1、Designation: D 1043 02Standard Test Method forStiffness Properties of Plastics as a Function ofTemperature by Means of a Torsion Test1This standard is issued under the fixed designation D 1043; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope *1.1 This test m
3、ethod 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 st
4、andard 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 is
5、not equivalent to ISO 458/1:1985 or ISO458/2:1985 and results cannot be directly compared between the twomethods.2. Referenced Documents2.1 ASTM Standards:D 618 Practice for Conditioning Plastics for Testing2D 638 Test Method for Tensile Properties of Plastics2D 747 Test Method for Apparent Bending
6、Modulus ofPlastics by Means of a Cantilever Beam2D 883 Terminology Relating to Plastics2D 1053 Test Method for Rubber PropertyStiffening atLow Temperatures: Flexible Polymers and Coated Fab-rics3D 4000 Classification System for Specifying Plastic Mate-rials4D 4066 Classification System for Nylon Inj
7、ection and Ex-trusion Materials4D 4805 Terminology for Plastics Standards53. Terminology3.1 DefinitionsFor definitions of the technical terms per-taining to plastics used in this test method, see TerminologyD 883 or Terminology D 4805.4. Significance and Use4.1 The property measured by this test is
8、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
9、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 the specimen may be deflected beyond itselastic limit, the calculated value may not represent the truemodulus of rigi
10、dity within the elastic limit of the material. Inaddition, the value obtained by this test method will also beaffected by the creep characteristics of the material, since theload application time is arbitrarily fixed. For many materials,there may be a specification that requires the use of this test
11、method, but with some procedural modifications that takeprecedence when adhering to the specification. Therefore, it isadvisable to refer to that material specification before using thistest method. Table 1 in Classification D 4000 lists the currentASTM materials standards.4.3 This test method is us
12、eful 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 diagr
13、am 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)1This test method is under the jurisdiction of AST
14、M Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved April 10, 2002. Published June 2002. Originallypublished as D 1043 49. Last previous edition D 1043 99.2Annual Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM S
15、tandards, Vol 09.01.4Annual Book of ASTM Standards, Vol 08.02.5Annual Book of ASTM Standards, Vol 08.03.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.or higher. Some
16、 machines also allow varying the span, which is especiallyimportant if shearing failures can occur (as in laminates at a span/width of6).NOTE 3The amount of torque may be varied to suit the stiffness of thetest specimen, and various weights should be available for this purpose.The actual amount of t
17、orque being applied by any given combination ofweights, torque wheel radii, and shaft bearings should be determined bycalibration. The accuracy of the apparatus can be subject to change, andtherefore periodic calibration is necessary to ensure reliable test results.Testing machine calibration proced
18、ures are given in Annex A2 and AnnexA3.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 ThermometerA thermometer
19、 graduated in 1C divi-sions and having the necessary range. The bulb shall be locatedin close proximity to the test specimen. A digitalreadout RTDthermometer having an accuracy of 6 1C or better may beused.5.2.3 Timer, for controlling load application time.5.2.4 Heat-Transfer MediumFor normal labora
20、tory pur-poses, a substance that is liquid over the desired temperaturerange shall be used for the heat-transfer medium, provided ithas 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
21、hexane, silicone oil, and a mixture of methyl 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 may be found useful.5.2.5 RefrigerationMeans shall be provided for coolingthe heat-transfer me
22、dium. This cooling can be by means of 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-effi
23、cient low-temperature use of the equipment,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
24、heater in theDewar flask shall be used 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 Equipment The modifica-tions described in
25、 Annex A4 will increase the accuracy andsensitivity of the testing equipment. The modifications arereadily adaptable to several types of test equipment used fortesting plastics. Some of the modifications are desirable, butnot a necessity, for obtaining meaningful data.6. Test Specimens6.1 GeometryTe
26、st specimens shall be of the rectangulargeometry shown in Fig. 2. They may be cut from compression-molded sheets, extruded sheet, or from parts of uniformthickness having flat parallel surfaces. The specimens may alsobe injection molded. Care shall be taken to ensure that the testspecimens are isotr
27、opic. Where the testing machine permitsvarying the span, the span to width (L/a) ratio should be 6 to 8.It is recommended that spans of 38 to 100 mm (1.5 to 4 in.) beused. The specimen may be used for nonrigid materials on thelow-range machine which has a span (L) of 38 mm (1.5 in.).6.2 ThicknessThe
28、 thickness of the specimen may varybetween approximately 1 and 3 mm (0.040 and 0.125 in.). Thisrange normally makes it possible to test materials of widelydifferent stiffnesses.6.3 Duplicate specimens of each material shall be tested.More replications are often needed, especially for nonhomo-geneous
