1、Designation: E1215 93 (Reapproved 2017)Standard Specification forTrailers Used for Measuring Vehicular Response to RoadRoughness1This standard is issued under the fixed designation E1215; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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 specification covers the design, performance, andoperating features of a trailer used for measur
3、ing response toroad roughness.1.2 The specified trailer is a two-wheeled, single-axle ve-hicle that is towed on highways at typical traffic speeds whilethe relative movement between the axle and body is transducedand recorded as an indication of road roughness.1.3 The instrumentation for sensing the
4、 movements of thetrailer is not covered in this specification. One example ofinstrumentation is described in Test Method E1082.1.4 The values stated in inch-pound units are to be regardedas the standard.1.5 The following caveat pertains only to Section 5 of thisspecification: This standard does not
5、purport to address all ofthe safety 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.1.6 This international standard was develo
6、ped in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Docum
7、ents2.1 ASTM Standards:2E1082 Test Method for Measurement of Vehicular Responseto Traveled Surface RoughnessE1136 Specification for P195/75R14 Radial Standard Refer-ence Test Tire2.2 Other Document:A4082 TPC Tire Performance Criteria, Procedures andSpecifications33. Terminology3.1 Definitions of Ter
8、ms Specific to This Standard:3.1.1 sprung massthe total mass minus the unsprungmass.3.1.2 suspension deflectionthe change in the vertical dis-tance between the axle at its centerline and a hypotheticalreference line directly above the axle centerline on the rigidframe structure.4. Other Requirements
9、4.1 Damping Ratio of Suspension SystemThe dampingratio of the suspension system on the assembled trailer shall beevaluated by measuring the accumulated suspension movementon the trailer as it is towed over a known or standard calibrationtest surface. It must be verified that it meets one of theaccep
10、tance criteria.3The design requirements for the shockabsorbers (5.1.1.3) may be used as an alternative to thisrequirement.4.2 Spring RateThe spring force constant (spring rate) ofthe assembled suspension shall be measured as follows:4.2.1 Apparatus:4.2.1.1 Dial Indicators, with a nominal accuracy of
11、0.001 in. (0.025 mm). Two are required.4.2.1.2 Loading Weights, permitting load increments ofapproximately 20 lbf (89 N) are required.4.2.2 ProcedureMeasure the vertical deflections of thesuspension by placing the dial indicators at points proximate tothe coil springs. With the trailer parked on a l
12、evel surface,gently apply the weights, in approximately 20-lbf (89-N)increments, on the longitudinal centerline of the trailer directlyabove the centerline of the axle while recording the suspensiondeflection values observed on each dial indicator. Take care notto jar the trailer when applying the w
13、eights. Once all the1This specification is under the jurisdiction ofASTM Committee E17 on Vehicle- Pavement Systems and is the direct responsibility of Subcommittee E17.31 onMethods for Measuring Profile and Roughness.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in
14、1987. Last previous edition approved in 2012 as E1215 93 (2012).DOI: 10.1520/E1215-93R17.2For 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 Summ
15、ary page onthe ASTM website.3Available from General Motors Engineering Staff, GM Proving Ground,Milford, MI 48042.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationa
16、lly recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1weights have been applied up to the total mass, remove
17、them inthe same manner while recording the deflection measurementsat each increment.4.2.3 Data ReductionSeparately plot the load-deflectionvalues for each suspension system (left and right) on rectilineargraph paper. Draw a straight line that best reflects the slope ofthe upward (loading) and downwa
18、rd (unloading) data points,ignoring the initial data point if necessary. The slope of thatline is the spring rate and must fall within the range of 180 to220 lbf/in. (32 to 39 N/mm).4.3 Legal Requirements:4.3.1 The vehicle and trailer shall comply with all appli-cable state and federal laws, includi
