1、Designation: F2869 10Standard Practice forRadial Light Truck Tires to Establish Equivalent TestSeverity Between a 1.707-m (67.23-in.) Diameter RotatingRoadwheel and a Flat Surface1This standard is issued under the fixed designation F2869; the number immediately following the designation indicates th
2、e year oforiginal adoption or, in the case of 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.1. Scope1.1 This practice describes the procedure to identify
3、equiva-lent test severity conditions between a 1.707-m diameterlaboratory roadwheel surface and a flat or highway surface forradial pneumatic light truck (LT) tires.1.1.1 Tire operational severity, as defined as the running oroperational temperature for certain specified internal tire loca-tions, is
4、 not the same for these two test conditions. It istypically higher for the laboratory roadwheel at equal load,speed and inflation pressure conditions due to the curvatureeffect.1.1.2 The practice applies to specific operating conditions oflight truck tires up through load range E for such tires used
5、 onvehicles having a gross vehicle weight rating (GVWR) #4536kg (10000 lb).1.1.3 The specific operating conditions under which theprocedures of the practice are valid and useful are completelyoutlined in Section 6, (Limitations) of this standard.1.1.4 It is important to note that this standard is co
6、mposed oftwo distinct formats:1.1.4.1 The usual text format as published in this volume ofthe Book of Standards (Vol. 09.02).1.1.4.2 A special interactive electronic format that uses aspecial software tool, designated as prediction profilers orprofilers. This special profiler may be used to determin
7、elaboratory test conditions that provide equivalent tire internaltemperatures for the belt edge region for the two operationalconditions, that is, the curved laboratory roadwheel and flathighway test surfaces.1.2 The prediction profilers are based on empirically devel-oped linear regression models o
8、btained from the analysis of alarge database that was obtained from a comprehensive experi-mental test program for roadwheel and flat surface testing oftypical radial light truck (LT) tires. See Section 7 and theresearch report2for more details.1.2.1 For users viewing the standard on CD-ROM or PDF,w
9、ith an active and working internet connection, the profilerscan be accessed on the ASTM website by clicking on the linksin 7.5 and 7.6.1.2.2 For users viewing the standard in a printed format, theprofilers can be accessed by entering the links to the ASTMwebsite in 7.5 and 7.6 into their internet br
10、owsers.1.3 For this standard, SI units shall be used, except whereindicated.1.4 This standard 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 determi
11、ne the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3F414 Test Method for Energy Absorbed by a Tire WhenDeformed by Slow-Moving PlungerF538 Terminology Relating to the Characteristics and Per-formance of TiresF551 Practice for Using a 67.23-in. (1.7
12、07-m) DiameterLaboratory Test Roadwheel in Testing TiresF1922 Test Method for Tires, Pneumatic, Vehicular, High-wayF2779 Practice for Commercial Radial Truck-Bus Tires toEstablish Equivalent Test Severity Between a 1.707-m(67.23-in.) Diameter Roadwheel and a Flat SurfaceIEEE/ASTM SI 10 American Nati
13、onal Standard for Use ofthe International System of Units (SI): The Modern MetricSystem1This practice is under the jurisdiction of ASTM Committee F09 on Tires and isthe direct responsibility of Subcommittee F09.30 on Laboratory (Non-Vehicular)Testing.Current edition approved Oct. 1, 2010. Published
14、January 2011. DOI: 10.1520/F2869-10.2Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: F09-1002.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual B
15、ook 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.3. Terminology3.1 Definitions:3.1.1 belt edge (BE) temperature, nin the cross se
16、ction ofa radial tire, the temperature at the edge of the stabilizer pliesor belts, for example, in the rubber region of the two belt edges.3.1.2 contained air temperature, nthe temperature of theair contained within the tire cavity when the tire is mountedand inflated on the proper rim.3.1.3 curved
17、 equivalent test severity, nin tire testing, thetest conditions (load, rotational speed, tire inflation pressure)on the flat or highway surface that will provide equivalentinternal tire temperatures, for example, at the belt edge, to aknown set of curved 1.707-m roadwheel surface test condi-tions.3.
