ASTM_F_1614_-_99.pdf

Designation:F 1614 99An American National StandardStandard Test Method forShock Attenuating Properties of Materials Systems forAthletic Footwear1This standard is issued under the fixed designation F 1614;the number immediately following the designation indicates the year oforiginal adoption or,in the case 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 attenuating characteristics,rapid rate force-displacementrelationships,of materials systems employed in the midsole ofathletic footwear intended for use in normal running move-ments.This test method covers three different procedures forperformance of the rapid rate force application:Procedure Afor falling weight impact machines,Procedure B for compres-sion force controlled machines,and Procedure C for compres-sion displacement controlled machines.1.2 The material system response for rapid rate forceapplication may be different for each of the three procedures ofthis test method.1.3 This test method is empirically based on the use of an8.5-kg mass dropped from 50 mm(1.97 in.)to generate peakcompressive forces which are comparable to that experiencedby a midsole in heel strike tests for normal running move-ment.2,3This requires the specimen to be rigidly supported andthe energy to be delivered through a 45-mm(1.8-in.)diameterflat tup.1.4 This test method imposes an impulse to generate a rapidrate compressive force-displacement hysteresis cycle andevaluates shock attenuating characteristics of the specimen.The maximum energy applied to the specimen occurs at peakdisplacement and must be within 610%of a reference valuethat is used to normalize the data for comparative purposes.1.5 Shock attenuating characteristics,for this test method,are in terms of absorbed energy loss during the hysteresiscycle,peak pressure,maximum strain,and average stiffness.Each of these characteristics will have varying importance,depending on the design objectives for the material system inthe athletic footwear product.1.6 Test results obtained by this test method shall bequalified by the specimen thickness and the reference maxi-mum energy applied.1.6.1 Nominal specimen thickness values for this testmethod are in the range from 5 to 35 mm(0.2 to 1.4 in.),see7.1.1.6.2 The standard value for the reference maximum energyapplied of this test method is 5.0 J.Other values may be used,if they are clearly stated in the report.NOTE1For Procedure A,the use of a 8.5-kg mass and an initialdistance of 50 mm between tup and specimen will produce the requiredimpulse and result in maximum energy applied values in the range of 5 60.5 J(44.2 6 4.4 in.-lb),depending on specimen thickness and materialresponse.NOTE2For Procedures B and C,the required impulse is produced byhaving the maximum energy applied within the range of 610%of thereference value(5 J,see 1.6.2)and the time to peak controlling variable(force or displacement)being 15 6 5 ms.NOTE3There is no evidence to support comparisons of data for testswhich used either different reference maximum energy applied values orfor Procedure A,different mass and drop height conditions.NOTE4Applications involving more vigorous(for example,basket-ball)use of athletic shoes may require shock absorption tests which utilizelarger reference impulse values to generate comparable compressive forcehysteresis cycles.NOTE5Shock attenuation is strongly dependent on specimen thick-ness.This test method can be used to identify the effects of thicknessvariations on shock attenuating properties of midsole materials andathletic footwear products,see 7.2.NOTE6Comparisons of different material systems by this test methodshould take careful consideration of prior impact conditioning.The abilityof footwear materials to attenuate shock tends to decrease with repeatedimpact.21.7 The values stated in SI units are to be regarded as thestandard.The inch-pound units given in parentheses are forinformation only.1.8 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 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1This test method is under the jurisdiction of ASTM Committee F-8 on SportsEquipment and Facilities and is the direct responsibility of Subcommittee F08.54 onFootwear.Current edition approved May 10,1999.Published August 1999.Originallypublished as F 1614 95.Last previous edition F 1614 95.2Misevich,K.W.and Cavanagh,P.R.,“Material Aspects of ModelingShoe/Foot Interaction,”Sports Shoes and Playing Surfaces,(E.C.Frederick,ed),Human Kinetics:Champaign,Illinois,1982,pp.4775.3Denoth,J.,“Load on the Locomotor System and Modeling,”Chapter 3,Biomechanics of Running Shoes,(B.M.Nigg,ed.),Human Kinetics:Cham