ASTM_C_273_-_C_273M_-_16.pdf

Designation:C273/C273M16Standard Test Method forShear Properties of Sandwich Core Materials1This standard is issued under the fixed designation C273/C273M;the number immediately following the designation indicates the yearof 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()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the determination of shearproperties of sandwich construction core materials associatedwith shear distortion of planes parallel to the facings.It coversthe determination of shear strength parallel to the plane of thesandwich,and the shear modulus associated with strains in aplane normal to the facings.The test may be conducted on corematerials bonded directly to the loading plates or the sandwichfacings bonded to the plates.Permissible core material formsinclude those with continuous bonding surfaces(such as balsawood and foams)as well as those with discontinuous bondingsurfaces(such as honeycomb).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 non-conformancewith the standard.1.2.1 Within the text the inch-pound units are shown inbrackets.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:2C271/C271M Test Method for Density of Sandwich CoreMaterialsC393 Test Method for Flexural Properties of SandwichConstructionsD792 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 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-tionD5961/D5961M Test Method for Bearing Response of Poly-mer Matrix Composite LaminatesE4 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 DefinitionsTerminology D3878 defines terms relatingto high-modulus fibers and their composites,as well as termsrelating to sandwich constructions.Terminology D883 definesterms relating to plastics.Terminology E6 defines termsrelating to mechanical testing.Terminology E456 and PracticeE177 define terms relating to statistics.In the event of aconflict between terms,Terminology D3878 shall have prece-dence over the other terminologies.3.2 Symbols:b=width of specimenCV=coefficient of variation statistic of a sample populationfor a given property(in percent)G=core shear modulusL=length of specimenP=force on specimenS=P/u,slope of initial portion of force-deflection curve1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.09 onSandwich Construction.Current edition approved April 1,2016.Published April 2016.Originallyapproved in 1951.Last previous edition approved in 2011 as C273 11.DOI:10.1520/C0273_C0273M-16.2For 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 Sn-1=standard deviation statistic of a sample population fora given propertyt=thickness of coreu=displacement of loading platesx1=test result for an individual specimen from the samplepopulation for a given propertyx5mean or average(estimate of mean)of a samplepopulation for a given property=core engineering shear strain=core shear stress4.Summary of Test Method4.1 This test method consists of subjecting a sandwich coreor sandwich panel to monotonically increasing shear forceparallel to the plane of its faces.The force is transmitted to thespecimen through bonded loading plates that are su