1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1998 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001RECOMMENDEDPRACTICEJ1183REV.FEB1998Issued 1978-11Revised 1998-02Supersed
4、ing J1183 MAY97Recommended Guidelines for Fatigue Testing of Elastomeric Materials and ComponentsForewordThese guidelines describe:a. A set of definitions and terminology to allow interchange of information on a common basis. (Section3)b. The manner in which elastomeric materials and components unde
5、rgo changes due to stresses and/orstrains in a fatigue environment that ultimately culminate in failure. (Sections 4 and 5)c. Factors to be considered in selecting from available test methods or in developing a test method tomeet specific requirements. (Sections 6 through 10)d. Important considerati
6、ons in the evaluation and reporting of test information. (Section 11)1. ScopeThe purpose of this SAE Recommended Practice is to review factors that influence the behavior ofelastomers under conditions of dynamic stress and to provide guidance concerning laboratory procedures fordetermining the fatig
7、ue characteristics of elastomeric materials and fabricated elastomeric components.2. References2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 SAE
8、 PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J1085Test for Dynamic Properties of Elastomeric IsolatorsSAE J1883Elastomeric Bushing “TRAC” Application CodeSAE Fatigue Design Handbook, Third Edition, 19972.1.2 ASTM PUBLICATIONSAvailable from ASTM, 100 Barr Har
9、bor Drive, West Conshohocken, PA 19428-2959.ASTMD429-81Test Methods for Rubber PropertyAdhesion to Rigid SubstratesASTMD430-95Test Methods for Rubber DeteriorationDynamic FatigueASTMD623-93Test Methods for Rubber PropertyHeat Generation and Flexing Fatigue inCompressionASTM D 813-95Test Method for R
10、ubber DeteriorationCrack GrowthASTMD1052-85Test Method for Measuring Rubber DeteriorationCut Growth Using Ross FlexingApparatusASTMD1149-91Test Method for Rubber DeteriorationSurface Ozone Cracking in a ChamberCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSA
11、E J1183 Revised FEB1998-2-2.1.3 OTHER PUBLICATIONS1. P. W. Allen, P. B. Lindley, and A. R. Payne, “Use of Rubber in Engineering,“ London: Maclaren andSons, Ltd., 1967, pp. 60-71.2. Anonymous, “Fatigue Failure and Its Reduction in Natural Rubber.“ Akron: Monsanto TechnicalBulletin O/RC-7.3. Anonymous
12、, “Fatigue to Failure Tester.“ Akron: Monsanto Literature with attachments.4. A. B. Davey and A. R. Payne, “Rubber in Engineering Practice.“ New York: Palmerton Publishers,1964.5. McPherson and Klemin, “Engineering Uses of Rubber.“ New York: Rheinhold, 1956. pp. 132-134, 139,165-167, 170.6. A. R. Pa
13、yne and J. R. Scott, “Engineering Design with Rubber,“ New York Interscience Publishers, Inc.,1960, pp. 104-106.7. J. R. Scott, “Physical Testing of Rubber,“ New York: Palmerton Publishing Co. 1965 pp. 129-113.8. SAE Fatigue Design Handbook, Vol. 4, 1968.9. Charles R. Hicks, “Fundamental Concepts in
14、 the Design of Experiments,“ New York: Holt, Rinehartand Winston, 1964.10. Bernard Ostle, “Statistics in Research,“ Iowa State University Press, 1964.11. United States Department of Commerce, “Experimental Statistics,“ Washington, D.C.: U.S.Government Printing Office (1963).12. “ASTM Rubber Products
15、, Industrial Specifications and Related Test Methods; Carbon Black; Gaskets;Tires.“ Annual Book of ASTM Standards, Part 37, 1976.13. “Websters New Collegiate Dictionary,“ Springfield: G while at other frequencies, damping energy is absorbed by the elastomer. Thus the life ofthe components elastomeri
16、c material can be highly frequency dependent as well as load dependent.6.2.1.5 Waveform of Dynamic ExcitationThe type of waveform excitation, i.e., sinusoidal, random, continuous orintermittent, should be specified. Alternatively, real-time dynamic loads may also be specified if road loaddata has be
17、en measured and test equipment is available to reproduce the measured loads.6.2.2 PART TEMPERATUREElastomers are functional over a rather narrow temperature range compared to othermaterials such as metals. Further, each component of a given elastomer has its own temperature rangewhere it is function
18、al. Within that functional range will lie a band of temperatures at which maximum fatiguelife is obtained. It is not unusual for fatigue life to change by a factor of two or more over a 20 C change intemperature near the boundaries of that band. Therefore, the temperature specified should berepresen
19、tative of service conditions, and part temperature should be controlled throughout the test.6.2.2.1 Definition of Part TemperatureSince rubber is a poor heat conductor, thick parts will usually have largetemperature gradients. Measurements should, therefore, be made by placing the temperature sensin
