exceed 1%of the total deflection of the testspecimen during test,or appropriate corrections shall be made.The load-indicating mechanism shall be essentially free ofinertial lag at the crosshead rate used.The accuracy of thetesting machine shall be verified in accordance with PracticesE4.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.18 on Reinforced Thermoset-ting Plastics.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 1985.Last previous edition approved in 2009 as D4476-09.DOI:10.1520/D4476_D4476M-14.2For 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.*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 States1 6.2 Loading Nose and SupportsThe loading nose shallhave cylindrical surfaces.In order to avoid excessive indenta-tion or failure due to stress concentration directly under theloading nose,the radius of the nose shall be at least 6.4 mm 14in.for all specimens.Larger-radius noses are recommended ifsignificant indentation or compressive failure occurs.Thecurvature of the loading nose in contact with the specimen shallbe suffici