SAE J 1085-1999 Testing Dynamic Properties of Elastomeric Isolators《弹性隔离器的动态特性测试》.pdf

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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 1999 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001RECOMMENDEDPRACTICESubmitted for recognition as an American National Sta

4、ndardJ1085REV.MAY1999Issued 1971-09Revised 1999-05Superseding J1085 NOV95Testing Dynamic Properties of Elastomeric Isolators1. ScopeThese methods cover testing procedures for defining and specifying the dynamic characteristics ofsimple elastomers and simple fabricated elastomeric isolators used in v

5、ehicle components. Simple, here, isdefined as solid (non-hydraulic) components tested at frequencies less than or equal to 25 Hz.2. References2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein.2.1.1 ASTM PUBLICATIONSAvailable from AS

6、TM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTMD1349Recommended Practice for RubberStandard Temperatures and Atmospheres forTesting and ConditioningASTMD2231Recommended Practice for Rubber Properties in Forced VibrationASTMD2234Method for Collection of a Gross Sample of CoalASTM E 1

7、77Practice for Use of the Terms Precision and Bias in ASTM Test Methods2.1.2 RAPRA PUBLICATIONSAvailable from RAPRA Technology Ltd., Shawberry, Shrewsberry, ShrapshireSY44NR, U.K.D. Hands, “Simple Methods for Heat Flow Calculations,” RAPRA Technical Review No. 60, Class No. 96,July 1971Marion D. Tho

8、mpson, “Cooling Rubber Slabs,” RAPRA Bulletin, May 19722.1.3 OTHER PUBLICATIONSS. D. Gehman, “Heat Transfer in Processing and Use of Rubber,” Rubber Chem. the recommended height is 25.4 mm(1.0in).6.1.2 The preferred shape factor for comparing elastomer properties is 0.5 where:(Eq. 6)6.1.3 The prefer

9、red shape is a right circular cylinder with faces parallel within 0.001 mm/mm or 0.001 in/in.6.1.4 TEST INTERFACEFor best reproducibility, the sample mentioned in 6.1.2 should have metal plates bondedto both faces during vulcanization.6.1.5 OPTIONAL-TEST INTERFACEThe test machine will be equipped wi

10、th loading plates top and bottom ofsufficient area to support the loaded specimen. The specimen will be held in place with 300 grit sandpaper,securely bonded to both loading plates. The sandpaper prevents specimen lateral movement and aids inbulge control. The two plates exciting the specimen shall

11、be parallel within 0.001 mm/mm (0.001 in/in) ofplaten length in neutral position. Plate parallelism will be within tolerances on orthogonal lines.Shape factor area of one loaded facearea free to bulge-=COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085

12、Revised MAY1999-7-6.2 Standard Shear SpecimensShear specimens shall comply with ASTM D 2234 for general configuration.Dimensions may be adjusted to provide required spring rates. Supporting fixtures should be sufficiently rigid tomaintain parallelism of all plates.6.3 Fabricated Mountings or Bushing

13、sThe following considerations shall apply when fabricated mountings orbushings are tested:6.3.1 Supporting fixtures shall be designed to restrain lateral movement of the top or bottom surfaces of themounting as a result of forces applied in the test direction.6.3.2 It shall be carefully determined t

14、hat any lateral forces which may develop as a result of forces applied in thetest direction do not influence the test readings.6.4 Standard specimens to be tested must be clearly marked for identification.6.5 Standard specimens used for standardizing test machines shall be aged no less than one mont

15、h and shall beaccepted only after repetitive testing indicates that dynamic properties have stabilized.7. Preferred Test ApparatusForced Nonresonant System7.1 General DescriptionA forced nonresonant system is comprised of a drive mechanism which forces thespecimen through a desired sinusoidal load,

16、displacement, or energy. The desired frequency and amplitude ofthe test are not affected by the specimens dynamic response; therefore, test conditions may be quite easilychanged.7.1.1 THEORYIn a forced nonresonant system, the sample is excited with a sinusoidal oscillation which is eitherforce or di

17、splacement controlled. The forcing medium causing this sinusoidal oscillation can be anelectromechanical, electrohydraulic system, or a pure mechanical system.This method assumes that the existing force or displacement and the response of the specimen can beconsidered to be sinusoidal. If this is no

