1、Designation: G203 10Standard Guide forDetermining Friction Energy Dissipation in ReciprocatingTribosystems1This standard is issued under the fixed designation G203; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers and is intended for use in interpretingthe friction forces recorded in reciprocating tribosystems. Theguid
3、e applies to any reciprocating tribosystem, whether it is awear or fretting test or an actual machine or device.1.2 The energy dissipation guide was developed in analyz-ing friction results in the Test Method G133 reciprocatingball-on-flat test, but it applies to other ASTM or ISO recipro-cating tes
4、ts. This technique is frequently used to record thefriction response in fretting tribosystems.1.3 Specimen material may play some role in the results ifthe materials under test display viscoelastic behavior. Thisguide as written is for metals, plastics, and ceramics that do notdisplay viscoelastic b
5、ehavior. It also applies to lubricated andnon-lubricated contacts.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It i
6、s 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.2. Referenced Documents2.1 ASTM Standards:2G40 Terminology Relating to Wear and ErosionG115 Guide for Measuring and Reporting
7、 Friction Coeffi-cientsG133 Test Method for Linearly Reciprocating Ball-on-FlatSliding WearG163 Guide for Digital Data Acquisition in Wear andFriction Measurements3. Terminology3.1 Definitions:3.1.1 coeffcient of friction, nin tribology, the dimension-less ratio of the friction force (F) between two
8、 bodies to thenormal force (N) pressing these bodies together. G403.1.2 frettingsmall amplitude oscillatory motion, usuallytangential between two solid surfaces in contact. G403.2 Definitions of Terms Specific to This Standard:3.2.1 friction envelopewhen making friction energy lossmeasurements, the
9、graphic representation of the cyclic frictionforce versus time history of a tribosystem in which theboundaries surrounding these variations in time produces ashape with a measurable area.3.2.2 reciprocating tribosystemsliding system where thedirection of motion of the moving member periodically re-v
10、erses (for example, piston in a cylinder).3.3 Acronyms:3.3.1 DAS, ndata acquisition system.3.3.2 FED, nfriction energy dissipated. The work re-quired to overcome the resistance to motion encountered insliding one solid on another expressed in energy units (joules).3.3.3 RFED, nrelative friction ener
11、gy dissipated. Thework required to overcome the resistance to motion encoun-tered in sliding one solid on another solid expressed in arbitraryunits for comparison studies on candidate tribocouples.4. Summary of Guide4.1 Frictional effects can be a concern in many tribosystemsso it is common to monit
12、or friction force in laboratory tests andeven field evaluations of machines. There are many ways ofreporting the recorded friction forces: friction force (see GuideG115), average friction force for a test, average coefficient offriction, static and kinetic coefficient of friction, coefficient offric
13、tion at periodic time intervals, etc. This guide presents amethodology to convert friction forces monitored throughout atest cycle into a test metric called friction energy dissipated(FED). For within-lab tests the metric is relative friction energy1This guide is under the jurisdiction of ASTM Commi
14、ttee G02 on Wear andErosion and is the direct responsibility of Subcommittee G02.50 on Friction.Current edition approved April 1, 2010. Published May 2010. DOI:10.1520/G020310.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. Fo
15、r Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.dissipated (RFED). Both of these terms represent an integra-tion of th
16、e area within the force/tangential displacement outputof the force measurement system.4.2 The FED parameter will have energy units; the RFEDparameter can have arbitrary units because it is used tocompare various candidates in the same test in the samelaboratory using the same test equipment.5. Signi
17、ficance and Use5.1 Many sliding systems exhibit intermittent high frictionforce excursions compared to competing tribosystems. How-ever, where friction forces or friction coefficients are averaged,the test data may show that the two systems have the samefriction characteristics, when in fact they we
18、re not the same;there was a friction “problem” in the one with the periodicaberrations. The FED takes into account all friction forces thatoccur in the test increment. It is all of the friction energy thatthe couple dissipated in the designated test duration. It capturesthe friction profile of a sys
19、tem in a single number that can beused to screen candidate couples for friction characteristics.5.2 If the friction energy used in a reciprocating tribosystemis of concern this metric along with the friction recording,average coefficient of friction, and standard deviation of theforce readings, prod
20、uces the most meaningful data. It is ametric of the energy loss in a tribosystem.6. Apparatus6.1 This guide can be used with any reciprocating wear testor device that is instrumented to produce a friction forcerecording for the entire test interval with a force recording atintervals that allow chara
21、cterization of each reciprocating(forward and back) cycle. A chart recorder produces adaptableforce information and any data logging system that allowsintegration of the area of a force/distance recording for a testcan be used (see Guide G163). Fig. 13is an example of suitableexperimental data from
