1、Designation: D 3914 02Standard Test Method forIn-Plane Shear Strength of Pultruded Glass-ReinforcedPlastic Rod1This standard is issued under the fixed designation D 3914; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the in-plane shear strength of pultruded, glass-fiber reinforced, ther-m
3、osetting plastic rod of diameters ranging from 19 to 32 mm(34 to 114in.).1.2 The values stated in SI units are to be regarded as thestandard.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
4、to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Note 2 and Note 3.NOTE 1There is no similar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:D 618 Practi
5、ce for Conditioning Plastics for Testing2D 695 Test Method for Compressive Properties of RigidPlastics2E 4 Practices for Force Verification of Testing Machines33. Terminology3.1 Definition:3.1.1 in-plane shear strengththe shear strength at maxi-mum load in which the plane of fracture is centrally lo
6、catedalong the longitudinal axis of the specimen between twodiametrically opposed notches machined halfway through itsdiameter.4. Summary of Test Method4.1 In-plane shear strength, as determined by this testmethod, is measured by applying a compressive load tonotched cylindrical specimens of the typ
7、e shown in Fig. 1.Loading of the specimen is accomplished with a subpress, orcompression tool, such as those shown in Fig. 1 and Fig. 2 ofTest Method D 695. Failure of the specimen occurs in shearbetween two centrally located notches, diametrically opposedand machined halfway through its diameter at
8、 a fixed distanceapart. The notches are accurately machined in the specimenwith maximum reproducibility by means of a special notchingjig (Fig. 2a and Fig. 2b) designed specifically for this purpose.5. Significance and Use5.1 Shear tests of various kinds are widely used in thereinforced plastics ind
9、ustry to assess the strength of thereinforcement-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 fibro
10、us reinforcement industry, since they canbe used to determine the potential of new sizing systems for thesurface treatment of glass fibers.5.2 The in-plane shear strength of pultruded cylindricalcomposites is an important property from an engineeringstandpoint, since pultruded rod, as such, is used
11、in manystructural applications.6. Apparatus6.1 Testing MachineAny suitable testing machine capableof control of constant-rate-of-crosshead movement and com-prising essentially the following:6.1.1 Drive MechanismA drive mechanism for impartingto the movable member a uniform, controlled velocity withr
12、espect 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 carried by the testspecimen. The mechanism shall be essentially free of inertiallag at the specified rate of testing and shall indicate the loadwith an
13、accuracy of 61 % of the maximum indicated value ofthe test (load). The accuracy of the testing machine shall beverified at least once a year in accordance with Practices E 4.6.1.3 Notching JigA notching jig of the type shown inFig. 2a and Fig. 2b, or the equivalent, for notching the testspecimens.6.
14、1.4 Compression ToolA compression tool for applyingthe load to the test specimen, such as those shown in Fig. 1 andFig. 2 of Test Method D 695.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.18 on Reinforced Thermoset-
15、ting Plastics.Current edition approved March 10, 2002. Published May 2002. Originallypublished as D 3914 80. Last previous edition D 3914 96.2Annual Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM Standards, Vols 03.01 and 04.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C70
16、0, West Conshohocken, PA 19428-2959, United States.6.1.5 MicrometersSuitable micrometers, reading to 0.025mm or 0.001 in., for measuring the diameter of the specimen,as well as the depth of, and distance between, the notches.7. Test Specimens7.1 ConfigurationTest specimens shall be carefully ma-chin
17、ed from the rod sample of interest and shall conform to theshape and dimensions given in Fig. 1. The ends of thespecimen shall be machined flat and parallel to prevent pointloading upon application of the compressive load.7.2 PreparationAfter machining the specimen to properlength, insert it in the
18、notching jig, flush it with one face of thejig, and tighten the cap screws of the jig to secure it in place.Push the assembly (jig and specimen) into a diamond gritcutoff wheel (or equivalent blade) after setting the blade to givethe proper depth of notch. This arrangement is shown in Fig. 3.Guidanc
19、e of the jig during specimen notching is by means ofsliding contact with the fence of the table saw as the jig ispushed along the table to a stop. After machining one notch,turn the tool over and repeat the procedure to provide a secondnotch in the specimen diametrically opposed to the first and ata
20、 fixed, defined distance (Fig. 1) from it.NOTE 2Caution: When fabricating composite specimens by machin-ing operations, a fine dust consisting of particles of fibers or the matrixmaterial, or both, may be formed. These fine dusts can be a health or safetyhazard, or both. Adequate protection should b
21、e afforded operating person-nel and equipment. This may require adequate ventilation or dustcollecting facilities, or both, at a minimum.7.3 NumberA minimum of five specimens shall be tested.FIG. 1 Notched Rod In-Plane Shear Specimen; Dimensions: Top, mm; Bottom, in.D 39142FIG. 2A Details of Specime
