ASTM G115-98
(Guide)Standard Guide for Measuring and Reporting Friction Coefficients
Standard Guide for Measuring and Reporting Friction Coefficients
SCOPE
1.1 This guide presents information to assist in the selection of a method for measuring the frictional properties of materials. Requirements for minimum data and a format for presenting these data are suggested. The use of the suggested reporting form will increase the long-term usefulness of the test results within a given laboratory and will facilitate the exchange of test results between laboratories. It is hoped that the use of a uniform reporting format will provide the basis for the preparation of handbooks and computerized databases.
1.2 This guide applies to most solid materials and to most friction measuring techniques and test equipment.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: G 115 – 98
Standard Guide for
Measuring and Reporting Friction Coefficients
This standard is issued under the fixed designation G 115; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 2047 Test Method for Static Coefficient of Friction of
Polish-Coated Floor Surfaces as Measured by the James
1.1 This guide presents information to assist in the selection
Machine
of a method for measuring the frictional properties of materi-
D 2394 Methods for Simulated Service Testing of Wood
als. Requirements for minimum data and a format for present-
and Wood-Base Finish Flooring
ing these data are suggested. The use of the suggested reporting
D 2714 Test Method for Calibration and Operation of the
form will increase the long-term usefulness of the test results
Falex Block-on-Ring Friction and Wear Testing Machine
within a given laboratory and will facilitate the exchange of
D 3028 Test Method for Kinetic Coefficient of Friction of
test results between laboratories. It is hoped that the use of a
Plastic Solids
uniform reporting format will provide the basis for the prepa-
D 3108 Test Method for Coefficient of Friction, Yarn to
ration of handbooks and computerized databases.
Solid Material
1.2 This guide applies to most solid materials and to most
D 3247 Test Method for Coefficient of Static Friction of
friction measuring techniques and test equipment.
Corrugated and Solid Fiberboard (Horizontal Plane
1.3 This standard does not purport to address all of the
Method)
safety concerns, if any, associated with its use. It is the
D 3248 Test Method for Coefficient of Static Friction of
responsibility of the user of this standard to establish appro-
Corrugated and Solid Fiberboard (Inclined Plane Method)
priate safety and health practices and determine the applica-
D 3334 Method of Testing Fabrics Woven from Polyolefin
bility of regulatory limitations prior to use.
Monofilaments
2. Referenced Documents
D 3412 Test Method for Coefficient of Friction, Yarn-to-
Yarn
2.1 ASTM Standards:
D 4103 Practice for Preparation of Substrate Surfaces for
B 460 Test Method for Dynamic Coefficient of Friction and
Coefficient of Friction Testing
Wear of Sintered Metal Friction Materials Under Dry
E 122 Practice for Choice of Sample Size to Estimate a
Conditions
Measure of Quality for a Lot or Process
B 461 Test Method for Frictional Characteristics of Sintered
E 303 Test Method for Measuring Surface Frictional Prop-
Metal Friction Materials Run in Lubricants
erties Using the British Pendulum Tester
B 526 Test Method for Coefficient of Friction and Wear of
E 305 Practices for Establishing and Controlling Spectro-
Sintered Metal Friction Materials Under Dry-Clutch Con-
chemical Analytical Curves
ditions
E 510 Practice for Determining Pavement Surface Fric-
C 122 Test Method of Panel Spalling Testing Super–Duty
tional and Polishing Characteristics Using a Small Torque
Fireclay Brick
Device
C 808 Guideline for Reporting Friction and Wear Test
Results of Manufactured Carbon and Graphite Bearing and
Seal Materials
D 1894 Test Method for Static and Kinetic Coefficients of
Annual Book of ASTM Standards, Vol 08.02.
4 6
Annual Book of ASTM Standards, Vol 04.10.
Friction of Plastic Film and Sheeting
Annual Book of ASTM Standards, Vol 05.02.
Annual Book of ASTM Standards, Vol 07.01.
Discontinued—See 1987 Annual Book of ASTM Standards, Vol 15.09.
1 10
This guide is under the jurisdiction of ASTM Committee G-2 on Wear and Discontinued—See 1988 Annual Book of ASTM Standards, Vol 07.01.
Erosion and is the direct responsibility of Subcommittee G02.50 on Friction. Annual Book of ASTM Standards, Vol 07.02.
Current edition approved October 10, 1998. Published January 1999. Originally Annual Book of ASTM Standards, Vol 15.04.
e1 13
published as G 115 - 93. Last previous edition G 115 - 93 . Annual Book of ASTM Standards, Vol 14.02.
2 14
Discontinued—See 1989 Annual Book of ASTM Standards, Vol 02.05.
Annual Book of ASTM Standards, Vol 04.03.
Annual Book of ASTM Standards, Vol 15.01. Annual Book of ASTM Standards, Vol 03.05.
