1、Designation: F1805 12F1805 16Standard 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
2、 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 test method covers a procedure for measuring the driving traction of passenger car and lig
3、ht truck tires while travelingin 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 specially instrumenteddrive axle to measure fore-aft and vertical forces acting on a single driven test tire.1.3
4、This test method is suitable for research and development purposes where tires are compared during a single series of tests.They may not be suitable for regulatory statutes or specification acceptance because the values obtained may not necessarily agreeor correlate either in rank order or absolute
5、traction performance level with those obtained under other environmental conditionson other surfaces or the same surface after additional use.1.4 The values stated in SI units are to be regarded as the standard. Ordinarily, N and kN should be used as units of force. Thisstandard may utilize kgf as a
6、 unit of force in order to accommodate the use of load and pressure tables, as found in other standardsboth domestic and global that are commonly used with this standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns
7、, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1136 Specification for P195/75R14 Radial Stan
8、dard Reference Test TireF377 Practice for Calibration of Braking/Tractive Measuring Devices for Testing TiresF538 Terminology Relating to the Characteristics and Performance of TiresF1046 Guide for Preparing Artificially Worn Passenger and Light Truck Tires for TestingF1572 Test Methods for Tire Per
9、formance Testing on Snow and Ice SurfacesF1650 Practice for Evaluating Tire Traction Performance Data Under Varying Test ConditionsF2493 Specification for P225/60R16 97S Radial Standard Reference Test Tire2.2 Other Standards:The European Tyre and Rim Technical Organisation Standards Manual3The Japan
10、 Automobile Tyre Manufacturers Association ManualAssociation, Inc. Yearbook4The Tire the test results for this tire have significance as a base valueor internal benchmark. F5383.1.11 snow, hard pack, n in tire testing, packed base without loose snow. F5383.1.12 snow, medium pack, n in tire testing,
11、groomed packed base with 2.5 to 5.0 cm (1 to 2 in.) loose snow. F5383.1.13 snow, medium hard pack, n in tire testing, packed base with some loose snow. F5383.1.14 snow, soft pack, n in tire testing, freshly fallen or deeply groomed base snow with 5.0 to 7.5 cm (2 to 3 in.) loose snow.F5383.1.15 spin
12、 velocity, nthe angular velocity of the wheel about its spin axis. F5383.1.16 standard reference test tire (SRTT), na tire that is used as a control tire or surface monitoring tire (for example,Specification E1136 and Specification F2493 tires). F5383.1.16.1 DiscussionWhile ASTM designates several t
13、ire specifications as Standard Reference Test Tires, Test Method F1805 has historically used theSpecification E1136 tire as its primary reference tire and this specification is specifically identified as the control tire in the RMATire Information Service Bulletin Vol. 37/No. 3, which specifies requ
14、irements for application of the Severe Snow Use Symbol (3peak mountain snowflake).3.1.17 surface monitoring tire, na reference tire used to evaluate changes in the test surface over a selected time period. F5383.1.18 test (or testing), na procedure performed on an object (or set of nominally identic
15、al objects) using specified equipmentthat produces data unique to the object (or set). F5383.1.18.1 DiscussionTest data are used to evaluate or model selected properties or characteristics of the object (or set of objects). The scope of testingdepends on the decisions to be made for any program, and
16、 sampling and replication plans (see definitions below) need to bespecified for a complete program description.3.1.19 test matrix, n in tire testing a group of candidate tires, usually with specified reference tires; all tests are normallyconducted in one testing program. F5383.1.20 test run, na sin
17、gle pass of a loaded tire over a given test surface. F538F1805 1623.1.21 test tire, na tire used in a test. F5383.1.22 test tire set, none or more test tires, as required by the test equipment or procedure, to perform a test, thereby producinga single test result. F5383.1.22.1 DiscussionThe four nom
18、inally identical tires required for vehicle stopping distance testing constitute a test tire set. In the discussion belowwhere the test tire is mentioned, it is assumed that the test tire set may be substituted for the test tire, if a test tire set is requiredfor the testing.3.1.23 traction test, n
19、in tire testing, a series of n test runs at a selected operational condition; a traction test is characterizedby an average value for the measured performance parameter. F5383.1.24 vertical load, nthe normal reaction of the tire on the road which is equal to the negative of normal force. F5384. Summ
20、ary of Test Method4.1 These test methods describe the use of an instrumented vehicle with a single test wheel capable of measuring the tireperformance properties under drive torque on snow and ice surfaces when traveling in a straight line.4.2 The test is conducted by driving the test vehicle over t
