ASTM_C_272_-_C_272M_-_16.pdf

Designation:C272/C272M16Standard Test Method forWater Absorption of Core Materials for SandwichConstructions1This standard is issued under the fixed designation C272/C272M;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 the relativeamount of water absorption by various types of sandwichconstruction core materials when immersed in water,or whensubjected to a high relative humidity environment.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 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 PlasticsD1193 Specification for Reagent WaterD3878 Terminology for Composite MaterialsE122 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 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 Dpre-immersion mass of a test specimen.3.2.3 hheight of a test specimen.3.2.4 llength of a test specimen.3.2.5 Sn1standard deviation statistic of a sample popula-tion for a given property.3.2.6 x1test result for an individual specimen from thesample population for a given property.3.2.7 xmean or average(estimate of mean)of a samplepopulation for a given property.3.2.8 Vvolume of a test specimen.3.2.9 wwidth of a test specimen.3.2.10 Wmass of a test specimen.4.Summary of Test Method4.1 This test method consists of exposing sandwich corespecimen to a defined moisture condition,and determining theamount of water absorbed by measuring the mass increase inthe specimen.5.Significance and Use5.1 Absorbed water affects the characteristic properties ofsandwich core materials,such as electrical properties(forexample,dielectric constant,loss tangent,and electrical resis-tance)and mechanical properties(for example,strength and1This 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 2012 as C272 12.DOI:10.1520/C0272_C0272M-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 modulus).The mass of absorbed water may also affect thebehavior of sandwich structures.It should be noted that in asandwich panel the presence of facings bonded on two sides ofthe core may affect the amount of water absorbed by the core.5.2 This test method provides a standard method of obtain-ing sandwich core moisture absorption data for designproperties,material specifications,research and developmentapplications,and quality assurance.5.3 Factors that influence the water absorption and shalltherefore be reported include the following:core material,methods of material fabrication,core geometry(honeycombcell size,honeycomb cell wall thickness,foam pore size,etc.),specimen geometry,specimen preparation,methods of massand dimensional measurement,specimen conditioning,andmoisture content during mass and dimensional measurements.6.Interferences6.1 Materia