1、Designation: D 3846 08Standard Test Method forIn-Plane Shear Strength of Reinforced Plastics1This standard is issued under the fixed designation D 3846; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber 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 the determination of the in-pla
3、ne shear strength of reinforced thermosetting plastics in flatsheet form in thicknesses ranging from 2.54 to 6.60 mm (0.100to 0.260 in.). This protocol in not for reinforced pultrudedthermoset products, which may use Test Method D 2344/D 2344M.1.2 The values stated in SI units are to be regarded as
4、thestandard. The values given in parentheses are for informationonly.1.3 This standard 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
5、applica-bility of regulatory limitations prior to use.NOTE 1This standard has no known ISO equivalent.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 695 Test Method for Compressive Properties of RigidPlasticsD 2344/D 2344M Test Method for Short-Beam
6、Strength ofPolymer Matrix Composite Materials and Their LaminatesE4 Practices for Force Verification of Testing MachinesE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 in-plane shear strengththe shear strength at ru
7、pturein which the plane of fracture is located along the longitudinalaxis of the specimen between two centrally located notchesmachined halfway through its thickness on opposing faces.4. Summary of Test Method4.1 In-plane shear strength, as determined by this testmethod, is measured by applying a co
8、mpressive load to anotched specimen of uniform width. The specimen is loadededgewise in a supporting jig of the same description as thatreferenced in Test Method D 695 for testing thin specimens. Aschematic of the specimen used for this test and the supportingjig is shown in Fig. 1. Failure of the s
9、pecimen occurs in shearbetween two centrally located notches machined halfwaythrough its thickness and spaced a fixed distance apart onopposing faces.5. Significance and Use5.1 Shear tests of various kinds are widely used in thereinforced plastics industry to assess the strength of thereinforcement-
10、to-resin bond in polyester-, vinyl ester-, andepoxy-resin composites. In addition to their importance for thegeneration of data for research and development, qualitycontrol, and specification purposes, such tests are of fundamen-tal value to the fibrous reinforcement industry, since they canbe used
11、to assess the potential of new sizing systems for thesurface treatment of glass fibers.5.2 This test method is useful for establishing the shearstrength of laminates or other reinforced plastics havingrandomly dispersed fiber reinforcement. While the test alsolends itself to parallel-fiber reinforce
12、d plastics, it has beendesigned to accommodate nonparallel-fiber reinforced materi-als that cannot be tested satisfactorily by the short-beamprocedure described in Test Method D 2344.6. Apparatus6.1 Testing MachineAny suitable testing machine capableof control of constant-rate-of-crosshead movement
13、and com-prising essentially the following:6.1.1 Drive MechanismA drive mechanism for impartingto the movable member a uniform, controlled velocity withrespect to the stationary member, as required in 10.3.6.1.2 Load IndicatorA load-indicating mechanism ca-pable of showing the total compressive load
14、carried by the test1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.18 on Reinforced Thermoset-ting Plastics.Current edition approved May 1, 2008. Published June 2008. Originallyapproved in 1979. Last previous edition ap
15、proved in 2002 as D 3846 - 02.2For 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.1Copyright ASTM International,
16、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.specimen. The mechanism shall be essentially free of inertiallag at the specified rate of testing and shall indicate the loadwith an accuracy of 61 % of the maximum indicated value ofthe test (load). The accuracy of
17、the testing machine shall beverified at least once a year in accordance with Practices E4.6.1.3 Compression ToolA compression tool for applyingthe load to the test specimen, such as those shown in Figs. 1and 2 of Test Method D 695.6.1.4 Supporting JigA supporting jig, shown schemati-cally in Fig. 1,
18、 and conforming to the dimensions of that shownin Fig. 4 of Test Method D 695.6.1.5 MicrometersSuitable micrometers, reading to 0.025mm (0.001 in.) for measuring the width and thickness of thespecimens, as well as the depth of, and distance between, thenotches.6.1.6 Torque WrenchA suitable torque wr
19、ench for tight-ening the nuts of the supporting jig of 6.1.4 to the torqueprescribed in 10.2.7. Test Specimens7.1 ConfigurationTest specimens shall conform to theshape and dimensions given in Fig. 1. The edges of thespecimens shall be smooth, but not rounded or beveled.7.2 PreparationTwo parallel cu
20、ts, one on each oppositeface of the specimen and 6.4 mm (0.25 in.) apart, shall besawed across the entire width of the specimen and centrallylocated along its length. The width and depth of notch shallconform to the dimensions shown in Fig. 1. For laminatedmaterials, the notch shall be of sufficient
21、 depth to sever thecenter ply of the reinforcement, located midway between thetwo faces of the laminate.7.3 NumberFive specimens shall be tested wheneverisotropic materials are under test. When testing material that issuspected or known to be anisotropic, ten specimens (fivenormal to and five parall
22、el with the principal axis of anisot-ropy) shall be tested.8. Conditioning8.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 5 % relative humidity for not lessthan 40 h prior to test in accordance with Procedure A ofPractice D 618, for those tests where conditioning is req