20、gelement as close to the area of heat generation as possible. The location chosen and the type oftemperature measurement should be carefully defined and consistently adhered to.6.2.2.2 Part Temperature ControlPart temperature is a function of ambient temperature, hysteresis of thespecimen, energy in
21、put, external friction, and heat dissipation off the surface of the part.Ambient temperature control is necessary. First, it is recommended that the part and associated fixturingbe allowed to reach equilibrium with the environment before starting the test. Guidelines for achieving thisare given in t
22、he Appendix to SAE J1085 for elevated temperature testing. For elevated temperaturetesting, it is suggested that the part be enclosed in an air circulating heat chamber. At moderatetemperatures, circulation of air over the specimen is commonly used to control part temperature. It shouldbe recognized
23、, however, that in some situations this may lower specimen surface temperature but have arelatively small effect on temperature within the specimen. Air cooling magnifies the ability of any fixturingin contact with the specimen to conduct heat out of the specimen (i.e., to behave as a heat sink) so
24、caremust be taken to ensure consistency in fixture contact area, shape, and mass. In cases where correlationbetween test facilities is necessary, air cooling may be undesirable as another source of variability.Internal heat generation due to the combination of hysteresis and energy input should not
25、cause the part toexceed the desired test temperature. Hysteresis in elastomers will cause an increase in componenttemperature which will be proportional to frequency and/or amplitude test conditions. This sometimesmakes it necessary to adjust test conditions when elastomers of different hysteresis l
26、evels are tested. Inmost cases, it is desirable to design the test in such a way that a significant portion of the testing takesplace after the part temperature has stabilized.Sometimes elastomer hysteresis is falsely blamed for high specimen temperature when the source heat isactually friction due
27、to slip between elastomer and metal components and/or test fixtures. When this is thecase, and the elastomer has low hysteresis, reducing the test amplitude and/or load and increasingfrequency will sometimes reduce temperature without adding significantly to test time.6.2.3 OTHER PARAMETERS6.2.3.1 O
28、zone ConcentrationSome elastomers are inherently ozone resistant so that ozone has little effect ontheir fatigue life. Other elastomers are not ozone resistant and must be chemically protected to preventozone cracking in stressed areas. Ozone cracking results in shortened flex life, particularly so
29、forspecimens with a high ratio of exposure surface to mass. Ozone crack rate increases with stress level andtemperature.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1183 Revised FEB1998-8-It is desirable to avoid uncontrolled and excessive ozone concen
30、trations as can be found in close proximityto electrical discharges or some motors. In critical situations, ozone concentration should be measuredand reported in test conditions. ASTMD1149 (see 2.1.3 12) describes ozone concentrationmeasurement.The antiozonants used in many elastomer compositions mu
31、st migrate to the surface of the specimenbefore they become fully effective. Testing of recently molded specimens should not be conducted beforeprotective agents have migrated to the surface. Usually, 24 h is the minimum time for migration.6.2.3.2 OxidationThe reaction of oxygen (oxidation) with man
32、y elastomers can initiate crack formation as well asresult in hardening or softening. At temperatures higher than room temperature, the effect of oxygen isaccelerated. Test specimens should not be stored for long time periods at elevated temperatures unlessthis is a necessary and controlled part of
33、the test requirement.6.2.3.3 Deleterious Fluids and GasesNo elastomer is resistant to all fluids and gases. Oils, oil vapor, andsolvents can seriously degrade non-resistant elastomers. Water, steam, coolants, acids, and alkalis in fluidor vapor form can reduce specimen fatigue life. The atmosphere s
34、urrounding the test specimen should befree of deleterious fluids and gases unless they are a necessary and controlled part of the testrequirement.6.2.4 ACCELERATION METHODSTable 1 describes examples of acceleration methods and possible affects theymay have on the test and/or specimen.An elevated tem
