1、Designation: F1650 98 (Reapproved 2014)Standard Practice forEvaluating Tire Traction Performance Data Under VaryingTest Conditions1This standard is issued under the fixed designation F1650; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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.INTRODUCTIONTire traction testing programs at proving grounds or other exterior test sites are often extended o
3、vera period of days or weeks. During this time period test conditions may change due to a number ofvarying factors, for example, temperature, rain or snow fall, surface texture, water depth, and windvelocity and direction. If tire performance comparisons are to be made over any part of the testprogr
4、am (or the entire program) where these test condition variations are known or suspected to affectperformance, the potential influence of these variations must be considered in any final evaluation oftraction performance.1. Scope1.1 This practice covers the required procedures for exam-ining sequenti
5、al control tire data for any variation due tochanging test conditions. Such variations may influence abso-lute and also comparative performance of candidate tires, asthey are tested over any short or extended time period. Thevariations addressed in this practice are systematic or biasvariations and
6、not random variations. See Appendix X1 foradditional details.1.1.1 Two types of variation may occur: time or testsequence “trend variations,” either linear or curvilinear, and theless common transient or abrupt shift variations. If anyobserved variations are declared to be statistically significant,
7、the calculation procedures are given to correct for the influenceof these variations. This approach is addressed in Method A.1.2 In some testing programs, a policy is adopted to correctall candidate traction test data values without the application ofa statistical routine to determine if a significa
8、nt trend or shift isobserved. This option is part of this practice and is addressedin Method B.1.3 The issue of rejecting outlier data points or test valuesthat might occur among a set of otherwise acceptable datavalues obtained under identical test conditions in a short timeperiod is not part of th
9、is practice. Specific test method or otheroutlier rejection standards that address this issue may be usedon the individual data sets prior to applying this practice and itsprocedures.1.4 Although this practice applies to various types of tiretraction testing (for example, dry, wet, snow, ice), the p
10、roce-dures as given in this practice may be used for any repetitivetire testing in an environment where test conditions are subjectto change.1.5 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
11、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:2E501 Specification for Rib Tire for Pavement Skid-Resistance TestsE524 Specification for Smooth Tire for Pavement Skid-Resistance T
12、estsE826 Practice for Testing Homogeneity of a Metal Lot orBatch in Solid Form by Spark Atomic Emission Spec-trometryE1136 Specification for P195/75R14 Radial Standard Refer-ence Test Tire1This practice is under the jurisdiction ofASTM Committee F09 on Tires and isthe direct responsibility of Subcom
13、mittee F09.20 on Vehicular Testing.Current edition approved Jan. 1, 2014. Published February 2014. Originallyapproved in 1995. Last previous edition approved in 2005 as F1650 98 (2005).DOI: 10.1520/F1650-98R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custo
14、mer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1F538 Terminology Relating to the Char
15、acteristics and Per-formance of Tires3. Terminology3.1 Descriptions of Terms Specific to This StandardDescriptions of terms particular to this practice are listed eitheras principal terms or under principal terms as derived terms.3.2 Discussion:3.2.1 The terminology in this section is currently unde
16、rreview by Subcommittee F09.94 on Terminology. This termi-nology is subject to change and should be considered tentative.3.2.2 candidate tire (set), na test tire (or test tire set) thatis part of an evaluation program; each candidate tire (set)usually has certain unique design or other features that
17、 distin-guish it from other candidate tires in the program.3.2.3 control tire (set), na reference tire (or reference set)repeatedly tested in a specified sequence throughout an evalu-ation program, that is used for data adjustment or statisticalprocedures, or both, to offset or reduce testing variat
18、ion andimprove the accuracy of candidate tire (set) evaluation ordetect test equipment variation, or both.3.2.4 reference tire (set), na special test tire (test tire set)that is used as a benchmark in an evaluation program; thesetires usually have carefully controlled design features tominimize vari