23、uired.In case of disagreement, the tolerances shall be 61C (61.8F)and 62 % relative humidity.8.2 Test ConditionsConduct tests in the standard labora-tory atmosphere of 23 6 2C (73.4 6 3.6F) and 50 6 5%relative humidity, unless otherwise specified. In cases ofdisagreement, the tolerances shall be 61C
24、 (61.8F) and62 % relative humidity.9. Speed of Testing9.1 Speed of testing shall be the relative rate of motion ofthe grips or test fixtures during the test. Rate of motion of thedriven grip or fixture when the machine is running idle may beused if it can be shown that the resulting speed of testing
25、 iswithin the limits of variation allowed.9.2 The standard speed of testing shall be 1.36 0.3 mm/min(0.050 6 0.010 in./min).10. Procedure10.1 Measure the width of the specimen between thenotches to the nearest 0.025 mm (0.001 in.).10.2 Mount the specimen in the supporting jig (Fig. 1)sothat it is fl
26、ush with the base and centered. Tighten the nuts ofthe jig with the torque wrench of 6.1.6 to a torque of0.113 + 0.000, 0.028 Nm (1.00 + 0.00, 0.25 lbfin.). Placethe assembly in the compression tool described in 6.1.3.10.3 Set the speed control at 1.3 mm/min (0.050 in./min)and start the machine.10.4
27、 Record the maximum load carried by the specimenduring the test. (Usually this will be the load at the moment ofrupture.)10.5 Determine the length of the failed (sheared) area to thenearest 0.025 mm (0.001 in.) by measurement of this surfacewith respect to either half of the ruptured specimen. Thist
28、echnique affords the most accurate determination of the lengthof the sheared plane defined by the separation of the notchesmachined in the specimen.11. Calculation11.1 In-Plane Shear StrengthCalculate the in-plane shearstrength by dividing the maximum shear load carried by thespecimen during the tes
29、t by the product of the width of thespecimen (see 10.1) and the length of the failed area, asdetermined in 10.5. Express the result in megapascals orpounds-force per square inch and report it to three significantfigures.12. Report12.1 Report the following information:FIG. 1 Specimen and Loading Jig
30、for In-Plane Shear TestD 3846 08212.1.1 Complete identification of the material tested, includ-ing type, source, manufacturers code number, form, principaldimensions, previous history, etc.,12.1.2 Method of preparing test specimens,12.1.3 Conditioning procedure used,12.1.4 Atmospheric conditions in
31、test room,12.1.5 Number of specimens tested,12.1.6 A brief description of the type of testing machineused, and the date on which it was last verified (see 6.1.2) andby whom,12.1.7 In-plane shear strength, average value, and standarddeviation, and12.1.8 Date of test.13. Precision and Bias13.1 Table 1
32、 is based on a round robin conducted in 2001 inaccordance with Practice E 691, involving two materials testedby five laboratories. For each material, all the samples wereprepared at one source, but the individual specimens wereprepared at the laboratories which tested them. Each test resultwas the a
33、verage of five individual determinations. Each labo-ratory obtained four test results for each material. (WarningThe explanation of “r” and “R” in 13.2.1 and 13.2.2 are onlyintended to present a meaningful way of considering theapproximate precision of this test method. The data in Table 1should not
34、 be applied to acceptance or rejection of materials, asthese data apply only to the materials tested in the round robinand are unlikely to be rigorously representative of other lots,formulations, conditions, materials, or laboratories. Users ofthis test method should apply the principles outlined in
35、 PracticeE 691 to generate data specific to their materials and laboratory(or between specific laboratories). The principles of 13.2-13.2.2 would then be valid for such data.)13.2 Concept of “r” and “R” in Table 1If Srand SRhavebeen calculated from a large enough body of data, and for testresults th
36、at were averages from testing five specimens for eachtest result, then:13.2.1 Repeatability:Two results obtained within one laboratory shall be judgednot equivalent if they differ by more than the “r” value for thatmaterial. “r” is the interval representing the critical differencebetween two test re
37、sults for the same material, obtained by thesame operator using the same equipment on the same day in thesame laboratory.13.2.2 Reproducibility:Two test results obtained by different laboratories shall bejudged not equivalent if they differ by more than the “R” valuefor that material. “R” is the int
38、erval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.13.3 Any judgement in accordance with 13.2.1 or 13.2.2would have an approximate 95% (0.95) probability of beingcorrect.13.4 Ther
39、e are no recognized standards by which to esti-mate bias of this method.14. Keywords14.1 compressive shear; in-plane shear; plastics; reinforcedplasticsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Us
40、ers of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed ever
41、y five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible techni
42、cal committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke
43、n, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Precision Statement f
44、or In-Plane ShearMaterial Mean SrASRBrCRDVinyl Ester 3042 775 1241 2171 3474Polyester 2898 710 1296 1989 3631ASr= within laboratory standard deviation for the indicated material. It isobtained by pooling the within-laboratory standard deviations of the test results forall of the participating labora
45、tories:Sr5 S1!21 S2!21 Sn!2/n 12BSR= between-laboratories reproducibility, expressed as standard deviation:SR5 Sr21 SL2#12where SL= standard deviation of laboratory means.Cr = within-laboratory critical interval between tow test results = 2.8 3 Sr.DR = between-laboratories critical interval between tow test results = 2.8 3 SR.D 3846 083
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