1、Designation: F 355 01An American National StandardStandard Test Method forShock-Absorbing Properties of Playing Surface Systemsand Materials1This standard is issued under the fixed designation F 355; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase 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 measurement of certainshock-absorbing characteristics, the i
3、mpact force-time relation-ships, and the rebound properties of playing surface systems.This test method is applicable to natural and artificial playingsurface systems and to components thereof. Typical playingsurfaces are wrestling mats, football fields, soccer fields,playgrounds, and so forth.NOTE
4、1This test method may also be used to measure the shock-attenuation properties of materials used as protective padding, such as thepadding on trampoline frames, football goal posts, gymnasium wall,shoulder pads, body padding, and so forth. It should not be used, withoutsome modifications, to test th
5、e finished products.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this stand
6、ard 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:2D 1596 Test Method for Dynamic Shock Cushioning Char-acteristics of Packaging MaterialE 105 Practice for Probability Sampling o
7、f MaterialsE 122 Practice for Calculating Sample Size to Estimate,With a Specified Tolerable Error, the Average for Charac-teristic of a Lot or ProcessE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodF 1292 Specification for Impact Attenuation of Surfa
8、ceSystems Under and Around Playground Equipment2.2 SAE Standard:SAE Recommended Practice J 211-1 March 1995 Instru-mentation for Impact Tests, Part 1Electronic Instrumen-tation33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 playing surface systema composite that includes thec
9、ontact surface, energy-absorbing materials, if any, and thesubstrates.3.1.2 baselinethe starting reference plane of the playingsurface system from which the total penetration is determined.It is taken as the top plane of the playing surface system, whensubjected to a static compression of 6.8 kPa (1
10、.0 psi) forProcedure A.3.1.3 accelerationthe instantaneous time rate of changeof velocity which may be positive or negative.3.1.4 Gthe ratio of the magnitude of missile accelerationduring impact to the acceleration of gravity, expressed in thesame units.3.1.5 Gmaxthe maximum value of G encountered d
11、uringimpact.3.1.6 severity indexan arbitrary parameter equal to theintegral of G2.5dt (at 0.05-ms integration interval) over thetotal duration of impact.3.1.7 head injury criteria (HIC)a measure of impactseverity that takes into account the duration over which themost critical section of the deceler
12、ation pulse persists as well asthe peak level of that deceleration.3.1.8 impact velocitythe velocity of the missile as mea-sured within 2.54 cm (1.0 in.) of the point of impact.3.1.9 rebound velocitythe velocity of the missile as itcrosses the baseline on rebound.3.1.10 time to Gmaxthe difference be
13、tween the time themissile crosses the baseline on impact and the time Gmaxisreached.1This test method is under the jurisdiction of ASTM Committee F08 on SportsEquipment, Surfaces, and Facilities and is the direct responsibility of SubcommitteeF08.52 on Playing Surfaces and Facilities.Current edition
14、 approved Nov. 10, 2001. Published January 2002. Originallypublished as F 355 72. Last previous edition F 355 95.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the
15、 standards Document Summary page onthe ASTM website.3Available from Society of Automotive Engineers, 400 Commonwealth Drive,Warrendale, PA 15096.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.11 dynamic hardness indexthe stress
16、on a material dueto rapid indentation by a moving missile with the geometrydescribed in Procedure A.3.1.12 time to maximum penetrationthe difference be-tween the time the missile crosses the baseline on impact andthe time maximum penetration is reached.4. Summary of Test Method4.1 A test specimen is
17、 impacted at a specified velocity witha missile of given mass and geometry.Atransducer mounted inthe missile monitors the acceleration-time history of theimpact, which is recorded with the aid of an oscilloscope orother recording device. Optionally, with the use of penetrationmeasuring devices, the
18、displacement history of the impact mayalso be recorded.4.2 The three procedures covered in this test method are asfollows:4.2.1 Procedure A uses a cylindrical missile with a circular,flat, metal impacting surface with specified mass, geometry,and impact velocity appropriate for the intended end use.
