1、Designation: F1805 12Standard Test Method forSingle Wheel Driving Traction in a Straight Line on Snow-and Ice-Covered Surfaces1This standard is issued under the fixed designation F1805; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 test method covers a procedure for measuring thedriving traction of passenger car and light truck
3、tires whiletraveling in a straight line on snow- or ice-covered surfaces.1.2 This test method utilizes a dedicated, instrumented,four-wheel rear-wheel drive test vehicle with a speciallyinstrumented drive axle to measure fore-aft and vertical forcesacting on a single driven test tire.1.3 This test m
4、ethod is suitable for research and develop-ment purposes where tires are compared during a single seriesof tests. They may not be suitable for regulatory statutes orspecification acceptance because the values obtained may notnecessarily agree or correlate either in rank order or absolutetraction per
5、formance level with those obtained under otherenvironmental conditions on other surfaces or the same surfaceafter additional use.1.4 The values stated in SI units are to be regarded as thestandard. Ordinarily, N and kN should be used as units of force.This standard may utilize kgf as a unit of force
6、 in order toaccommodate the use of load and pressure tables, as found inother standards both domestic and global that are commonlyused with this standard. The values given in parentheses are forinformation only.1.5 This standard does not purport to address all of thesafety concerns, if any, associat
7、ed 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.2. Referenced Documents2.1 ASTM Standards:2E1136 Specification for P195/75R14 Radial Standard Refer-ence
8、 Test TireF377 Practice for Calibration of Braking/Tractive MeasuringDevices for Testing TiresF538 Terminology Relating to the Characteristics and Per-formance of TiresF1046 Guide for Preparing Artificially Worn Passenger andLight Truck Tires for TestingF1572 Test Methods for Tire Performance Testin
9、g on Snowand Ice SurfacesF1650 Practice for Evaluating Tire Traction PerformanceData Under Varying Test ConditionsF2493 Specification for P225/60R16 97S Radial StandardReference Test Tire2.2 Other Standards:European Tyre and Rim Technical Organisation Manual3JapanAutomobile Tyre ManufacturersAssocia
10、tion Manual4Tire the test results for this tire have significance as a basevalue or internal benchmark. F5383.1.10 snow, hard pack, n in tire testing, packed basewithout loose snow. F5383.1.11 snow, medium pack, n in tire testing, groomedpacked base with 2.5 to 5.0 cm (1 to 2 in.) loose snow. F5383.
11、1.12 snow, medium hard pack, n in tire testing, packedbase with some loose snow. F5383.1.13 snow, soft pack, n in tire testing, freshly fallen ordeeply groomed base snow with 5.0 to 7.5 cm (2 to 3 in.) loosesnow. F5383.1.14 spin velocity, nthe angular velocity of the wheelabout its spin axis. F5383.
12、1.15 standard reference test tire (SRTT), na tire that isused as a control tire or surface monitoring tire (for example,Specification E1136 and Specification F2493 tires). F5383.1.15.1 DiscussionWhile ASTM designates several tirespecifications as Standard Reference Test Tires, Test MethodF1805 has h
13、istorically used the Specification E1136 tire as itsprimary reference tire and this specification is specificallyidentified as the control tire in the RMA Tire InformationService Bulletin Vol. 37/No. 3, which specifies requirementsfor application of the Severe Snow Use Symbol (3 peakmountain snowfla
14、ke).3.1.16 surface monitoring tire, na reference tire used toevaluate changes in the test surface over a selected time period.F5383.1.17 test (or testing), na procedure performed on anobject (or set of nominally identical objects) using specifiedequipment that produces data unique to the object (or
15、set).F5383.1.17.1 DiscussionTest data are used to evaluate ormodel selected properties or characteristics of the object (or setof objects). The scope of testing depends on the decisions to bemade for any program, and sampling and replication plans (seedefinitions below) need to be specified for a co
16、mplete programdescription.3.1.18 test matrix, n in tire testing a group of candidatetires, usually with specified reference tires; all tests arenormally conducted in one testing program. F5383.1.19 test run, na single pass of a loaded tire over a giventest surface. F5383.1.20 test tire, na tire used
17、 in a test. F5383.1.21 test tire set, none or more test tires, as required bythe test equipment or procedure, to perform a test, therebyproducing a single test result. F5383.1.21.1 DiscussionThe four nominally identical tires re-quired for vehicle stopping distance testing constitute a test tireset.
