1、Designation: D1596 97 (Reapproved 2011)Standard Test Method forDynamic Shock Cushioning Characteristics of PackagingMaterial1This standard is issued under the fixed designation D1596; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers
3、a procedure for obtainingdynamic shock cushioning characteristics of packaging mate-rials through acceleration-time data achieved from dropping afalling guided platen assembly onto a motionless sample. Thistest method does not address any effects or contributions ofexterior packaging assemblies.1.2
4、The data acquired may be used for a single point or foruse in developing a dynamic cushion curve for the specificmaterial being tested. Such data may be used for comparisonamong different materials at specific input conditions, orqualifying materials against performance specifications. Cau-tion shou
5、ld be used when attempting to compare data fromdifferent methods or when using such data for predictingin-package performance. Depending upon the particular mate-rials of concern, correlation of such data (from among differingprocedures or for predicting inpackage performance) may behighly variable.
6、NOTE 1Alternative and related method for possible consideration isTest Method D4168.1.3 The values stated in inch-pound units are to be regardedas the standard. The SI units given in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety problems, if any,
7、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.2. Referenced Documents2.1 ASTM Standards:2D996 Terminology of Packaging and Distribution Enviro
8、n-mentsD4168 Test Methods for Transmitted Shock Characteristicsof Foam-in-Place Cushioning MaterialsD4332 Practice for Conditioning Containers, Packages, orPackaging Components for TestingE105 Practice for Probability Sampling of MaterialsE122 Practice for Calculating Sample Size to Estimate,With Sp
9、ecified Precision, the Average for a Characteristicof a Lot or Process3. Terminology3.1 DefinitionsGeneral definitions for packaging and dis-tribution environments are found in Terminology D996.3.2 Definitions of Terms Specific to This Standard:3.2.1 accelerationthe rate of change of velocity of a b
10、odywith respect to time, measured in in./s2(m/s2).3.2.2 displacementthe magnitude of movement of a body,point, or surface from a fixed reference point, measured ininches (metres).3.2.3 dynamic cushion curve a graphic representation ofdynamic shock cushioning or transmitted shock (in Gs) over avariet
11、y of static loading conditions (psi or kg/square m) for aspecific cushioning material thickness (or structure) at aspecific equivalent free fall drop height.3.2.3.1 Such representations can encompass the averageresponse readings in Gs of a number of drops, the average ofdrops, two to five for each t
12、est phase, or represent a single,specific drop number in a drop sequence (that is, first or thirddrop data).3.2.4 equivalent free-fall drop heightthe calculated heightof free fall in vacuum required for the dropping platen to attaina measured or given impact velocity.3.2.5 equivalent free-fall impac
13、t velocitythe calculatedimpact velocity of the dropping platen if it were to free fall ina vacuum from a specific test drop height.3.2.6 platen drop heightthe actual drop height of the testmachine platen required to obtain an equivalent free fall impactvelocity.1This test method is under the jurisdi
14、ction of ASTM Committee D10 onPackaging and is the direct responsibility of Subcommittee D10.13 on InteriorPackaging.Current edition approved Aug. 1, 2011. Published November 2011. Originallypublished in 1959. Last previous edition approved in 2003 as D1596 97 (2003).DOI: 10.1520/D1596-97R11.2For re
15、ferenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, W
16、est Conshohocken, PA 19428-2959, United States.3.2.7 reaction massa mass, consisting of the impactsurface and any other rigidly attached mass that reacts in anopposing manner to the forces produced during the impact ofthe dropping platen on the impact surface.3.2.8 static loadingthe applied mass in
17、pounds (kilo-grams) divided by the area, measured in square inches (metres)to which the mass is applied (lbs/in.2or kg/m2). Sometimesreferred to as static stress loading.3.2.9 velocitythe rate of change of position of a body in aspecified direction with respect to time, measured in inches persecond
18、(metre per second).3.3 Symbols: Symbols:3.3.1 g symbol for the acceleration due to the effects ofthe earths gravitational pull. While somewhat variable, it isusually considered a constant of value 386 in./s2or (9.8 m/s2).3.3.2 Gsymbol for the dimensionless ratio between anacceleration in length per