19、4.2.2 Procedure B uses a missile with a hemispherical,metal impacting surface of specified mass, radius, and impactvelocity appropriate for the intended end use.4.2.3 Procedure C uses the ANSI C size metal headformwith a specified mass, geometry, and impact velocity appro-priate for the end use. For
20、 the purposes of this test method, thepositioning of the headform shall be such that all impacts occuron the crown.4.2.4 The specific mass and geometry of the missiles foreach procedure are detailed in 6.2.5. Significance and Use5.1 Dynamic data obtained by these procedures are indica-tive of the cu
21、shioning properties of the playing surface systemsand materials under the specific conditions selected.6. Apparatus6.1 Testing MachineAny type of dynamic testing appara-tus that impacts the test material on a massive, rigid anvil witha missile at a prescribed impact velocity and monitors andrecords
22、the acceleration-time history is acceptable. The anvilmass (impacted base) should be at least 100 times that of themissile. The test apparatus may optionally be designed to testa playing surface in-place. In either case, the test specimenshall have dimensions larger than the impact area of the missi
23、leas specified in 7.1. The test machine and missile shall havesufficient rigidity to eliminate undesirable vibrations in theapparatus that might be recorded on the acceleration-timecurve.6.2 MissileThe missile shall be designed to meet thegeneral requirements of 4.2.1-4.2.3. Provision shall be mades
24、uch that the accelerometer can be securely fastened within65 of the vertical axis of the missile. The mass and geometryfor each procedure is referenced in Table 1.6.3 Recording EquipmentThe recording equipment shallmeet the following criteria:6.3.1 Acceleration-TimeThe selection of the specificaccel
25、eration-time recording equipment, including transducersand recorders, is optional. However, the recording system shallhave a frequency response adequate to measure the peakacceleration value to an accuracy of6 5 % of the true value.The total system, detection and recording, shall be capable ofmeasur
26、ing impulses up to 500 g at frequencies from 20 to 1000Hz to an accuracy of 65 %. The minimum system samplingrate required is 20 000 Hz or 20 000 samples/s. The accelera-tion transducer system shall comply with the requirements ofSAE J 211-1 for a channel frequency Class 1000 data channel.A low pass
27、 filter having a 4-pole Butterworth transfer functionand a corner frequency of 1650 Hz meets this requirement. Adigital filter complient with Appendix C of SAE J 211 may besubstituted.NOTE 2Since impact test data may have high-frequency componentsTABLE 1 Mass and Geometry of MissilesProcedure Weight
28、 GeometryA9.1kg6 50g(206 0.11 lb) 129 6 2.0-cm2(20 6 1.0-in.2) facewith a circumference-relieved radiusof 2 6 0.25 mm (0.08 6 0.01 in.) toeliminate sharp edgesB6.8kg6 50g(156 0.011 lb) radius of 82.6 6 2.5mm(3.26 0.01in.)C5.0kg6 50g(116 0.011 lb) specified in Fig. 1NOTE 1All dimensions in inches (1
29、in. = 25.4 mm).FIG. 1 Contour Dimensions of Test Headform for Procedure CF355012above 1000 Hz, analog filtering should be used before sampling in orderto prevent aliasing errors in the sampling process.6.3.2 Impact and Rebound VelocitiesThe dynamic testequipment must have means of recording the impa
30、ct velocitiesof the missile to an accuracy of 65 % of the true value. Anymethod that does not physically interfere with the impact andgive erroneous acceleration-time results is acceptable.6.3.3 Displacement TimeIt is optional, but desirable, thatthe displacement-time history also be recorded. Any m
31、ethodthat provides a linear signal proportional to displacement alongthe impact axis which can be monitored coincidentally with theacceleration-time trace is acceptable. If displacement is re-corded, the test equipment shall have means to determine andrecord the top plane (baseline) of the playing s
32、urface systemfrom which total penetration is determined (see 3.1.2).6.3.4 In the event that a means is available for accuratelydetermining both the impact and rebound velocities, it ispossible to perform two time integrations to yield thedisplacement-time history. The initial and final conditions on
33、the velocity can be used as a check on the integral ofdeceleration that yields the velocity-time record. If the integra-tion that yields the velocity yields initial and final velocitiesthat agree with the directly measured values of these param-eters then the displacement-time history should also be
34、 able tobe accurately determined by using the same integration methodon the velocity-time record and using 0 as the initial value ofdisplacement (once the baseline has been properly deter-mined).7. Test Specimen7.1 Test specimens shall represent the playing surface orprotective padding as it is inte