21、he test surface. Driving torque is gradually increased to the test wheelwhile maintaining the vehicle speed by applying braking torque to the non-test wheels of the vehicle. The driving tractioncoefficient is determined from the measured values of longitudinal and vertical forces over a specified sl
22、ip or time range. Therecommended vehicle test speed is 8.0 km/hr (5.0 mph).5. Significance and Use5.1 This test method describes a technique for assessing the performance characteristics of tires in a winter environment onsnow and ice surfaces. When snow is referred to hereafter, ice is implied as a
23、ppropriate.5.2 The measured values quantify the dynamic longitudinal traction properties of tires under driving torque. Dynamic tractionproperties are obtained on snow surfaces prepared in accordance with the stated test procedures and attempts to quantify the tiresperformance when integrated into a
24、 vehicle-environmental system. Changing any one of these environmental factors will changethe measurements obtained on a subsequent test run.5.3 This test method addresses longitudinal driving traction properties only on snow and ice surfaces. Refer to Test MethodsF1572 for test methods for braking
25、and lateral traction properties on snow or ice, or both.6. Interferences6.1 Factors that may affect tire snow performance and must be considered in the final analysis of data include:6.1.1 Snow temperature,6.1.2 Ambient temperature,6.1.3 Mechanical breakdown of the agglomerated snowflake into granul
26、ar crystals,6.1.4 Solar load,6.1.5 Tire temperature,6.1.6 Tire wear condition (preparation),6.1.7 Tire 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 maintaining the specified test speed 6 0.
27、8 km/h (6 0.5 mph) during all levelsof driving torque application.7.2 The test vehicle shall be equipped with an automatic throttle actuator to allow the gradual increase of driving torque at apredetermined (repeatable) rate.7.3 The test vehicle shall be a rear drive, four wheel passenger car or a l
28、ight truck less than or equal to 44.5 kN (10 000 lbf)GVW. The range of test tires and load conditions will determine the vehicle size and selection. Utilizing a front wheel drive testvehicle is not addressed in this standard although the basic procedures could be applied with appropriate conditional
29、 modifications.7.4 The test vehicle shall be instrumented to measure longitudinal and vertical forces at the tire and test surface interface duringthe application of driving torque.F1805 1637.5 The test vehicle shall have provisions to automatically and completely disengage the brake on the test whe
30、el (if installed)prior to throttle application. Complete disengagement is necessary to eliminate all drag that might be caused by the brake assembly.7.6 Opposite Tire:7.6.1 The tire installed opposite the instrumented test wheel shall have a sufficiently large traction coefficient to minimize slipof
31、 this tire during the traction test. The opposite tire should have a coefficient at least 50 % greater than the expected coefficientof the test tire. A tire chain may be utilized to increase the traction of the opposite tire when testing on snow surfaces.7.6.2 The opposite tire shall be selected to
32、have an outside diameter that is within 62.5 cm (61 in.) of that of the test tire.7.7 A suitable ride height adjustment system on the rear axle shall be provided to permit adjustment for each tire size and loadto minimize transducer crosstalk as established during calibration.7.8 InstrumentationThe
33、test wheel position on the test vehicle shall be equipped with a wheel rotational velocity measuringsystem and with transducers to measure the dynamic longitudinal force and vertical load at the test wheel.7.8.1 General Requirements for Measurement SystemThe instrumentation system shall conform to t
34、he following overallrequirements at ambient temperatures between 23 and 43C (10 and 110F):7.8.1.1 Overall system accuracy, force6 1.5 % of vertical load or traction force from 450 N (100 lbf) to full scale.7.8.1.2 Overall system accuracy, speed6 1.5 % of speed from 6.4 km/h (4.0 mph) to 48.0 km/h (3
35、0.0 mph).7.8.1.3 Shunt CalibrationAll strain-gage transducers shall be equipped with shunt calibration resistors that can be connectedbefore or after test runs. The calibration signal shall be in the range of the expected measurement for each analogue channel7.8.1.4 RuggednessThe exposed portions of
36、 the system shall tolerate 100 % relative humidity (rain or spray) and all otheradverse conditions such as dust, shock, and vibrations which may be encountered in regular operation.7.8.2 Vehicle SpeedVehicle forward speed (normally obtained from a front non-driven wheel on the test vehicle) shall be
37、measured digitally with an encoder or optical system having a minimum of 500 counts per revolution. Output shall be directlyvisible to the driver and shall be simultaneously recorded. It may be necessary on a very low coefficient surface, i.e., ice, todisconnect any braking action to the wheel being
38、 utilized for measuring vehicle speed. A separate fifth-wheel system may beutilized to measure vehicle forward speed.7.8.3 Test Wheel SpeedTest wheel speed shall be measured digitally with an encoder or optical system having a minimum of1000 counts per wheel revolution. The output shall be recorded.
