1、Designation: F1887 14 An American National StandardStandard Test Method forMeasuring the Coefficient of Restitution (COR) of Baseballsand Softballs1This standard is issued under the fixed designation F1887; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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 procedure is intended to standardize a method ofmeasuring the coefficient of
3、restitution (COR) of baseballs andsoftballs.1.2 This procedure is established to provide a single,repeatable, and uniform test method.1.3 This procedure is for a ball that is intended for use in thegame of baseball or softball.1.4 The test method is based on ball speed measurementsbefore and after i
4、mpact with either of two test surfaces: woodor metal.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
5、ibility 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:E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Cond
6、ucting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 baseball and softball, nany ball defined by the rulesfor the game of baseball or softball.3.1.2 coeffcient of restitution (COR), n a numerical valuedetermi
7、ned by the exit speed of the ball after contact divided bythe incoming speed of the ball before contact with a massive,rigid, flat wall of either wood or metal.4. Summary of Test Method4.1 Method AThe strike plate is a rigid metal surface, andball speed is measured before and after impact with the s
8、trikeplate.4.2 Method BThe strike plate is a rigid wood surface, andball speed is measured before and after impact with the strikeplate.5. Significance and Use5.1 The ball coefficient of restitution is a ball dynamicproperty of relative velocity change caused by impact with arigid wall.5.2 This test
9、 method is suitable for obtaining data inresearch and development, quality control, and classifyingballs by liveliness.5.3 Sports associations can use coefficient of restitutionstandards in specifications for official baseballs and softballs.5.4 This same test procedure can be utilized at impactspee
10、ds other then that prescribed in this procedure and so notedin any reported test results.6. Apparatus6.1 Strike Plate, Method A:6.1.1 Material, 5.08-cm (2-in.) thick steel.6.1.2 Size, 61 by 61 cm (24 by 24 in.).6.1.3 Mounting, secured flush to a massive rigid wall ofcinder block or concrete, minimal
11、ly 20.3-cm (8-in.) thick, andbolted at all four corners sufficiently secure to prevent move-ment during ball impact.6.2 Strike Plate, Method B:6.2.1 Material, 10.2-cm (4-in.) thick northern white ashwood with moisture content between 10 and 15 % with a flatsmooth surface.6.2.2 Same as 6.1.2.6.2.3 Sa
12、me as 6.1.3.6.3 Ball Throwing DeviceA ball throwing device capableof delivering the ball through the electronic speed monitor at1This test method is under the jurisdiction of ASTM Committee F08 on SportsEquipment, Playing Surfaces, and Facilities and is the direct responsibility ofSubcommittee F08.2
13、6 on Baseball and Softball Equipment.Current edition approved May 1, 2014. Published June 2014. Originallyapproved in 1998. Last previous edition approved in 2009 as F1887 09. DOI:10.1520/F1887-14.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Uni
14、ted States126.82 m/s (60 mph) with a maximum tolerance of 60.30 m/s.The machine should be calibrated using the electronic speedmonitor.6.4 Electronic Speed MonitorsAn electronic ball speedmeasuring system consisting of two vertical light screensmounted 30.48 cm (12 in.) apart with a tolerance of 60.
15、32 cm,and a photoelectric sensor located at each screen that triggersa timing device on ball passage to measure the time for the ballto traverse the distance between the two vertical planes beforeand after impact with the strike plate. Resolution shall be60.03 m/s.6.5 Ball Trajectory TargetA lightwe
16、ight target with a30.48-cm (12-in.) diameter circular opening positioned at thesecond light screen and centered on the ball line of travelbetween the throwing device and the center of the strike plate.7. Preparation of Apparatus7.1 Mount the strike plate on a rigid wall such that thecenter is approx
17、imately 1.22 cm (4 ft) from the floor. Tightenall mounting bolts before each test. Torque to 81.35 N-m (60ft-lb) min.7.2 Position the first speed monitor (light screen) 30.48 60.32 cm (12 6 0.125 in.) from the strike plate (see Fig. 1).7.3 Position the second speed monitor (light screen) 30.486 0.07
18、9 cm (12 6 0.312 in.) from the first speed monitor.7.4 Position the ball throwing device such that the ballimpacts the strike plate within 15.24 cm (6 in.) of the centerand on rebound, passes through the 30.48 cm (12 in.) targetmounted at the second light screen.8. Conditioning8.1 Ball Conditioning
19、and Test Room Conditions:8.1.1 Test balls shall be stored in an environmentallycontrolled space for at least 14 days immediately beforetesting.8.1.2 Temperature is to be maintained at 72 6 4F (22 62C).8.1.3 Relative humidity is to be maintained between 40 and60 %.8.1.4 Temperature and relative humid
