1、Designation: D1043 10Standard 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 Department of Defense.1. Scope*1.1 This test metho
3、d 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 standa
4、rd 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 ISO
5、 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
6、 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
7、 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 elasti
8、city, 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.
9、 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
10、 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
11、 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 ca
12、pable 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 range of
13、 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 acceptable to var
14、y 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 shaft1This test method is under the jurisdiction of
15、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 sta
16、ndards, 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM Int
17、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.bearings 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 g
18、iven inAnnexA2and 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
19、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 laboratory pur-poses, a substance that is liquid over the desired tempe
20、raturerange 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
21、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 arefrigeration cooling co
22、il 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 equipment,space for cooling en
23、ough 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 in conjunction with an a
24、gitator tovary 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 testi
25、ng equipment. 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.
26、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 permitsvarying the span, use a span to
27、 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 rangebetween approximately
28、 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 materials. If the results from testing the first twospe
29、cimens 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 Practice D618 unless otherwisespecified by contract or the relevant ASTM materi
30、al 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 same tempera-ture and humidity used for conditioning with tolerances inaccordan
31、ce with Section 7 of Practice D618 unless otherwisespecified by contract or the relevant ASTM material specifica-tion.FIG. 1 Torsion TesterFIG. 2 Test SpecimenD1043 1028. Procedure8.1 Measure the width and thickness of the specimen to onesignificant digit.8.2 Carefully mount the specimen in the appa
32、ratus. 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 with the heat-transfer medium
33、. 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 temperature. This heating
34、 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 to its initialposition. If
35、 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 the same tempera-ture.NOTE
36、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 that are assmall as practic
37、al 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 torques are chosen suchthat t
38、he 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. If desired,it is acceptable to lower the torque prior to each
39、 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 = applied torque, Nm (or in.lbf),L = specimen length (span), mm (or in.),a = specimen width (larger cro
40、ss-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 b. Table 1 gives thevalues of u for various ratios of a to b. A third columngives thickness if t
41、he 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 logarithmic scale versus tempera-ture on a linear scale.9.3 CalculationSpecific Modulus of Rigidi
42、ty9.3.1 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 apparent modulus of rigid
43、ityis 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 the temperature for a spe
44、cific 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 the temperature (TSp) for the specific modulus ofrigidity using the equation:TSp5 T11T2 T1! 3 lo
45、g 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 test temperatures,GT1= apparent modulus of rigidity at temperature T1, psi,andGT2= apparent modulu
46、s 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 testing,10.1.4 I
47、dentification 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 9.3.1), and10.1.8 Date of test.11. Precision and Bias
48、11.1 Limited precision information is available from onelaboratory testing a flexible vinyl material (plasticized PVC) todetermine the temperature at which the apparent modulus ofD1043 103rigidity, G, is equal to 241.3 MPa (35,000 psi). Based on thisdata, the repeatability r is approximately 62C for
49、 a materialwith a mean value of 35.7C (r = 2.83 3 standard deviation,see Practice E177).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 thickness, mm (or in.).A1.2 Calculation of Apparent Modulus of ElasticityA1.2.1 The relationship betwe
