ASTM_D_1043_-_10.pdf

Designation:D104310Standard Test Method forStiffness Properties of Plastics as a Function ofTemperature by Means of a Torsion Test1This standard is issued under the fixed designation D1043;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 covers the determination of the stiff-ness characteristics of plastics over a wide temperature rangeby direct measurement of the apparent modulus of rigidity.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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 458-1 and ISO 458-2 address thesame subject matter,but differ in technical content.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD747 Test Method for Apparent Bending Modulus of Plas-tics by Means of a Cantilever BeamD883 Terminology Relating to PlasticsD1053 Test Methods for Rubber PropertyStiffening atLow Temperatures:Flexible Polymers and Coated FabricsD4000 Classification System for Specifying Plastic Materi-als3.Terminology3.1 DefinitionsFor definitions of the technical terms per-taining to plastics used in this test method,see TerminologyD883.4.Significance and Use4.1 The property measured by this test is the apparentmodulus of rigidity,G,sometimes called the apparent shearmodulus of elasticity.It is important to note that this propertyis not the same as the modulus of elasticity,E,measured intension,flexure,or compression.The relationship betweenthese properties is shown in Annex A1.4.2 The measured modulus of rigidity is termed“apparent”since it is the value obtained by measuring the angulardeflection occurring when the specimen is subjected to anapplied torque.Since it is possible that the specimen will bedeflected beyond its elastic limit,the calculated value will notalways represent the true modulus of rigidity within the elasticlimit of the material.In addition,the value obtained by this testmethod will also be affected by the creep characteristics of thematerial,since the load application time is arbitrarily fixed.Formany materials,it is possible that there is a specification thatrequires the use of this test method,but with some proceduralmodifications that take precedence when adhering to thespecification.Therefore,it is advisable to refer to that materialspecification before using this test method.Table 1 in Classi-fication D4000 lists the current ASTM material standards.4.3 This test method is useful for determining the relativechanges in stiffness over a wide range of temperatures.5.Apparatus5.1 Testing MachineA machine capable of exerting atorque sufficient to deflect a test specimen in the range of 5 to100 of arc,depending on the stiffness of the specimen and itsspan.A schematic diagram of a suitable machine is shown inFig.1.NOTE2Two machines of different torque capacities are being used:one covers the range of approximately 0.0113 to 0.113 Nm(0.1 to 1.0in.lbf)and the other of approximately 0.113 to 1.81 Nm(1.0 to 16 in.lbf)or higher.Some machines also allow varying the span,which is especiallyimportant if shearing failures can occur(as in laminates at a span/width of6).NOTE3It is acceptable to vary the amount of torque to suit thestiffness of the test specimen,and it is necessary to have various weightsavailable for this purpose.Determine the actual amount of torque beingapplied by any given combination of weights,torque wheel radii,and shaftbearings by calibration.The accuracy of the apparatus can be subject to1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved April 1,2010.Published April 2010.Originallyapproved in 1949.Last previous edition approved in 2009 as D1043-09.DOI:10.1520/D1043-10.2For 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.*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 change,and therefore periodic calibration is necessary to ensure reliabletest results.Testing machine c