20、ity are to be measuredand recorded hourly within 60.5F (60.3C) and 62%RHover conditioning and test duration.9. Procedure9.1 The ball throwing device is set to deliver the ball at26.82 6 0.305 m/s (60 mph). All shots above or below thistolerance range will not be used.9.2 Each ball is shot at the str
21、ike plate a minimum of sixtimes to a maximum of 12 times. A minimum 30-s rest periodis required between each shot.9.3 Only those speed readings for impacts falling within the6-in. target at the strike plate, within the 12-in. target at thesecond speed monitor, and thrown within the prescribed speedr
22、ange will be used in the calculation of COR.9.4 The average of the six acceptable COR values for eachball is used to determine the ball COR.9.4.1 Formulae:COR 5 Vb/Va 516FVb1Va11Vb2Va21Vb3Va31Vb4Va41Vb5Va51Vb6Va6G(1)where:Va = incoming speed, andVb = exit speed.10. Report10.1 Report the following in
23、formation:10.1.1 Name of the test facility and test operator,10.1.2 Test date,10.1.3 Hourly measurements of test conditions, including:10.1.3.1 Relative humidity and temperature of the ballconditioning and test room environments,10.1.3.2 Number of hours ball was in conditioning environ-ment.10.1.4 T
24、est equipment used for this test method,FIG. 1 Test ApparatusF1887 14210.1.5 Test ball information, model, weight tested, and anyother pertinent data such as condition of the ball,10.1.6 For each event impact (including invalid impacts),ball inbound speed, rebound speed,10.1.7 Average ball COR in ac
25、cordance with Section 9 ofthis standard,10.1.8 Any and all unique observations, including but notexclusively, any damage to the ball, and10.1.9 Calibration certificate numbers for measurement de-vices and velocity timers.11. Precision and Bias211.1 The precision of this test method is based on anint
26、erlaboratory study conducted in 2012. Six laboratoriesparticipated in this study. Each of the six labs reported as manyas three replicate test results for each of 78 different balls.Every “test result” reported represents an individual determi-nation. Except for the very limited number of replicates
27、reported, Practice E691 was followed for the design andanalysis of the data.11.1.1 Repeatability (r)The difference between repetitiveresults obtained by the same operator in a given laboratoryapplying the same test method with the same apparatus underconstant operating conditions on identical test m
28、aterial withinshort intervals of time would in the long run, in the normal andcorrect operation of the test method, exceed the followingvalues only in one case in 20.11.1.1.1 Repeatability can be interpreted as the maximumdifference between two results, obtained under repeatabilityconditions, that i
29、s accepted as plausible due to random causesunder normal and correct operation of the test method.11.1.1.2 Repeatability limits are listed in .11.1.2 Reproducibility (R)The difference between twosingle and independent results obtained by different operatorsapplying the same test method in different
30、laboratories usingdifferent apparatus on identical test material would, in the longrun, in the normal and correct operation of the test method,exceed the following values only in one case in 20.11.1.2.1 Reproducibility can be interpreted as the maximumdifference between two results, obtained under r
31、eproducibilityconditions, that is accepted as plausible due to random causesunder normal and correct operation of the test method.11.1.2.2 Reproducibility limits are listed in Table 1.11.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.11.1.
32、4 Any judgment in accordance with statements 11.1.1and 11.1.2 would normally have an approximate 95 % prob-ability of being correct, however the precision statistics ob-tained in this ILS must not be treated as exact mathematicalquantities which are applicable to all circumstances and uses.The limit
33、ed number of laboratories reporting replicate resultsguarantees that there will be times when differences greaterthan predicted by the ILS results will arise, sometimes withconsiderably greater or smaller frequency than the 95 %2Supporting data have been filed at ASTM International Headquarters and
34、maybe obtained by requesting Research Report RR:F08-1013. Contact ASTM CustomerService at serviceastm.org.TABLE 1 CORMATERIAL Xbar sr sR r RAS1 0.39667 0.00179 0.00438 0.00500 0.01226AS2 0.46814 0.00274 0.00548 0.00767 0.01535AS3 0.48080 0.00283 0.00573 0.00793 0.01604AS4 0.39850 0.00196 0.00516 0.0
35、0550 0.01444AS5 0.44961 0.00137 0.00374 0.00382 0.01047AS6 0.54680 0.00177 0.00429 0.00496 0.01202AB1 0.55502 0.02148 0.02148 0.06015 0.06015AB2 0.56559 0.00211 0.00571 0.00591 0.01598AB3 0.56478 0.00313 0.00313 0.00876 0.00876AB4 0.56458 0.00284 0.00495 0.00795 0.01387AB5 0.56607 0.00458 0.00458 0.
