1、Designation: F 1890 05An American National StandardStandard Test Method forMeasuring Softball Bat Performance Factor1This standard is issued under the fixed designation F 1890; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a method for determining batperformance by measuring the bat-ball coefficient of restit
3、ution(BBCOR), deriving the bat performance factor (BPF) andcalculating a batted ball speed (BBS). It is applicable tosoftball bats of any construction or material. The methodprovides a quantitative measure of bat dynamic performancethat may be used for comparison purposes.1.2 The BBCOR, BPF, and BBS
4、 are each calculated frommeasurements taken in the laboratory on test equipmentmeeting the requirements defined in this specification.1.3 The values stated in inch-pound units are to be regardedas the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associate
5、d 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 requirements prior to use.2. Referenced Documents2.1 ASTM Standards:2F 1887 Test Method for Measuring the Coefficient of Res-titut
6、ion (COR) of Baseballs and SoftballsF 1888 Test Method for Compression-Displacement ofBaseballs and SoftballsF 2398 Test Method for Measuring Moment of Inertia andCenter of Percussion of a Baseball or Softball Bat3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 balance point, n
7、distance to the center of mass of abat when measured from the distal end of the bat knob.3.1.2 bat-ball coeffcient of restitution (BBCOR), nCORof a specific ball colliding with a bat as defined in this testmethod. See coeffcient of restitution (COR).3.1.3 bat performance factor (BPF), nratio of BBCO
8、R toball COR as defined in this test method.3.1.4 center of percussion (COP), nalso known as thecenter of oscillation, the length of a simple pendulum with thesame period as a physical pendulum, as in a bat oscillating ona pivot. Forces and impacts at this location will not induceaxial reactions at
9、the pivot point.3.1.5 coeffcient of restitution (COR), nmeasure of impactefficiency calculated as the relative speed of the objects afterimpact divided by the relative speed of the objects beforeimpact.3.1.6 moment of inertia (MOI), nmeasure of mass distri-bution relative to an axis of rotation. It
10、is the product of themass multiplied by the square of the distance to the mass,summed over the entire bat.4. Significance and Use4.1 This test method offers a laboratory means to comparethe performance of a softball bat.4.2 Use of this test method can provide sports governingbodies a means to compar
11、e calculated BBS and other physicalproperties of bats.5. Apparatus5.1 Test BallsOfficial softballs approved for play andtested in accordance with the following procedures. Performball compression test of Test Method F 1888 prior to ball CORtest of Test Method F 1887.5.1.1 Compression350 to 375 lb at
12、 0.25-in. deflection(1557 to 1668 N at 6.4-mm deflection) in accordance with TestMethod F 1888. Balls to be labeled with compression value.5.1.2 Weight6.25 to 6.75 oz (177.2 to 191.4 g). Balls to belabeled with weight value.5.1.3 Size12.00 to 12.25-in. (304.8 to 311.1-mm) circum-ference. Balls to be
13、 labeled with size value.5.1.4 Core MaterialPolyurethane.5.1.5 Ball COR0.450 to 0.470 in accordance with TestMethod F 1887. Balls to be labeled with COR and test speed inft/s.5.2 Bat-Ball COR Test Apparatus:5.2.1 Ball CannonA device capable of shooting a ball ata speed of 88 ft/s. The ball shall not
14、 have a spin rate in excessof 10 rpm. Typical pitching machines cannot yield the aimingaccuracy required by this test method. Cannon exhaust air must1This test method is under the jurisdiction of ASTM Committee F08 on SportsEquipment and Facilities and is the direct responsibility of Subcommittee F0
15、8.26 onBaseball and Softball Equipment.Current edition approved Oct. 1, 2005. Published November 2005. Originallyapproved in 1998. Last previous edition approved in 2004 as F 1890 04.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
16、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.not cause motion of the bat in the absence of an impact. Thebal
17、l cannon can be any distance from impact location, as longas it can meet the ball aim requirements and provide six validimpacts in twelve shots or less.5.2.2 Bat Speed GateAlight trap device, or an equivalent,capable of measuring an edge traveling at speeds of between 5and 15 ft/s with a resolution