22、a single back and forth cycle. Thefigure shows force as the vertical axis and sliding distance asthe horizontal axis in a fretting test. Fig. 2 is the force/distancerecording from Test Method G133 sphere-on-flat test modifiedto produce four hours of rubbing using Option B (see 8.1.2).The ability to
23、record friction forces depends on the samplingrate of the DAS. Thus, when using friction energy dissipationas a test metric, all tests used in ranking tribosystems shoulduse the same force measurement system, force sampling rate,DAS and energy analysis technique.7. Test Specimen Configuration7.1 Thi
24、s friction assessment methodology has been used onreciprocating sphere-on-flat, block-on-ring, and flat-on-flatspecimens.8. Procedure8.1 Two options are described, depending on the type offriction-measuring and recording system available for use. InOption A, discrete friction loop capture, the featu
25、res ofindividual cycles are recorded by a high-speed DAS (forexample, see Fig. 1). In Option B, details of individual cyclesare not clearly observable, but rather, the general trend of thecyclic friction force variation, called a friction envelope, isobtained.8.1.1 Option A, Cumulative Friction Loop
26、 MethodTheDAS shall have sufficiently high recording rate and frictionforce resolution to enable the details of friction versus timeplots for individual forward and back cycles, called frictionloops, to be captured. It is the responsibility of the user toensure the proper calibration of the force an
27、d displacementsensors. The area enclosed by each loop, in force-time space, isa measure of the frictional energy dissipated during that loop.Cumulative summation of the areas of all loops generatedduring a given test represents the total FED. A variation of thefriction loop method is when time, rath
28、er than displacement ismeasured during reciprocating motion.An example is shown inFig. 2. In that case, the time axis is converted to slidingdistance, using the known velocity characteristics of thetribosystem, and the areas enclosed by the friction force traceand the horizontal axis are summed to p
29、rovide the FED.8.1.2 Option B, Friction Envelope MethodThis methodprovides a relative measure of the frictional energy dissipatedand is useful for within-laboratory comparisons. It can utilizelower speed DAS or chart recorders where the details ofindividual loops cannot be resolved. In that case, th
30、e shapeproduced by the friction force versus sliding distance or timerecord is enclosed and measured (see Fig. 3). These enclosingshapes can be called friction envelopes. If the velocity charac-teristics of the tribosystem do not change during the test, thenthe time can be used as one axis of the fr
31、iction envelope plot.Comparing the areas enclosed by friction envelopes, plottedusing the same axes scales, provides a measure of the RFED.NOTE 1Option A versus Option BFig. 4 represents the frictionenvelope produced by enclosing the detailed friction force versus elapsedtime trace shown in Fig. 2.
32、It is clear that by enclosing the plot, thefrictional energy of the spaces between loops included in the tally.Therefore, the use of Option B should not be assumed to provide anaccurate measure of the frictional energy dissipated by individual recip-rocating cycles, but rather it can be used as a co
33、nvenient way ofcomparing the frictional behavior of various material combinations undersimilar test conditions.9. Report9.1 Information on the FED may be included as a supple-ment to the report that describes the testing parameters,specimen preparation, cleaning methods, materials, and otheraspects
34、associated with selected friction test method to whichthese data apply. Examples of supplementary information onFED, reported in the form of Option B, are given in Fig. 5.10. Keywords10.1 friction; friction coefficient; friction energy3Mohrbacher, H., et al, “The Influence of Humidity on the Behavio
35、r of PVD TiNCoatings,” Wear, Vol 180, 1995, pp. 43-52.G203 102FIG. 1 Tangential Force-Displacement Hysteresis Loops between Measured during Fretting between TiN (Sample B) and Corundum in(a)Moist(RH10%)AirG203 103FIG. 2 Areas Under the Traces of Individual StrokesNOTEArea can be measured by counting
36、 squares, inputting the shapes into a CAD analysis program, etc.FIG. 3 Strip Chart Recordings from Test Method G133 Used in RFED DeterminationG203 104FIG. 4 Area Enclosed by the Total Friction EnvelopeG203 105APPENDIXES(Nonmandatory Information)X1. FRETTING LOOPSX1.1 Fretting tribosytems usually pro
37、duce significantchanges in friction forces as testing cycles increased. If data islogged in detail for each fretting cycle (for example, 100readings per test cycle) the FED can be presented in 3D formatwith time (number of cycles) as the third axis as shown in Fig.X1.1. The volume enclosed on the sh
38、ape can be an RFEDparameter.FIG. 5 Typical RFED ReportG203 106X2. DEALING WITH SHORT-LIVED FRICTION ABERRATIONSX2.1 Some tribosystems produce instantaneous forcespikes that are significant but may not significantly increase thearea in an RFED evaluation. This is the reason why this guiderecommends i
39、ncluding the force recording in the test report.The force aberrations will be evident. Inclusion of the standarddeviation of the force recording is another tool that can be usedto quantify these friction results (Fig. X2.1).FIG. X1.1 “Friction Energy Volume” from a Fretting TestG203 107ASTM Internat
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43、ds, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832
44、-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).FIG. X2.1 Use of Standard Deviation to Deal with Short-Lived Friction Force ExcursionsG203 108