19、ng those related to hitchconnections and lighting of towed vehicles.4.3.2 Reasonable precautions shall be taken beyond thoseimposed by laws and regulations to ensure maximum safety ofoperating personnel and other traffic.5. Design Requirements5.1 ChassisThe chassis shall consist of a rigid framesusp
20、ension, two wheels mounted on a rigid axle, and a towhitch.5.1.1 Suspension SystemThe trailer frame shall be sus-pended on the axle by a system that includes the followingcomponents:5.1.1.1 Horizontal Linkages shall separately constrain theaxle in the longitudinal and lateral directions while allowi
21、ngfree vertical excursion.5.1.1.2 SpringsTwo coil springs connecting the axle andframe shall be mounted vertically over the centerline of theaxle. The force constant of each spring shall be 200 620 lbfin. (3506 35 N/mm or m). The springs shall beequidistant from the longitudinal centerline of the tr
22、ailer at adistance not less than 15 in. (0.38 m).5.1.1.3 Shock AbsorbersTwo shock absorbers, mountedvertically from the axle to the trailer frame, shall be equidistantfrom the longitudinal centerline of the trailer. The ratios of theshock absorbers damping value over12 the sprung mass(2C/MS) shall b
23、e in the range of 5.5 to 13 s1with a mean valueof 8 s1.4The performance requirement for the damping rate ofthe suspension system in 4.1 may be used as an alternative tothis requirement.5.1.2 Axle and WheelsThe trailer shall have a two-wheelrigid axle in accordance with the following requirements:5.1
24、.2.1 WheelsThe wheels shall be 15 by 6 in. rims.Radial runout at the bead seats of the wheels when installed onthe axle shall be less than 0.01 in. (0.25 mm) peak-to-peak. Therim shall be marked to indicate the “low-point” for matchingwith the tire. The low-point is established by determining thepoi
25、nts of minimum radius on each bead seat and locating thelow-point intermediately between those points in proportion totheir relative magnitudes.5.1.2.2 TiresThe tires shall be size P215/75R15, orequivalent, or Specification E1136, and shall meet the GMTPCSpecification.3Before operation, set the tire
26、 inflation pressureat the tire manufacturers maximum recommended pressure forsize and type of tire used at ambient temperature.5.1.2.3 Optional AlternativeIf the equipment given in4.2.1 is used, the dial indicators are placed close to the tires tomeasure axle-to-road displacement. The tire pressure
27、is ad-justed to give a116-in. (1.6-mm) vertical displacement when200 lbf (890 N) is used rather than the manufacturersmaximum recommended pressure.5.1.2.4 Tire-Wheel AssemblyThe tires shall be mounted onthe wheels so that the painted dot indicating peak tire runoutreaches the low-point mark on the w
28、heel. The tire-wheelassemblies shall be balanced within 8.0 in./oz (0.58 cm/kg).5.1.2.5 Wheel TrackThe lateral distance between the cen-ter planes of the two tires shall be 68 6 5 in. (1.73 6 0.13 m).5.1.3 Tow HitchA ball-type hitch receptacle shall bemounted at the forward end of the frame on the l
29、ongitudinalcenterline of the trailer.NOTE 1The towing vehicle must have power enough to pull the trailerat whatever uniform velocity is specified, even up 6 % grades, and mustbe in good operating condition, particularly its shock absorbers.5.1.3.1 WheelbaseThe trailer shall be designed so that thelo
30、ngitudinal distance between the center of the ball-hitch andthe centerline of the axle shall be 120 6 1 in. (3.05 6 0.03 m).5.1.4 Total MassThe mass of the fully assembled trailershall be 1660 6 50 lbm (753 6 23 kg), and it shall bedistributed so that the ground load at each of the wheels will be780
31、 6 20 lbf (3470 6 89 N), and the hitch load shall be 1006 10 lbf (445 6 44 N). The center of percussion in the verticalplane shall be located as near to the axle as possible.5.1.5 Unsprung MassThe total mass of the axle, wheels,and tires, together with that of the suspension system, shall be320 6 30
32、 lbm (145 6 14 kg).5.1.6 Sprung Massshall normally be 1340 lbm (608 kg).NOTE 2The ratio of the unsprung mass to the sprung mass (Mu/Ms)ishigher than many automobiles.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:E17-1002. Cont
33、actASTM CustomerService at serviceastm.org.E1215 93 (2017)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such pat
34、ent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited eit
35、her for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair
36、hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this stand
37、ard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 93 (2017)3