18、of one hundredth of 1 ft/s (0.01ft/s) with an accuracy of at least 61 % when the distancebetween the first and second sensor is between 3 in. (76.2 mm)and 3.6 in. (94.1 mm). The first sensor shall trigger when thebat rotates no less than 25 and no more than 30 from its startposition. It is suggested
19、 the second trigger be 3 in. (76.2 mm)away from the first and must not be any further than 3.6 in.(91.4 mm) away on a 6-in. (15.24-cm) radius.5.2.3 Ball Speed GateA light trap device, or an equiva-lent, capable of measuring a sphere traveling at speeds inexcess of 88 ft/s (26.8 m/s) with an accuracy
20、 of 0.5 ft/s (0.2m/s) or better. The device shall measure across a length of noless than half the ball diameter to avoid centering error. Forexample, when testing softballs, the device shall sense anobject across a 2.0-in. (50.8-mm) line. The first sensor shalltrigger when the ball is no more than 1
21、2 in. (30.5 cm) from thebat surface. The second sensor shall trigger between 3.6 in.(91.4 mm) and 8 in. (203.2 mm) from the first sensor. Thesecond sensor is located between the first sensor and the batsurface.5.2.4 Bat Pivot SupportA turntable, rotating in the hori-zontal plane, with clamps to supp
22、ort and align the bat in thepath of the ball. The clamp surfaces shall be a 45 Vee clampwith a radius no greater than 2.0 in. (50.8 mm). The rotatingclamp and shaft assembly shall not weigh more than 6 lb (2.7kg) and shall spin freely via ball bearings (see Fig. 1). Thepolar MOI for the clamp turnta
23、ble assembly shall not exceed192 oz-in.2(35 117 g-cm2). The actual MOI of the clampturntable assembly shall be determined and used in theperformance calculations.6. Calibration and Standardization6.1 Ball Speed GateThe distances between the sensors ofthe speed gates must be known and recorded to the
24、 statedtolerances. The accuracy of the timers used in the velocitysensors must be adequate to provide the stated velocityaccuracy at maximum stated speeds. The timers used shall becalibrated on at least a yearly basis.6.2 Reference Standards and BlanksA standard bat andball shall be used for referen
25、ce purposes to verify propermachine operation.7. Conditioning7.1 Ball and Bat Conditioning:7.1.1 Balls shall be placed in an environmentally controlledspace for at least 14 days immediately before testing. Woodbats shall be stored at these environmental conditions for atleast 24 h prior to testing.
26、Non-wood bats shall be stored atthese environmental conditions for at least 2 h prior to testing.7.1.2 Temperature is to be maintained at 72 6 4F (22 62C).7.1.3 Relative humidity is to be maintained at 50 6 10 %.7.1.4 Ball and bat tests should be completed within1hofremoval from controlled area.7.2
27、Test Room Conditions:7.2.1 The test room shall be controlled environmentally.7.2.2 Temperature is to be maintained at 72 6 4F (22 62C).7.2.3 Relative humidity is to be maintained between 20 and60 %.8. Procedure8.1 Determination of Bat Features and Test LocationDetermine bat balance point (BP), bat M
28、OI, and bat COP inaccordance with Test Method F 2398.8.2 Bat Test Procedure:8.2.1 Ready and calibrate ball and bat speed gates inaccordance with the manufacturers instructions.8.2.2 Select a test ball in accordance with 5.1, and record theactual values of compression, weight, size, and COR of the ba
29、llin accordance with 5.1.8.2.3 Set ball cannon to fire the ball at the desired impactspeed of 88 ft/s (26.8 m/s). Valid test speeds are considered tobe those within 61 % of the targeted test speed.8.2.4 Mount bat in the clamps on the bat pivot support. Thedistal end of the bat knob must be 6 in. (15
30、2.4 mm) from theaxis of rotation of the turntable assembly.FIG. 1 Bat Testing MachineF18900528.2.5 The ball impact must be centered vertically andhorizontally on the bat diameter at the previously measuredCOP.8.2.6 Position the bat against the start position reference,which must place the bat axis p
31、erpendicular to the ball line oftravel. (See Fig. 1.)8.2.7 Verify that all speed traps are reset and ready to takedata.8.2.8 Load selected test ball in ball cannon. Attempt to loadtest ball so that its impact with the bat will be between thestitches of the ball.8.2.9 Shoot the ball at the bat, obser
32、ving the necessarysafety precautions.8.2.10 Record ball inbound speed and bat rebound speed.Do not use data where the ball inbound speed deviates by morethan the tolerances stated in 8.2.3 from the targeted test speed.8.2.11 Continue testing for six valid impact readings or fortwelve total impacts.
