ASTM_D_6416_-_D_6416M_-_01_2012.pdf

Designation:D6416/D6416M01(Reapproved 2012)Standard Test Method forTwo-Dimensional Flexural Properties of Simply SupportedSandwich Composite Plates Subjected to a DistributedLoad1This standard is issued under the fixed designation D6416/D6416M;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 two-dimensional flex-ural properties of sandwich composite plates subjected to adistributed load.The test fixture uses a relatively large squarepanel sample which is simply supported all around and has thedistributed load provided by a water-filled bladder.This type ofloading differs from the procedure of Test Method C393,whereconcentrated loads induce one-dimensional,simple bending inbeam specimens.1.2 This test method is applicable to composite structures ofthe sandwich type which involve a relatively thick layer of corematerial bonded on both faces with an adhesive to thin-facesheets composed of a denser,higher-modulus material,typically,a polymer matrix reinforced with high-modulusfibers.1.3 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.1.4 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:2C274 Terminology of Structural Sandwich ConstructionsC365/C365M Test Method for Flatwise Compressive Prop-erties of Sandwich CoresC393 Test Method for Flexural Properties of SandwichConstructionsD792 Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by DisplacementD2584 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 MaterialsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE251 Test Methods for Performance Characteristics of Me-tallic Bonded Resistance Strain GagesE1237 Guide for Installing Bonded Resistance Strain Gages2.2ASTM Adjunct:Sandwich Plate Test Fixture and Hydromat Pressure Blad-der,ASTM D6416/D6416M33.Terminology3.1 Terminology D3878 defines terms relating to high-modulus fibers and their composites.Terminology C274 de-fines terms relating to structural sandwich constructions.Ter-minology E6 defines terms relating to mechanical testing.Inthe event of a conflict between terms,Terminology D3878 shallhave precedence over the other terminology standards.3.2 Definitions of Terms Specific to This Standard:3.2.1 bending stiffness,nthe sandwich property whichresists bending deflections.3.2.2 core,na centrally located layer of a sandwichconstruction,usually low density,which separates and stabi-lizes the facings and transmits shear between the facings andprovides most of the shear rigidity of the construction.3.2.3 face sheet,nthe outermost layer or composite com-ponent of a sandwich construction,generally thin and of high1This 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 Aug.1,2012.Published December 2012.Originallyapproved in 1999.Last previous edition approved in 2007 as D6416/D6416M 01(2007).DOI:10.1520/D6416_D6416M-01R12.2For 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.3Detailed drawings for the fabrication of the 500mm test fixture and pressurebladder shown in Fig.3 and Fig.4 are available from ASTM Headquarters.OrderAdjunct No.ADJD6416.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 density,which resists most of the edgewise loads and flatwisebending moments:synonymous with face,skin,and facing.3.2.4 footprint,nthe enclosed area of the face sheetsurface of a sandwich panel in contact with the pressurebladder during loading.3.2.5 hydromat,na pressure bladder with a square perim-eter fabricated from two square pieces of industrial beltingwhich are superposed and clamped at the edges with through-bolted,mild steel bar stock.3.2.6 isotropic mater