1、Designation: F736 95 (Reapproved 2011)F736 17Standard 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, i
2、n the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the energy required to initiate failure i
3、n monolithic polycarbonate sheetmaterial under specified conditions of impact using a free falling weight.1.2 Two specimen types are defined as follows:1.2.1 Type A consists of a flat plate test specimen and employs a clamped ring support.1.2.2 Type B consists of a simply supported three-point loade
4、d beam specimen (Fig. 1) and is recommended for use withmaterial which can not be failed using the Type A specimen. For a maximum drop height of 6.096 m (20 ft) and a maximum dropweight of 22.68 kg (50 lb), virgin polycarbonate greater than 12.70 mm (12 in.) thick will probably require use of the Ty
5、pe Bspecimen.NOTE 1See also ASTM Methods: D1709, D2444 and D3029.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3.1 ExceptionThe inch-pound units in parentheses are provided for information only.1.4 This standard does n
6、ot purport to address all of the safety concerns, 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. For specific hazard statement, See Secti
7、on 7.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers
8、to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials3. Terminology3.1 Definitions of Terms Specific to This Standard
9、:3.1.1 failure (of test specimen)failure is signified by the presence of any crack or split in the impact-deformed area that wascreated by the impact of the falling weight and that can be seen by the naked eye.4. Summary of Test Method4.1 The test procedure to cause failure covers a range of impact
10、energies and differs with respect to geometry and support oftest specimen Type A and test specimen Type B. Guidelines are established to control drop heights, impact velocity, drop weights,impactor heads, impactor release, impactor rebound, impact location, and specimen configuration which are appli
11、cable to a fallingweight impact tester designed to accommodate TypeAor Type B test specimens, or both, fabricated from monolithic polycarbonatesheet material.1 This test method is under the jurisdiction of ASTM Committee F07 on Aerospace and Aircraft and is the direct responsibility of Subcommittee
12、F07.08 on TransparentEnclosures and Materials.Current edition approved Dec. 1, 2011June 1, 2017. Published April 2012June 2017. Originally approved in 1981. Last previous edition approved in 20062011 as F736 95(2006).(2011). DOI: 10.1520/F0736-95R11.10.1520/F0736-17.2 For referencedASTM standards, v
13、isit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM 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 stan
14、dard an 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 AST
15、M is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 This practice is applicable for qualitatively evaluating coated and uncoated monolithic polycarbonate sheet materia
16、l, formonitoring process control, for screening studies, and as an aid in the prediction of hardware performance when exposed to impactservice conditions.5.2 A limitation of Type A specimen testing is that a thick sheet may not fail since the available impact energy is limited bythe maximum drop hei
17、ght and falling weight capacity of the test apparatus. Use Specimen Type A for material less than 12.7 mm(0.50 in.) thick.5.3 Within the range of drop heights of this system, tests employing different velocities are not expected to produce differentresults. However, for a given series of tests, it i
18、s recommended that the drop height should be held approximately constant so thatvelocity of impact (strain rate) will not be a variable.5.4 As the polycarbonate specimen undergoes large plastic deformation under impact, the down (opposite impact) side is undertensile loading and most influential in
19、initiating failure. Polycarbonate For that reason, polycarbonate sheet coated on one side mayyield significantly different test results when should be tested with the coated side down versus the coated side up.down.5.5 Direct comparison of specimen Type A and specimen Type B test results should not
20、be attempted. For test programs thatwill require the comparison of interlaboratory test results the specimen type and the approximate drop height must be specified.5.6 Monolithic polycarbonate sheet is notch sensitive. Data obtained from other test methods, particularly notched Izod/Charpytest resul
21、ts, and extremely high- or low-strain rate test results, should not be compared directly to data obtained from this method.It is noted that Type A specimens, free of flaws, have not experienced the characteristic ductile-to-brittle transition between thin,less than 3.18 mm (18 in.), and thick, great
22、er than 7.94 mm (516 in.), sheet as reflected by other test methods.6. Apparatus6.1 Impact TesterThe apparatus shall be constructed essentially as shown in Fig. 2. Although not specified, materials calledout have been found to be satisfactory.6.1.1 Drop HeightAlifting carrier shall be provided to ra
23、ise or lower the falling weight impactor that will be adjustable withinthe range of 0.305 m (1 ft) to maximum drop height and measurable to the nearest 25.40 mm (1 in.).6.1.2 Drop WeightThe falling weights shall be detachable, interchangeable, and variable in small known increments from atotal of 0.
24、45 kg (1 lb) to a maximum drop weight of 50 kg (110 lb).6.1.3 ImpactorThe loading nose to be used with Type A specimens is shown in Fig. 3; with Type B specimens as shown inFig. 4. The impactor surface shall be free of nicks or other surface irregularities. The impactor geometry for Type B specimens
25、corresponds to Test Method D790.FIG. 1 Type B Specimen Geometry and LoadingF736 1726.1.4 Impact LocationThe center of mass of the falling weight shall be guided by a two cable system or other suitable meansto repeatedly strike within 2.54 mm (0.10 in.) of the center of the specimen support fixture a
26、s measured in the plane of thespecimen, in order to assure uniform, reproducible drops. Friction retarding the falling weight shouldshall be minimal so that theimpact velocity approaches=2ghwhere:g = acceleration of gravity, andFIG. 2 Falling Weight Impact TesterF736 173h = drop height.6.1.5 Support
27、sClamp and support rings as shown in Fig. 5 and Table 1 willshall be used to accommodate Type A platespecimens. Adjustable D790Test Method 1 supports willshall be used to accommodate the Type B simply supported beamspecimens of 6 + 1 span-to-depth ratio. Specimens shall be supported so that the surf
28、ace to be impacted is horizontal and at anangle of 90 (6 1) (pi/2 radians) with respect to the falling weight guides.6.1.6 ReleaseAn electromagnetic or mechanical releasing mechanism, capable of supporting the maximum falling weight,willshall be providedused to assure uniform and reproducible drops.
