1、Designation: F2117 10An American National StandardStandard Test Method forVertical Rebound Characteristics of Sports Surface/BallSystems; Acoustical Measurement1This standard is issued under the fixed designation F2117; the number immediately following the designation indicates the year oforiginal a
2、doption or, in 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 test method covers the quantitative measurementand normalization
3、 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 su
4、rface.1.4 The methods described are applicable in both laboratoryand field settings.1.5 The values stated in metric units are to be regarded asthe standard. The inch-pound units given in parentheses are forreference only.1.6 This standard does not purport to address all of thesafety concerns, if any
5、, 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 Section 5
6、.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 sub
7、floor). 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: l
8、ayers 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 comp
9、lete 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 differences
10、 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 impact p
11、oint (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 in.)
12、 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 within
13、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 rati
14、o (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 jurisd
15、iction of ASTM Committee F08 on SportsEquipment and Facilities and is the direct responsibility of Subcommittee F08.52 onMiscellaneous Playing Surfaces.Current edition approved June 1, 2010. Published July 2010. Originally approvedin 2001. Last previous edition approved in 2001 as F2117 01 which was
16、withdrawn in February 2010 and reinstated in June 2010. DOI: 10.1520/F2117-10.2Available from DIN, Burggrafenstrasse 6, D-10787 Berlin, Germany.3Available from BSI, 389 Chiswick High Road, London W4 4AL, UK.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942
17、8-2959, United States.surface rebound measurement is found to be unrepeatable, thecoefficient of restitution should be used instead.4. Summary of Test Method4.1 This test method provides a means for evaluating therebound height produced by a test ball on a test surface. Theprocedure can be used to e
18、valuate vertical ball reboundperformance on a reference athletic surface, evaluate surfacevertical rebound performance using a reference athletic ball, orto evaluate the effects of ball-surface interactions. A ball isreleased from a known height and allowed to impact thereference surface. The releas
19、e should not impart any horizontalmotion. An acoustical measurement system measures therebound height obtained on the test surface. The ball is thenreleased from the same height and allowed to impact the testsurface, where again, the rebound height is measured. Thevertical rebound ratio, presented a
20、s a percentage, is obtainedfrom the ratio of the vertical rebound height on the sportingsurface to the vertical rebound height on the reference surface.5. Significance and Use5.1 The ball-surface interaction is just one of the importantproperties of a sports surface. It may be an indicator of thepla
21、yability or suitability of the surface.5.2 Manufacturers of sporting balls may use this method toevaluate the effects of design changes on the rebound heightproduced.5.3 Manufacturers of sports surfaces may use this method toevaluate the effects of design changes in the sports surfacesystem on the r
22、ebound height produced.5.4 The tendency of modern facilities to support multiplesports on a single surface may require that test surfaces betested for several types of sporting balls. Examples include, butare not limited to: basketball, soccer, tennis, and baseball.5.5 The measurement of rebound hei
23、ght may be affected ifthe temperature of the ball has not reached equilibrium with theenvironment.6. Apparatus6.1 Ball-Release Apparatus, capable of releasing the sport-ing ball from a consistent height, without imparting significantspin or horizontal motion to the sporting ball. The ball releaseapp
24、aratus is typically an adjustable-height tripod. The releasemechanism may be mechanical, electromagnetic, vacuum, ormanual.6.2 Sound Recording and Analysis SystemA system withthe minimum requirements as follow: acoustic sampling fre-quency 11 000 Hz, 8-bit resolution, on a single acousticchannel. Th
25、e system must be capable of determining the timeof the first (tl) and second (t2) impacts using the peak acousticsignal generated to determine tland t2through either the use ofhardware or software.6.2.1 ExamplePersonal computer, sound-card, and micro-phone have been found to produce adequate results
26、.7. Testing Conditions7.1 The following general testing conditions should berecorded and included in the test report for informationpurposes only:7.1.1 All Surfaces: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 pla
27、ying surface. Measurements may be obtainedusing hand-held commercially available temperature and rela-tive humidity sensors.7.1.1.2 The vertical ball rebound should 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