19、time squared units and the accelera-tion of gravity in the same units.4. Summary of Test Method4.1 An apparatus having a guided dropping platen capableof having variable mass, inputs a dynamic force into a testspecimen placed on a rigid impact surface at a predeterminedimpact velocity that equates t
20、o a free fall drop height. Anaccelerometer rigidly mounted to the dropping platen andconnected to a data acquisition system records the shockexperienced (acceleration-time history) during the impact onthe test specimen. By changing the variables, such as impactvelocity, static loading (dropping plat
21、en mass), and the numberof test impacts for any given test, dynamic shock cushioningcharacteristics (cushion curves) of the packaging material canbe developed.5. Significance and Use5.1 Dynamic cushioning test data obtained by this testmethod are applicable to the cushioning material and notnecessar
22、ily the same as obtained in a package. In addition tothe influence of the package, the data can also be affected bythe specimen area, thickness, loading rate, and other factors.6. Apparatus6.1 Testing Machine:6.1.1 Any guided vertical drop testing system that willproduce test conditions conforming t
23、o the requirements speci-fied in this section is acceptable. The system shall consist of arigid flat faced dropping platen, a rigid flat impact surfacewhose face is parallel to the dropping platen face.NOTE 2Lack of rigidity can cause undesirable vibrations in theapparatus that are recorded in the a
24、cceleration-time curve. This conditionhas also been a suspected cause for discontinuities in dynamic data wherethe mass of the dropping platen is varied at constant height. The existenceof flexing in the apparatus often can be verified with aid of high-speedvideo and subsequently corrected.6.1.2 The
25、 dropping platen should have provisions for firmlymounting additional mass to adjust its total mass to a desiredvalue. Its mass may be determined by consideration of thestatic loading of the items the dynamic test is simulating.Various testing systems will have different ranges of testingcapability,
26、 both for drop height and static loadings.6.1.3 All dropping platens are influenced by guide systemfriction and air resistance. The significance of these effectsvaries with the type of apparatus and the mass on the droppingplaten. For this reason, the equivalent free fall impact velocityof the dropp
27、ing platen is equated to a free fall drop heightrather than an actual platen drop height. (ExampleUsing theformula in 11.2, a 30 in. (0.7 m) free fall is equated to a 152in./s (3.9 m/s) impact velocity of the dropping platen.)6.2 Reaction Mass:6.2.1 The testing machine shall be attached to a reactio
28、nmass. The reaction mass shall be sufficiently heavy and rigid sothat not more than 2 % of the impact acceleration is lost to thereaction mass while conducting dynamic tests. The rigidimpact surface should be in intimate contact with the reactionmass so that the two bodies move as one (surface prepa
29、rationor grouting may be required). This performance may beverified by using shock sensors, one located on the droppingplaten and one on the impact surface or on the reaction massimmediately next to the impact surface to measure the accel-eration levels. The ratio of the measured impact acceleration
30、 ofthe reaction mass divided by the measured acceleration of thedropping platen shall be equal to or less than 2 %.6.2.2 As an alternative to measuring the acceleration levelof the reaction mass for each test condition, the reaction massis acceptable if it is 50 times the maximum mass of thedropping
31、 platen. Neither the depth nor the width of such a massshall be less than half the length.6.3 Instrumentation and Shock Sensors:6.3.1 Instrumentation is required to measure the impactvelocity to an accuracy of 62 % of the true value.6.3.2 Accelerometers, signal conditions, and data storageapparatus
32、are required to monitor acceleration versus timehistories. The instrumentation systems shall have the followingminimum properties:6.3.2.1 Frequency response range from 2 Hz or less to atleast 1000 Hz.6.3.2.2 Accuracy reading to be within 65 % of the actualvalue.6.3.2.3 Cross axis sensitivity less th
33、an 5 % of full scale.7. Sampling7.1 The choice of sampling plans for materials depends onthe purpose of the testing. Practice E105 is recommended.7.2 The number of test specimens for each condition of test(for example, static loading) depends on the desired degree ofprecision and the availability of
34、 materials. Practice E122 andmany statistical tests provide excellent guidance on the choiceof sample size. It is recommended that at least three replicatetest specimens be used for each initial test condition. Then,depending on the accuracy and degree of certainty required,this sample size may be i