18、 In the discussion below where the test tire is mentioned, itis assumed that the test tire set may be substituted for the testtire, if a test tire set is required for the testing.3.1.22 traction test, n in tire testing, a series of n test runsat a selected operational condition; a traction test is c
19、haracter-ized by an average value for the measured performanceparameter. F5383.1.23 vertical load, nthe normal reaction of the tire onthe road which is equal to the negative of normal force. F5384. Summary of Test Method4.1 These test methods describe the use of an instrumentedvehicle with a single
20、test wheel capable of measuring the tireperformance properties under drive torque on snow and icesurfaces when traveling in a straight line.4.2 The test is conducted by driving the test vehicle over thetest surface. Driving torque is gradually increased to the testwheel while maintaining the vehicle
21、 speed by applying brakingtorque to the non-test wheels of the vehicle. The drivingtraction coefficient is determined from the measured values oflongitudinal and vertical forces over a specified slip or timerange. The recommended vehicle test speed is 8.0 km/hr(5.0 mph).5. Significance and Use5.1 Th
22、is test method describes a technique for assessing theperformance characteristics of tires in a winter environment onsnow and ice surfaces. When snow is referred to hereafter, iceis implied as appropriate.5.2 The measured values quantify the dynamic longitudinaltraction properties of tires under dri
23、ving torque. Dynamictraction properties are obtained on snow surfaces prepared inaccordance with the stated test procedures and attempts toquantify the tires performance when integrated into a vehicle-environmental system. Changing any one of these environmen-tal factors will change the measurements
24、 obtained on asubsequent test run.5.3 This test method addresses longitudinal driving tractionproperties only on snow and ice surfaces. Refer to TestMethods F1572 for test methods for braking and lateral tractionproperties on snow or ice, or both.6. Interferences6.1 Factors that may affect tire snow
25、 performance and mustbe considered in the final analysis of data include:F1805 1226.1.1 Snow temperature,6.1.2 Ambient temperature,6.1.3 Mechanical breakdown of the agglomerated snow-flake into granular crystals,6.1.4 Solar load,6.1.5 Tire temperature,6.1.6 Tire wear condition (preparation),6.1.7 Ti
26、re pressure,6.1.8 Tire vertical load,6.1.9 Snow surface characteristics, and6.1.10 Rim selection.7. Apparatus7.1 The test vehicle shall have the capability of maintainingthe specified test speed 6 0.8 km/h (6 0.5 mph) during alllevels of driving torque application.7.2 The test vehicle shall be equip
27、ped with an automaticthrottle actuator to allow the gradual increase of driving torqueat a predetermined (repeatable) rate.7.3 The test vehicle shall be a rear drive, four wheelpassenger car or a light truck less than or equal to 44.5 kN(10 000 lbf) GVW. The range of test tires and load conditionswi
28、ll determine the vehicle size and selection. Utilizing a frontwheel drive test vehicle is not addressed in this standardalthough the basic procedures could be applied with appropri-ate conditional modifications.7.4 The test vehicle shall be instrumented to measurelongitudinal and vertical forces at
29、the tire and test surfaceinterface during the application of driving torque.7.5 The test vehicle shall have provisions to automaticallyand completely disengage the brake on the test wheel (ifinstalled) prior to throttle application. Complete disengage-ment is necessary to eliminate all drag that mig
30、ht be caused bythe brake assembly.7.6 Opposite Tire:7.6.1 The tire installed opposite the instrumented test wheelshall have a sufficiently large traction coefficient to minimizeslip of this tire during the traction test. The opposite tire shouldhave a coefficient at least 50 % greater than the expec
31、tedcoefficient of the test tire. A tire chain may be utilized toincrease the traction of the opposite tire when testing on snowsurfaces.7.6.2 The opposite tire shall be selected to have an outsidediameter that is within 62.5 cm (61 in.) of that of the test tire.7.7 Asuitable ride height adjustment s
32、ystem on the rear axleshall be provided to permit adjustment for each tire size andload to minimize transducer crosstalk as established duringcalibration.7.8 InstrumentationThe test wheel position on the testvehicle shall be equipped with a wheel rotational velocitymeasuring system and with transduc
33、ers to measure the dy-namic longitudinal force and vertical load at the test wheel.7.8.1 General Requirements for Measurement SystemTheinstrumentation system shall conform to the following overallrequirements at ambient temperatures between 23 and 43C(10 and 110F):7.8.1.1 Overall system accuracy, fo