35、perature presoak may be used to condition the component. This serves to acceleratetesting.A cut may be used to initiate the crack before the start of the test. TABLE 1ACCELERATION METHODSMethod of Acceleration Possible Effects on Test and SpecimenIncrease static load or displacement Increase or decr
36、ease in cycles to failure (depending upon the load applied and the load-deflection characterisistics of the part).Failure by splitting and tearing (tensile failure) rather than by abrasive wear or fatigue cracking.Failure due to pinching (see definitions).Increased bulge area (compression).Decreased
37、 cross-sectional area (tension).Increased creep.Slip between specimen and fixturing.More data scatter (hardness sensitivity).Increase dynamic load or displacement Decrease in cycles to failure.Increase in temperature due to hysteresis.Increase in temperature due to slip between specimen and fixturin
38、g.Decrease in modulus.Tensile failure rather than abrasive wear or fatigue cracking.Increased bulge area (compression).Decreased cross-sectional area (tension).More data scatter (hardness sensitivity).Increase frequency of dynamic load or displacementIncreased heat generation per unit time.Change fr
39、om mechanical to chemical failure.Change in load or displacement waveform.Change in dynamic response of specimen.Increase or decrease in cycles to failure.Increase ambient temperature (Presoak) Increased specimen temperature.Decrease in modulus.Change in cycles to failure.Change in dynamic response
40、of specimen.Change in mode of failure.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1183 Revised FEB1998-9-6.2.4.1 Effects of AccelerationAcceleration can introduce obvious or subtle factors that affect the test bychanging the point of failure initiatio
41、n, final location failure, propagation, and major cause of failure. Thiscan be misleading when materials for end use are chosen based on results of such a test. 7. Proper Test Procedures7.1 Application of ParametersMethods of applying static and dynamic deformation must be studied carefully toensure
42、 that only the intended parameter is applied to the specimen. Most methods have inherentcharacteristics resulting from mass, friction, geometry, compliance, misalignment, and nonlinearity which mayaffect the parameter being applied. Through design, many of these undesirable effects can be reduced to
43、 anacceptable level.7.2 Property MeasurementSince the properties of different elastomeric specimens in a fatigue environmentchange differently, it is desirable to measure as many of these changes as possible. The instrumentationrequired will depend on the nature and purpose of the test, i.e., a mate
44、rial evaluation would call for moredetailed data than a quality control test. In all cases, however, the instrumentation must be adequate toobserve both:a. Changes corresponding to those that adversely affect performance in the intended application andwhich, therefore, qualify as criteria for failur
45、e.b. Changes which can affect the severity of the test, obscure the point of failure, or affect the mode offailure, thereby giving misleading results. Stress relaxation, set, and excessive heat buildup due toaccelerated test conditions are examples of such changes.7.2.1 Temperature influences all of
46、 the failure definitions previously mentioned. One common situation concernsperiodic evaluation of some physical property during fatigue testing. The specimen will heat up duringtesting due to internal heat generation. Consequently, when the periodic test is run, the specimen must beallowed to cool
47、down or the initial property must be run at this elevated temperature. This is especiallyimportant when running low ambient temperature tests.Tables 2a and 2b show changes that can be anticipated and examples of the types of instrumentation thatcan be used to detect them.7.3 InstrumentationProper in
48、strumentation is a good aid to accuracy in that error can be seen in the parametermeasurement and, if recognized as such, and the source of error identified, be corrected. In measuringdisplacement, direct specimen deflection measurement is recommended rather than that of a test machinecomponent atta
49、ched to the specimen. In measuring loads, a load measuring device located in series betweenthe specimen and the loading mechanism is recommended.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1183 Revised FEB1998-10-TABLE 2AINSTRUMENTATION TO DETECT PHYSICAL CHANGES IN TEST SPECIMENChange in Specimen Method of Observation NotesAbrasive wear Weight change May be dry or tacky depending on polymer type and formulation.Amplitude of vibration under fixed force inputLVDT(1), velocity transducer (integrated), accele
