1、Designation: F2650 13 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 case of rev
2、ision, 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 testmethods and impact attenuation specifications o
3、f sports equip-ment and surfaces.1.2 This terminology is appropriate for use in the develop-ment of standards that describe gravity-driven impact testmethods or specify impact attenuation performance criteria andwhich fall under the jurisdiction of ASTM Committee F08 onSports Equipment and Facilitie
4、s.1.3 This terminology defines common terms that are appli-cable to many sports-related impact tests including those usedin the context of sports surfaces, athletic footwear, protectiveequipment and padding. The use of a common terminologywill promote greater consistency among standards and reduceth
5、e risk of misinterpretation.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.2. Terminology2.1 Definitions:acceleration, nrate of change of velocity with time.DISCUSSIONAcceleration is a vector quantity, having both magni-tu
6、de and direction. Acceleration magnitude is expressed in units ofm/s2(ft/s2) and direction is defined relative to a Cartesian coordinatesystem or other spatial reference frame.assisted impact test, nan impact test in which the missile isaccelerated by means other than gravity alone, for example,by a
7、n actuator.drop height (h), nheight from which a missile is droppedduring a gravity-driven impact test, measured as the verticaldistance between the lowest point of the elevated missile andits first point of contact with the impacted surface or anvil.theoretical drop height, ndrop height (h) that, u
8、nderstandard conditions, would result in an impact velocity equal toa missiles measured impact velocity (V0).DISCUSSIONThe “standard conditions” assume standard gravity andthat friction and air resistance do not affect the fall of the missile. In afree-fall impact test the actual drop height will ap
9、proximate thetheoretical drop height. In a guided impact test, the theoretical dropheight will be less than the actual drop height, due to the effects offriction in the guidance mechanism.g, n(pronounced “gee”) a unit of acceleration equal tostandard gravity. Missile accelerations expressed in g uni
10、tsare the ratio of the missile acceleration to standard gravityand are hence dimensionless.DISCUSSIONThe symbol g is properly written in lowercase anditalic, to distinguish it from the symbol G (uppercase, used to indicatethe gravitational constant) and g (not italicized) which is an abbrevia-tion o
11、f the gram unit.g-max, nmaximum acceleration magnitude recorded duringa single impact, expressed in g units.average g-max, narithmetic average of a specified set ofg-max values.gravity-driven impact test, nan impact test in which themissile is accelerated by gravity alone, during a period offree-fal
12、l.head injury criterion (HIC), nweighted impulse criterioncalculated from a head impact acceleration-time profile andused to quantify head impact severity. The HIC calculationresults in a severity index that is weighted by both impactacceleration magnitude and by the time for which highmagnitude acc
13、elerations persist.DISCUSSIONHIC scores can only be directly referenced to the headinjury risk data on which the criterion is based if the impactacceleration-time profile is recorded using a human head or a biofidelicheadform. HIC scores determined using rigid missiles and headformstend to over esti
14、mate head injury risk.headform, nmissile with mass and geometry approximatingthose of the human head.biofidelic headform, nheadform with elastic propertiesapproximating those of the human head.rigid headform, nheadform fabricated from very stiffmaterials (for example, steel or aluminum) such that it
15、sdeformation during an impact is negligible.1This terminology is under the jurisdiction of ASTM Committee F08 on SportsEquipment, Playing Surfaces, and Facilities and is the direct responsibility ofSubcommittee F08.80 on Common Terminology, Methods and Laboratory Prac-tices.Current edition approved
16、June 1, 2013. Published July 2013. Originally approvedin 2007. Last previous edition approved in 2007 as F2650 07. DOI: 10.1520/F2650-13.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1impact attenuation, nreduction of loads produced
17、in thecourse of an impact by means of a cushioning system ordevice, relative to a load criterion or to the loads producedby a reference system.DISCUSSIONLoad measures used to quantify impact magnitudeinclude force, acceleration, stress and pressure and their time deriva-tives.impact energy, nthe kin
18、etic energy of a missile at the instantof initial contact with the target.DISCUSSIONIn a gravity-driven test, impact energy is equal to thepotential energy of the missile at the theoretical drop height. See alsototal energy input.missile, nin a gravity-driven impact test, the object mass thatfalls u
19、nder gravity to produce an impact.reference plane, nplane parallel to the surface or normal tothe path of the missile and from which missile displacementis measured.rigid surface, na reference surface (for example, a concretesurface covered by a steel plate) used as the basis formeasuring force redu
20、ction.shock absorption, nsee shock attenuation.shock attenuation, nimpact attenuation where the measureof load is the peak magnitude of acceleration produced by animpact. (See impact attenuation.)standard gravity, nnominal value of the acceleration due togravity at sea level having an international
21、standard value ofexactly 9.80665 m/s2(approximately 32.174 ft/s2).time to g-max, nelapsed time from the onset of impact untilthe 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 zeroreference plane or
22、 as the time at which a measured deceleration of themissile exceeds a small threshold value.total energy input, nthe total energy transferred to thetarget, up to the point of maximum target displacement, thesum of the impact energy and the additional potential energytransferred during target displac
23、ement.3. Keywords3.1 athletic equipment; athletic field; impact; impact testing;playground 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 ment
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27、ox C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F2650 132
