1、Designation: D 1043 09Standard 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 () 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 met
3、hod 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 stan
4、dard 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 and I
5、SO 458-1 and ISO 458-2 address thesame subject matter, but differ in technical content.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 638 Test Method for Tensile Properties of PlasticsD 747 Test Method for Apparent Bending Modulus ofPlastics by Means
6、 of a Cantilever BeamD 883 Terminology Relating to PlasticsD 1053 Test Methods for Rubber PropertyStiffening atLow Temperatures: Flexible Polymers and Coated FabricsD 4000 Classification System for Specifying Plastic Mate-rials3. Terminology3.1 DefinitionsFor definitions of the technical terms per-t
7、aining to plastics used in this test method, see TerminologyD 883.4. 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
8、 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
9、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 characte
10、ristics 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 advis
11、able to refer to that materialspecification before using this test method. Table 1 in Classi-fication D 4000 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 ma
12、chine 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.NOTE 2Two machines of different torque capacities are being used:one covers the
13、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).NOTE 3It is acceptabl
14、e 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 being1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of
15、Subcommittee D20.10 on Mechanical Properties.Current edition approved Sept. 1, 2009. Published September 2009. Originallyapproved in 1949. Last previous edition approved in 2002 as D 1043 - 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
16、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.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, U
17、nited States.applied 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 calibration procedures are given inAn
18、nexA2and 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 ThermometerA thermometer having the necessary
19、temperature 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 laboratory pur-poses, a substance that is liquid over the desired temperatureran
20、ge 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 hexane, silicone oil, and a mixture of methyl phosphateand water in the ra
21、tio 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 arefrigeration cooling coil built
22、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 equipment,space for cooling enough cont
23、ainers 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 in conjunction with an agitator t
24、ovary the temperature.5.3 MicrometerAmicrometer 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 Annex A4 will increase the accuracy andsensitivity of the testing equipm
25、ent. The modifications arereadily adaptable to several types of test equipment used fortesting plastics. Some of the modifications are desirable, butnot necessary, for obtaining meaningful data.6. Test Specimens6.1 GeometryTest specimens shall be of the rectangulargeometry shown in Fig. 2. Cut test
26、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 permitsvarying the span, use a span to width (L
27、/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 rangebetween approximately 1 and 3
28、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 materials. If the results from testing the first twospecimens di
29、ffer 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 at 23 62C (73.4 6 3.6F) and 50 6 10 % relative humidity for notless than 40 h prior to test in accordance with Procedure A
30、ofPractice D 618 unless otherwise specified by contract or therelevant ASTM material specification. Reference pre-test con-ditioning, to settle disagreements, shall apply tolerances of61C (1.8F) and 65 % relative humidity.7.2 Test ConditionsConduct the tests at 23 6 2C (73.4 63.6F) and 50 6 10 % rel
31、ative 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) and 65 % relativehumidity.FIG. 1 Torsion TesterFIG. 2 Test SpecimenD10430928. Procedure8.1 Measure the width a
32、nd thickness of the specimen to onesignificant digit.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 internalsurfaces.8.3 Place the thermometer in position with its bulb orsensing t
33、ip in close proximity to the test specimen.8.4 Fill the Dewar flask with 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 inte
34、rmittent 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 aminimum of 3 min.8.8 Release the torque pulley. After 5 s
35、 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 (10 to 100 for nonrigid materials),vary the applied torque in such a way as to produce such areading. If it is necessary to v
36、ary the applied torque, waitanother 3 min and repeat the procedure at the 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
37、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 successivereadings, particularly in the temperature range where the material israpidly
38、 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 temperature.8.9 After each suitable reading is obtained, repeat the stepsindicated in 8.6-8.
39、8 for the next desired temperature. If desired,it is acceptable to lower the torque prior to each reading (Note7 and Note 8).9. Calculation9.1 Calculate the apparent modulus of rigidity, G, for eachtemperature as follows:G 5 917TL/ab3uf (1)where:G = apparent modulus of rigidity, Pa (or psi),T = appl
40、ied 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 deflection of torque pulley, degrees, andu = value depending on the ratio of a to
41、 b. Table 1 gives thevalues of u for various ratios of a to b. A third columngives thickness if the width is 6.350 mm (0.250 in.). IfTable 1 is not adequate, calculateu by means of theequation given in Annex A1.9.2 Plot the apparent modulus of rigidity values, calculatedin accordance with 9.1, on a
42、logarithmic scale versus tempera-ture on a linear scale.9.3 CalculationSpecific 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 ps
43、i, 35 000 psi, 45 000 psi, or 135 000psi). The temperature at which the apparent 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 5
44、F), it is often possible to interpolate betweentest points to determine the temperature for a specific apparentmodulus of rigidity, such as 310.3 MPa (45,000 psi).9.3.2.1 Locate the apparent modulus of rigidity above andbelow the desired modulus of rigidity and within 634.5 MPa(65000 psi ).Calculate
45、 the temperature (TSp) for the specific modulus ofrigidity using the equation:TSp5 T11T2 T1! 3 log GT1 log specific modulus of rigidity!log GT1 log GT2!(2)For TF, the equation is:TF5 T11T2 T1! 3 log GT1 log 45000!log GT1 log GT2!(3)where:T1= lower of the two test temperatures,T2= higher of the two t
46、est 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 Dime
47、nsions of the test specimen,10.1.3 Details of conditioning the 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
48、 modulus ofrigidity values, if desired (see 9.3.1), 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 ofD1043093rigidity, G, is
49、equal to 241.3 MPa (35,000 psi). Based on thisdata, the repeatability r is approximately 62C for a materialwith a mean value of 35.7C (r = 2.83 3 standard deviation,see Practice E 177).12. Keywords12.1 Clash-Berg; modulus of rigidity; plastics; shear;torsionANNEXESA1. CALCULATIONSA1.1 Calculation of Factor uA1.1.1 One method to calculate the factor u by the follow-ing equation:u 5 5.33 2 3.36 b/a!1 2 b4/12a4!# (A1.1)where:u = factor depending on the ratio of a to b,a = specimen width, mm (or in.), andb = specimen
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