ASTM_D_7078_-_D_7078M_-_12.pdf

Designation:D7078/D7078M12Standard Test Method forShear Properties of Composite Materials by V-Notched RailShear Method1This standard is issued under the fixed designation D7078/D7078M;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 covers the determination of the shearproperties of high-modulus fiber-reinforced composite materi-als by clamping the ends of a V-notched specimen between twopairs of loading rails.When loaded in tension,the railsintroduce shear forces into the specimen through the specimenfaces.In comparison,the specimen of Test Method D5379/D5379M is loaded through its top and bottom edges.Faceloading allows higher shear forces to be applied to thespecimen,if required.Additionally,the present test methodutilizes a specimen with a larger gage section than theV-notched specimen of Test Method D5379/D5379M.In bothtest methods,the use of a V-notched specimen increases thegage section shear stresses in relation to the shear stresses inthe vicinity of the grips,thus localizing the failure within thegage section while causing the shear stress distribution to bemore uniform than in a specimen without notches.Incomparison,Test Method D4255/D4255M utilizes an un-notched specimen clamped between two pairs of loading railsthat are loaded in tension.Also in contrast to Test MethodD4255/D4255M,the present test method provides specimengripping without the need for holes in the specimen.The composite materials are limited to continuous-fiber ordiscontinuous-fiber-reinforced composites in the following ma-terial forms:1.1.1 Laminates composed only of unidirectional fibrouslaminae,with the fiber direction oriented either parallel orperpendicular to the fixture rails.1.1.2 Laminates of balanced and symmetric construction,with the 0 direction oriented either parallel or perpendicular tothe fixture rails.1.1.3 Laminates composed of woven,braided,or knittedfabric filamentary laminae.1.1.4 Short-fiber-reinforced composites with a majority ofthe fibers being randomly distributed.1.2 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.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:2D792 Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by DisplacementD883 Terminology Relating to PlasticsD2584 Test Method for Ignition Loss of Cured ReinforcedResinsD2734 Test Methods for Void Content of Reinforced PlasticsD3171 Test Methods for Constituent Content of CompositeMaterialsD3878 Terminology for Composite MaterialsD4255/D4255M Test Method for In-Plane Shear Propertiesof Polymer Matrix Composite Materials by the Rail ShearMethodD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsD5379/D5379M Test Method for Shear Properties of Com-posite Materials by the V-Notched Beam MethodD6856 Guide for Testing Fabric-Reinforced“Textile”Com-posite MaterialsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE111 Test Method for Youngs Modulus,Tangent Modulus,1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.04 onLamina and Laminate Test Methods.Current edition approved July 15,2012.Published December 2012.Originallyapproved in 2005.Last previous edition approved in 2005 as D7078/D7078M-05.DOI:10.1520/D7078_D7078M-12.2For 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 and Chord ModulusE122 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 MethodsE251 Test Methods for Performance Characteristics of Me-tallic Bonded Resistance Strain GagesE456 Terminology Relating to Quality and StatisticsE1237 Guide for Installing Bonded Resistance Str