ASTM_D_7766_-_D_7766M_-_16.pdf

Designation:D7766/D7766M16Standard Practice forDamage Resistance Testing of Sandwich Constructions1This standard is issued under the fixed designation D7766/D7766M;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 practice provides instructions for modifying lami-nate quasi-static indentation and drop-weight impact test meth-ods to determine damage resistance properties of sandwichconstructions.Permissible core material forms include thosewith continuous bonding surfaces(such as balsa wood andfoams)as well as those with discontinuous bonding surfaces(such as honeycomb,truss cores and fiber-reinforced cores).1.2 This practice supplements Test Methods D6264/D6264M(for quasi-static indentation testing)and D7136/D7136M(for drop-weight impact testing)with provisions fortesting sandwich specimens.Several important test specimenparameters(for example,facing thickness,core thickness andcore density)are not mandated by this practice;however,repeatable results require that these parameters be specified andreported.1.3 Three test procedures are provided.Procedures A and Bcorrespond to D6264/D6264M test procedures for rigidly-backed and edge-supported test conditions,respectively.Pro-cedure C corresponds to D7136/D7136M test procedures.Allthree procedures are suitable for imparting damage to asandwich specimen in preparation for subsequent damagetolerance testing.1.4 In general,Procedure A is considered to be the mostsuitable procedure for comparative damage resistanceassessments,due to reduced influence of flexural stiffness andsupport fixture characteristics upon damage formation.However,the selection of a test procedure and associatedsupport conditions should be done in consideration of theintended structural application,and as such Procedures B andC may be more appropriate for comparative purposes for someapplications.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.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 non-conformance with thestandard.1.5.1 Within the text the inch-pound units are shown inbrackets.1.6 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 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 MaterialsD6264/D6264M Test Method for Measuring the DamageResistance of a Fiber-Reinforced Polymer-Matrix Com-posite to a Concentrated Quasi-Static Indentation ForceD7136/D7136M Test Method for Measuring the DamageResistance of a Fiber-Reinforced Polymer Matrix Com-posite to a Drop-Weight Impact EventE6 Terminology Relating to Methods of Mechanical TestingE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and Statistics1This practice is under the jurisdiction of ASTM Committee D30 on CompositeMaterials and is the direct responsibility of Subcommittee D30.09 on SandwichConstruction.Current edition approved May 15,2016.Published June 2016.Originallyapproved in 2011.Last previous edition approved in 2011 as D7766/D7766M11.DOI:10.1520/D7766_D7766M-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 E2533 Guide for Nondestructive Testing of Polymer MatrixComposites Used in Aerospace Applications2.2 Other Documents:CMH-17-3GComposite Materials Handbook,Volume3Polymer Matrix Composites:Materials Usage,Designand Analysis3CMH-17-6Composite Materials Handbook,Volume6Structural Sandwich Composites3MIL-HDBK-728/1 Nondestructive Testing4MIL-HDBK-731A Nondestructive Testing Methods ofComposite MaterialsThermography4MIL-HDBK-732ANondestructive Testing Methods ofComposite MaterialsAcoustic Emission4MIL-HDBK-733A Nondestructive Testing Methods ofComposite MaterialsRadiography4MIL-HDBK-787A Nondestructive Testing Methods ofComposite MaterialsUltrasonics43.Terminology3.1 DefinitionsTerminolog