29、6.1.7 Rebound CatcherMeans must be provided to catch the weight if it rebounds to prevent restriking the specimen andcausing further damage.6.1.8 Energy AbsorberAn energy absorbent material must be provided beneath the specimen to prevent damage to the fixturewhen the impactor penetrates the specime
30、n.7. Hazards7.1 To reduce a hazard to the test operator or witness, or both, a protective enclosure shall be placed around the test specimenimpact area to contain any flying particles which may be generated during the test. No further adjustments to the specimen shallbe made after positioning the fa
31、lling weight at the selected drop height.8. Test Specimens8.1 All specimens must be initially without flaws unless the flaws constitute variables under study. Type B specimens must befree of machining stresses. Edge stresses associated with standard shop practice do not affect the test results for T
32、ypeAspecimens.If no combination of falling weight/drop height is available that will give satisfactory results using Type A specimens because ofhigh impact resistance, the use of Type B specimens is recommended shall be used to produce failure at a lower energy level.8.1.1 Type AFlat plates shall be
33、 round or square and have the physical dimensions specified in Table 2. These dimensionsprovide adequate edge distance for clamping on the plate support 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 thickness ofthe beam, the specim
34、en width shall be two times the thickness, not to exceed 50.80 mm (2.00 in.), and the overhang on each endshall be four times the thickness to prevent the specimen from slipping through the supports.NOTE 2With care, Type A plate specimens mayshall be bandsawed without machined, or bandsawed carefull
35、y to avoid inducing failure from edgeeffects. Type B beam specimens must have deburred finish-machined edges that are free of stress risers.9. Conditioning9.1 Unless otherwise specified, condition the test specimens in accordance with Procedure A of MethodsPractice D618.TABLE 1 Plate Support Ring Ge
36、ometryNOTE 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 (8.00)4 292.1 (11.50) 381.0 (15.00) 304.8 (12.00)TABLE 2 Type A Specimen Geomet
37、ryASpecimen Thickness SpanB (“A” + 2R) Diameter or Width Span/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
38、.26) 304.8 (12.00) 381.0 (15.00) 15.89.5A Specified 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 sh
39、ould be tested at the same span.B Reference Fig. 5.F736 17410. Procedure10.1 Measure and record the thickness and geometry of each specimen.10.2 Choose a specimen at random from the sample.10.3 Lightly clamp (20 in.-lbs) plate specimens.10.4 Adjust the falling weight to that weight which is expected
40、 to cause failure.10.5 Position the falling weight at the proper height to provide the predicted failure energy at impact.10.6 Release the weight to strike the center of the specimen. If rebound occurs, prevent the impactor from restriking thespecimen.10.7 Examine the specimen to determine if it fai
41、led. Test each specimen only once. If over (full penetration) or under thethreshold of failure, remove or add an increment of weight as derived from results observed from the specimen tested immediatelyprior and repeat the test procedure.10.8 Use a sufficient number of specimens to determine the thr
42、eshold of failure, using trial and error test runs. Test six replicatesat failure energy so that at least two, and not more than four, of the samples tested fail at the given energy level.10.9 Exercise care to avoid accidental exposure of polycarbonate test samples to toluene, MEK vapors, and other
43、harmfulsolvents. Degradation can occur with no visual evidence of damage.11. Calculation11.1 The energy required to produce failure, expressed in Joules (foot-pounds), is obtained by multiplying the falling weightin Newtons (pounds) by the drop height in meters (feet).12. Report12.1 The report shall
44、 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,12.1.4 Thickness,Thickness for Type A specimen, and thickness and width for Type B specimen,12.1.5 Number of test specimens employed to determine thresh
45、old of failure,12.1.6 Test conditions and 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, or brittle fracture),12.1.11 Replicate data,NOTE 1All loading surfaces to have surface roughness of 1.53.0 m (64128 in.).FIG.
46、 3 Impactor Loading NoseType A Plate Specimen (Stainless Steel)F736 17512.1.12 Deviation(s) from test procedure, and12.1.13 Date of test.NOTE 1All loading surfaces to have surface roughness of 1.53.0 m (64128 in.).FIG. 4 Impactor Loading NoseType B Beam Specimen (Stainless Steel)NOTE 1Reference Tabl
47、e 1 for dimensions “A” and “C”.NOTE 2All loading surfaces to have surface roughness of 1.53.0 m (64128 in.).FIG. 5 Clamping and Support RingsType A Plate SpecimenF736 17613. Precision and Bias13.1 PrecisionThis test method does not yet contain a numerical precision statement. However, limited data f
48、rom onelaboratory indicates repeatability to approximately 6 5 % for either specimen Type A or Type B for material exhibiting ductilebehavior. The precision of this test method is under investigation by a task group of Subcommittee F07.08 via an interlaboratorystudy. Anyone wishing to participate in
49、 this work may contact the Chairman, Subcommittee F07.08, ASTM, 100 Barr HarborDrive, West Conshohocken, PA, 19428.13.2 BiasThe procedure in this test method for measuring resistance to a falling weight has no bias because the value forresistance to a falling weight is defined only in terms of this test method.14. Keywords14.1 falling weight; impact resistance; polycarbonateASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
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