1、Designation: F2650 13F2650 17 An American National StandardStandard Terminology Relating toImpact Testing of Sports Surfaces and Equipment1This standard is issued under the fixed designation F2650; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e 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 terminology covers terms related to impact test methods and impact attenuation specifi
3、cations of sports equipment andsurfaces.1.2 This terminology is appropriate for use in the development of standards that describe gravity-driven impact test methodsor specify impact attenuation performance criteria and which fall under the jurisdiction of ASTM Committee F08 on SportsEquipment and Fa
4、cilities.1.3 This terminology defines common terms that are applicable to many sports-related impact tests including those used in thecontext of sports surfaces, athletic footwear, protective equipment and padding. The use of a common terminology will promotegreater consistency among standards and r
5、educe the risk of misinterpretation.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in t
6、he Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Terminology2.1 Definitions:acceleration, nrate of change of velocity with time.DISCUSSIONAcceleration is a vector
7、quantity, having both magnitude and direction. Acceleration magnitude is expressed in units of m/s2 (ft/s2) and direction isdefined relative to a Cartesian coordinate system or other spatial reference frame.assisted impact test, nan impact test in which the missile is accelerated by means other than
8、 gravity alone, for example, by anactuator.drop height (h),nheight from which a missile is dropped during a gravity-driven impact test, measured as the vertical distancebetween the lowest point of the elevated missile and its first point of contact with the impacted surface or anvil.theoretical drop
9、 height, ndrop height (h) that, under standard conditions, would result in an impact velocity equal to a missilesmeasured impact velocity (V0).DISCUSSIONThe “standard conditions” assume standard gravity and that friction and air resistance do not affect the fall of the missile. In a free-fall impact
10、 test theactual drop height will approximate the theoretical drop height. In a guided impact test, the theoretical drop height will be less than the actual dropheight, due to the effects of friction in the guidance mechanism.g, n(pronounced “gee”) a unit of acceleration equal to standard gravity. Mi
11、ssile accelerations expressed in g units are the ratioof the missile acceleration to standard gravity and are hence dimensionless.1 This terminology is under the jurisdiction ofASTM Committee F08 on Sports Equipment, Playing Surfaces, and Facilities and is the direct responsibility of SubcommitteeF0
12、8.80 on Common Terminology, Methods and Laboratory Practices.Current edition approved June 1, 2013Sept. 15, 2017. Published July 2013October 2017. Originally approved in 2007. Last previous edition approved in 20072013 asF2650 07.F2650 13. DOI: 10.1520/F2650-13.10.1520/F2650-17.This document is not
13、an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate.
14、 In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1DISCUSSIONThe symbol g is properly written in lowercase and italic, t
15、o distinguish it from the symbol G (uppercase, used to indicate the gravitational constant)and g (not italicized) which is an abbreviation of the gram unit.g-max, nmaximum acceleration magnitude recorded during a single impact, expressed in g units.average g-max, narithmetic average of a specified s
16、et of g-max values.gravity-driven impact test, nan impact test in which the missile is accelerated by gravity alone, during a period of free-fall.head injury criterion (HIC), nweighted impulse criterion calculated from a head impact acceleration-time profile and used toquantify head impact severity.
17、 The HIC calculation results in a severity index that is weighted by both impact accelerationmagnitude and by the time for which high magnitude accelerations persist.DISCUSSIONHIC scores can only be directly referenced to the head injury risk data on which the criterion is based if the impact accele
18、ration-time profile is recordedusing a human head or a biofidelic headform. HIC scores determined using rigid missiles and headforms tend to over estimate head injury risk.headform, nmissile with mass and geometry approximating those of the human head.biofidelic headform, nheadform with elastic prop
19、erties approximating those of the human head.rigid headform, nheadform fabricated from very stiff materials (for example, steel or aluminum) such that its deformationduring an impact is negligible.impact attenuation, nreduction of loads produced in the course of an impact by means of a cushioning sy
20、stem or device, relativeto a load criterion or to the loads produced by a reference system.DISCUSSIONLoad measures used to quantify impact magnitude include force, acceleration, stress and pressure and their time derivatives.impact energy, nthe kinetic energy of a missile at the instant of initial c
21、ontact with the target.DISCUSSIONIn a gravity-driven test, impact energy is equal to the potential energy of the missile at the theoretical drop height. See also total energy input.impact test, na mechanical test in which an instrumented missile impacts a target.DISCUSSIONThe outcomes of the impact
22、are measured and used to characterize the impact attenuation of the target under initial conditions imposed by the testmethod.missile, nin a gravity-driven impact test, the object mass that falls under gravity to produce an impact.reference plane, nplane parallel to the surface or normal to the path
23、 of the missile and from which missile displacement ismeasured.rigid surface, na reference surface (for example, a concrete surface covered by a steel plate) used as the basis for measuringforce reduction.shock absorption,nsee shock attenuation.shock attenuation, nimpact attenuation where the measur
24、e of load is the peak magnitude of acceleration produced by an impact.(See impact attenuation.)sprung-mass impact test, nan impact test in which a calibrated linear spring is interposed between the missile and the target.DISCUSSIONThe spring limits the maximum impact force or acceleration produced b
25、y an impact on a stiff or rigid surface to a value determined by the stiffnessof the spring.F2650 172standard gravity, nnominal value of the acceleration due to gravity at sea level having an international standard value of exactly9.80665 m/s2 (approximately 32.174 ft/s2).time to g-max, nelapsed tim
26、e from the onset of impact until the time at which g-max occurs.DISCUSSIONDepending on the application, the “onset of impact” may be defined as the time at which the missile intersects a zero reference plane or as the timeat which a measured deceleration of the missile exceeds a small threshold valu
27、e.total energy input, nthe total energy transferred to the target, up to the point of maximum target displacement, the sum of theimpact energy and the additional potential energy transferred during target displacement.3. Keywords3.1 athletic equipment; athletic field; impact; impact testing; playgro
28、und equipment; playground surfaces; sports; sportsequipment; sports field; sports surfacesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination
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