33、For a given test ball, rotate the ball in thecannon between impacts so that the impact area of the ball isdifferent for each impact. A single test ball may be tested onceon each impact area of the ball with no rest period betweenimpacts. Following this series of up to four impacts on a singleball, a
34、 rest period of at least 10 min following the last impactis required prior to retesting, using the same ball. If six validimpacts are not achieved prior to twelve total impacts, fix theset-up to alleviate cause of invalid impacts. Verify supportsystem for the ball cannon, ball speed gate, and bat pi
35、votsupport are rigid.9. Calculation of Results9.1 Calculate the BBCOR for each valid impact using Eq 1:BBCOR 5S1 1IwR2DSDRtdrTD 1 (1)where:D = distance between bat speed sensors, in. (cm),d = distance between ball speed sensors, in. (cm),I = MOI of bat, oz-in.2(g-cm2),R = COP distance, in. (cm),r =
36、radius to bat speed sensors, in. (cm),T = time for bat to travel through bat speed sensors, s,t = time for ball to travel through ball speed sensors, s, andw = weight of the ball used in each event, oz (g).9.2 CalibrationDetermine the value of the combinations(D/dr) using Eq 2 as follows. Place a la
37、rge calibration mass(MOI $ 30 000 oz-in.2) in the bat position on the pivotingstage. Measure its MOI and COP in accordance with TestMethod F 2398. Shoot a ball of known COR and weight (w).Measure t and T. Determine (D/dr) from ball COR as follows:Ddr51 1 Ball CORS1 1IwR2DSRtTD(2)9.3 Calculate the BP
38、F for each valid impact using Eq 3:BPF 5BBCORBall COR5SS1 1IwR2DSDdrDSRtTD1DBall COR(3)9.4 Calculate the average BPF for the test bat from the sixvalid impacts using Eq 4. When different balls are used to testthe same bat, always be sure to calculate the BBCOR and BPFusing the actual size, weight, c
39、ompression, and COR of the ballused in each of the six valid impacts:BPFavg5BPF!11 BPF!21 . 1 BPF!6!6(4)9.5 Calculate the BBS value of the test bat using Eq 5 and6:k 5SwWD1SwR a!2I Wa2!D(5)BBS 5V1 1 e! 1 ve k!1 1 k!(6)where:V = bat swing speed (mph) at the COP,v = pitch speed (mph), the horizontal s
40、peed of theball incoming to the batter,W = bat weight, oz,w = weight of ball used in each event, oz (g),I = MOI of bat, oz-in.2(g-cm2),e = BPF 3 (SB COR 4 TB COR),a = distance from pivot to center of mass (balancepoint),R = COP,k = ball-bat inertia ratio,SBCOR = 0.46, andTBCOR = the measured COR of
41、the test ball.10. Report10.1 Report the following information:10.1.1 Name of the test facility and test operator,10.1.2 Test date,10.1.3 Test conditions,10.1.3.1 Humidity and temperature of test room,10.1.3.2 Humidity and temperature of the ball and batconditioning environment,10.1.3.3 Number of hou
42、rs ball and bat were in conditioningenvironment,10.1.4 Test equipment used for this test method,10.1.5 Test ball information in accordance with 5.1, includ-ing the compression, weight, size, and COR of the test ball,10.1.6 Bat model, length, weight tested, and any otherpertinent data, such as condit
43、ion of the bat or modification tothe bat,10.1.7 Bat MOI and COP, and MOI of the bat pivot support,10.1.8 For each impact (including invalid impacts) ballinbound speed, bat rebound speed, BBCOR, and BPF,10.1.9 Final Average Bat Performance FactorAssumingcurrent ball COR measurement variations are 60.
44、01, theBBCOR uncertainty is currently 60.02. This results in a BPFuncertainty of 60.05. To reflect this uncertainty, the BPFassigned to each bat will be the measured average BPF reducedby the 0.05 uncertainty. Expected future improvements inmeasurement equipment and product control will reduce theab
45、ove uncertainty,10.1.10 Any and all unique observations including, but notexclusively, any damage to the bat or test ball, misdirected ballimpacts, and any odd noises or vibrations, andF189005310.1.11 Calibration certificate numbers for measurementdevices and velocity timers.11. Precision and Bias11
46、.1 Precision and bias evaluations have not been conductedfor this test method. When such data are available, a precisionand bias section will be added.12. Keywords12.1 bat performance; BBCOR; BBS; BPF; COR; softballbats; softballsASTM International takes no position respecting the validity of any pa
47、tent 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 patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revisio
48、n 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 either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your com
49、ments 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 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 standard may be obtained by contacting ASTM at the aboveaddress or at 610-8
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