ASTM_G_203_-_10_2016.pdf

Designation:G20310(Reapproved 2016)Standard Guide forDetermining Friction Energy Dissipation in ReciprocatingTribosystems1This standard is issued under the fixed designation G203;the number immediately following the designation indicates the year oforiginal adoption or,in the case of 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 guide covers and is intended for use in interpretingthe friction forces recorded in reciprocating tribosystems.Theguide applies to any reciprocating tribosystem,whether it is awear or fretting test or an actual machine or device.1.2 The energy dissipation guide was developed in analyz-ing friction results in the Test Method G133 reciprocatingball-on-flat test,but it applies to other ASTM or ISO recipro-cating tests.This technique is frequently used to record thefriction response in fretting tribosystems.1.3 Specimen material may play some role in the results ifthe materials under test display viscoelastic behavior.Thisguide as written is for metals,plastics,and ceramics that do notdisplay viscoelastic behavior.It also applies to lubricated andnon-lubricated contacts.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 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:2G40 Terminology Relating to Wear and ErosionG115 Guide for Measuring and Reporting Friction Coeffi-cientsG133 Test Method for Linearly Reciprocating Ball-on-FlatSliding WearG163 Guide for Digital Data Acquisition in Wear andFriction Measurements3.Terminology3.1 Definitions:3.1.1 coeffcient of friction,nin tribology,the dimension-less ratio of the friction force(F)between two bodies to thenormal force(N)pressing these bodies together.G403.1.2 frettingsmall amplitude oscillatory motion,usuallytangential between two solid surfaces in contact.G403.2 Definitions of Terms Specific to This Standard:3.2.1 friction envelopewhen making friction energy lossmeasurements,the graphic representation of the cyclic frictionforce versus time history of a tribosystem in which theboundaries surrounding these variations in time produces ashape with a measurable area.3.2.2 reciprocating tribosystemsliding system where thedirection of motion of the moving member periodically re-verses(for example,piston in a cylinder).3.3 Acronyms:3.3.1 DAS,ndata acquisition system.3.3.2 FED,nfriction energy dissipated.The work requiredto overcome the resistance to motion encountered in slidingone solid on another expressed in energy units(joules).3.3.3 RFED,nrelative friction energy dissipated.Thework required to overcome the resistance to motion encoun-tered in sliding one solid on another solid expressed in arbitraryunits for comparison studies on candidate tribocouples.4.Summary of Guide4.1 Frictional effects can be a concern in many tribosystemsso it is common to monitor friction force in laboratory tests andeven field evaluations of machines.There are many ways ofreporting the recorded friction forces:friction force(see GuideG115),average friction force for a test,average coefficient offriction,static and kinetic coefficient of friction,coefficient offriction at periodic time intervals,etc.This guide presents amethodology to convert friction forces monitored throughout atest cycle into a test metric called friction energy dissipated(FED).For within-lab tests the metric is relative friction energy1This guide is under the jurisdiction of ASTM Committee G02 on Wear andErosion and is the direct responsibility of Subcommittee G02.50 on Friction.Current edition approved July 1,2016.Published July 2016.Originally approvedin 2010.Last previous edition approved in 2010 as G203 10.DOI:10.1520/G020310R16.2For 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 dissipated(RFED).Both of these terms represent an integra-tion of the area within the force/tangential displacement outputof the force measurement system.4.2 The FED parameter will have energy units;the RFEDparameter can have arbitrary units because it is used tocompare various candidates in the same test in the samelaboratory using the same test equipment.5.Significance and Use5.1 Many sliding systems exhibit intermittent high frictionforce excursions compared to competing tribosystems.However,where friction forces or friction coeffic