18、1.4 endurance, nof a tire, the ability of a tire to performas designed in its intended usage conditions such as load,inflation pressure, speed, time, and environmental conditions.3.1.5 high speed performance, nof a tire, the rotationalspeed capability of a tire to perform as designed in its intended
19、usage conditions such as load, inflation pressure, speed, time,and environmental conditions.3.1.6 highway equivalent test severity, nin tire testing, thetest conditions (load, rotational speed, tire inflation pressure)on the 1.707-m roadwheel that will provide equivalent internaltire temperatures, f
20、or example, at the belt edge, to a known setof highway or flat surface conditions.3.1.7 light truck tire, na tire that has a LT prefix or suffixin the tire size description: this indicates that the tire wasprimarily intended for service on light trucks with gross vehicleweights (GVWR) #4536 kg.3.1.8
21、 load range, nof a light truck tire, a letter designation(B, C, D, E) used to identify a given size tire with its load andinflation limits when used in a specific type of service.F414, F19223.1.9 maximum rated load, nthe load corresponding to amaximum tire load capacity at the rated inflation pressu
22、re inaccordance with the publications of tire and rim standardscurrent at the time of manufacture.3.1.10 measured inflation pressure, ngauge pressure of atire measured at a given time under ambient temperature andbarometric pressure. F5383.1.11 rated inflation pressure, nthe minimum cold infla-tion
23、pressure specified at the maximum rated load of a tire inaccordance with the publications of tire and rim standardscurrent at the time of manufacture.3.1.12 rim, nspecially shaped circular periphery to whicha tire may be mounted with appropriate bead fitment. F5383.1.13 test inflation pressure, nspe
24、cified gauge pressureof a tire mounted on a rim, measured at a given time underambient temperature and barometric pressure for evaluationpurposes.3.1.14 test load, nthe force applied to a tire through therim; it is normal to the metal loading plate onto which the tireis loaded. F5383.1.15 tire, pneu
25、matic, na hollow tire that becomes load-bearing upon inflation with air, or other gas, to a pressureabove atmospheric. F5383.1.16 tire, radial, na pneumatic tire in which the plycords that extend to the beads are laid substantially at 90 to thecenter line of the tread, the tire being stabilized by a
26、 belt.F5383.1.17 tire speed rating, nthe maximum speed for whichthe use of the tire is rated under certain conditions asdesignated by the speed symbol marked on the tire sidewall ormaximum speed rating as determined by the manufacturer.3.1.18 tire test speed, nthe tangential speed at the point ofcon
27、tact with the road curved surface of a rotating tire forevaluation purposes.4. Summary of Practice4.1 This practice provides a procedure to determine the1.707-m diameter roadwheel tire test conditions (speed, load,and inflation pressure) for flat surface equivalent test severity.It also enables the
28、user to determine the 1.707-m diameterroadwheel test conditions for a specific increase or decrease inseverity with respect to flat surface test severity. The converseis also true, determining the flat surface test conditions thatprovide equal test severity to a selected set of 1.707-mdiameter roadw
29、heel test conditions.4.2 This practice provides a prediction profiler procedure(see Section 7 and Annex A1) to establish equivalent testseverity between a 1.707-m diameter rotating wheel (PracticeF551) and a flat surface, by adjusting test speed, load andinflation pressure. The prediction profiler p
30、rovides the abilityto identify numerous test conditions and resultant belt edgetemperature differentials within the confines of this practice asdescribed in Section 6.4.3 Equivalent test severity is defined as the set of testconditions (load, speed, and tire inflation pressure) that provideequivalen
31、t steady state tire internal operating temperatures atthe belt edge (BE) for: (1) a conversion from flat surfaceconditions to a 1.707-m diameter roadwheel conditions or (2)a conversion from a 1.707-m diameter roadwheel conditions toa flat surface conditions.25. Significance and Use5.1 Historically,
32、tires have been tested for endurance by avariety of test methods. Some typical testing protocols havebeen: (1) proving grounds or highway testing over a range ofspeeds, loads, and inflations, (2) testing on fleets of vehicles forextended periods of time, and (3) indoor (laboratory) testing oftires l
33、oaded on a rotating 1.707-m diameter roadwheel; how-ever, the curved surface of a 1.707-m diameter roadwheelresults in a significantly different tire behavior from thatobserved on a flat or highway surface.5.1.1 This practice addresses the need for providing equiva-lent test severity over a range of
34、 typical tire operating condi-tions between a 1.707-m diameter roadwheel surface (PracticeF551) and a flat surface. There are different deformations of thetire footprint on curved versus flat surfaces resulting indifferent footprint mechanics, stress/strain cycles, and signifi-cantly different inter
35、nal operating temperatures for the twotypes of contact surface. Since tire internal temperatures arekey parameters influencing tire endurance or operating char-acteristics under typical use conditions, it is important to beable to calculate internal temperature differentials betweenF2869 102curved a
36、nd flat surfaces for a range of loads, inflation pressuresand rotational velocities (speeds).5.2 Data from lab and road tire temperature measurementtrials were combined, statistically analyzed, and tire tempera-ture prediction models derived.25.2.1 The fit of the models to the data is shown as theco
37、efficient of determination, R2, for the critical belt edge:R2= 0.90Two Standard Deviations (2-sigma) = 3.2C(that is, 95 % of the variation from the meansis within 63.2C)5.2.2 These prediction models were used to develop theprediction profilers outlined in Section 7 and Annex A1.6. Limitations6.1 The
38、 procedures as given are valid for radial pneumaticLT tires up through load range E for the following ranges oftest speed, tire inflation pressure and test load, for flat testsurfaces and a 1.707-m diameter roadwheels:6.1.1 Tire test speed in the range of 80 to 137 km/h (flat andcurved surface).6.1.