19、ation.3.2.5 standard reference test tire, SRTT, n a tire that meetsthe requirements of Specification E1136, commonly used as acontrol tire or surface monitoring tire.3.2.6 surface monitoring tire (set), n a reference tire (orreference set), used to evaluate changes in the test surface overa selected
20、 time period.3.2.7 test, na technical procedure performed on an object(or set of objects) using specified equipment, that producesdata; the data are used to evaluate or model selected propertiesor characteristics of the object (or set of objects).3.2.8 test run, nin tire testing, a single pass (over
21、 a testsurface) or sequence of data acquisition, or both, in the act oftesting a tire or tire set under selected test conditions.3.2.9 test tire, na tire used in a test.3.2.10 test tire set, none or more tires, as required by thetest equipment or procedure, to perform a test, producing asingle set o
22、f results; these tires are usually nominally identical.3.2.11 traction test, n in tire testing, a series of n test runsat a selected operational condition; a traction test is character-ized by an average value for the measured performanceparameter.4. Significance and Use4.1 Tire testing is conducted
23、 to make technical decisions onvarious performance characteristics of tires, and good technicaldecisions require high quality test data. High quality test dataare obtained with carefully designed and executed tests.However, even with the highest quality testing programs,unavoidable time or test sequ
24、ence trends or other perturbationsmay occur. The procedures as described in this practice aretherefore needed to correct for these unavoidable testingcomplications.5. Summary of Practice5.1 This practice specifies certain test plans for testingcontrol tires. Testing begins with an initial test of th
25、e controltire or tire set.Anumber of candidate tire traction tests are thenconducted followed by a repeat test of the control tire tractiontest. Additional candidate traction tests are conducted prior tothe next control tire traction test. This sequential procedure isrepeated for the entire evaluati
26、on program.5.2 Using control tire average measured performanceparameters, the performance parameters of the candidate tires(sets) are corrected for any changes in test conditions. Twocorrection procedures are described (Method A and Method B)that use different reference points for data correction an
27、d assuch give different values for the corrected actual or absolutetraction parameters. However, both test methods give the samerelative ratings or traction performance indexes. See Section 10for more details. The two test methods are summarized in moredetail in Section 6 and Section 9. Both Methods
28、 A and B haveadvantages and disadvantages.5.2.1 Method A uses the initial operational conditions de-fined by the first control traction test as a reference point. Thecalculations correct all traction test performance parameters(for example, traction coefficients) to the initial level orcondition of
29、the pavement or other testing conditions, or both.With this test method, corrections may be made after only afew candidate and control sets have been evaluated.5.2.2 Method B uses essentially the midpoint of any evalu-ation program, with the grand average traction test value as areference point. Thi
30、s grand average value is obtained withhigher precision than the initial control traction test average ofMethod A, since it contains more values. However, Method Bcorrections cannot be made until the grand average value isestablished, which is normally at the end of any program.5.3 Annex A1 provides
31、illustrations of several types oftypical variation patterns for control tire data. It additionallyprovides an example of the Method A correction calculationsrequired to evaluate a set of candidate test tires. Method Bcorrections follow the same general approach as illustrated inAnnex A1, with Cavgus
32、ed in place of C1.5.4 Annex A2 provides a recommended technique forweighting the correction of the two or three candidate values(for example, T1, T2, T3) between each pair of control values.This gives a slightly improved correction that may be impor-tant in certain testing operations.5.5 Appendix X1
33、 provides a statistical model for the trac-tion measurement process. This may help the user of thispractice to sort out the differences between fixed or biascomponents of variation and random components of variation.Appendix X1 gives a rationale for the procedures as outlined inthis practice.F1650 9
34、8 (2014)25.6 Annex A2 contains some background and details on thepropagation of error or test variation that occurs when correc-tions are applied to the measured traction performance param-eters and when traction performance indexes are calculated.METHOD ADATA CORRECTIONS BASED ONINITIAL CONTROL TRA
