ASTM F408-1999(2015) Standard Test Method for Tires for Wet Traction in Straight-Ahead Braking Using a Towed Trailer《用拖挂车朝正前方制动时潮湿牵引用轮胎的标准试验方法》.pdf
《ASTM F408-1999(2015) Standard Test Method for Tires for Wet Traction in Straight-Ahead Braking Using a Towed Trailer《用拖挂车朝正前方制动时潮湿牵引用轮胎的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM F408-1999(2015) Standard Test Method for Tires for Wet Traction in Straight-Ahead Braking Using a Towed Trailer《用拖挂车朝正前方制动时潮湿牵引用轮胎的标准试验方法》.pdf(6页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: F408 99 (Reapproved 2015)Standard Test Method forTires for Wet Traction in Straight-Ahead Braking, Using aTowed Trailer1This standard is issued under the fixed designation F408; the number immediately following the designation indicates the year of originaladoption or, in the case of re
2、vision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of brakingtraction of tires designed for passenger cars or lig
3、ht trucks.Such braking traction measurements are applicable to condi-tions wherein the vehicle is traveling straight ahead on a wet,paved surface.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not pu
4、rport 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 determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E
5、274 Test Method for Skid Resistance of Paved SurfacesUsing a Full-Scale TireE1337 Test Method for Determining Longitudinal PeakBraking Coefficient of Paved Surfaces Using StandardReference Test TireF377 Practice for Calibration of Braking/Tractive MeasuringDevices for Testing TiresF457 Test Method f
6、or Speed and Distance Calibration ofFifth Wheel Equipped With Either Analog or DigitalInstrumentationF538 Terminology Relating to the Characteristics and Per-formance of TiresF1650 Practice for Evaluating Tire Traction PerformanceData Under Varying Test Conditions3. Terminology3.1 Definitions:3.1.1
7、braking force, F, nof a tire, the negative longitu-dinal force resulting from braking torque application. F5383.1.2 braking force coeffcient, nof a tire, the ratio ofbraking force to normal force. F5383.1.3 braking force coeffcient, peak, nof a tire, the maxi-mum value of tire braking force coeffici
8、ent that occurs prior towheel lockup as the braking torque is progressively increased.F5383.1.4 braking force coeffcient, slide, nof a tire, the valueof braking force coefficient obtained on a locked wheel. F5383.1.5 braking torque, ML2/T2, nof a vehicle, thenegative wheel torque. F5383.1.6 lockup,
9、nof a wheel, the condition of a wheel inwhich its rotational velocity about the wheel spin axis is zeroand it is prevented from rotating in the presence of appliedwheel torque.3.1.7 longitudinal force, F, nof a tire, the component ofthe tire force vector in the X direction. F5383.1.8 normal force, F
10、, nof a tire, the component of a tireforce vector in the Z direction. F5383.1.9 skid number (SN), nslide braking force coefficientmultiplied by 100. F5383.1.10 test run, na single pass of a loaded tire over a giventest surface. F5383.1.11 tire axis system, nthe origin of the tire-axis systemis the c
11、enter of the tire contact where the X-axis is theintersection of the wheel plane and the road plane with apositive direction forward, the Z-axis is perpendicular to theroad plane with a positive direction downward, and the Y-axisis in the road plane, its direction being chosen to make the axissystem
12、 orthogonal and right-hand.3.1.11.1 DiscussionSee Fig. 1. F5383.1.12 tire forces, F, nthe external forces acting on a tireby the road. F5383.1.13 torque, FL, nof a wheel, the external torqueapplied to a tire from a vehicle about the wheel spin axis.3.1.13.1 DiscussionDriving torque is positive wheel
13、torque; braking torque is negative wheel torque. F5381This test method is under the jurisdiction of ASTM Committee F09 on Tiresand is the direct responsibility of Subcommittee F09.20 on Vehicular Testing.Current edition approved May 1, 2015. Published June 2015. Originallyapproved in 1975. Last prev
14、ious edition approved in 2008 as F408 99 (2008).DOI: 10.1520/F0408-99R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe A
15、STM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.14 vertical load, nthe normal reaction of the tire onthe road which is equal to the negative of the normal force.F5384. Summary of Test Method4.1 The measurements are con
16、ducted on tires mounted on atrailer towed by a vehicle. Brakes are applied firmly until oneor both test tire(s) are locked and then held locked for a periodof at least 1.5 s at speeds ranging from 32 km/h (20 mph) to 96km/h (60 mph).4.2 Recommended vehicle test speeds are: 32, 64, and 96km/h (20, 40
17、, and 60 mph).5. Significance and Use5.1 The measured values are traction properties of tiresobtained with the towed trailer described here on a given roadsurface, under given environmental conditions (ambient androad surface temperature, humidity, wind speed and direction,purity and film depth of w
18、ater used to wet the road surface).They are carried out in accordance with the stated testprocedures and reflect the performance of the total tire-vehicleenvironmental system. A change in any of these factors maychange the measurements on a subsequent run of the test.5.2 These test methods are suita
19、ble for research and devel-opment purposes, where tires are compared during a singleseries of tests. They may not be suitable for regulatory statutesor specification acceptance, because the values obtained maynot necessarily agree or correlate either in rank order orabsolute traction performance lev
20、el with those obtained onother road surfaces (or the same surface after additional wear),under other environmental conditions, or other towed trailers,or other test devices, or with results obtained with other testprocedures.6. Apparatus6.1 The apparatus consists of tow vehicle and trailer. Ve-hicle
21、 and trailer must comply with all applicable state andfederal laws when operated on public roads.6.2 Tow Vehicle:6.2.1 The tow vehicle shall have the capability of towing thetrailer at specified speeds in the range from 32 to 96 km/h (20to 60 mph), which are to be kept constant to within 0.8 km/h(0.
22、5 mph), even at maximum level of application of brakingforces.6.2.2 The tow vehicle shall be equipped with the followingaccessories:6.2.2.1 Equipment to actuate brakes on towed trailer,6.2.2.2 A water tank to store sufficient water to supply thewatering system unless external watering is used,6.2.2.
23、3 Recording equipment to record signals from trans-ducers installed on the towed trailer,6.2.2.4 Hitch with adjustable height for towing the trailer,and6.2.2.5 Optional equipment to monitor and control brakelinepressure, brake application rate, and water application rate.6.3 Towed TrailerThe trailer
24、 shall be equipped with a towhitch and one or two test wheels which shall be instrumentedas described. A self-watering system is optional (see 6.3.6).Trailers shall be designed to accommodate the range ofpassenger car and light truck rim sizes to be tested.6.3.1 The hitch height shall be no higher t
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