1、Designation: F 2117 01An American National StandardStandard Test Method forVertical Rebound Characteristics of Sports Surface/BallSystems; Acoustical Measurement1This standard is issued under the fixed designation F 2117; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of revision, the year 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 the quantitative measurementand normalizat
3、ion of the vertical rebound produced duringimpacts between athletic balls and athletic surfaces.1.2 Measurements may be conducted on nonathletic sur-faces to test the performance properties of the ball.1.3 Measurements may be conducted using nonathletic ballsto test the performance properties of the
4、 surface.1.4 The values stated in metric units are to be regarded asthe standard. The inch-pound units given in parentheses are forreference only.1.5 The methods described are applicable in both laboratoryand field settings.1.6 This standard does not purport to address all of thesafety concerns, if
5、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 DIN (Deutsches Institut fur Normung):218032 Part II, 1991 Sectio
6、n 5.82.2 British Standards:37044, 1990, Section 2.13. Terminology3.1 Definitions:3.1.1 area elastic surface, nsurfaces where the energy atimpact is dispersed throughout an area significantly larger thanthe impact point (for example, sprung wooden basketballfloors, poured urethane floors over sprung
7、subfloor). Areaelastic surfaces tend to produce a noticeable vibration whenimpacted.3.1.1.1 subfloor, nany structural members found betweenthe playing surface and the underlying concrete base. Subfloorsystems are typically found in sprung indoor playing surfacesand can include but are not limited to
8、: layers consisting ofsheets of plywood, layers consisting of strips of plywood, andsolid-wood members.3.1.2 athletic surface, nan athletic surface appropriate forthe sport(s) of interest should be selected for testing. Thesurface may be selected from previously installed surfaces andtested in its c
9、omplete form, or smaller samples may be testedunder laboratory settings.3.1.3 coeffcient of restitution (CR), nthe ratio of reboundheight to release height. This parameter is useful for nonin-flated balls that are found to be damaged by impacts with aconcrete reference surface. Construction differen
10、ces and sen-sitivity to inflation pressure make this parameter inappropriatefor comparing different playing surfaces based on resultsobtained using inflated sporting balls.3.1.4 point elastic surface, nsurface where the energy atimpact is dispersed throughout an area that negligibly exceedsthe impac
11、t point (for example, natural turf, artificial turf,poured urethane surfaces). Point elastic surfaces do not pro-duce noticeable vibrations when impacted.3.1.5 reference surface, nany section of a concrete slabwith a smooth uniform, uncracked surface with a minimumhorizontal dimension of 30 cm (12 i
12、n.) that produces a reboundwith minimal horizontal movement.3.1.6 sporting ball, na sporting ball appropriate for thesport(s) of interest should be selected for testing. The test ballshould be inspected to verify that it is spherical and devoid ofbulges. Bulges indicate structural damage exists with
13、in theball, that could affect the testing results. In the case of inflatedsporting balls, the pressure should conform to manufacturersguidelines.3.1.7 vertical rebound height, nthe highest heightachieved by sporting ball during its first rebound after contact-ing the surface.3.1.8 vertical rebound r
14、atio (VRR), nthe ratio of therebound on the test surface to the rebound on the referencesurface, expressed as a percentage. This parameter may not beappropriate for all sporting balls, as some may experiencedamage when impacting the reference surface. When reference1This test method is under the jur
15、isdiction of ASTM Committee F08 on SportsEquipment and Facilities and is the direct responsibility of Subcommittee F08.52 onMiscellaneous Playing Surfaces.Current edition approved June 10, 2001. Published October 2001.2Available from DIN, Burggrafenstrasse 6, D-10787 Berlin, Germany.3Available from
16、BSI, 389 Chiswick High Road, London W4 4AL, UK.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.surface rebound measurement is found to be unrepeatable, thecoefficient of restitution should be used instead.4. Summary of Test Method4.1
17、 This test method provides a means for evaluating therebound height produced by a test ball on a test surface. Theprocedure can be used to evaluate vertical ball reboundperformance on a reference athletic surface, evaluate surfacevertical rebound performance using a reference athletic ball, orto eva
18、luate the effects of ball-surface interactions. A ball isreleased from a known height and allowed to impact thereference surface. The release should not impart any horizontalmotion. An acoustical measurement system measures therebound height obtained on the test surface. The ball is thenreleased fro
