1、Designation: D5628 10Standard Test Method forImpact Resistance of Flat, Rigid Plastic Specimens byMeans of a Falling Dart (Tup or Falling Mass)1This standard is issued under the fixed designation D5628; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e case of revision, 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.1. Scope*1.1 This test method covers the determination of the thresh-old value of impact-failure e
3、nergy required to crack or breakflat, rigid plastic specimens under various specified conditionsof impact of a free-falling dart (tup), based on testing manyspecimens.1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.1.3 This stan
4、dard 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. Specific hazardstatements a
5、re given in Section 8.NOTE 1This test method and ISO 6603-1 are technically equivalentonly when the test conditions and specimen geometry required forGeometry FE and the Bruceton Staircase method of calculation are used.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plasti
6、cs for TestingD883 Terminology Relating to PlasticsD1600 Terminology for Abbreviated Terms Relating toPlasticsD1709 Test Methods for Impact Resistance of Plastic Filmby the Free-Falling Dart MethodD2444 Test Method for Determination of the Impact Resis-tance of Thermoplastic Pipe and Fittings by Mea
7、ns of aTup (Falling Weight)D3763 Test Method for High Speed Puncture Properties ofPlastics Using Load and Displacement SensorsD4000 Classification System for Specifying Plastic Materi-alsD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensD6779 Classification System for Polyamide Mo
8、lding andExtrusion Materials (PA)E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standards:3ISO 291 Standard Atmospheres for Conditioning and Test-ingISO 6603-1 PlasticsDetermination of Multiaxial ImpactBehavior of Rigid PlasticsPart 1: Falling
9、 Dart Method3. Terminology3.1 Definitions:3.1.1 For definitions of plastic terms used in this testmethod, see Terminologies D883 and D1600.3.2 Definitions of Terms Specific to This Standard:3.2.1 failure (of test specimen)the presence of any crackor split, created by the impact of the falling tup, t
10、hat can beseen by the naked eye under normal laboratory lightingconditions.3.2.2 mean-failure energy (mean-impact resistance)theenergy required to produce 50 % failures, equal to the productof the constant drop height and the mean-failure mass, or, tothe product of the constant mass and the mean-fai
11、lure height.3.2.3 mean-failure height (impact-failure height)theheight at which a standard mass, when dropped on testspecimens, will cause 50 % failures.NOTE 2Cracks usually start at the surface opposite the one that isstruck. Occasionally incipient cracking in glass-reinforced products, forexample,
12、 is difficult to differentiate from the reinforcing fibers. In suchcases, a penetrating dye can confirm the onset of crack formation.3.2.4 mean-failure mass (impact-failure mass)the mass ofthe dart (tup) that, when dropped on the test specimens from astandard height, will cause 50 % failures.1This t
13、est method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved July 1, 2010. Published July 2010. Originally approvedin 1994. Last previous edition approved in 2007 as D5628 - 07. DOI: 10.
14、1520/D5628-10.2For referenced 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.3Available from American National Standards Ins
15、titute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.5 tupa dart with a hemispherical no
16、se. See 7.2 andFig. 1.4. Summary of Test Method4.1 A free-falling dart (tup) is allowed to strike a supportedspecimen directly. Either a dart having a fixed mass is droppedfrom various heights, or a dart having an adjustable mass isdropped from a fixed height. (See Fig. 2).4.2 The procedure determin
17、es the energy (mass 3 height)that will cause 50 % of the specimens tested to fail (meanfailure energy).4.3 The technique used to determine mean failure energy iscommonly called the Bruceton Staircase Method or the Up-and-Down Method (1).4Testing is concentrated near the mean,reducing the number of s
18、pecimens required to obtain a reason-ably precise estimate of the impact resistance.4.4 Each test method permits the use of different tup and testspecimen geometries to obtain different modes of failure,permit easier sampling, or test limited amounts of material.There is no known means for correlati
19、ng the results of testsmade by different impact methods or procedures.5. Significance and Use5.1 Plastics are viscoelastic and therefore are likely to besensitive to changes in velocity of the mass falling on theirsurfaces. However, the velocity of a free-falling object is afunction of the square ro
20、ot of the drop height. A change of afactor of two in the drop height will cause a change of only 1.4in velocity. Hagan et al (2) found that the mean-failure energyof sheeting was constant at drop heights between 0.30 and 1.4m. This suggests that a constant mass-variable height methodwill give the sa
