ASTM_F_811_-_02_2010.pdf

Designation:F81102(Reapproved 2010)Standard Practice forAccelerometer Use in Vehicles for Tire Testing1This standard is issued under the fixed designation F811;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,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 practice covers guidelines for using accelerometersin test vehicles to evaluate dynamic accelerations resultingfrom various maneuvers such as braking,accelerating,orcornering.1.2 This practice is applicable to accelerometers that arerigidly attached to the body of the test vehicle or stabilized tothe earth-fixed axis system by means of a gyroscope.1.3 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.4 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 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific precau-tions are given in Section 6.2.Referenced Documents2.1 ASTM Standards:2F538 Terminology Relating to the Characteristics and Per-formance of Tires3.Terminology3.1 Definitions:3.1.1 accelerometer,nan instrument that senses inertialreaction to measure linear or angular acceleration.F5383.1.2 bandwidth,1/T,nthe range of frequencies withinwhich certain performance characteristics occur;specific limitsnormally apply.F5383.1.3 g,na unit of acceleration where 1 g is equal to theacceleration of gravity,9.8 m/s2(32.2 ft/s2).F5383.1.4 gyro-stabilized accelerometer,na precision verticalgyroscope fitted with one to three accelerometers to provideorthogonal measurements referenced to the earth-fixed axissystem.F5383.1.5 servo accelerometer,nan accelerometer containingservo mechanisms,electronics,and a seismic element to senseinertial reaction.F5383.1.6 strain gage accelerometer,nan accelerometer usingstrain gages to sense the motion of the seismic element.F5383.2 Definitions of Terms Specific to This Standard:3.2.1 performance accelerometer,na packaged accelera-tion measuring system with integral data processing capability.4.Significance and Use4.1 The measured accelerometer output can be used tocalculate traction properties of combined tire-vehicle systemsfor passenger cars,light trucks,and heavy trucks through useof applicable methods of testing.4.2 This practice is intended to achieve uniformity in testvehicle accelerometer use and in accelerometer signal process-ing.Through such usage,a basis for meaningful comparisonsof test results from different sources will be obtained.4.3 This practice is not applicable to accelerometers used indestructive testing,such as vehicle crash tests or vehiclevibration measurements.5.Apparatus5.1 Body-Mounted AccelerometerAn accelerometer shallbe used to measure vehicle accelerations in any of the threeprimary vehicle axes(use x,y,z as illustrated in Fig.1)andshall have the following specifications:5.1.1 RangeThe full-scale range of the accelerometershall be at least 61.0 g and not more than 65.0 g for units usedin the x and y axes,and at least 62.0 g and not more than 65.0g for units used in the z axis.5.1.2 AccuracyAmplitude accuracy shall be equal or bet-ter than 61%of full scale including all error sources.5.1.3 BandwidthThe frequency response of the completesystem shall be from DC to a minimum of 20 Hz.The outputshall not vary more than 62%of the static output over thisfrequency range.5.1.4 TemperatureThe operating temperature range shallbe,as a minimum,between 23 and 66C(10 and 150F)1This practice is under the jurisdiction of ASTM Committee F09 on Tires and isthe direct responsibility of Subcommittee F09.10 on Equipment,Facilities andCalibration.Current edition approved Feb.1,2010.Published May 2010.Originallyapproved in 1983.Last previous edition approved in 2002 as F811 02.DOI:10.1520/F0811-02R10.2For 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 ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 with a temperature sensitivity of less than 0.054%/C(0.03%/F)of full scale of the sensor.5.1.5 Cross-Axis SensitivityThe measured output shall notbe affected by more than 63%of the accelerations actingperpendicular to the measurement axis.5.2 Gyro-Stabilized AccelerometerAccelerometers thatare attached to a gyro-stabilized platform for the purpose ofeliminating the effects of vehicle pitch or roll attitudes mustmeet the requirements of 5.1.5.2.1 Gyro-Stabilized PlatformThe platform shall main-tain the accelerometer(s)in a horizontal p