4 16
Annual Book of ASTM Standards, Vol 08.01. Discontinued—See 1984 Annual Book of ASTM Standards, Vol 04.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
G115
E 670 Test Method for Side Force Friction on Paved Sur-
faces Using the Mu-Meter
E 707 Test Method for Skid Resistance Measurements Us-
ing the North Carolina State University Variable-Speed
Friction Tester
F 489 Test Method for Static Coefficient of Friction of Shoe
Sole and Heel Materials as Measured by the James
Machine
F 609 Test Method for Static Slip Resistance of Footwear,
Sole, Heel, or Related Materials by Horizontal Pull Slip-
FIG. 1 Typical Force versus Distance Behavior for a System that
meter (HPS)
Exhibits Stick-Slip Behavior
F 695 Practice for Evaluation of Test Data Obtained by
Using the Horizontal Pull Slipmeter (HPS) or the James
triboelement.) G40 –93
Machine for Measurement of Static Slip Resistance of
Footwear, Sole, Heel, or Related Materials
4. Summary of Guide
F 732 Practice for Reciprocating Pin-on-Flat Evaluation of
4.1 Current ASTM friction test standards are tabulated in
Friction and Wear Properties of Polymeric Materials for
this document so that users can review available test methods
Use in Total Joint Prosthesis
and determine which method may be most applicable for a
G 40 Terminology Relating to Wear and Erosion
particular application. Any of the listed tests or other accepted
G 65 Test Method for Measuring Abrasion Using the Dry
tests may be used. General friction testing precautions are cited
Sand/Rubber Wheel Apparatus
and a prescribed method of recording friction data is recom-
G 143 Test Method for Measurement of Web/Roller Fric-
mended. This guide is intended to promote the use of this
tion Characteristics
standard reporting system and standard friction test methods.
3. Terminology
5. Significance and Use
3.1 Definitions:
5.1 This guide points out factors that must be considered in
3.1.1 coeffıcient of friction, μ or f, n—in tribology—the
conducting a valid test for determination of the coefficient of
dimensionless ratio of the friction force (F) between two bodies
friction of a tribosystem, and it encourages the use of a
to the normal force (N) pressing these bodies together. (See
standard reporting format for friction data.
also static coeffıcient of friction and kinetic coeffıcient of
5.1.1 The factors that are important for a valid test may not
friction.) G40 –93
be obvious to non-tribologists, and the friction tests referenced
3.1.2 friction force, n—the resisting force tangential to the
will assist in selecting the apparatus and test technique that is
interface between two bodies when, under the action of
most appropriate to simulate a tribosystem of interest.
external force, one body moves or tends to move relative to the
5.2 The tribology literature is replete with friction data that
other. (See also coeffıcient of friction.) G 40– 93
cannot readily be used by others because specifics are not
3.1.3 kinetic coeffıcient of friction, n— the coefficient of
presented on the tribosystem that was used to develop the data.
friction under conditions of macroscopic relative motion be-
The overall goal of this guide is to provide a reporting format
tween two bodies. G40 –93
that will enable computer databases to be readily established.
3.1.4 static coeffıcient of friction, n— the coefficient of
These databases can be searched for material couples and
friction corresponding to the maximum friction force that must
tribosystems of interest. Their use will significantly reduce the
be overcome to initiate macroscopic motion between two
need for each laboratory to do its own testing. Sufficient
bodies. G40 –93
information on test conditions will be available to determine
3.1.5 stick-slip—a relaxation oscillation usually associated
applicability of the friction data to the engineer’s specific
with decrease in coefficient of friction as the relative velocity
needs.
increases. (The usual manifestation is a cycling (decrease and
subsequent increase) in the friction force as sliding proceeds
6. Apparatus
(Fig. 1).)
6.1 Any of the devices shown schematically in Table 1 can
3.1.6 triboelement, n—one of two or more solid bodies that
be used to measure the friction forces in a sliding system. Wear
comprise a sliding, rolling, or abrasive contact, or a body
test machines are often equipped with sensors to measure
subjected to impingement or cavitation. (Each triboelement
friction forces also. The appropriate device to use is the one
contains one or more tribosurfaces.) G40 –93
that closely simulates a tribosystem of interest.
3.1.7 tribosystem, n—any system that contains one or more
6.2 The key part of simulating a tribosystem is to use
triboelements, including all mechanical, chemical, and envi-
specimen geometries that resemble the components in the
ronmental factors relevant to tribological behavior. (See also
system of interest. Other important factors to simulate are
normal force (contact pressure), velocity, type of motion
(reciprocating versus unidirectional) and environment. For
Annual Book of ASTM Standards, Vol 15.07.
example, if an application involves flat surfaces in contact
Annual Book of ASTM Standards, Vol 13.01.
