ASTM_D_6415_-_D_6415M_-_06a_2013.pdf

Designation:D6415/D6415M06a(Reapproved 2013)Standard Test Method forMeasuring the Curved Beam Strength of a Fiber-ReinforcedPolymer-Matrix Composite1This standard is issued under the fixed designation D6415/D6415M;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 This test method determines the curved beam strength ofa continuous fiber-reinforced composite material using a 90curved beam specimen(Fig.1 and Fig.2).The curved beamconsists of two straight legs connected by a 90 bend with a6.4-mm 0.25 in.inner radius.An out-of-plane(through-the-thickness)tensile stress is produced in the curved region of thespecimen when force is applied.This test method is limited touse with composites consisting of layers of fabric or layers ofunidirectional fibers.1.2 This test method may also be used to measure theinterlaminar tensile strength if a unidirectional specimen isused where the fibers run continuously along the legs andaround the bend.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.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.Within the text theinch-pound units are shown in brackets.The values stated ineach system are not exact equivalents;therefore,each systemmust be used independently of the other.Combining valuesfrom the two systems may result in nonconformance with thestandard.2.Referenced Documents2.1 ASTM Standards:2D792 Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by DisplacementD883 Terminology Relating to PlasticsD3171 Test Methods for Constituent Content of CompositeMaterialsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsD5687/D5687M Guide for Preparation of Flat CompositePanels with Processing Guidelines for Specimen Prepara-tionE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE122 Practice for Calculating Sample Size to Estimate,WithSpecified Precision,the Average for a Characteristic of aLot or ProcessE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE1309 GuideforIdentificationofFiber-ReinforcedPolymer-Matrix Composite Materials in DatabasesE1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in DatabasesE1471 Guide for Identification of Fibers,Fillers,and CoreMaterials in Computerized Material Property Databases3.Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto high-modulus fibers and their composites.TerminologyD883 defines terms relating to plastics.Terminology E6 definesterms relating to mechanical testing.Terminology E456 andPractice E177 define terms relating to statistics.In the event ofa conflict between terms,Terminology D3878 shall haveprecedence over the other terminologies.3.2 Definitions of Terms Specific to This Standard:NOTE1If the term represents a physical quantity,its analyticaldimensions are stated immediately following the term(or letter symbol)infundamental dimension form,using the following ASTM standard sym-bology for fundamental dimensions,shown within square brackets:Mfor mass,L for length,T for time,for thermodynamic temperature,and nd for nondimensional quantities.Use of these symbols is restrictedto analytical dimensions when used with square brackets,as the symbolsmay have other definitions when used without the brackets.3.2.1 applied moment,M ML2T2,nthe moment appliedto the curved test section of the specimen.1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of D30.06 on InterlaminarProperties.Current edition approved Oct.1,2013.Published October 2013.Originallyapproved in 1999.Last previous edition approved in 2006 as D6415 06A1.DOI:10.1520/D6415_D6415M-06AR13.2For 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 3.2.2 curved beam strength,CBS ML1T2,nthe momentper unit width,M/w,applied to the curved test section whichcauses a sharp decrease in applied load or delamination(s)toform.3.2.3 interlaminar tensile strength,F3uML1T2,nthestrength of the co