1、Designation: F2650 171An 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.1NOTEEditorially corrected standard gravity in November 2017.1. Scope1.1 This terminology covers terms related
3、to impact testmethods and impact attenuation specifications of 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 jurisd
4、iction of ASTM Committee F08 onSports Equipment and Facilities.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 terminology
5、will promote greater consistency among standards and reducethe 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.1.5 This international standard was developed in accor-dance with internationally reco
6、gnized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Terminology2.1 Definitions:acceleration, nrate of change of
7、velocity with time.DISCUSSIONAcceleration is a vector quantity, having both magni-tude 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
8、 which the missile isaccelerated by means other than gravity alone, for example,by an 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
9、with the impacted surface or anvil.theoretical drop height, ndrop height (h) that, understandard 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 affe
10、ct 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 in the guidance mechanism.g, n(pronounced “gee”) a uni
11、t 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 distinguish it from the symbol G (uppercase, used to in
12、dicatethe 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 ofg-max values.gravity-driven impact test, nan impact
13、test in which themissile is accelerated by gravity alone, during a period offree-fall.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 weigh
14、ted by both impactacceleration magnitude and by the time for which highmagnitude 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 biofideli
15、c1This 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 Sept. 15, 2017. Published October 2017. Ori
16、ginallyapproved in 2007. Last previous edition approved in 2013 as F2650 13. DOI:10.1520/F2650-17E01.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognize
17、d principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1headform. HIC scores determined using rigid missiles and headformste
18、nd 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 aluminu
19、m) 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 m
20、agnitudeinclude force, acceleration, stress and pressure and their time deriva-tives.impact energy, nthe kinetic 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 dr
21、op height. See alsototal energy input.impact test, na mechanical test in which an instrumentedmissile impacts a target.DISCUSSIONThe outcomes of the impact are measured and used tocharacterize the impact attenuation of the target under initial conditionsimposed by the test method.missile, nin a grav
22、ity-driven impact test, the object mass thatfalls under 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 ste
23、el plate) used as the basis formeasuring force reduction.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.)sprung-mass impact test, nan impact test in which aca
24、librated linear spring is interposed between the missile andthe target.DISCUSSIONThe spring limits the maximum impact force or accel-eration produced by an impact on a stiff or rigid surface to a valuedetermined by the stiffness of the spring.standard gravity, nnominal value of the acceleration due
25、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, the “onset of impact”may be defined as the time at which
26、the missile intersects a zeroreference plane or 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 po
27、tential energytransferred during target displacement.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 r
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