1、Designation: F736 95 (Reapproved 2011)Standard Test Method forImpact Resistance of Monolithic Polycarbonate Sheet byMeans of a Falling Weight1This standard is issued under the fixed designation F736; the number immediately following the designation indicates the year of originaladoption or, in the c
2、ase of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the energyrequired to initiate failure in mo
3、nolithic polycarbonate sheetmaterial under specified conditions of impact using a freefalling weight.1.2 Two specimen types are defined as follows:1.2.1 Type A consists of a flat plate test specimen andemploys a clamped ring support.1.2.2 Type B consists of a simply supported three-pointloaded beam
4、specimen (Fig. 1) and is recommended for usewith material which can not be failed using the Type Aspecimen. For a maximum drop height of 6.096 m (20 ft) anda maximum drop weight of 22.68 kg (50 lb), virgin polycar-bonate greater than 12.70 mm (12 in.) thick will probablyrequire use of the Type B spe
5、cimen.NOTE 1See also ASTM Methods: D1709, D2444 and D3029.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3.1 ExceptionThe inch-pound units in parentheses areprovided for information only.1.4 This standard does not purport
6、 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. For specific hazardstatement, See Section 7.2. R
7、eferenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materials3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 failure (of test specim
8、en)failure is signified by thepresence of any crack or split in the impact-deformed area thatwas created by the impact of the falling weight and that can beseen by the naked eye.4. Summary of Test Method4.1 The test procedure to cause failure covers a range ofimpact energies and differs with respect
9、 to geometry andsupport of test specimen Type A and test specimen Type B.Guidelines are established to control drop heights, impactvelocity, drop weights, impactor heads, impactor release,impactor rebound, impact location, and specimen configurationwhich are applicable to a falling weight impact tes
10、ter designedto accommodate Type A or Type B test specimens, or both,fabricated from monolithic polycarbonate sheet material.5. Significance and Use5.1 This practice is applicable for qualitatively evaluatingcoated and uncoated monolithic polycarbonate sheet material,for monitoring process control, f
11、or screening studies, and as anaid in the prediction of hardware performance when exposed toimpact service conditions.5.2 A limitation of Type A specimen testing is that a thicksheet may not fail since the available impact energy is limitedby the maximum drop height and falling weight capacity of th
12、etest apparatus. Use Specimen TypeAfor material less than 12.7mm (0.50 in.) thick.5.3 Within the range of drop heights of this system, testsemploying different velocities are not expected to producedifferent results. However, for a given series of tests, it isrecommended that the drop height be held
13、 approximatelyconstant so that velocity of impact (strain rate) will not be avariable.5.4 As the polycarbonate specimen undergoes large plasticdeformation under impact, the down (opposite impact) side isunder tensile loading and most influential in initiating failure.Polycarbonate sheet coated on on
14、e side may yield significantly1This test method is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 onTransparent Enclosures and Materials.Current edition approved Dec. 1, 2011. Published April 2012. Originallyapproved in 1
15、981. Last previous edition approved in 2006 as F736 95 (2006).DOI: 10.1520/F0736-95R11.2For 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 Summar
16、y page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.different test results when tested with the coated side downversus the coated side up.5.5 Direct comparison of specimen Type A and specimenType B test results
17、should not be attempted. For test programsthat will require the comparison of interlaboratory test resultsthe specimen type and the approximate drop height must bespecified.5.6 Monolithic polycarbonate sheet is notch sensitive. Dataobtained from other test methods, particularly notched Izod/Charpy t