21、me results as the constant height-variable masstechnique. On the other hand, different materials responddifferently to changes in the velocity of impact. Equivalence ofthese methods should not be taken for granted. While bothconstant-mass and constant-height techniques are permitted bythese methods,
22、 the constant-height method should be used forthose materials that are found to be rate-sensitive in the rangeof velocities encountered in falling-weight types of impacttests.5.2 The test geometry FA causes a moderate level of stressconcentration and can be used for most plastics.5.3 Geometry FB cau
23、ses a greater stress concentration andresults in failure of tough or thick specimens that do not failwith Geometry FA (3). This approach can produce a punchshear failure on thick sheet. If that type of failure is undesir-able, Geometry FC should be used. Geometry FB is suitable forresearch and devel
24、opment because of the smaller test arearequired.5.3.1 The conical configuration of the 12.7-mm diametertup used in Geometry FB minimizes problems with tuppenetration and sticking in failed specimens of some ductilematerials.5.4 The test conditions of Geometry FC are the same asthose of Test MethodAo
25、f Test Method D1709. They have beenused in specifications for extruded sheeting.Alimitation of thisgeometry is that considerable material is required.5.5 The test conditions of Geometry FD are the same as forTest Method D3763.5.6 The test conditions of Geometry FE are the same as forISO 6603-1.5.7 B
26、ecause of the nature of impact testing, the selection ofa test method and tup must be somewhat arbitrary. Although achoice of tup geometries is available, knowledge of the final orintended end-use application shall be considered.5.8 Clamping of the test specimen will improve the preci-sion of the da
27、ta. Therefore, clamping is recommended. How-ever, with rigid specimens, valid determinations can be madewithout clamping. Unclamped specimens tend to exhibitgreater impact resistance.5.9 Before proceeding with this test method, referenceshould be made to the specification of the material being teste
28、d.Table 1 of Classification System D4000 lists the ASTMmaterials standards that currently exist. Any test specimenspreparation, conditioning, dimensions, or testing parameters orcombination thereof covered in the relevant ASTM materialsspecification shall take precedence over those mentioned in this
29、test method. If there are no relevant ASTM material specifica-tions, then the default conditions apply.6. Interferences6.1 Falling-mass-impact-test results are dependent on thegeometry of both the falling mass and the support. Thus,impact tests should be used only to obtain relative rankings ofmater
30、ials. Impact values cannot be considered absolute unlessthe geometry of the test equipment and specimen conform tothe end-use requirement. Data obtained by different procedureswithin this test method, or with different geometries, cannot, ingeneral, be compared directly with each other. However, the
31、relative ranking of materials is expected to be the samebetween two test methods if the mode of failure and the impactvelocities are the same.6.1.1 Falling-mass-impact types of tests are not suitable forpredicting the relative ranking of materials at impact velocitiesdiffering greatly from those imp
32、osed by these test methods.6.2 As cracks usually start at the surface opposite the onethat is struck, the results can be greatly influenced by thequality of the surface of test specimens. Therefore, the com-position of this surface layer, its smoothness or texture, levelsof and type of texture, and
33、the degree of orientation introducedduring the formation of the specimen (such as during injectionmolding) are very important variables. Flaws in this surfacewill also affect results.6.3 Impact properties of plastic materials can be verysensitive to temperature. This test can be carried out at anyre
34、asonable temperature and humidity, thus representing actualuse environments. However, this test method is intendedprimarily for rating materials under specific impact conditions.7. Apparatus7.1 Testing MachineThe apparatus shall be constructedessentially as is shown in Fig. 2. The geometry of the sp
35、ecimenclamp and tup shall conform to the dimensions given in 7.1.1and 7.2.4The boldface numbers in parentheses refer to a list of references at the end ofthe text.D5628 102Dimensions of Conical Dart (Not to scale.)Fig. 1(b)NOTE 1Unless specified, the tolerance on all dimensions shall be 62%.Position
36、 Dimension, mm Dimension, in.A 27.2 1.07B 15 0.59C 12.2 0.48D 6.4 0.25E 25.4 1F 12.7 0.5R 6.35 6 0.05 0.250 6 0.002(nose radius)r (radius) 0.8 0.03S (diameter)A6.4 0.25u 25 6 1 25 6 1ALarger diameter shafts shall be used.FIG. 1 Tup Geometries for Geometries FA (1a), FB (1b), FC (1c), FD (1d), and FE
37、 (1e)D5628 1037.1.1 Specimen ClampFor flat specimens, a two-pieceannular specimen clamp similar to that shown in Fig. 3 isrecommended. For Geometries FAand FD, the inside diametershould be 76.0 6 3.0 mm (3.00 6 0.12 in.). For Geometry FB,the inside diameter should be 38.1 6 0.80 mm (1.5 6 0.03 in.).