39、7.8.4 Vertical LoadThe vertical load-measuring transducer shall measure the vertical load at the test wheel during drivingtorque application. The transducer full scale range shall be in excess of the dynamic loading during a test. Data points shall beevaluated to ensure dynamic loading is within the
40、 calibrated range of the transducer. The static load should be less than 80 % ofthe calibrated range. The transducer design and location shall minimize inertial effects and vibration-induced mechanicalresonance. The transducer shall have an output directly proportional to the force with less than 1
41、% hysteresis and less than 1 %nonlinearity at full scale. It shall have less than 2 % cross-axis sensitivity at full scale. The transducer shall be installed in sucha manner as to experience less than 1 angular rotation with respect to its measuring axes at a maximum expected driving torque.The tran
42、sducers typically have a minimum full scale range of 0 to 8.9 kN (2000 lbf).7.8.5 Driving Traction ForcesThe driving traction force-measuring transducers shall measure longitudinal force generated atthe tire-road interface as a result of driving torque application with a full scale range of at least
43、 100 % of the applied static verticalload. Otherwise, the transducers shall have the same specifications as those described in 7.8.4.7.8.6 Signal Conditioning and Recording SystemAll signal conditioning and recording equipment shall provide linear outputwith necessary gain and reading resolution to
44、meet the requirements of 7.8.1. Additionally, it shall have the followingspecifications:7.8.6.1 Minimum Frequency Responseflat from dc to 18 Hz, within 61 %,NOTE 1Based on a study of a sample acquisition and force transducer system, a resonant frequency of 20 Hz was measured.7.8.6.2 Signal-to-Noise
45、Ratioat least 20/1,7.8.6.3 Gain shall be sufficient to permit full-scale display for full-scale input signal level,7.8.6.4 Input impedance shall be at least ten times larger than the output impedance of the signal source,7.8.6.5 The system must be insensitive to vibrations, acceleration, and changes
46、 in ambient temperature. The error in readingshall not exceed 1 % full scale when subjected to vibration acceleration of 49.0 m/s2 (5 gs) in the 0.5 to 40 Hz frequency rangeand operating temperature range from 23 to 43C (10 to 110F),7.8.6.6 The system shall not be affected by storage temperature var
47、iations between 40 and 71C (40 and 160F),7.8.6.7 The individual data inputs shall have a sample rate of not less than 100 samples/s. For a given sample, vehicle speed,test wheel speed, vertical load, and driving traction force shall all be recorded within 0.0005 s,7.8.7 Power SupplyThe power supply
48、for transducers and recording system shall meet or exceed requirements specified bytransducer and recorder manufacturers.7.8.8 Temperature measurement devices for taking surface and ambient temperatures shall have a resolution of 0.5C (1F) andan accuracy of 61C (62F).7.8.9 Pressure measurement devic
49、es for setting tire pressure shall have a resolution of 3.5 kPa (12 psi) and an accuracy of 63.5kPa (612 psi).F1805 1648. Calibration8.1 All instrumentation shall be calibrated within six months prior to testing.8.2 Calibrate the reference load cell by inputting known vertical and horizontal forces. The known forces must be traceable tothe National Institute of Standards and Technology (NIST).8.3 Calibrate the transducer for measuring vertical and horizontal forces on the test wheel with the reference load cell inaccordance with P