18、t the case, special methods of analysis are required.The transmitted force is measured by a load cell in contact with the sample, preferably on the stationary sideto minimize errors due to acceleration of the mass of the fixture. The component of this force which is inphase with velocity and the com

19、ponent that is in phase with the displacement are usually determinedelectronically. From this information, the values of C and K are usually determined. The vector phaserelationships are illustrated in Figure 1.7.1.2 COMPONENTSThe basic elements of a forced nonresonant system are the drive system, t

20、he control system,a loading frame, transducers, and the instrumentation for readout.7.1.2.1 Drive SystemThe system should be capable of providing sinusoidal dynamic operation, with minimumharmonic distortion, in the same direction as the applied force.7.1.2.2 ControlA means of precise control over t

21、he input drive unit is required for repeatable test results.Controls for mean input, dynamic input, and frequency should be independently selectable for the desiredtest condition.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085 Revised MAY1999-8-FIGUR

22、E 1VECTOR PHASE RELATIONSHIPS7.1.2.3 Transducers and InstrumentationCommon transducer signals used in forced nonresonant systems forobtaining data are load, displacement, and/or velocity. Each transducer should be calibrated to thefollowing minimum accuracies:a. Load 0.5% of full-scale for each cali

23、brated rangeb. Displacement 0.5% of full-scale for each calibrated rangec. Velocity 0.1% of full-scale for each calibrated rangeReadout instrumentation for load, displacement, and velocity transducers should provide a sufficientnumber of ranges so that it will not be necessary to use less than 20% o

24、f range.Precautions listed in ASTM D 2231, paragraph 4.2 should be observed in selecting transducers,electronics, and techniques of calibration.7.1.2.4 Preferred Location of TransducersThe load cell shall be mounted on the stationary side of the samplebeing tested.The displacement and/or velocity tr

25、ansducer should be located to accurately measure the motion of thedynamic surface of the sample. It should be located parallel to and as close as possible to the centerline ofthe existing force.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085 Revised

26、MAY1999-9-7.1.2.5 Load Path ComplianceA correction factor will be required unless the overall spring rate of the fixturesand the machine elements that are included in the measurement is sufficiently high. The machine andfixture spring rate should be at least 100 times greater than the nominal spring

27、 rate of the test specimen. Ifthis degree of rigidity cannot be achieved, the correction factor shall be calculated and applied.7.1.2.6 Fixture MassThe mass of the fixture located on the stationary platen shall be minimized to reduce errorsdue to mass-inertia accelerations. The fixture located on th

28、e moving platen shall be rigid to eliminate anypossibility of structural resonance near operating frequencies.8. Report8.1 Test ConditionsThe report shall include the following:8.1.1 Type of testing machine used.8.1.2 Test specimen(s) identification.8.1.3 Type of specimen loading, for example, compr

29、ession or shear. For specimens of complex configuration, fulldescription of fixtures used, with diagrams if necessary.8.1.4 Date of test.8.1.5 Preload1.8.1.6 Frequency1 used at each test point in Hertz.8.1.7 Double amplitude displacement1 used at each test point.8.1.8 Ambient temperature1.8.1.9 Spec

30、imen internal temperature (optional). If internal temperature is used, the following additional informationis required:8.1.9.1 Internal temperature before flexing.8.1.9.2 Ambient temperature.8.1.9.3 Exact location of the temperature measuring transducer.8.1.9.4 Time from start of flexing until tempe

31、rature and dynamic property readings are taken.8.2 Calculated ValuesThe method for computing C and K from the measured variable shall be described.8.2.1 Dynamic (elastic) spring rate, K.8.2.2 Damping coefficient, C.8.2.3 Loss tangent, C/K1. Include both actual and specified, if different.COPYRIGHT S

32、ociety of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085 Revised MAY1999-10-8.2.4 For all test machines, as applicable:8.2.4.1 Range scale settings.8.2.4.2 Mode of test control, that is, stroke or load.8.2.4.3 All observed and recorded data on which calculations are bas

33、ed.9. Precision or ReproducibilityPrecision as defined in ASTM E 177-71T is a function of the operator,compound, and maintenance of constant test conditions. The test conditions that can influence “level” are:preload, frequency, double amplitude displacement, temperature, and others not yet well def

