ASTM F2398-10
(Test Method)Standard Test Method for Measuring Moment of Inertia and Center of Percussion of a Baseball or Softball Bat
Standard Test Method for Measuring Moment of Inertia and Center of Percussion of a Baseball or Softball Bat
SIGNIFICANCE AND USE
This test method offers a laboratory means to measure the inertial properties of bats, specifically weight, balance point, center of percussion, and MOI, in support of other test methods including the ASTM standards referenced in this document.
Use of this test method can provide sports governing bodies the means to establish rules regarding the physical properties of bats, specifically MOI.
SCOPE
1.1 Method for determining the moment of inertia (MOI), the center of percussion (COP), and the balance point (BP) of baseball and softball bats. These physical properties are used in Test Method F1881, Test Method F1890, and Test Methods F2219.
1.2 The MOI, COP, and BP are measured in the laboratory on test equipment meeting the requirements defined in this test method.
1.3 The values stated in inch-pound units are to be regarded as the standard.
1.4 This standard does not purport to address all of the safety concerns, 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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An American National Standard
Designation:F2398–10
Standard Test Method for
Measuring Moment of Inertia and Center of Percussion of a
1
Baseball or Softball Bat
This standard is issued under the fixed designation F2398; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.3 cycle, n—one complete oscillation of a pendulum
supported at the pivot point, 6 in. (152 mm) from the distal end
1.1 Method for determining the moment of inertia (MOI),
of the bat.
the center of percussion (COP), and the balance point (BP) of
3.1.4 moment of inertia (MOI), n—also known as the mass
baseballandsoftballbats.Thesephysicalpropertiesareusedin
moment of inertia, the measure of the bat’s resistance to
Test Method F1881, Test Method F1890, and Test Methods
changes in its rotation rate about the pivot point, 6 in. (152
F2219.
mm) from the distal end of the bat.
1.2 The MOI, COP, and BP are measured in the laboratory
3.1.5 period, n—the time required for a pendulum to oscil-
on test equipment meeting the requirements defined in this test
late through one complete cycle.
method.
1.3 The values stated in inch-pound units are to be regarded
4. Significance and Use
as the standard.
4.1 This test method offers a laboratory means to measure
1.4 This standard does not purport to address all of the
the inertial properties of bats, specifically weight, balance
safety concerns, if any, associated with its use. It is the
point, center of percussion, and MOI, in support of other test
responsibility of the user of this standard to establish appro-
methods including the ASTM standards referenced in this
priate safety and health practices and determine the applica-
document.
bility of regulatory limitations prior to use.
4.2 Use of this test method can provide sports governing
2. Referenced Documents bodies the means to establish rules regarding the physical
2
properties of bats, specifically MOI.
2.1 ASTM Standards:
F1881 Test Method for Measuring Baseball Bat Perfor-
5. Apparatus
mance Factor
5.1 Bat MOI Test Apparatus:
F1890 Test Method for Measuring Softball Bat Perfor-
5.1.1 Ruler, suitable for measuring lengths up to 42 in.
mance Factor
(1067 mm) to the nearest 0.03 in. (0.8 mm).
F2219 Test Methods for Measuring High-Speed Bat Perfor-
5.1.2 Weight Scales, suitable for measuring weight up to 48
mance
oz (1364 g) to the nearest 0.0035 oz (0.1 g).
3. Terminology 5.1.3 Electronic Timer, suitable device sufficiently accurate
for measuring time to the nearest 1 µs (0.000001 s).
3.1 Definitions of Terms Specific to This Standard:
5.1.4 Pendulum Stand—A frame with a pivoting bat collar-
3.1.1 balance point (BP), n—the distance to the center of
clamp large enough to allow a bat held in a vertical position to
mass measured from the distal end of the bat.
swing freely (see Fig. 1).
3.1.2 center of percussion (COP), n—also known as the
5.1.5 Bat Collar-Clamp—Alightweight clamp or collar that
center of oscillation. Forces and impacts at this location will
can hold the weight of a bat and provide a fixed pivot location.
not induce reactions at the pivot point, 6 in. (152 mm) from the
The clamp shall be rotationally balanced and have a maximum
distal end of the bat.
2 2
MOI of 4 oz-in. (80 kg-mm ) measured about the bat pivot
location (see Fig. 1). The MOI of the clamp shall not change
1
This test method is under the jurisdiction of ASTM Committee F08 on Sports
with the diameter of the bat being tested.
