ASTM_D_6671_-_D_6671M_-_13e1.pdf

Designation:D6671/D6671M131Standard Test Method forMixed Mode I-Mode II Interlaminar Fracture Toughness ofUnidirectional Fiber Reinforced Polymer Matrix Composites1This standard is issued under the fixed designation D6671/D6671M;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.1NOTECharacters in equations 2,3,10,12,13,and 1721 corrected editorially in May 2015.1.Scope1.1 This test method describes the determination of inter-laminar fracture toughness,Gc,of continuous fiber-reinforcedcomposite materials at various Mode I to Mode II loadingratios using the Mixed-Mode Bending(MMB)Test.1.2 This test method is limited to use with compositesconsisting of unidirectional carbon fiber tape laminates withbrittle and tough single-phase polymer matrices.This testmethod is further limited to the determination of fracturetoughness as it initiates from a delamination insert.Thislimited scope reflects the experience gained in round robintesting.This test method may prove useful for other types oftoughness values and for other classes of composite materials;however,certain interferences have been noted(see Section 6).This test method has been successfully used to test thetoughness of both glass fiber composites and adhesive joints.1.3 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.1.4 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:2D883 Terminology Relating to PlasticsD2651 Guide for Preparation of Metal Surfaces forAdhesiveBondingD2734 Test Methods for Void Content of Reinforced 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 MaterialsD5528 Test Method for Mode I Interlaminar Fracture Tough-ness of Unidirectional Fiber-Reinforced Polymer MatrixCompositesE4 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 Statistics3.Terminology3.1 Terminology D3878 defines terms relating to high-modulus fibers and their composites.Terminology D883 de-fines terms relating to plastics.Terminology E6 defines termsrelating to mechanical testing.Terminology E456 and PracticeE177 define terms relating to statistics.In the event of conflictbetween terms,Terminology D3878 shall have precedenceover the other terminology standards.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,u for thermodynamic temperature,and nd for non-dimensional 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 Definitions of Terms Specific to This Standard:3.2.1 crack opening mode(Mode I)fracture mode inwhich the delamination faces open away from each other andno relative crack face sliding occurs.1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.06 onInterlaminar Properties.Current edition approved Oct.1,2013.Published November 2013.Originallyapproved in 2001.Last previous edition approved in 2006 as D6671/D6671M 06.DOI:10.1520/D6671_D6671M-13E01.2For 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 crack sliding mode(Mode II)fracture mode in whichthe delamination faces slide over each other in the direction ofdelamination growth and no relative crack face opening occurs.3.2.3 mixed-mode fractu