22、n Notching Jig for In-Plane Shear Test, Dimensioned in mmD 39143FIG. 2B Details of Specimen Notching Jig for In-Plane Shear Test Dimensioned in Inches8. 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
23、 in accordance with Procedure A ofPractice D 618, for those tests where conditioning is required.In cases 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%relativ
24、e humidity, unless otherwise specified. In cases ofdisagreement, the tolerances shall be 61C (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 t
25、he machine is running idle may beused if it can be shown that the resulting speed of testing iswithin the limits of variation allowed.9.2 The standard speed of testing shall be 1.3 6 0.3 mm(0.050 6 0.010 in.)/min.10. Procedure10.1 Measure the diameter of the specimen between thenotches to the neares
26、t 0.025 mm or 0.001 in.10.2 Center the specimen in the compression tool of 6.1.4and mount the tool between the loading heads of the testingmachine.10.3 Set the speed control at 1.3 mm/min (0.050 in./min)and start the machine.10.4 Record the maximum load carried by the specimenduring the test (usuall
27、y, this will be the load at the moment ofrupture).NOTE 3Caution: When testing composite materials, it is possible tostore considerable energy in the test specimen which can be released withconsiderable force on rupture. This can release small high velocityparticles and dust consisting of fractured f
28、ibers and matrix materials. Theparticles and fine dust can potentially be a health or safety hazard, or both.Adequate protection should be afforded operating personnel, bystanders,and the equipment. This may require shielding or dust collection facilities,or both, at a minimum.10.5 Determine the len
29、gth of the failed (sheared) area to thenearest 0.025 mm or 0.001 in. by measurement of this surfacewith respect to either half of the ruptured specimen. ThisD 39144technique affords the most accurate determination of the lengthof the sheared plane defined by the separation of the notchesmachined in
30、the specimen.NOTE 4The width of the notches and the distance between them mayvary somewhat from the dimensions indicated in Fig. 1, depending uponthe actual thickness of the circular saw blade used to machine the notchesand the particular notching jig used. However, round-robin tests of rods ofvario
31、us diameters, employing different notching tools and saw blades ofthickness up to 3.2 mm (18 in.), have shown little, if any, influence on thetest results due to variation of the notches attributed to these factors. Aparticularly attractive feature of the notching jig shown in Fig. 2a and Fig.2b is
32、its ability to accommodate rods ranging in diameter from 19 to 32mm (34 to 114 in.).11. Calculations11.1 In-Plane Shear StrengthCalculate the in-plane shearstrength by dividing the maximum shear load carried by thespecimen during the test by the product of the specimensdiameter (see 10.1) and the le
33、ngth 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 The report shall include the following:12.1.1 Complete identification of the material tested, includ-ing type, source, manufacturers
34、 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 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 whi
35、ch 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 Bias413.1 RepeatabilityTesting in a single laboratory of asample of pultruded laminate resulted in a within-laboratorycoefficient of variation
36、 of 5.9%. The within-laboratory criticalinterval (cr) between two test results is 16.58% (2.8 3 Vr). Tworesults obtained within one laboratory on the same materialshall be judged not equivalent if they differ by more than thecritical interval (cr). Attempts to develop a full precision andbias statem
37、ent for this test method have not been successful.For this reason, data on precision and bias cannot be given.Because this test method does not contain a round robin basednumerical precision and bias statement, it shall not be used as4Round-robin data for this test method may be obtained from ASTM H
38、eadquar-ters. Request RR:D-20-1083.FIG. 3 Arrangement for Machining Notches in Pultruded Rod Specimens. Notching Jig Accommodates Rods Ranging in Diameter from19 mm (34 in.) to 32 mm (114 in.)D 39145a referee method in case of dispute. Anyone wishing toparticipate in the development of precision and
39、 bias datashould contact the Chairman, Subcommittee D20.18 (Section20.18.02), ASTM, 100 Barr Harbor Drive, West Consho-hocken, PA 19428.NOTE 5An attempt to run a round robin in 2001 resulted in insuffi-cient laboratories to develop a bias between laboratory precision state-ments. Only three laborato
40、ries were available for participation when aminimum of six is required.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of
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42、 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 technical committee, which you may attend. If you feel that your comments have not rece
43、ived 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 Conshohocken, 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).D 39146