29、 materials. If the results from testing the first twospecimens differ significantly, test a third specimen and discardthe outlier (the valve that varies the most from the other two).7. Conditioning7.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 5 % relative humidity for
30、 not lessthan 40 h prior to test in accordance with Procedure A ofPractice D 618 unless otherwise specified by contract or theFIG. 1 Torsion TesterFIG. 2 Test SpecimenD1043022relevant ASTM material specification. Reference pre-test con-ditioning, to settle disagreements, shall apply tolerances of61C
31、 (1.8F) and 62 % relative humidity.7.2 Test ConditionsConduct the tests at 23 6 2C (73.4 63.6F) and 50 6 5 % relative humidity unless otherwisespecified by contract or the relevant ASTM material specifica-tion. Reference testing conditions, to settle disagreements,shall apply tolerances of 61C (1.8F
32、) and 62 % relativehumidity.8. Procedure8.1 Measure the width and thickness of the specimen tothree significant digits.8.2 Carefully mount the specimen in the apparatus. Adjustthe clamps so that the specimen is not under compression ortension and is in complete contact with the clamps internalsurfac
33、es.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 with the heat-transfer medium. Theheat-transfer medium may be precooled to a temperature lowerthan the lowest desired test temperature.8.5 Place the flask in position
34、 on the instrument, and startthe agitator.8.6 By intermittent use of the immersion heater, bring thebath to the desired test 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 amini
35、mum of 3 min.8.8 Release the torque pulley. After 5 s note the angulardeflection of the pulley and return the torque pulley to its initialposition. If the reading thus obtained does not fall within therange from 5 to 100 of arc, vary the applied torque in such away as to produce such a reading. For
36、nonrigid materials, thisreading should fall between 10 and 100. If it necessary to varythe applied torque, wait another 3 min. and repeat the proce-dure at the same temperature.NOTE 7In order to obtain measured values of apparent modulus ofrigidity, G, that are comparable to the true value of G, it
37、is desirable thatmeasurements be made within the elastic limit of the material being tested.Therefore, torques shall be chosen that will cause deflections that are assmall as practical to measure accurately on the machine being used. It isoften desirable to reduce the torque slightly before taking s
38、uccessivereadings, particularly in the temperature range where the material israpidly decreasing in rigidity.NOTE 8Better reproducibility is obtained if torques are chosen suchthat the deflection obtained at a given temperature is similar to or greaterthan that obtained at the previous lower tempera
39、ture.8.9 After each suitable reading is obtained, repeat the stepsindicated in 8.6-8.8 for the next desired temperature. Thetorque may be lowered prior to each reading, if desired (Note7 and Note 8).9. Calculation9.1 Calculate the apparent modulus of rigidity, G, for eachtemperature as follows:G 5 9
40、17TL/ab3uf (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 = specimen width (larger cross-sectional dimension),mm (or in.),b = specimen thickness (smaller cross-sectional dimen-sion), mm (or in.),f = angle of deflect
41、ion of torque pulley, degrees, andu = value depending on the ratio of a to b. Table 1 givesthe values of u for various ratios of a to b. A thirdcolumn gives thickness if the width is 6.350 mm(0.250 in.). If Table 1 is not adequate, u may becalculated by means of the equation given in AnnexA1.9.2 Plo
42、t the apparent modulus of rigidity values, calculatedin accordance with 9.1, on a logarithmic scale versus tempera-ture on a linear scale.9.3 If desired, read from the graph the temperature at whichthe apparent modulus of rigidity is equal to a specific value,such as 68.95 MPa, 241.3 MPa, 310.3 MPa,
43、 or 930.8 MPa (10000 psi, 35 000 psi, 45 000 psi, or 135 000 psi). Thetemperature at which the apparent modulus of rigidity is equalto 310 MPa (45 000 psi) has been designated TF(see NoteA1.1).NOTE 9If the increments of temperature change used in the test arerelatively small (for example about 3C or
44、 5F) it may be possible tointerpolate between test points to determine the temperature for a specificapparent modulus of rigidity, such as 310.3 MPa or 45 000 psi. However,this interpolation should be done on a semi-log basis to be approximatelyequivalent to the results of the semi-log plot. That is
45、, the log of themodulus must be used to interpolate between the test temperatures, usingthe following formula, which is an example for interpolating to determinethe TF(310 MPa or 45 000 psi).TF5 T11T2 T1! X log GT1 log 45000!log GT1 log GT2!(2)where:T1= lower of the two test temperatures,T2= higher
46、of the two test temperatures,GT1= apparent modulus of rigidity at temperature T1, psi,andGT2= apparent modulus of rigidity at temperature T2, 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
47、.)2.50 3.99 2.540 mm (0.100 in.)2.75 4.11 2.311 mm (0.091 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
48、, Report 334, National Advisory Committee forAeronautics, 1929.D104302310. 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
49、specimen prior to testing,10.1.4 Identification of the heat transfer medium used,10.1.5 Table of data and results,10.1.6 Plot of logarithm of apparent modulus of rigidityversus temperature,10.1.7 The temperature at the specified apparent modulus ofrigidity values, if desired (see 9.3), and10.1.8 Date of test.11. Precision and Bias11.1 Limited precision information is available from onelaboratory testing a flexible vinyl material (plasticized PVC) todetermine the temperature at which the apparent modulus ofrigidity, G, is equal