39、2 Tire test inflation pressure in the range of 50 to 110 %of the inflation pressure associated with the maximum loadcapacity of the tire, for example, sidewall stamped.6.1.3 Tire test load in the range of 41 to 143 % of themaximum load capacity of the tire, for example, sidewall-stamped maximum rate
40、d load.6.2 The procedures described in Section 7 determineequivalent operating conditions between a flat surface and a1.707-m diameter roadwheel by using empirical models tomatch tire internal belt edge temperatures. These empiricalmodels are derived from a wide variety of tires tested withinthe abo
41、ve ranges and can be used to interpolate at anyconditions within the constraints listed above. It is not recom-mended that the procedures be used for extrapolation beyondthe constraints listed above.7. Procedure7.1 Equivalent Test Severity Prediction Profilers:7.1.1 The flat-to-curved (FTC) predicti
42、on profilers are SASJMP interactive displays based on algorithms developed fromlaboratory and highway tire temperature measurements. Theyprovide 1.707-m diameter roadwheel tire test (rotational)speed, tire test load, and tire test inflation pressure conditionsfor equivalent test severity (as well as
43、 for lesser or more severetest severity) based upon the belt edge region temperatures.Before using the profilers, the user will have targeted aroadwheel “delta temperature” amount in degrees C for the tirerunning on a flat surface, that is, the targeted operatingdifference in temperature between the
44、 roadwheel and highwaycondition. By first identifying the desired “delta tempera-ture(s),” the user will be able to identify (via the profilers)roadwheel test conditions to achieve the temperature “del-ta(s).” The equivalency determination is based upon a “delta”in rotational speed (km/h), % load, a
45、nd/or % inflation from theknown highway operating conditions within the limitationsspecified in Section 6.7.1.2 The converse also applies for equivalent highway testconditions that can be identified from specified roadwheel testconditions by use of the curved-to-flat (CTF) predictionprofilers.7.2 Wh
46、en using either the FTC (or CTF) Delta DegCprediction profilers, three variables are available for interactivemodification:Delta 1.7 m Dia RW KPH The change in tire rotational speedfor the roadwheel relative to thehighway speed in km/h.1.7 m Dia RW % Flat SurfaceInflationThe percent change in roadwh
47、eeltire inflation relative to thehighway tire inflation.1.7 m Dia RW % Flat SurfaceLoadThe percent change in roadwheeltire load relative to thehighway tire load.7.2.1 These variables appear along the x-axis of the predic-tion profiler and can be changed by clicking and dragging.Effects of changing t
48、hese variables can be viewed as tempera-ture changes in the belt edge region identified on the y-axis as:“LT BE Flat Surface to 1.7 m Dia RW Delta DegC”7.3 The curved-to-flat (CTF) prediction y-axis is labeled“LT BE 1.7 m Dia RW to Flat Surface Delta DegC” while thex-axis are labeled from the perspe
49、ctive of identifying therequired changes from roadwheel conditions to flat conditionsin order to achieve the targeted severity levels on the flatsurface.7.4 See Annex A1 for examples of prediction profilersoutputs.7.5 Flat-to-Curved (FTC) Prediction Profiler Macro But-ton (available on electronic copy or ASTM F09 site):http:/www.astm.org/F2869_flat_to_curved.html7.6 Curved-to-Flat Surface (CTF) Prediction Profiler Macro Button (available on electronic copy or ASTM F09site):http:/www.astm.org/F2869_curved_to_flat.html8. Keywords8.1 curved to flat surface; en