18、est results, and extremely high- or low-strain rate testresults, should not be compared directly to data obtained fromthis method. It is noted that Type A specimens, free of flaws,have not experienced the characteristic ductile-to-brittle tran-sition between thin, less than 3.18 mm (18 in.), and thi
19、ck,greater than 7.94 mm (516 in.), sheet as reflected by other testmethods.6. Apparatus6.1 Impact TesterThe apparatus shall be constructed es-sentially as shown in Fig. 2. Although not specified, materialscalled out have been found to be satisfactory.6.1.1 Drop HeightA lifting carrier shall be provi
20、ded toraise or lower the falling weight impactor that will be adjust-able within the range of 0.305 m (1 ft) to maximum drop heightand measurable to the nearest 25.40 mm (1 in.).6.1.2 Drop WeightThe falling weights shall be detach-able, interchangeable, and variable in small known incrementsfrom a t
21、otal of 0.45 kg (1 lb) to a maximum drop weight of 50kg (110 lb).6.1.3 ImpactorThe loading nose to be used with Type Aspecimens is shown in Fig. 3; with Type B specimens as shownin Fig. 4. The impactor surface shall be free of nicks or othersurface irregularities. The impactor geometry for Type Bspe
22、cimens corresponds to Test Method D790.6.1.4 Impact LocationThe center of mass of the fallingweight shall be guided by a two cable system or other suitablemeans to repeatedly strike within 2.54 mm (0.10 in.) of thecenter of the specimen support fixture as measured in the planeof the specimen, in ord
23、er to assure uniform, reproducibledrops. Friction retarding the falling weight should be minimalso that the impact velocity approaches=2ghwhere:g = acceleration of gravity, andh = drop height.6.1.5 SupportsClamp and support rings as shown in Fig.5 and Table 1 will be used to accommodate Type A plate
24、specimens. Adjustable D790Test Method 1 supports will beused to accommodate the Type B simply supported beamspecimens of 6 + 1 span-to-depth ratio. Specimens shall besupported so that the surface to be impacted is horizontal andat an angle of 90 (6 1) (p/2 radians) with respect to the fallingweight
25、guides.FIG. 1 Type B Specimen Geometry and LoadingTABLE 1 Plate Support Ring GeometryNOTE 1Reference Fig. 5 for definition of “A” and “C.”Ring Size “A”“C” Spanmm (in.) mm (in.) mm (in.)1 88.9 (3.50) 127.0 (5.00) 101.6 (4.00)2 114.3 (4.50) 157.5 (6.20) 127.0 (5.00)3 190.5 (7.50) 254.0 (10.00) 203.2 (
26、8.00)4 292.1 (11.50) 381.0 (15.00) 304.8 (12.00)F736 95 (2011)26.1.6 ReleaseAn electromagnetic or mechanical releasingmechanism, capable of supporting the maximum fallingweight, will be provided to assure uniform and reproducibledrops.6.1.7 Rebound CatcherMeans must be provided to catchthe weight if
27、 it rebounds to prevent restriking the specimen andcausing further damage.6.1.8 Energy AbsorberAn energy absorbent material mustbe provided beneath the specimen to prevent damage to thefixture when the impactor penetrates the specimen.7. Hazards7.1 To reduce a hazard to the test operator or witness,
28、 orboth, a protective enclosure shall be placed around the testFIG. 2 Falling Weight Impact TesterF736 95 (2011)3specimen impact area to contain any flying particles which maybe generated during the test. No further adjustments to thespecimen shall be made after positioning the falling weight atthe
29、selected drop height.8. Test Specimens8.1 All specimens must be initially without flaws unless theflaws constitute variables under study. Type B specimens mustbe free of machining stresses. Edge stresses associated withstandard shop practice do not affect the test results for Type Aspecimens. If no
30、combination of falling weight/drop height isavailable that will give satisfactory results using Type Aspecimens because of high impact resistance, the use of TypeB specimens is recommended to produce failure at a lowerenergy level.8.1.1 Type AFlat plates shall be round or square and havethe physical
31、 dimensions specified in Table 2. These dimensionsprovide adequate edge distance for clamping on the platesupport rings.8.1.2 Type BFor beam specimens greater than 12.7 mm(0.50 in.) thick the support span shall be six times the thicknessof the beam, the specimen width shall be two times thethickness
