1、Designation: D1043 16Standard 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 r
2、evision, 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
3、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 s
4、tandard 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.NOTE 1This test method an
5、d 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 Mea
6、ns 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-alsD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE177
7、Practice for Use of the Terms Precision and Bias inASTM Test Methods2.2 ISO Standards:3ISO 458-1 PlasticsDetermination of Stiffness in Torsionof Flexible Materials, Part 1: General MethodISO 458-2 PlasticsDetermination of Stiffness in Torsionof Flexible Materials, Part 2: Application to PlasticizedC
8、ompounds of Homopolymers and Copolymers of VinylChloride3. 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, somet
9、imes 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 “a
10、pparent”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
11、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 t
12、est 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 i
13、s useful for determining the relativechanges in stiffness over a wide range of temperatures.1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved Sept. 1, 2016. Published S
14、eptember 2016. Originallyapproved in 1949. Last previous edition approved in 2010 as D1043 - 10. DOI:10.1520/D1043-16.2For 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 t
15、o the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.*A Summary of Changes section appears at the end of this
16、 standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. 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 spec
17、imen and itsspan. A schematic diagram of a suitable machine is shown inFig. 1.NOTE 2Two 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
18、 machines also allow varying the span, which is especiallyimportant if shearing failures can occur (as in laminates at a span/width of6).NOTE 3It 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 purpos
19、e. 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 tochange, and therefore periodic calibration is necessary to ensure reliabletest results. Testing machine cali
20、bration procedures are given in AnnexA2and Annex A3.NOTE 4For operation at low temperatures the shaft of the machinemust be provided with a heated collar next to the lower bearing to preventthe formation of ice.5.2 Temperature Control:5.2.1 FlaskA Dewar flask of suitable dimensions.5.2.2 Thermometer
21、A thermometer having the necessarytemperature range and having an accuracy of 61C or better.The bulb or sensing tip shall be located in proximity to the testspecimen.5.2.3 Timer, for controlling load application time.5.2.4 Heat-Transfer MediumFor normal laboratorypurposes, a substance that is liquid
22、 over the desired tempera-ture range shall be used for the heat-transfer medium, providedit has been shown that the liquid does not soften or otherwiseaffect the test specimen.NOTE 5Among the liquids found useful are acetone, ethanol, butanol,methanol, normal hexane, silicone oil, and a mixture of m
23、ethyl phosphateand water in the ratio of 87 to 13 by volume. For temperatures to 70C(94F), a mixture of 50 parts ethanol, 30 parts ethylene glycol, and 20parts water is potentially useful.5.2.5 RefrigerationMeans shall be provided for coolingthe heat-transfer medium. This cooling can be by means of
24、arefrigeration cooling coil built into the instrument and im-mersed in the Dewar flask of heat transfer fluid or by means ofa low temperature chamber in which Dewar flasks of heattransfer liquid are placed to pre-cool before starting the test.NOTE 6For time-efficient low-temperature use of the equip
25、ment,space for cooling enough containers of the heat-transfer medium for adays work is desirable. Depending on the temperature ranges involved,mechanical refrigeration or a dry-ice chest, or both, will be advantageous.5.2.6 HeaterA controlled electric immersion heater in theDewar flask shall be used
26、 in conjunction with an agitator tovary the temperature.5.3 MicrometerA micrometer accurate to within 60.0025mm (60.0001 in.) or better shall be used for measuringspecimen thickness and width.5.4 Modifications to Testing EquipmentThe modificationsdescribed in Annex A4 will increase the accuracy and
27、sensi-tivity of the testing equipment. The modifications are readilyadaptable to several types of test equipment used for testingplastics. Some of the modifications are desirable, but notnecessary, for obtaining meaningful data.6. Test Specimens6.1 GeometryTest specimens shall be of the rectangularg
28、eometry shown in Fig. 2. Cut test specimens fromcompression-molded sheets, extruded sheet, or from parts ofuniform thickness having flat parallel surfaces, or prepare themby injection molding. Care shall be taken to ensure that the testspecimens are isotropic. Where the testing machine permitsvaryin
29、g the span, use a span to width (L/a) ratio of 6 to 8. It isrecommended that spans of 38 to 100 mm (1.5 to 4 in.) be used.These test specimens are acceptable for use for nonrigidmaterials on the low-range machine which has a span (L)of38mm (1.5 in.).6.2 ThicknessThe thickness of the specimen shall r
30、angebetween approximately 1 and 3 mm (0.040 and 0.125 in.). Thisrange normally makes it possible to test materials of widelydifferent stiffnesses.FIG. 1 Torsion Tester FIG. 2 Test SpecimenD1043 1626.3 Duplicate specimens of each material shall be tested.More replications are often needed, especially
31、 for nonhomo-geneous materials. If the results from testing the first twospecimens differ significantly, test a third specimen and discardthe outlier (the value that varies the most from the other two).7. Conditioning7.1 ConditioningCondition the test specimens in accor-dance with Procedure A of Pra
