1、Designation: F 2650 07Standard Terminology Relating toImpact Testing of Sports Surfaces and Equipment1This standard is issued under the fixed designation F 2650; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 terminology covers terms related to impact testmethods and impact attenuation specifications of sports equip-ment and sur
3、faces.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 Facilities.1.3 This terminology defi
4、nes 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 reducethe risk of misinterpretation
5、.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-tude and direction. Accelerat
6、ion magnitude is expressed in units ofm/s2(ft/s2) and direction is defined relative to a Cartesian coordinatesystem or other spatial reference frame.drop height (h), nheight from which a missile is droppedduring a gravity-driven impact test, measured as the verticaldistance between the lowest point
7、of the elevated missile andits first point of contact with the impacted surface or anvil.theoretical drop height, ndrop height (h) that, understandard conditions, would result in an impact velocity equalto a missiles measured impact velocity (V0).DISCUSSIONThe “standard conditions” assume standard g
8、ravity andthat friction and air resistance do not affect the fall of the missile. In afree-fall impact test the actual drop height will approximate thetheoretical drop height. In a guided impact test, the theoretical dropheight will be less than the actual drop height, due to the effects offriction
9、in the guidance mechanism.g, n(pronounced “gee”) a unit of acceleration equal tostandard gravity. Missile accelerations expressed in g unitsare the ratio of the missile acceleration to standard gravityand are hence dimensionless.DISCUSSIONThe symbol g is properly written in lowercase anditalic, to d
10、istinguish it from the symbol G (uppercase, used to indicatethe gravitational constant) and g (not italicized) which is an abbrevia-tion of 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
11、ofg-max values.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 high
12、magnitude accelerations 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
13、 to over estimate 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)
14、 such that itsdeformation during an impact is negligible.impact attenuation, nreduction of loads produced 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 mag
15、nitudeinclude force, acceleration, stress and pressure and their time deriva-tives.1This terminology is under the jurisdiction of ASTM Committee F08 on SportsEquipment and Facilities and is the direct responsibility of Subcommittee F08.80 onCommon Terminology, Methods and Laboratory Practices.Curren
16、t edition approved Aug. 1, 2007. Published September 2007.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.missile, nin a gravity-driven impact test, the object mass thatfalls under gravity to produce an impact.reference plane, nplane
17、 parallel to the surface or normal tothe path of the missile and from which missile displacementis measured.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.)st
18、andard gravity, nnominal value of the acceleration due togravity at sea level having an international 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, th
19、e “onset of impact”may be defined as the time at which the missile intersects a zeroreference plane or as the time at which a measured deceleration of themissile exceeds a small threshold value.3. Keywords3.1 athletic equipment; athletic field; impact; impact testing;playground equipment; playground
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23、 fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box 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).F 2650 072