35、nded to be used. The minimumdistance between the outer dimension of the missile and theedge of the specimen shall be at least 25.4 mm (1 in.) and noless than the thickness of the specimen.8. Number of Specimens8.1 The number of specimens tested as a sample can varywidely, depending upon the intended
36、 use of the data. It isrecommended that at least two specimens be tested for each setof conditions. To obtain a specific quality assurance level, thesampling procedures of Practices E 105 and E 122 should befollowed.9. Conditioning9.1 Do not stack the specimens during any conditioning.They shall be
37、under the intended use condition or precondi-tioned at 50 6 2 % relative humidity and 23 6 2C for aminimum of 4 h, or until desired temperature is attained.Samples to be tested at other than these conditions shall bestored in the desired environment for at least 4 h, or until theyreach the desired t
38、emperature, before testing. Samples shall betested (that is, impacted) within 10 s after removal from theenvironmental chamber. Samples shall be returned to theenvironmental chamber within 20 s after impact and stored forat least 2 h between drops. Testing at other than ambientprecludes conducting s
39、uccessive drops at short time intervals.NOTE 3Due to differing thermal conductivities and the extreme timedependence of temperature profiles in most materials exposed to extremesurface temperature changes there may be variability introduced by thistype of testing.10. Procedure10.1 Prewarm the record
40、ing equipment as recommended bythe manufacturer. Calibrate G time and penetration-time re-corder in accordance with the recommended procedure of theequipment manufacturer.10.2 Place the specimen under the missile, or orient thedynamic test equipment over the playing surface system.10.3 Determine the
41、 baseline by preloading the test specimento 6.8 kPa (1.0 psi) for Procedure A and adjusting the recorderto read zero penetration. When testing at other than ambientconditions, determine the baseline with the sample at thedesired test temperature.NOTE 4When using Procedures B or C, care should be exe
42、rcised tolower the missile gently onto the sample when establishing the baseline.10.4 Set the missile-propelling mechanism to obtain thedesired impact velocity.10.5 Release the missile, and record the results in accor-dance with the recommended procedures of the equipmentmanufacturers.10.6 Make thre
43、e consecutive drops at intervals of 36 0.25min, unless otherwise specified (see 9.1).NOTE 5Calculation of Theoretical Drop Height: For comparison ofdata based on drop height, only the theoretical drop height should be used.The following calculation should be used (see Test Method D 1596):H 5 V2/2g (
44、1)where:H = theoretical height, mm (in.),V = velocity, mm/s (in./s), andg = acceleration of gravity, 9806 mm/s/s (386 in./s/s).This calculation eliminates variations in using actual drop height, whichmay be affected by frictional losses.11. Calculation11.1 GmaxDetermine the maximum deceleration in t
45、hetime-deceleration history to the closest G.11.2 Time to GmaxDetermine the time to maximum decel-eration to the nearest 0.05 ms.11.3 Severity IndexThe time integral of deceleration ex-ponentiated 2.5 times may be calculated by dividing thedeceleration-time record into equally sized time subinterval
46、s ofmagnitude of 0.05 ms and summing the deceleration values (inG) exponentiated 2.5 times between the two intersections ofthe deceleration record and the time axis. Multiply this resultby the time subinterval length (in seconds) and the result is theSeverity Index in G-s.11.4 Head Injury CriterionM
47、ore sophisticated methods ofdata integration such as the Head Injury Criterion (HIC) maybe used if desired. The HIC evolved from the Severity Indexcalculation and requires the maximization of the mathematicalexpression, involving the time-average acceleration by varyingof the time interval over whic
48、h the average is calculated.Numerical evaluation of the HIC requires analog-to-digitalconversion of the acceleration time profile using a samplingrate sufficient to characterize the pulse accurately. These dataF355013are easily processed by a digital computer. The HIC number isdetermined by evaluati
49、ng the equation for all iterative combi-nations of the integration limits that the time interval allows forthe evaluation. The equation4,5for calculating the HIC value isas follows:HIC 5Ft22 t1!S1t22 t1!*t1t2adtD2.5Gmax (2)A time interval of 0.05 ms should be used.11.5 Maximum PenetrationDetermine the maximum dis-placement to the nearest 0.254 mm (0.01 in.).11.6 Time to Maximum PenetrationDetermine the time tomaximum penetration.11.7 Rebound VelocityUse a straightedge to draw a tan-gent line at the exit of the penetration-time trace. The slope of
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