28、 Wood Playing SurfacesThe wood moisture content(%) should be included. Measurements may be obtained usinghand-held commercially available wood moisture sensors.7.1.3 Outdoor Playing SurfaceThe general moisture levelof the surface should be included. In general, the surfaceshould be characterized as
29、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).7.1.4.2 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
30、 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, andthe surface should be allowed at least4htoacclimate to theenvironment.8.2 Measure and record ambient temperature to the nearest1C and the rela
31、tive 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 relative 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. Th
32、isincludes 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 surroundings and dimensions thatallow the test points to be relocated. Effort should be made tolocate and test rebound properties of the pl
33、aying surface onareas representative of the surface conditions present andconstruction methods used in the playing surface. Tests shouldalso be conducted on areas considered heavy-use and non-useareas. Examples include but are not limited to the following:8.4.1.1 Natural TurfDensely covered areas an
34、d 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-face 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 pr
35、esent), joints in the sleeperlayer (if present), between sleepers (if present), seams inpadding layer (if present), individual pads (if present).8.4.2 When testing under laboratory conditions, include adescription of the overall system construction and a descriptionof construction details present at
36、 all test points.8.5 Set the drop height to the nominal desired height. Theactual drop height should be measured and recorded to theF2117 102nearest 0.005 m (0.2 in.). The surface/ball system should beevaluated using a nominal drop height of 1.800 m (72 in.) andany additional drop heights considered
37、 useful.8.6 Perform ball inspection; verify that construction is stillsound. When appropriate, verify that the inflation pressure iswithin manufacturers specifications and record actual pres-sure.8.7 Evaluate the rebound height from the desired point onthe reference surface by recording seven vertic
38、al 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 calculate the average timebetween impacts (tref-1) from the remaining five drops. Sport-ing balls without inflation valves (such as golf b
39、alls, racquet-balls, and so forth) are released from the drop height with arandom orientation. Sporting balls with inflation valves (soccerballs, basketballs, and so forth) are released with the inflationvalve pointing away from the impact surface.8.8 Move the release apparatus to the athletic surfa
40、ce, 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 characterize anyplaying surface. Record seven vertical rebound heights fromeach point. For each point, exclude the maximum and mini-mum value re
41、corded, 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 propertiesof 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 t
42、he rebound height has not changed duringtesting by retesting the reference point every 30 min (maxi-mum allowable time duration) and at the conclusion of everytested surface. Record seven rebound measurements, excludethe maximum and minimum values, and calculate the averagetime between rebounds (tre
43、f-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 information purposes only and can beobtained using a low-pressure gage of the type available atautomotive stores.9. Calculations9.1 Rebound height
44、 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 nearest0.001 s (tl, and t2are obtained from the moment of maximumsound intensity generated during the impact). The averagerebound height at each p
45、oint 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 maximum and minimum time differences shouldbe computed to the nearest 0.001 s for each point i tested onthe playing surface (Dti) and for each te
46、st j on the referencesurface (Dtrefj).Dt$i%5Dt11Dt21Dt31Dt41Dt55(2)9.3 The average time between the first and second impactsof the ball with the playing surface is then converted to verticalrebound height for each point i on the playing surface (hi)and for each point j on the reference surface (href
47、j)inmetres (feet), where g = 9.81 m/s2(g = 32.2 ft/s2).h$i%5g8Dt$i%!2(3)9.4 When appropriate, calculate the vertical rebound ratio(VRRi) to the nearest 1 % for each point i of the playingsurface tested. The reference surface rebound height obtainedprior to j and subsequent to j + 1, the point of int
48、erest, areused to compute the vertical rebound ratio for each point.VRR$i%! 5h$i%href $j%1 href $j 1 1%!/2100 (4)9.5 When appropriate, calculate the vertical rebound ratio tothe nearest 1 % for entire surface (VRR) using the average.VRR 5(i 5 1nVRR$i%n(5)9.6 When appropriate, calculate the standard
49、deviation ofthe vertical rebound ratio (sVRR) to the nearest 0.01 % for theentire surface.sVRR 5(i 5 1nVRR$i%!2 VRR!2n 1(6)9.7 When appropriate, calculate the coefficient of restitution(CR) to the nearest 0.01 for each point of the playing surfacetested, using the rebound height for each point i and therelease height (hrelease).CR 5h$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
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