32、ctice D618 unless otherwisespecified by contract or the relevant ASTM material specifica-tion. Temperature and humidity tolerances shall be in accor-dance with Section 7 of Practice D618 unless specifieddifferently by contract or material specification.7.2 Test ConditionsConduct the tests at the sam
33、e tempera-ture and humidity used for conditioning with tolerances inaccordance with Section 7 of Practice D618 unless otherwisespecified by contract or the relevant ASTM material specifica-tion.8. Procedure8.1 Measure the width and thickness of the specimen to onesignificant digit.8.2 Carefully moun
34、t the specimen in the apparatus. Adjustthe clamps so that the specimen is not under compression ortension and is in complete contact with the clamps internalsurfaces.8.3 Place the thermometer in position with its bulb orsensing tip in close proximity to the test specimen.8.4 Fill the Dewar flask wit
35、h the heat-transfer medium. It isacceptable to precool the heat-transfer medium to a tempera-ture lower than the lowest desired test temperature.8.5 Place the flask in position on the instrument, and startthe agitator.8.6 By intermittent use of the immersion heater, bring thebath to the desired test
36、 temperature. This heating can becontrolled by an automatic temperature controller, if theinstrument is so equipped.8.7 Condition the specimen at the test temperature for aminimum of 3 min.8.8 Release the torque pulley. After 5 s note the angulardeflection of the pulley and return the torque pulley
37、to its initialposition. If the reading thus obtained does not fall within therange from 5 to 100 of arc (10 to 100 for nonrigid materials),vary the applied torque in such a way as to produce such areading. If it is necessary to vary the applied torque, waitanother 3 min and repeat the procedure at t
38、he same tempera-ture.NOTE 7In order to obtain measured values of apparent modulus ofrigidity, G, that are comparable to the true value of G, it is desirable thatmeasurements be made within the elastic limit of the material being tested.Therefore, torques shall be chosen that will cause deflections t
39、hat are assmall as practical to measure accurately on the machine being used. It isoften desirable to reduce the torque slightly before taking successivereadings, particularly in the temperature range where the material israpidly decreasing in rigidity.NOTE 8Better reproducibility is obtained if tor
40、ques are chosen suchthat the deflection obtained at a given temperature is similar to or greaterthan that obtained at the previous lower temperature.8.9 After each suitable reading is obtained, repeat the stepsindicated in 8.6 8.8 for the next desired temperature. Ifdesired, it is acceptable to lowe
41、r the torque prior to eachreading (Note 7 and Note 8).9. Calculation9.1 Calculate the apparent modulus of rigidity, G, for eachtemperature as follows:G 5 917TL/ab3u (1)where:G = apparent modulus of rigidity, Pa (or psi),T = applied torque, Nm (or in.lbf),L = specimen length (span), mm (or in.),a = s
42、pecimen width (larger cross-sectional dimension), mm(or in.),b = specimen thickness (smaller cross-sectional dimension),mm (or in.), = angle of deflection of torque pulley, degrees, andu = value depending on the ratio of a to b. Table 1 gives thevalues of u for various ratios of a to b. A third colu
43、mngives thickness if the width is 6.350 mm (0.250 in.). IfTable 1 is not adequate, calculate u by means of theequation given in Annex A1.9.2 Plot the apparent modulus of rigidity values, calculatedin accordance with 9.1, on a logarithmic scale versus tempera-ture on a linear scale.9.3 CalculationSpe
44、cific Modulus of Rigidity9.3.1 Graphic MethodIf desired, read from the graph thetemperature at which the apparent modulus of rigidity is equalto a specific value, such as 68.95 MPa, 241.3 MPa, 310.3 MPa,or 930.8 MPa (10 000 psi, 35 000 psi, 45 000 psi, or 135 000psi). The temperature at which the ap
45、parent modulus of rigidityis equal to 310 MPa (45 000 psi) has been designated TF(seeNote A1.1).9.3.2 Interpolation MethodIf the increments of tempera-ture change used in the test are relatively small (for exampleabout 3C or 5F), it is often possible to interpolate betweentest points to determine th
46、e temperature for a specific apparentmodulus of rigidity, such as 310.3 MPa (45,000 psi).TABLE 1 Values for uARatio ofWidth, a,toThickness, buThickness when Width is6.350 mm (0.250 in.)2.00 3.66 3.175 mm (0.125 in.)2.25 3.84 2.819 mm (0.111 in.)2.50 3.99 2.540 mm (0.100 in.)2.75 4.11 2.311 mm (0.091
47、 in.)3.00 4.21 2.108 mm (0.083 in.)3.50 4.37 1.829 mm (0.072 in.)4.00 4.49 1.600 mm (0.063 in.)4.50 4.59 1.422 mm (0.056 in.)5.00 4.66 1.270 mm (0.050 in.)6.00 4.77 1.067 mm (0.042 in.)7.00 4.85 0.914 mm (0.036 in.)ATaken from Trayer and March, Report 334, National Advisory Committee forAeronautics,
48、 1929.D1043 1639.3.2.1 Locate the apparent modulus of rigidity above andbelow the desired modulus of rigidity and within 634.5 MPa(65000 psi ).Calculate the temperature (TSp) for the specific modulus ofrigidity using the equation:TSp5 T11T22 T1! 3 logGT12 logspecific modulus of rigidity!logGT12 logG
49、T2!(2)For TF, the equation is:TF5 T11T22 T1! 3 logGT12 log45000!logGT12 logGT2!(3)where:T1= lower of the two test temperatures,T2= higher of the two test temperatures,GT1= apparent modulus of rigidity at temperature T1, psi,andGT2= apparent modulus of rigidity at temperature T2, psi.10. Report10.1 Report the following information:10.1.1 Complete identification of the material, includingname, stock or code number, date made, form, etc.,10.1.2 Dimensions of the test specimen,10.1.3 Details of conditioning the specimen prior to