19、m the same height and allowed to impact the testsurface, where again, the rebound height is measured. Thevertical rebound ratio, presented as a percentage, is obtainedfrom the ratio of the vertical rebound height on the sportingsurface to the vertical rebound height on the reference surface.5. Signi
20、ficance and Use5.1 The ball-surface interaction is just one of the importantproperties of a sports surface. It may be an indicator of theplayability or suitability of the surface.5.2 Manufacturers of sporting balls may use this method toevaluate the effects of design changes on the rebound heightpro
21、duced.5.3 Manufacturers of sports surfaces may use this method toevaluate the effects of design changes in the sports surfacesystem on the rebound height produced.5.4 The tendency of modern facilities to support multiplesports on a single surface may require that test surfaces betested for several t
22、ypes of sporting balls. Examples include, butare not limited to: basketball, soccer, tennis, and baseball.5.5 The measurement of rebound height may be affected ifthe temperature of the ball has not reached equilibrium with theenvironment.6. Apparatus6.1 Ball-Release Apparatus, capable of releasing t
23、he sport-ing ball from a consistent height, without imparting significantspin or horizontal motion to the sporting ball. The ball releaseapparatus is typically an adjustable-height tripod. The releasemechanism may be mechanical, electromagnetic, vacuum, ormanual.6.2 Sound Recording and Analysis Syst
24、emA system withthe minimum requirements as follow: acoustic sampling fre-quency 11 000 Hz, 8-bit resolution, on a single acousticchannel. The system must be capable of determining the timeof the first (tl) and second (t2) impacts using the peak acousticsignal generated to determine tland t2through e
25、ither the use ofhardware or software.6.2.1 ExamplePersonal computer, sound-card, and micro-phone have been found to produce adequate results.7. Testing Conditions7.1 The following general testing conditions should berecorded and included in the test report for informationpurposes only:7.1.1 All Surf
26、aces:7.1.1.1 Record temperature (to the nearest 1C) and relativehumidity (to the nearest 1 %) at an elevation of 30 cm (12 in.)above the playing surface. Measurements may be obtainedusing hand-held commercially available temperature and rela-tive humidity sensors.7.1.1.2 The vertical ball rebound sh
27、ould be tested using a1.800-m drop height. Additional drop heights may be testedand should be agreed onby the purchaser and the seller.7.1.2 Wood Playing SurfacesThe wood moisture content(%) should be included. Measurements may be obtained usinghand-held commercially available wood moisture sensors.
28、7.1.3 Outdoor Playing SurfaceThe general moisture levelof the surface should be included. In general, the surfaceshould be characterized as dry, damp, or wet.7.1.4 Laboratory Sample Sizes:7.1.4.1 Area elastic surfaces should be evaluated using aminimum sample size of 2.0 by 2.0 m (6.5 by 6.5 ft).7.1
29、.4.2 Point elastic surfaces should be evaluated using aminimum sample size of 1.0 by 1.0 m (3.3 by 3.3 ft).8. Procedure8.1 When the ball and test surface are introduced to a newenvironment, each should be allowed to acclimate. The ballshould be allowed to acclimate to the surroundings for 1 h, andth
30、e surface should be allowed at least4htoacclimate to theenvironment.8.2 Measure and record ambient temperature to the nearest1C and the relative humidity to the nearest 1 % at a height of30 cm (12 in.) over the reference surface.8.3 Measure and record ambient temperature to the nearest1C and the rel
31、ative humidity to the nearest 1 % at a height of30 cm (12 in.) over the athletic surface.8.4 Locate and document all points to be tested. Thisincludes points on the reference surface and on the athleticsurface.8.4.1 When testing under field conditions, include a diagramof the playing surface and its
32、 surroundings and dimensions thatallow the test points to be relocated. Effort should be made tolocate and test rebound properties of the playing surface onareas representative of the surface conditions present andconstruction methods used in the playing surface. Tests shouldalso be conducted on are
33、as considered heavy-use and non-useareas. Examples include but are not limited to the following:8.4.1.1 Natural TurfDensely covered areas and skinnedareas.8.4.1.2 Artificial TurfSeams in the turf layer, seams in thepadding layer (if present).8.4.1.3 Point Elastic SurfacesSeams in the playing sur-fac
34、e and seams in the padding layer (if present).8.4.1.4 Area Elastic SurfacesJoints in the playing surface,joints in the subfloor layer (if present), joints in the sleeperlayer (if present), between sleepers (if present), seams inpadding layer (if present), individual pads (if present).8.4.2 When test