Annual Book of ASTM Standards, Vol 03.02. under relatively light loads and with low slip velocities, a sled
G115
device may be applicable. If an application involves materials
such as friction composites, one of the brake type dynamom-
eter tests may be appropriate.
6.3 A very important consideration in selecting a test
apparatus is stiffness of the friction force measuring system. If
the sliding member in a test couple is set into motion by a metal
rod, chain, or similar device, there will be very little elastic
strain in the pulling device prior to initiation of motion, and the
force measuring transducer may not record a “breakaway”
force, a force spike that is higher than the mean force measured
FIG. 2 Typical Force versus Distance Recording for a System
during steady state sliding. This breakaway force is commonly
that has a Static Friction that is Higher than its Kinetic Friction
used to calculate static friction (Fig. 2). If initial friction is of
interest in a test, it is advisable to use a force measuring system
NOTE 1—Caution: More “elastic” systems may be more prone to
produce stick-slip behavior. In addition, elastic beams containing strain
with substantial elasticity. In sled type devices this is often
gages may produce different friction responses than a more rigid load cell
accomplished by using a nylon or similar plastic filament to
even if used on the same friction testing machine.
produce motion of the sliding member. The appropriate force
measuring system to use is the one that best simulates the 6.4 Initial friction force spikes will occur in many test
tribosystem of interest; pulling plastic film over a roll probably systems. Test surfaces that are prone to blocking or interlock-
involves significant elasticity in the system (from the low ing of surface features are particularly prone to showing a
elastic modulus of the plastic). In this case an elastic friction breakaway force spike. (Blocking is a term used to describe the
measuring system would be appropriate. When pulling a steel tendency of some plastic materials to stick to each other after
cable over the same roll, it would be more appropriate to use a long periods of contact.) Plasticized vinyl materials often block
stiff testing system. when self mated. Plasticizer migration can be the cause.
TABLE 1 ASTM Friction Tests and Applicable Materials
Standard/Committee Title Measured Parameters Test Configuration
B 460 Dynamic Coefficient Friction materials
of Friction and Wear versus metal
of Sintered Metal
B-9 on Friction Materials (μ versus temperature)
k
Metal Under Dry Conditions
Powders
and
Metal
Powder
Products
B 461 Frictional Friction materials
Characteristics of versus metal
Sintered Metal
Friction Materials (μ versus number of
k
Run in Lubricants engagements)
B-9 on (μ versus velocity)
k
Metal
Powders
and
Metal
Powder
Products
B 526 Coefficient of Friction materials
Friction and Wear of versus gray cast iron
Sintered Metal
Friction Under
Dry-Clutch Conditions
B-9 on Metal (μ and μ )
s k
Powders
and
Metal
Powder
Products
G115
Standard/Committee Title Measured Parameters Test Configuration
C 808 Reporting Friction Carbon versus other
and Wear Test Results materials
of Manufactured Carbon
any
C-5 on Manufactured and Graphite Bearing
Carbon and and Seal Materials (μ and μ )
s k
Graphite Products
D 1894 Static and Kinetic Plastic film versus stiff
D-20 on Coefficients of or other solids
Plastics Friction of Plastic (μ and μ )
s k
Films and Sheeting
D 2047 Static Coefficient Walking materials
of Friction of Polish- versus shoe heels and
Coated Floor Surfaces soles
D-21 on as Measured by the
Polishes James Machine (μ and μ )
s k
D 2394 Simulated Service Wood and wood base
Testing of Wood and flooring versus sole
D-7 on Wood-Base Finish leather
Wood Flooring (μ and μ )
s k
D 2714 Calibration and Steel ring versus steel
Operation of the block (lubricated
Falex Block-on-Ring with standard oil)
Friction and
D-2 on Petroleum Wear Testing
Products and Machine (μ )
k
Lubricants
G115
Standard/Committee Title Measured Parameters Test Configuration
D 3028 Kinetic Coefficients Plastic Sheets or
of Friction of solids versus other
D-20 Plastic Solids solids
Plastics (μ and μ )
s k
D 3108 Coefficient of Textile yarn versus
Friction, Yarn to solids
D-13 on Solid Material
Textiles (μ )
k
D 3247 Coefficient of Static Cardboard self-mated
Friction of Corrugated
D-6 on and Solid Fiberboard (μ )
s
Paper and (Horizontal
Paper Products Plane Method)
D 3248 Coefficient of Static Cardboard self-mated
Friction of Corrugated
and Solid Fiberboard
D-6 on (Inclined Plane (μ )
s
Paper and Paper Method)
Products
G115
Standard/Committee Title Measured Parameters Test Configuration
D 3334 Testing Fabrics Woven fabric
Woven from Polyolefin self-mated
D-13 on Monofilaments
Textiles (μ )
s
D 3412 Coefficient of Continuous filament and
...
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