32、, not to exceed 50.80 mm (2.00 in.), and the overhangon each end shall be four times the thickness to prevent thespecimen from slipping through the supports.NOTE 2With care, Type A plate specimens may be bandsawedwithout inducing failure from edge effects. Type B beam specimens musthave deburred fin
33、ish-machined edges that are free of stress risers.9. Conditioning9.1 Unless otherwise specified, condition the test specimensin accordance with Procedure A of Methods D618.10. Procedure10.1 Measure and record the thickness and geometry ofeach specimen.10.2 Choose a specimen at random from the sample
34、.10.3 Lightly clamp (20 in.-lbs) plate specimens.10.4 Adjust the falling weight to that weight which isexpected to cause failure.10.5 Position the falling weight at the proper height toprovide the predicted failure energy at impact.10.6 Release the weight to strike the center of the specimen.If rebo
35、und occurs, prevent the impactor from restriking thespecimen.10.7 Examine the specimen to determine if it failed. Testeach specimen only once. If over (full penetration) or under thethreshold of failure, remove or add an increment of weight asderived from results observed from the specimen tested im
36、me-diately prior and repeat the test procedure.10.8 Use a sufficient number of specimens to determine thethreshold of failure, using trial and error test runs. Test sixreplicates at failure energy so that at least two, and not morethan four, of the samples tested fail at the given energy level.10.9
37、Exercise care to avoid accidental exposure of polycar-bonate test samples to toluene, MEK vapors, and other harmfulsolvents. Degradation can occur with no visual evidence ofdamage.11. Calculation11.1 The energy required to produce failure, expressed inJoules (foot-pounds), is obtained by multiplying
38、 the fallingweight in Newtons (pounds) by the drop height in meters(feet).12. Report12.1 The report shall include the following:12.1.1 Complete identification of the material,12.1.2 Type of specimen (either A or B),12.1.3 Specimen fabrication procedure,TABLE 2 Type A Specimen GeometryASpecimen Thick
39、ness SpanB(“A”+2R) Diameter or WidthSpan/Thicknessmm (in.) mm (in.) mm (in.)3.175 (0.125) 7.94 (0.3125) 101.6 (4.00) 127.0 (5.00) 3212.87.95 (0.3130)12.80 (0.5040) 127.0 (5.00) 157.5 (6.20) 169.912.81 (0.5045)19.30 (0.760) 203.2 (8.00) 254.0 (10.00) 15.910.519.31 (0.765)32.00 (1.26) 304.8 (12.00) 38
40、1.0 (15.00) 15.89.5ASpecified specimen thicknesses are nominal thicknesses. Tolerances on actual material thickness could cause specimens from a given group to fall in more than onethickness range. This should not be permitted. All specimens having the same nominal thickness should be tested at the
41、same span.BReference Fig. 5.NOTE 1All loading surfaces to have surface roughness of 1.53.0 m(64128 in.).FIG. 3 Impactor Loading NoseType A Plate Specimen (StainlessSteel)F736 95 (2011)412.1.4 Thickness,12.1.5 Number of test specimens employed to determinethreshold of failure,12.1.6 Test conditions a
42、nd material history,12.1.7 Failure energy,12.1.8 Drop height,12.1.9 Drop weight,12.1.10 Failure mode (ductile deformation, penetration, orbrittle fracture),12.1.11 Replicate data,12.1.12 Deviation(s) from test procedure, and12.1.13 Date of test.13. Precision and Bias13.1 PrecisionThis test method do
43、es not yet contain anumerical precision statement. However, limited data from onelaboratory indicates repeatability to approximately 6 5 % foreither specimen Type A or Type B for material exhibitingductile behavior. The precision of this test method is underinvestigation by a task group of Subcommit
44、tee F07.08 via aninterlaboratory study. Anyone wishing to participate in thiswork may contact the Chairman, Subcommittee F07.08,ASTM, 100 Barr Harbor Drive, West Conshohocken, PA,19428.13.2 BiasThe procedure in this test method for measuringresistance to a falling weight has no bias because the valu
45、e forresistance to a falling weight is defined only in terms of this testmethod.14. Keywords14.1 falling weight; impact resistance; polycarbonateNOTE 1All loading surfaces to have surface roughness of 1.53.0 m (64128 in.).FIG. 4 Impactor Loading NoseType B Beam Specimen (Stainless Steel)F736 95 (201
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