1、Designation: D1596 97 (Reapproved 2011)D1596 14Standard 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 r
2、evision, 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 U.S. Department of Defense.1. Scope1.1 This test m
3、ethod covers a procedure for obtaining dynamic shock cushioning characteristics of packaging materials throughacceleration-time data achieved from dropping a falling guided platen assembly onto a motionless sample. This test method doesnot address any effects or contributions of exterior packaging a
4、ssemblies.1.2 The data acquired may be used for a single point or for use in developing a dynamic cushion curve for the specific materialbeing tested. Such data may be used for comparison among different materials at specific input conditions, or qualifying materialsagainst performance specification
5、s. Caution should be used when attempting to compare data from different methods or when usingsuch data for predicting in-package performance. Depending upon the particular materials of concern, correlation of such data(from among differing procedures or for predicting inpackage performance) may be
6、highly variable.NOTE 1Alternative and related method for possible consideration is Test Method D4168.1.3 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are forinformation only.1.4 This standard does not purport to address all of the safety
7、 problems, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D996 Terminology of Packaging and Dis
8、tribution EnvironmentsD4168 Test Methods for Transmitted Shock Characteristics of Foam-in-Place Cushioning MaterialsD4332 Practice for Conditioning Containers, Packages, or Packaging Components for TestingE105 Practice for Probability Sampling of MaterialsE122 Practice for Calculating Sample Size to
9、 Estimate, With Specified Precision, the Average for a Characteristic of a Lot orProcess3. Terminology3.1 DefinitionsGeneral definitions for packaging and distribution environments are found in Terminology D996.3.2 Definitions of Terms Specific to This Standard:3.2.1 accelerationthe rate of change o
10、f velocity of a body with 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 in inches(metres).3.2.3 dynamic cushion curvea graphic representation of dynamic shock cushioning or transmitted shock
11、(in Gs) over avariety of static loading conditions (psi or kg/square m) for a specific cushioning material thickness (or structure) at a specificequivalent free fall drop height.1 This test method is under the jurisdiction of ASTM Committee D10 on Packaging and is the direct responsibility of Subcom
12、mittee D10.13 on Interior Packaging.Current edition approved Aug. 1, 2011April 1, 2014. Published November 2011May 2014. Originally published in 1959. Last previous edition approved in 20032011 asD1596 97 (2003).(2011). DOI: 10.1520/D1596-97R11.10.1520/D1596-14.2 For referencedASTM standards, visit
13、theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an
14、 indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to
15、 be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.3.1 Such representations can encompass the average response readings in Gs of a number of drops, the average of drops,two to five for each test p
16、hase, or represent a single, specific drop number in a drop sequence (that is, first or third drop data).3.2.4 equivalent free-fall drop heightthe calculated height of free fall in vacuum required for the dropping platen to attain ameasured or given impact velocity.3.2.5 equivalent free-fall impact
17、velocitythe calculated impact velocity of the dropping platen if it were to free fall in a vacuumfrom a specific test drop height.3.2.6 platen drop heightthe actual drop height of the test machine platen required to obtain an equivalent free fall impactvelocity.3.2.7 reaction massa mass, consisting
18、of the impact surface and any other rigidly attached mass that reacts in an opposingmanner to the forces produced during the impact of the dropping platen on the impact surface.3.2.8 static loadingthe applied mass in pounds (kilograms) divided by the area, measured in square inches (metres) to which
19、the mass is applied (lbs/in.2 or kg/m2 ). Sometimes referred to as static stress loading.3.2.9 velocitythe rate of change of position of a body in a specified direction with respect to time, measured in inches persecond (metre per second).3.3 Symbols:3.3.1 gsymbol for the acceleration due to the eff
20、ects of the earths gravitational pull. While somewhat variable, it is usuallyconsidered a constant of value 386 in./s2 or (9.8 m/s2).3.3.2 Gsymbol for the dimensionless ratio between an acceleration in length per time squared units and the acceleration ofgravity in the same units.4. Summary of Test
21、Method4.1 An apparatus having a guided dropping platen capable of having variable mass, inputs a dynamic force into a test specimenplaced on a rigid impact surface at a predetermined impact velocity that equates to a free fall drop height.An accelerometer rigidlymounted to the dropping platen and co
22、nnected to a data acquisition system records the shock experienced (acceleration-timehistory) during the impact on the test specimen. By changing the variables, such as impact velocity, static loading (dropping platenmass), and the number of test impacts for any given test, dynamic shock cushioning
23、characteristics (cushion curves) of thepackaging material can be developed.5. Significance and Use5.1 Dynamic cushioning test data obtained by this test method are applicable to the cushioning material and not necessarily thesame as obtained in a package. In addition to the influence of the package,
24、 the data can also be affected by the specimen area,thickness, loading rate, and other factors.6. Apparatus6.1 Testing Machine:6.1.1 Any guided vertical drop testing system that will produce test conditions conforming to the requirements specified in thissection is acceptable. The system shall consi
25、st of a rigid flat faced dropping platen, a rigid flat impact surface whose face is parallelto the dropping platen face.NOTE 2Lack of rigidity can cause undesirable vibrations in the apparatus that are recorded in the acceleration-time curve. This condition has alsobeen a suspected cause for discont
26、inuities in dynamic data where the mass of the dropping platen is varied at constant height. The existence of flexingin the apparatus often can be verified with aid of high-speed video and subsequently corrected.6.1.2 The dropping platen should have provisions for firmly mounting additional mass to
27、adjust its total mass to a desired value.Its mass may be determined by consideration of the static loading of the items the dynamic test is simulating. Various testingsystems will have different ranges of testing capability, both for drop height and static loadings.6.1.3 All dropping platens are inf