35、CTION TEST6. Summary of Method A6.1 This method corrects the data obtained throughout theevaluation program to the initial conditions (test surface orother, or both)“ reference point” at the beginning of theprogram. The correction procedure (and calculation algorithm)for time trend variations is mat
36、hematically equivalent to thatdescribed in Practice E826. The procedure used for abrupt orstep changes is provisional and is subject to change asexperience is gained. In this method the initial traction testvalue for the control tire is a key data point. This method alsoallows for decisions on the n
37、eed for any correction, based on astatistical analysis of the control tire data.7. Procedure7.1 The test procedure is given in terms of testing tire sets offour tires, that is, one tire on each of four vehicle positions. Ifonly one tire is to be tested (trailer or other dynamometervehicle testing),
38、follow the procedure as outlined with theunderstanding that the one tire replaces the tire set.7.2 Assemble all the tire sets to be tested in any evaluationprogram or for daily testing. Select the test speeds to be usedand other operational test conditions as well as the order inwhich the candidate
39、tire sets are to be tested.7.2.1 For any selected order, a test plan is established withreference tire(s) designated as a control tire set tested at regularintervals among the selected candidate sets. Select the numberof test runs or replicates for both control and candidate tire sets.Acomplete test
40、 for a tire set is defined as the total of p tractiontests, one at each selected operational test condition, with nreplicate test runs for each operational condition (for example,speed and surface type).7.2.2 Tests with a surface monitoring tire may also beconducted on a regular basis in addition to
41、 the control tire.7.3 Test SequenceThe control tires may be standard tiresas specified in Specifications E501, E524, and E1136, or a tireset similar in design and performance level to the candidatesets. Conduct a complete test for the control sets in relation tothe candidate sets as given in Table 1
42、. Two test plans are given:Plan A, in which (excluding the initial control set) candidatetires constitute 67 % of the tires tested, and Plan B, in whichcandidate tires constitute 75 % of the tires tested.7.4 Number of Test Runs at Each Speed or OperationalConditionThe number of test runs or replicat
43、es, n, for eachspeed or other selected operational condition for each candi-date tire set and each control set, except the first set, shall beselected. The number of test runs depends on the test method.Good testing procedure calls for as many test runs as possible.If direction of test is important
44、on any test surface, one half ofthe test runs shall be in each direction.7.4.1 Number of Test Runs: Initial Control SetThe initialtest for the control, indicated by C1, is a key value used forcorrection of candidate set performance parameter values astesting proceeds. Therefore, the average performa
45、nce param-eters for C1 must be evaluated with a high degree of confidenceand the recommended number of test runs for C1 should be atleast two times the number of test runs selected in 7.4.7.4.2 More than One Control TireIn some types of testing,the control tire is damaged or changed by the testing t
46、o theextent that it ceases to function as a stable control. In suchsituations it is necessary to use more than one control tirethroughout any evaluation program. In such cases a control tireindication scheme such as C1-1, C1-2, C1-3, C2-4, C2-5, C2-6,C3-1, etc., is suggested. In this scheme, C1-1 =
47、control tire 1,sequence use 1; C1-2 = control tire 1, sequence use 2; . .,C2-4 = control tire 2, sequence use 4, etc.7.5 Table of ResultsPrepare a table of test results andrecord all data with columns for:7.5.1 Test sequence number, a sequential indication from 1to m, of all the tests for any progra
48、m of evaluation,7.5.2 Tire set identification,7.5.3 Speed or other selected operational test condition(s),and7.5.4 Average value (for n test runs) for the measuredparameter for that operational condition.7.6 Both control and candidate set data shall be included inthe table in the order as tested. If
49、 deemed important, a separatetable of ambient temperature, wind direction, wind velocity, orother weather information also shall be prepared on a selectedtime (hourly) basis.8. Calculations for Corrected Traction Performance Data8.1 Preliminary Control Set Data ReviewThe decision tocorrect data, for any part of the test program where candidateset comparisons are to be made, is based on the time or testsequence response of the control tire parameters for each speedor other selected operational test condition. Corrections mayalso be made for the entire test program.
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