Equipment and Facilities and is the direct responsibility of Subcommittee F08.26 on
Baseball and Softball Equipment.
6. Calibration and Standardization
Current edition approved May 1, 2010. Published June 2010. Originally
´1
approved in 2004. Last previous edition approved in 2004 as F2398 – 04 . DOI:
6.1 Calibration Rod—The calibration rod shall be 1 in.
10.1520/F2398-10.
(25.4 mm) in diameter by 34 in. (864 mm) long, solid
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
aluminum.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F2398–10
FIG. 1 MOI Fixture
6.2 Target Calibration MOI—Measure the length and the of the calibration rod is outside the allowed range, then check
weight of the calibration rod. Compute the target calibration the calibration of the scales and support fixture.
rod MOI using Eq. 1: 6.4 Mass Moment of Iner
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
An American National Standard
´1
Designation:F2398–04 Designation:F2398–10
Standard Test Method for
Measuring Moment of Inertia and Center of Percussion of a
1
Baseball or Softball Bat
This standard is issued under the fixed designation F2398; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1
´ NOTE—Figure 2 editorially corrected in July 2004.
1. Scope
1.1This test method covers a method for determining the moment of inertia (MOI) and balance point (BP) of baseball and
softball bats. These physical properties are used in calculations in other key ASTM standards.
1.2The MOI and BP are measured in the laboratory on test equipment meeting the requirements defined in this test method.
1.1 Methodfordeterminingthemomentofinertia(MOI),thecenterofpercussion(COP),andthebalancepoint(BP)ofbaseball
and softball bats. These physical properties are used in Test Method F1881, Test Method F1890, and Test Methods F2219.
1.2 The MOI, COP, and BP are measured in the laboratory on test equipment meeting the requirements defined in this test
method.
1.3 The values stated in inch-pound units are to be regarded as the standard.
1.4 This standard does not purport to address all of the safety concerns, 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.
2. Terminology Referenced Documents
2
2.1 ASTM Standards:
F1881 Test Method for Measuring Baseball Bat Performance Factor
F1890 Test Method for Measuring Softball Bat Performance Factor
F2219 Test Methods for Measuring High-Speed Bat Performance
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
2.1.1balance point (BP)—the distance to the center of mass measured from the distal end of the bat knob.
2.1.2center of percussion (COP)—alsoknownasthecenterofoscillation,thelengthofasimplependulumwiththesameperiod
as a physical pendulum, as in a bat oscillating on a pivot. Forces and impacts at this location will not induce axial reactions at the
pivot point.
2.1.3cycle—one complete performance of the oscillation of the bat, specifically, one full swing of the bat.
2.1.4moment of inertia (MOI)—a measure of mass distribution relative to an axis of rotation. It is the product of the mass
multiplied by the square of the distance to the mass, summed over the entire bat.
2.1.5period
3.1.1 balance point (BP), n—the distance to the center of mass measured from the distal end of the bat.
3.1.2 center of percussion (COP), n—alsoknownasthecenterofoscillation.Forcesandimpactsatthislocationwillnotinduce
reactions at the pivot point, 6 in. (152 mm) from the distal end of the bat.
3.1.3 cycle, n—one complete oscillation of a pendulum supported at the pivot point, 6 in. (152 mm) from the distal end of the
bat.
3.1.4 moment of inertia (MOI), n—also known as the mass moment of inertia, the measure of the bat’s resistance to changes
in its rotation rate about the pivot point, 6 in. (152 mm) from the distal end of the bat.
1
This test method is under the jurisdiction of ASTM Committee F08 on Sports Equipment and Facilities and is the direct responsibility of Subcommittee F08.26 on
Baseball and Softball Equipment and Facilities.
Current edition approved May 1, 2004. Published May 2004. DOI: 10.1520/F2398-04E01.on Baseball and Softball Equipment.
´1
Current edition approved May 1, 2010. Published June 2010. Originally approved in 2004. Last previous edition approved in 2004 as F2398–04 . DOI:
10.1520/F2398-10.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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F2398–10
3.1.5 period, n—the time required for a pendulum to oscillate through one complete cycle.
3.Significance and Use
3.1Thistestmethodoffersalaboratorymeanstomeasuretheinertialpropertiesofbats,specificallyweight,balancepoint,center
of percussion, and MOI, in support of other test methods including the ASTM standards referenced in this document.
3.2Use of thi
...
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