28、luenced by guide system friction and air resistance.The significance of these effects varies withthe type of apparatus and the mass on the dropping platen. For this reason, the equivalent free fall impact velocity of the droppingplaten is equated to a free fall drop height rather than an actual plat
29、en drop height. (ExampleUsing the formula in 11.2, a 30 in.(0.7 m) free fall is equated to a 152 in./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 reaction mass. The reaction mass shall be sufficiently heavy and rigid so thatno
30、t more than 2 % of the impact acceleration is lost to the reaction mass while conducting dynamic tests. The rigid impact surfaceshould be in intimate contact with the reaction mass so that the two bodies move as one (surface preparation or grouting may berequired). This performance may be verified b
31、y using shock sensors, one located on the dropping platen and one on the impactsurface or on the reaction mass immediately next to the impact surface to measure the acceleration levels.The ratio of the measuredimpact acceleration of the reaction mass divided by the measured acceleration of the dropp
32、ing platen shall be equal to or less than2 %.D1596 1426.2.2 As an alternative to measuring the acceleration level of the reaction mass for each test condition, the reaction mass isacceptable if it is 50 times the maximum mass of the dropping platen. Neither the depth nor the width of such a mass sha
33、ll be lessthan half the length.6.3 Instrumentation and Shock Sensors:6.3.1 Instrumentation is required to measure the impact velocity to an accuracy of 62 % of the true value.6.3.2 Accelerometers, signal conditions, and data storage apparatus are required to monitor acceleration versus time historie
34、s.The instrumentation systems shall have the following minimum properties:6.3.2.1 Frequency response range from 2 Hz or less to at least 1000 Hz.6.3.2.2 Accuracy reading to be within 65 % of the actual value.6.3.2.3 Cross axis sensitivity less than 5 % of full scale.7. Sampling7.1 The choice of samp
35、ling plans for materials depends on the 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 materials. Practice E122 and many statistical tests
36、 provide excellent guidance on the choice ofsample size. It is recommended that at least three replicate test specimens be used for each initial test condition. Then, dependingon the accuracy and degree of certainty required, this sample size may be increased or decreased.7.3 Randomization of test s
37、pecimens from the sample of material and randomization of the order of testing are recommended.This may be accomplished by the use of random number tables, lottery, or other accepted procedures of randomization.8. Test Specimens8.1 Test specimens shall be right square prisms or other configuration a
38、s desired with the maximum length and widthdimensions less than the corresponding drop platen dimensions. It is recommended that the minimum length and width dimensionsbe 4 by 4 in. (101.6 by 101.6 mm). Because pneumatic effects and buckling properties of cushioning materials may be influencedby siz
39、e and shape of the specimen, 8 by 8 in. (203.2 by 203.2 mm) specimens are recommended whenever possible. Whencomparing data for different cushions, identically shaped specimens should be used.NOTE 3Not all test apparatus are able to provide static loadings across the usable range of all possible mat
40、erials to be tested. For this reason it isimportant to prominently note the sizes of specimens tested in the test report.9. Conditioning9.1 Materials, such as cellulosic materials, that undergo changes in physical properties as the temperature and the relativehumidity to which they are exposed are v
41、aried need to be preconditioned in accordance with Practice D4332. For polymericcushions, condition test specimens prior to test for a sufficient length of time to essentially achieve and maintain equilibrium inaccordance with any requirements. In the absence of other requirements, use standard cond
42、itioning atmosphere of 236 23 6 2C(73.4 6 3.6F) and 50 6 2 % relative humidity.10. Procedure10.1 DimensionsDetermine measurements for area calculations with an apparatus yielding values accurate to 0.01 in. (0.3mm).10.2 ThicknessLoad top surface of conditioned specimen as furnished or cut, to 0.025
43、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.2 0.025 psi (41290 mm2 (1 106) 17.55kg/m2 = a load of 1.6 lb (0.725 kg).) After a 30 s interval, and while the specimen is still under 0.025 psi (17.55 kg/m2) load,measure the thickness to the nea
44、rest 0.01 in. (0.3 mm) at the specimen top surface geometric center. As an alternative procedure,average the thickness measurements taken at the four corners of the specimen. Record this value as the specimen thickness. Forodd shapes report where measurements were taken.10.3 Area and MassMeasure the
45、 top surface area of the specimen with apparatus yielding values accurate to 132 in. or 1 mm.Measure the mass of the specimen with apparatus yielding values accurate to 30 g.10.4 Dynamic TestCenter the test specimen on the impact surface face and prepare the dropping platen to strike the cushionon i
46、ts top surface area. Then impact the specimen with a series of five drops at a predetermined static loading and impact velocityin the dynamic tester, allowing a minimum of 1 min between drops. When testing under special conditions, if possible, returnspecimen to the special condition between drops.
47、Do not allow specimen to be out of the special condition for more than 30 min.As an alternative, condition test specimens in the chamber. Place testing machine in chamber, check impact velocity of droppingplaten. Test at temperature, with recording instrumentation outside of chamber. Take a complete
48、 acceleration-time record for eachdrop and measure the impact velocity of the platen just before impact to ensure it is representative of the impact velocity equatedto the desired free drop height. To obtain dynamic data of a general nature for a given cushion, it is necessary to repeat the fivetest
49、 drops on a new specimen varying some condition of test such as static loading, impact velocity, or cushion thickness. As anD1596 143option, upon the completion of the five drops measure the final thickness of the specimen in accordance with the procedure outlinedin 10.2 to determine dynamic set. This test method does not recommend predictive methods to estimate transmitted shocks as theycan have high degrees of error and produce cushion curves with misleading data.311. Calculation11.1 Calculate the density of a test specimen as follows:Inch2p
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