35、ncreased or decreased.7.3 Randomization of test specimens from the sample ofmaterial and randomization of the order of testing are recom-mended. This may be accomplished by the use of randomnumber tables, lottery, or other accepted procedures of ran-domization.D1596 97 (2011)28. Test Specimens8.1 Te
36、st specimens shall be right square prisms or otherconfiguration as desired with the maximum length and widthdimensions less than the corresponding drop platen dimen-sions. It is recommended that the minimum length and widthdimensions be 4 by 4 in. (101.6 by 101.6 mm). Becausepneumatic effects and bu
37、ckling properties of cushioning mate-rials may be influenced by size and shape of the specimen, 8 by8 in. (203.2 by 203.2 mm) specimens are recommendedwhenever possible. When comparing data for different cush-ions, identically shaped specimens should be used.NOTE 3Not all test apparatus are able to
38、provide static loadings acrossthe usable range of all possible materials to be tested. For this reason it isimportant to prominently note the sizes of specimens tested in the testreport.9. Conditioning9.1 Materials, such as cellulosic materials, that undergochanges in physical properties as the temp
39、erature and therelative humidity to which they are exposed are varied need tobe preconditioned in accordance with Practice D4332. Forpolymeric cushions, condition test specimens prior to test for asufficient length of time to essentially achieve and maintainequilibrium in accordance with any require
40、ments. In theabsence of other requirements, use standard conditioningatmosphere of 236 2C (73.4 6 3.6F) and 50 6 2 % relativehumidity.10. Procedure10.1 DimensionsDetermine measurements for area calcu-lations with an apparatus yielding values accurate to 0.01 in.(0.3 mm).10.2 ThicknessLoad top surfac
41、e of conditioned specimenas furnished or cut, to 0.025 psi (17.55 kg/m2). (ExampleSpecimen size of 8 by 8 in. (203.2 by 203.2 mm) = 64 in.2(41290 mm2); 64 in.23 0.025 psi (41290 mm24(1 3 106) 3 17.55 kg/m2= a load of 1.6 lb (0.725 kg).) After a30 s interval, and while the specimen is still under 0.0
42、25 psi(17.55 kg/m2) load, measure the thickness to the nearest 0.01in. (0.3 mm) at the specimen top surface geometric center. Asan alternative procedure, average the thickness measurementstaken at the four corners of the specimen. Record this value asthe specimen thickness. For odd shapes report whe
43、re measure-ments were taken.10.3 Area and Mass Measure the top surface area of thespecimen with apparatus yielding values accurate to132 in. or1 mm. Measure the mass of the specimen with apparatusyielding values accurate to 30 g.10.4 Dynamic Test Center the test specimen on the impactsurface face an
44、d prepare the dropping platen to strike thecushion on its top surface area. Then impact the specimen witha series of five drops at a predetermined static loading andimpact velocity in the dynamic tester, allowing a minimum of1 min between drops. When testing under special conditions, ifpossible, ret
45、urn specimen to the special condition betweendrops. Do not allow specimen to be out of the special conditionfor more than 30 min. As an alternative, condition testspecimens in the chamber. Place testing machine in chamber,check impact velocity of dropping platen. Test at temperature,with recording i
46、nstrumentation outside of chamber. Take acomplete acceleration-time record for each drop and measurethe impact velocity of the platen just before impact to ensure itis representative of the impact velocity equated to the desiredfree drop height. To obtain dynamic data of a general nature fora given
47、cushion, it is necessary to repeat the five test drops ona new specimen varying some condition of test such as staticloading, impact velocity, or cushion thickness. As an option,upon the completion of the five drops measure the finalthickness of the specimen in accordance with the procedureoutlined
48、in 10.2 to determine dynamic set.11. Calculation11.1 Calculate the density of a test specimen as follows:Inch2pound units D 5 3.81 3 M!/L13 L23 T! (1)Metric! D 5 1 3 106! 3 M!/L13 L23 T!where:D = density, lb/ft3(kg/m3),M = mass of specimen, grams,L1= length of specimen, in. (mm),L2= width of specime
49、n, in. (mm), andT = original thickness of specimen, in. (mm).11.2 Equate an impact velocity to a free fall drop height orvice versa as follows:h 5 Vi2/2 g solving for free fall drop height! (2)Vi5 =2 gh solving for impact velocity!where:h = free fall drop height, in. (m),Vi= measured impact velocity, in./s (m/s), andg = acceleration due to gravity, 386 in./s2(9.8 m/s2).11.3 Calculate the dynamic set as follows:Dynamic set, % 5 T 2 F!/T 3 100 (3)where:T = original thickness of specimen, in. (mm), andF = thickness of specimen after test, in. (mm)