34、rce6 1.5 % of verticalload or traction force from 450 N (100 lbf) to full scale.7.8.1.2 Overall system accuracy, speed6 1.5 % of speedfrom 6.4 km/h (4.0 mph) to 48.0 km/h (30.0 mph).7.8.1.3 Shunt CalibrationAll strain-gage transducers shallbe equipped with shunt calibration resistors that can beconn
35、ected before or after test runs. The calibration signal shallbe in the range of the expected measurement for each analoguechannel7.8.1.4 RuggednessThe exposed portions of the systemshall tolerate 100 % relative humidity (rain or spray) and allother adverse conditions such as dust, shock, and vibrati
36、onswhich may be encountered in regular operation.7.8.2 Vehicle SpeedVehicle forward speed (normally ob-tained from a front non-driven wheel on the test vehicle) shallbe measured digitally with an encoder or optical system havinga minimum of 500 counts per revolution. Output shall bedirectly visible
37、to the driver and shall be simultaneouslyrecorded. It may be necessary on a very low coefficient surface,i.e., ice, to disconnect any braking action to the wheel beingutilized for measuring vehicle speed. A separate fifth-wheelsystem may be utilized to measure vehicle forward speed.7.8.3 Test Wheel
38、SpeedTest wheel speed shall be mea-sured digitally with an encoder or optical system having aminimum of 1000 counts per wheel revolution. The outputshall be recorded.7.8.4 Vertical LoadThe vertical load-measuring trans-ducer shall measure the vertical load at the test wheel duringdriving torque appl
39、ication. The transducer full scale range shallbe in excess of the dynamic loading during a test. Data pointsshall be evaluated to ensure dynamic loading is within thecalibrated range of the transducer. The static load should beless than 80 % of the calibrated range. The transducer designand location
40、 shall minimize inertial effects and vibration-induced mechanical resonance. The transducer shall have anoutput directly proportional to the force with less than 1 %hysteresis and less than 1 % nonlinearity at full scale. It shallhave less than 2 % cross-axis sensitivity at full scale. Thetransducer
41、 shall be installed in such a manner as to experienceless than 1 angular rotation with respect to its measuring axesat a maximum expected driving torque. The transducerstypically have a minimum full scale range of 0 to 8.9 kN(2000 lbf).7.8.5 Driving Traction ForcesThe driving traction force-measurin
42、g transducers shall measure longitudinal force gener-ated at the tire-road interface as a result of driving torqueapplication with a full scale range of at least 100 % of theapplied static vertical load. Otherwise, the transducers shallhave the same specifications as those described in 7.8.4.7.8.6 S
43、ignal Conditioning and Recording SystemAll sig-nal conditioning and recording equipment shall provide linearoutput with necessary gain and reading resolution to meet therequirements of 7.8.1. Additionally, it shall have the followingspecifications:7.8.6.1 Minimum Frequency Responseflat from dc to 18
44、Hz, within 61%,NOTE 1Based on a study of a sample acquisition and force transducersystem, a resonant frequency of 20 Hz was measured.F1805 1237.8.6.2 Signal-to-Noise Ratioat least 20/1,7.8.6.3 Gain shall be sufficient to permit full-scale displayfor full-scale input signal level,7.8.6.4 Input impeda
45、nce shall be at least ten times largerthan the output impedance of the signal source,7.8.6.5 The system must be insensitive to vibrations,acceleration, and changes in ambient temperature. The error inreading shall not exceed 1 % full scale when subjected tovibration acceleration of 49.0 m/s2(5 gs) i
46、n the 0.5 to 40 Hzfrequency range and operating temperature range from 23 to43C (10 to 110F),7.8.6.6 The system shall not be affected by storage tempera-ture variations between 40 and 71C (40 and 160F),7.8.6.7 The individual data inputs shall have a sample rateof not less than 100 samples/s. For a g
47、iven sample, vehiclespeed, test wheel speed, vertical load, and driving tractionforce shall all be recorded within 0.0005 s,7.8.7 Power Supply The power supply for transducers andrecording system shall meet or exceed requirements specifiedby transducer and recorder manufacturers.7.8.8 Temperature me
48、asurement devices for taking surfaceand ambient temperatures shall have a resolution of 0.5C(1F) and an accuracy of 61C (62F).7.8.9 Pressure measurement devices for setting tire pressureshall have a resolution of 3.5 kPa (12 psi) and an accuracy of63.5 kPa (612 psi).8. Calibration8.1 All instrumenta
49、tion shall be calibrated within sixmonths prior to testing.8.2 Calibrate the reference load cell by inputting knownvertical and horizontal forces. The known forces must betraceable to the National Institute of Standards and Technology(NIST).8.3 Calibrate the transducer for measuring vertical andhorizontal forces on the test wheel with the reference load cellin accordance with Practice F377.8.3.1 For longitudinal force calibration, place vehicle trans-mission in “park” position. Restrain the test vehicle using thevehicle brakes normall