34、ined.10. Test for Dynamic Properties of Elastomeric Isolators with Multi-Axis Preloads10.1 GeneralThe purpose of this section is to review the procedures to determine the dynamic characteristics ofautomotive elastomeric mounts with multi-axis preloads. To test the dynamic characteristics in its thre

35、eprinciple axes of the engine mount is a typical example. The following reference calculation and test setupsare suggested in the interests of standardization.10.2 Multi-Axis PreloadsFigure 2 shows two sandwich mountings in a vee with an included angle of 2 between the compression axes.FIGURE 2MOUNT

36、ING ARRANGEMENTAssume a vertical static force F acts on the system. Figure 3 shows the static force diagram of one isolator.FIGURE 3STATIC FORCE DIAGRAMCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085 Revised MAY1999-11-NotationF - Static vertical for

37、ce on the systemFc - Static compression force on one isolatorFs - Static shear force on one isolatorFh - Static horizontal force on one isolatorThe Fc and Fs can be calculated from the given F and .10.3 Preferred Test Conditions10.3.1 The reference test conditions, suggested in 5.3, are applicable e

38、xcept the preload.The following reference test preloads for the three principle axes are suggested in the interests ofstandardization. The preload should be chosen so that any sharp changes in the slope of the load-deflectioncurve are avoided.10.3.2 DYNAMIC CHARACTERISTICS IN COMPRESSION AXISThe app

39、lied excitation axis is in compression direction.The preload in this direction is Fc. There is an off-axis preload, Fs, should be applied on the test specimen.10.3.3 DYNAMIC CHARACTERISTICS IN SHEAR AXISThe excitation axis is in shear direction. The preload in thisdirection is Fs. There is an off-ax

40、is preload, Fc, should be applied on the test specimen.10.3.4 DYNAMIC CHARACTERISTICS IN FORE AND AFT AXISThe excitation axis is in Fore and Aft direction that isperpendicular to compression and shear axis. Sufficient preload in Fore and Aft direction should be appliedto prevent any separation of sa

41、mple-to-machine interfaces unless all interfaces are securely attached.There are two off-axis preloads, Fc and Fs, should be applied on the test specimen.10.4 Test SetupThere are several methods to apply the off-axis preloads. This section outlines three methods:10.4.1 MOVING LOAD CELLFigure 4 shows

42、 a test setup for shear and Fore and Aft characterization of isolators.The load cell is mounted on the actuator and the isolator is mounted on the mounting base. The DCconditioner shall compensate the moving load cell. This setup reduces actuator side load, bendingmoments on the load cell and fixtur

43、ing mass attached to the load cell, and applies a more easily controlledpreload. This method works up to about 15 Hz. The spherical bearings and links lower the amplitude ofbending moments and side loads introduced to the actuator and load cell. The attachment to the load cellshould be configured so

44、 that the dead load can be connected first and then the actuator can be attached tominimize misalignment.10.4.2 TEST TWO SPECIMENS IN PARALLELUse the arrangement shown in Figure 5. Two duplicate isolators aretested at the same time. A constant compression deflection is maintained on the mountings to

45、 simulate theresults of a compression loading while the mountings are being tested in the shear direction. Specialattention should be paid to the fixture design to minimize the fixture mass effect. This setup is not suitablefor two off-axis preloads test.10.4.3 MANUAL TRANSLATION PLATFORMA manual tr

46、anslation platform is mounted on the load cell and the testisolator is mounted on the platform. Figure 6 shows the setup. By adjusting the translation platform, an off-axis preload is applied on the specimen against a hydrostatic bearing actuator. The test system designshould minimize inertia effect

47、s.10.5 FixtureThe resonant frequency of the fixture should be high enough so that these resonances do not affectthe dynamic property measurements of the isolators.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085 Revised MAY1999-12-FIGURE 4MOVING LOAD

48、CELLFIGURE 5TWO ISOLATORS IN PARALLELCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085 Revised MAY1999-13-FIGURE 6MANUAL TRANSLATION PLATFORM11. Notes11.1 Marginal IndiciaThe change bar (l) located in the left margin is for the convenience of the user

49、in locatingareas where technical revisions have been made to the previous issue of the report. An (R) symbol to the leftof the document title indicates a complete revision of the report.PREPARED BY THE SAE VIBRATION ISOLATION COMPONENTS COMMITTEECOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1085 Revised MAY1999-14-APPENDIX AA.1 The following information is presented for guidance in determining the amount of time required for rubber