ASTM_C_394_-_C_394M_-_16.pdf

Designation:C394/C394M16Standard Test Method forShear Fatigue of Sandwich Core Materials1This standard is issued under the fixed designation C394/C394M;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.1.Scope1.1 This test method determines the effect of repeated shearforces on core material used in sandwich panels.Permissiblecore material forms include those with continuous bondingsurfaces(such as balsa wood and foams)as well as those withdiscontinuous bonding surfaces(such as honeycomb).1.2 This test method is limited to test specimens subjectedto constant amplitude uniaxial loading,where the machine iscontrolled so that the test specimen is subjected to repetitiveconstant amplitude force(stress)cycles.Either shear stress orapplied force may be used as a constant amplitude fatiguevariable.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.Within the text,the inch-pound units areshown in brackets.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:2C271/C271M Test Method for Density of Sandwich CoreMaterialsC273/C273M Test Method for Shear Properties of SandwichCore MaterialsD883 Terminology Relating to PlasticsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsE6 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 StatisticsE467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemE739 Practice for StatisticalAnalysis of Linear or LinearizedStress-Life(S-N)and Strain-Life(-N)Fatigue DataE1012 Practice for Verification of Testing Frame and Speci-men Alignment Under Tensile and Compressive AxialForce Application2.2 ISO Standards3ISO 13003:2003(E)Fibre-reinforced plastics:Determinationof fatigue properties under cyclic loading conditions3.Terminology3.1 Definitions:3.1.1 Terminology D3878 defines terms relating to high-modulus fibers and their composites,as well as terms relatingto sandwich constructions.Terminology D883 defines termsrelating to plastics.Terminology E6 defines terms relating tomechanical testing.Terminology E456 and Practice E177define terms relating to statistics.In the event of a conflictbetween terms,Terminology D3878 shall have precedenceover the other terminologies.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 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:1This 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 1957.Last previous edition approved in 2013 as C394 13.DOI:10.1520/C0394_C0394M-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.3Available from International Organization for Standardization(ISO),1,ch.dela Voie-Creuse,CP 56,CH-1211 Geneva 20,Switzerland,http:/www.iso.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.1 constant amplitude loading,nin fatigue,a loading inwhich all of the peak values of force(stress)are equal and allof the valley values of force(stress)are equal.3.2.2 fatigue loading transition,nin the beginning offatigue loading,the number of cycles before the force(stress)reaches the desired peak and valley values.3.2.3 force(str