35、ing under laboratory conditions, include adescription of the overall system construction and a descriptionof construction details present at all test points.8.5 Set the drop height to the nominal desired height. Theactual drop height should be measured and recorded to theF2117012nearest 0.005 m (0.2
36、 in.). The surface/ball system should beevaluated using a nominal drop height of 1.800 m (72 in.) andany additional drop heights considered useful.8.6 Perform ball inspection; verify that construction is stillsound. When appropriate, verify that the inflation pressure iswithin manufacturers specific
37、ations and record actual pres-sure.8.7 Evaluate the rebound height from the desired point onthe reference surface by recording seven vertical reboundheights produced from the specified testing height on thereference surface to the nearest 0.005 m (0.2 in.); exclude themaximum and minimum values, and
38、 calculate the average timebetween impacts (tref-1) from the remaining five drops. Sport-ing balls without inflation valves (such as golf balls, racquet-balls, and so forth) are released from the drop height with arandom orientation. Sporting balls with inflation valves (soccerballs, basketballs, an
39、d so forth) are released with the inflationvalve pointing away from the impact surface.8.8 Move the release apparatus to the athletic surface, andverify that the release height has not changed.8.9 A minimum of three points should be evaluated usingthe methods and accuracies described in 8.7 to chara
40、cterize anyplaying surface. Record seven vertical rebound heights fromeach point. For each point, exclude the maximum and mini-mum value recorded, and calculate the average vertical re-bound height from the remaining 5 drops for each test point.8.10 When the testing isconducted to evaluate the prope
41、rtiesof balls on a given surface, each ball will be dropped 7 times,and the maximum and minimum values will be discarded.8.11 Verify that the rebound height has not changed duringtesting by retesting the reference point every 30 min (maxi-mum allowable time duration) and at the conclusion of everyte
42、sted surface. Record seven rebound measurements, excludethe maximum and minimum values, and calculate the averagetime between rebounds (tref-2).8.12 Record the inflation pressure of the ball, when appro-priate, at the conclusion of evaluating the playing surface. Theinflation pressure is for informa
43、tion purposes only and can beobtained using a low-pressure gage of the type available atautomotive stores.9. Calculations9.1 Rebound height is approximated using the time duration(Dt) between the first (tl) and second (t2) impacts of the ballwith the surface, with Dt, tland t2measured to the nearest
44、0.001 s (tl, and t2are obtained from the moment of maximumsound intensity generated during the impact). The averagerebound height at each point evaluated should be computed byaveraging the time duration (Dt).Dts! 5 t2 t1(1)9.2 The average time between the first and second impactsexcluding the maximu
45、m and minimum time differences shouldbe computed to the nearest 0.001 s for each point i tested onthe playing surface (Dti) and for each test j on the referencesurface (Dtrefj).Dt$i%5Dt11Dt21Dt31Dt41Dt55(2)9.3 The average time between the first and second impactsof the ball with the playing surface
46、is then converted to verticalrebound height for each point i on the playing surface (hi)and for each point j on the reference surface (hrefj)inmetres (feet), where g = 9.81 m/s2(g = 32.2 ft/s2).h$i%5g8Dt$i%!2(3)9.4 When appropriate, calculate the vertical rebound ratio(VRRi) to the nearest 1 % for e
47、ach point i of the playingsurface tested. The reference surface rebound height obtainedprior to j and subsequent to j + 1, the point of interest, areused to compute the vertical rebound ratio for each point.VRR$i%! 5h$i%href $j%1 href $j 1 1%!/2100 (4)9.5 When appropriate, calculate the vertical reb
48、ound ratio tothe nearest 1 % for entire surface (VRR) using the average.VRR 5(i 5 1nVRR$i%n(5)9.6 When appropriate, calculate the standard deviation ofthe vertical rebound ratio (sVRR) to the nearest 0.01 % for theentire surface.sVRR 5(i 5 1nVRR$i%!2 VRR!2n 1(6)9.7 When appropriate, calculate the co
49、efficient of restitution(CR) to the nearest 0.01 for each point of the playing surfacetested, using the rebound height for each point i and therelease height (hrelease).CR 5h$i%hrelease(7)9.8 When appropriate, calculate the average coefficient ofrestitution (CR) for the entire playing surface tested, using theaverage time between impacts (Dti) from each point.CR 5g8S(i 5 1nDt$i%nD2/ hrelease(8)9.9 When appropriate, calculate the standard deviation ofthe coefficient of restitution (sCR) for the entire playingsurface tested.sCR 5Sg8