36、01283 0.01283AB6 0.56844 0.00342 0.00543 0.00958 0.01521BS1 0.40100 0.00316 0.00872 0.00886 0.02441BS2 0.47173 0.00361 0.00371 0.01010 0.01040BS3 0.47380 0.00171 0.00334 0.00480 0.00936BS4 0.39022 0.00030 0.00030 0.00084 0.00084BS5 0.44678 0.00235 0.00235 0.00659 0.00659BS6 0.54827 0.00334 0.00334 0
37、.00937 0.00937BB1 0.55884 0.00433 0.00599 0.01212 0.01678BB2 0.55756 0.00700 0.00700 0.01960 0.01960BB3 0.56273 0.00405 0.00828 0.01134 0.02319BB4 0.55937 0.00504 0.00504 0.01411 0.01411BB5 0.56718 0.00485 0.00811 0.01358 0.02270BB6 0.56314 0.00725 0.00725 0.02031 0.02031CS1 0.39931 0.00142 0.00675
38、0.00399 0.01890CS2 0.47396 0.00170 0.00504 0.00477 0.01411CS3 0.47616 0.00067 0.00186 0.00188 0.00520CS4 0.39578 0.00338 0.00669 0.00946 0.01873CS5 0.44549 0.00187 0.00741 0.00524 0.02074CS6 0.55945 0.00334 0.00334 0.00935 0.00935CB1 0.55716 0.00198 0.00424 0.00554 0.01188CB2 0.55874 0.00284 0.00924
39、 0.00796 0.02588CB3 0.55752 0.00144 0.00668 0.00402 0.01869CB4 0.55817 0.00167 0.00859 0.00468 0.02405CB5 0.56214 0.00145 0.00567 0.00406 0.01587CB6 0.56267 0.00247 0.00933 0.00692 0.02612DB1 0.55239 0.00177 0.00364 0.00495 0.01020DB2 0.55990 0.00115 0.00477 0.00321 0.01335DB3 0.55709 0.00364 0.0049
40、2 0.01020 0.01378DB4 0.56084 0.00205 0.00222 0.00574 0.00621DB5 0.55951 0.00367 0.00409 0.01027 0.01146DB6 0.56387 0.00159 0.00707 0.00444 0.01978ES1 0.40711 0.00346 0.00346 0.00970 0.00970ES2 0.47146 0.00123 0.00123 0.00346 0.00346ES3 0.48304 0.00238 0.00238 0.00667 0.00667ES4 0.40202 0.00233 0.005
41、07 0.00653 0.01421ES5 0.44263 0.00100 0.00100 0.00279 0.00279ES6 0.55238 0.00157 0.00240 0.00441 0.00671EB1 0.56669 0.00418 0.00418 0.01170 0.01170EB2 0.56752 0.00263 0.00263 0.00735 0.00735EB3 0.57242 0.00313 0.00313 0.00877 0.00877EB4 0.56817 0.00108 0.00196 0.00304 0.00549EB5 0.57354 0.00266 0.00
42、266 0.00746 0.00746EB6 0.56987 0.00188 0.00188 0.00526 0.00526FS1 0.40269 0.00218 0.00218 0.00609 0.00609FS2 0.47377 0.00597 0.00597 0.01672 0.01672FS3 0.47610 0.00114 0.00159 0.00320 0.00444FS4 0.40002 0.00165 0.00660 0.00462 0.01849FS5 0.44256 0.00115 0.00475 0.00323 0.01330FS6 0.54229 0.00114 0.0
43、0735 0.00320 0.02057FB1 0.56677 0.00358 0.00358 0.01002 0.01002FB2 0.56248 0.00284 0.00284 0.00795 0.00795FB3 0.56992 0.00197 0.00197 0.00552 0.00552FB4 0.56609 0.00319 0.00319 0.00893 0.00893FB5 0.57055 0.00349 0.00349 0.00978 0.00978FB6 0.57260 0.00311 0.00604 0.00872 0.01690GS1 0.39575 0.00134 0.
44、00134 0.00376 0.00376GS2 0.47907 0.00071 0.00071 0.00197 0.00197GS3 0.48905 0.00066 0.00066 0.00185 0.00185GS4 0.39476 0.00907 0.00907 0.02541 0.02541GS5 0.43295 0.00406 0.00406 0.01137 0.01137GS6 0.54005 0.00461 0.00461 0.01291 0.01291GB1 0.55873 0.00311 0.00311 0.00872 0.00872GB2 0.53785 0.01471 0
45、.01471 0.04119 0.04119GB3 0.55688 0.00294 0.00294 0.00824 0.00824F1887 143probability limit would imply. In cases were no duplicates werereported by the laboratories, only Reproducibility can beestimated. The repeatability limit and the reproducibility limitslisted should be considered as general gu
46、ides, and the associ-ated probability of 95 % as only a rough indicator of what canbe expected.11.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.11.3 The precision statement w
47、as determined through sta-tistical examination of all reported results, from sixlaboratories, on 78 balls.12. Keywords12.1 ball liveliness; ball resilience; baseball; coefficient ofrestitution; softballASTM International takes no position respecting the validity of any patent rights asserted in conn
48、ection 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 revision at any time by the respons
49、ible 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 comments 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 copyrighte
