ASTM_D_1621_-_16.pdf

Designation:D162116Standard Test Method forCompressive Properties of Rigid Cellular Plastics1This standard is issued under the fixed designation D1621;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript 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.Scope*1.1 This test method describes a procedure for determiningthe compressive properties of rigid cellular materials,particu-larly expanded plastics.1.2 The values stated in SI units are to be regarded as thestandard.The values in parentheses are for information only.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.NOTE1This test method and ISO 844 are technically equivalent.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingE4 Practices for Force Verification of Testing MachinesE83 Practice for Verification and Classification of Exten-someter SystemsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2ISO Standard:ISO 844 Cellular PlasticsCompression Test of Rigid Ma-terials33.Terminology3.1 Definitions:3.1.1 compliancethe displacement difference between testmachine drive system displacement values and actual specimendisplacement.3.1.2 compliance correctionan analytical method ofmodifying test instrument displacement values to eliminate theamount of that measurement attributed to test instrumentcompliance.3.1.3 compressive deformationthe decrease in length pro-duced in the gage length of the test specimen by a compressiveload expressed in units of length.3.1.4 compressive strainthe dimensionless ratio of com-pressive deformation to the gage length of the test specimen orthe change in length per unit of original length along thelongitudinal axis.3.1.5 compressive strengththe stress at the yield point if ayield point occurs before 10%deformation(as in Fig.1a)or,in the absence of such a yield point,the stress at 10%deformation(as in Fig.1b).3.1.6 compressive stress(nominal)the compressive loadper unit area of minimum original cross section within the gageboundaries,carried by the test specimen at any given moment,expressed in force per unit area.3.1.7 compressive stress-strain diagrama diagram inwhich values of compressive stress are plotted as ordinatesagainst corresponding values of compressive strain as abscis-sas.3.1.8 compressive yield pointthe first point on the stress-strain diagram at which an increase in strain occurs without anincrease in stress.3.1.9 deflectometera device used to sense the compressivedeflection of the specimen by direct measurement of thedistance between the compression platens.3.1.10 displacementcompression platen movement afterthe platens contact the specimen,expressed in millimetres orinches.3.1.11 gage lengththe initial measured thickness of thetest specimen expressed in units of length.3.1.12 modulus of elasticitythe ratio of stress(nominal)tocorresponding strain below the proportional limit of a materialexpressed in force per unit area based on the minimum initialcross-sectional area.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials-Plastics and Elastomers.Current edition approved May 1,2016.Published May 2016.Originallyapproved in 1959.Last previous edition approved in 2010 as D1621-10.DOI:10.1520/D1621-16.2For 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 American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.13 proportional limitthe greatest stress that a materialis capable of sustaining without any deviation from propor-tionality of stress-to-strain(Hookes law)expressed in forceper unit area.4.Significance and Use4.1 This test method provides information regarding thebehavior of cellular materials under compressive loads.Testdata is obtained,and from a complete load-deformation curveit is possible to compute the compressive stress at any load(such as compressive stress at proportional-limit load orcompressive strength at maximum load)and to compute theeffective modulus of elasticity.4.2 Compression tests provide