38、For Geometry FC, the inside diameter should be 127.0 6 2.5mm (5.00 6 0.10 in.). For Geometry FE an annular specimenclamp similar to that shown in Fig. 4 is required. The insidediameter should be 40 6 2 mm (1.57 6 0.08 in.) (see Table 1).For Geometries FA, FB, FC, and FD, the inside edge of theupper
39、or supporting surface of the lower clamp should berounded slightly; a radius of 0.8 mm (0.03 in.) has been foundto be satisfactory. For Geometry FE this radius should be 1 mm(0.04 in.).7.1.1.1 Contoured specimens shall be firmly held in a jig sothat the point of impact will be the same for each spec
40、imen.7.1.2 Tup Support, capable of supporting a 13.5-kg (30-lb)mass, with a release mechanism and a centering device toensure uniform, reproducible drops.NOTE 3Reproducible drops are ensured through the use of a tube orcage within which the tup falls. In this event, care should be exercised sothat a
41、ny friction that develops will not reduce the velocity of the tupappreciably.7.1.3 Positioning DeviceMeans shall be provided forpositioning the tup so that the distance from the impingingsurface of the tup head to the test specimen is as specified.7.2 Tup:7.2.1 The tup used in Geometry FA shall have
42、 a 15.86 60.10-mm (0.625 6 0.004-in.) diameter hemispherical head oftool steel hardened to 54 HRC or harder.Asteel shaft about 13mm (0.5 in.) in diameter shall be attached to the center of theflat surface of the head with its longitudinal axis at 90 to thatsurface. The length of the shaft shall be g
43、reat enough toaccommodate the maximum mass required (see Fig. 1(a) andTable 1).7.2.2 The tup used in Geometry FB shall be made of toolsteel hardened to 54 HRC or harder. The head shall have adiameter of 12.76 0.1 mm (0.500 6 0.003 in.) with a conical(50 included angle) configuration such that the co
44、nical surfaceis tangent to the hemispherical nose. A 6.4-mm (0.25-in.)diameter shaft is satisfactory (see Fig. 1(b) and Table 1).7.2.3 The tup used for Geometry FC shall be made of toolsteel hardened to 54 HRC or harder. The hemispherical headshall have a diameter of 38.1 6 0.4 mm (1.5 6 0.015 in.).
45、 Asteel shaft about 13 mm (0.5 in.) in diameter shall be attachedto the center of the flat surface of the head with its longitudinalFIG. 2 One Type of Falling Mass Impact TesterD5628 104axis at 90 to that surface. The length of the shaft shall be greatenough to accommodate the maximum mass (see Fig.
46、 1(c) andTable 1).7.2.4 The tup used in Geometry FD shall have a 12.70 60.25-mm (0.500 6 0.010-in.) diameter hemispherical head oftool steel hardened to 54 HRC or harder. A steel shaft about 8mm (0.31 in.) in diameter shall be attached to the center of theflat surface of the head with its longitudin
47、al axis at 90 to thesurface. The length of the shaft shall be great enough toaccommodate the maximum mass required (see Fig. 1(d) andTable 1).7.2.5 The tup used in Geometry FE shall have a 20.0 60.2-mm (0.787 6 0.008-in.) diameter hemispherical head oftool steel hardened to 54 HRC or harder.Asteel s
48、haft about 13mm (0.5 in.) in diameter shall be attached to the center of theflat surface of the head with its longitudinal axis at 90 to thesurface. The length of the shaft shall be great enough toaccommodate the maximum mass required (see Fig. 1(e) andTable 1).7.2.6 The tup head shall be free of ni
49、cks, scratches, or othersurface irregularities.7.3 MassesCylindrical steel masses are required that havea center hole into which the tup shaft will fit. A variety ofmasses are needed if different materials or thicknesses are to beFIG. 3 Support Plate/Specimen/Clamp Configuration for Geometries FA, FB, FC, and FDFIG. 4 Test-Specimen Support for Geometry FETABLE 1 Tup and Support Ring DimensionsGeometryDimensions, mm (in.)Tup Diameter Inside Diameter Support RingFA 15.86 6 0.10 76.0 6 3.0(0.625 6 0.004) (3.00 6 0.12)FB 12.7 6 0.1 38.1 6 0.8(0.500 6 0.003) (1.
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