ASTM_C_271_-_C_271M_-_16.pdf

Designation:C271/C271M16Standard Test Method forDensity of Sandwich Core Materials1This standard is issued under the fixed designation C271/C271M;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 covers the determination of the densityof sandwich construction core materials.Permissible corematerial forms include those with continuous bonding surfaces(such as balsa wood and foams)as well as those withdiscontinuous bonding surfaces(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:2D883 Terminology Relating to PlasticsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsE122 Practice for Calculating Sample Size to Estimate,WithSpecified Precision,the Average for a Characteristic of aLot or ProcessE171 Practice for Conditioning and Testing Flexible BarrierPackagingE177 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 E456 and Practice E177define terms relating to statistics.In the event of a conflictbetween terms,Terminology D3878 shall have precedenceover the other terminologies.3.2 Symbols:3.2.1 CVcoefficient of variation statistic of a samplepopulation for a given property(in percent)3.2.2 dIPdensity of a test specimen in inch-pound units3.2.3 dSIdensity of a test specimen in SI units3.2.4 llength of a test specimen3.2.5 Sn1standard deviation statistic of a sample popula-tion for a given property3.2.6 tthickness of a test specimen3.2.7 xitest result for an individual specimen from thesample population for a given property3.2.8 x mean or average(estimate of mean)of a samplepopulation for a given property3.2.9 wwidth of a test specimen3.2.10 Wmass of a test specimen4.Summary of Test Method4.1 This test method consists of environmentally condition-ing a sandwich core specimen,weighing the specimen,mea-suring the length,width and thickness of the specimen,andcalculating the density.5.Significance and Use5.1 Density is a fundamental physical property that can beused in conjunction with other properties to characterize thesandwich core.Most sandwich core structural properties,suchas strength and stiffness,are proportional to the density.5.2 This test method provides a standard method of obtain-ing sandwich core density data for design properties,materialspecifications,research and development applications,andquality assurance.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 March 15,2016.Published March 2016.Originallyapproved in 1951.Last previous edition approved in 2011 as C271/C271M 11.DOI:10.1520/C0271_C0271M-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 5.3 Factors that influence the density and shall therefore bereported include the following:core material,methods ofmaterial fabrication,core geometry(nominal cell size),speci-men geometry,specimen preparation,methods of weight anddimensional measurement,specimen conditioning,and mois-ture content during weight and dimensional measurements.6.Interferences6.1 Material and Specimen PreparationPoor material fab-rication practices and damage induced by improper specimenmachining are known causes of high data scatter in compositesand sandwich structures in general.Important aspects ofsandwich core specimen preparation that contribute to datascatter include the existence of joints,voids or other coredisconti