1、Designation: D953 18Standard Test Method forPin-Bearing Strength of Plastics1This standard is issued under the fixed designation D953; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthes
2、es 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 U.S. Department of Defense.1. Scope*1.1 This test method covers the determination of the pin-bearing streng
3、th of rigid plastics in either sheet form, moldedform, or in reinforced thermoset form. Procedures A and B areapplicable for thermoplastic materials in tension loading andcompression loading respectively. Procedure C is applicablefor thermoset reinforced plastics. See the significance and usesection
4、 (Section 5) for cautions in using this test standard.1.2 Test data obtained by this test method is relevant andappropriate for use in quality control and engineering design.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1
5、.4 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.
6、NOTE 1This standard and ISO 12815 address the same subject matter,but differ in technical content.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International
7、Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD5947 Test Methods for Physical Dimensions of So
8、lidPlastics SpecimensD7290 Practice for Evaluating Material Property Character-istic Values for Polymeric Composites for Civil Engineer-ing Structural ApplicationsE4 Practices for Force Verification of Testing MachinesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE6 Termin
9、ology Relating to Methods of Mechanical TestingE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standards:ISO 12815 Fibre-reinforced plastic compositesDetermination of plain-pin bearing strength33. Terminology3.1 DefinitionsFor definitions of te
10、chnical terms used inthis test method and associated with plastics issues refer toterminology contained in ASTM D883.3.2 Definitions of Terms Specific to This Standard:43.2.1 pin-bearing areathe diameter of the hole multipliedby the thickness of the specimen.3.2.2 pin-bearing strengththe pin-bearing
11、 stress at whichthe pin-bearing hole is deformed 4 % of its diameter forthermoplastics. For thermosets, the pin-bearing strength is themaximum pin-bearing stress at which the sample fails.3.2.3 pin-bearing stressthe applied load in newtons (orpounds-force) divided by the pin-bearing area in mm2(or i
12、n2).3.2.4 edge distance ratiothe distance from the center ofthe pin-bearing hole to the edge of the specimen in thedirection of loading, divided by the diameter of the hole.3.2.5 maximum pin-bearing stressthe maximum load innewtons (or pounds-force) sustained by the specimen, dividedby the bearing a
13、rea.4. Summary of Test Method4.1 This test standard is intended to test the pin-bearingstrength of thermoplastic material using procedures A, B and1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.18 on Reinforced Thermos
14、et-ting Plastics.Current edition approved Nov. 1, 2018. Published November 2018. Originallyapproved in 1948. Last previous edition approved in 2010 as D953 - 10. DOI:10.1520/D0953-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
15、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Attention is also directed to Terminology E6.*A Su
16、mmary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization establish
17、ed in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1reinforced thermoset plastics using procedure C. In proceduresA and B, the sample with a pin-bearing hole wil
18、l be tested intension and compression respectively.While using procedureAand B, the load at which the hole deformation reaches 4 % ofhole diameter, that load shall be considered as maximumpin-bearing load to calculate the pin-bearing strength. Inprocedure C, the sample shall be tested in compression
19、 and themaximum failure load of the sample shall be used as maximumpin-bearing load to calculate the pin-bearing strength. Asreinforced thermoset plastics are much stiffer thanthermoplastics, the pin-bearing failure happens much beforethe hole deformation reaches 4 % of the hole diameter. Usingproce
20、dure C, it is allowed to test reinforced thermoset sampleswith over-sized holes for any engineering design purposes.Using the maximum pin-bearing load obtained by using anappropriate procedure, the pin-bearing strength of the materialwill be determined.5. Significance and Use5.1 This pin-bearing str
21、ength test for plastics is intended toapply in the specification of various thermoplastic or thermo-setting products in sheet form where rivets, bolts, or similarfastenings are to be used in joining members or sections. It alsois intended to apply wherever sheet materials of the classesindicated are
22、 required to sustain edgewise loads that areapplied by means of pins or rods of circular cross section whichpierce the sheet perpendicular to the surface.5.2 The purpose of the test using procedures A and B is todetermine the pin-bearing strength of thermoplastic materialand to plot the pin-bearing
23、stress versus the deformation of thehole. The allowable deformation of the hole in the materialshall be such as to produce no looseness of joints.5.3 The purpose of procedure C is to determine the ultimatepin-bearing strength of reinforced thermoset material. This testprocedure enables the user to t
24、est the part in any direction thatis intended to carry the pin-bearing loads. The sample size usedin this procedure will cover thermoset reinforced plastics thatare commonly used in infrastructure applications.5.4 While it is a known fact that higher strength materialswill generally give higher bear
25、ing strengths, there is nosatisfactory method to estimate pin-bearing strength fromtensile or compressive properties of the material.5.5 Before proceeding with this test method, reference shallbe made to the specification of the material being tested. Anytest specimen preparation, conditioning, dime
26、nsions or testingparameters or combination thereof covered in the relevantASTM materials specification shall take precedence over thosein this test method. If there are no relevant ASTM materialspecifications then the default conditions apply.6. Apparatus6.1 Testing MachineA properly calibrated univ
27、ersal test-ing machine that is capable to be operated at a speed of 1.3 60.3 mm (0.05 6 0.01 in.)/min, except that in cases of certaintypes of materials where it is necessary to operate at a slowerspeed. The percentage of error of the testing machine shall beno more than 61 % of the applied load as
28、determined inaccordance with Practices E4.6.2 Tension Loading Fixture for Procedure AAthree-platefixture of hardened steel similar to that shown in Fig. 1.6.3 Extension IndicatorA suitable instrument reading in0.0025 mm (0.0001 in.) for indicating the movement of the freeend of the specimen with rel
29、ation to the bearing pin in thetension loading fixture. A dial gauge fitted with accessories forthis purpose is shown in Fig. 2.6.4 Compression Loading Fixture for Procedure BA typeof support with a suitable bearing pin similar to Fig. 3.6.5 Compression IndicatorA suitable instrument readingto 0.002
30、5 mm (0.0001 in.) for indicating the movement of thefree end of the specimen with relation to the bearing pin in thecompression loading fixture. A schematic of the dial gaugeassembly for this purpose is shown in Fig. 4.6.6 Compression Loading Fixture for Procedure CThefixture as shown in Fig. 5 (A)
31、is made up of two properlyaligned steel angle uprights welded to a steel base plate. Thewelding of the angle uprights has to be on the outside only andnot for the surfaces against which the specimen makes contact1Hardened spacer plate.26.3-mm (-in.) steel bolts in reamed holes.3Hardened side plate.4
32、Extensometer span.5Hardened steel pin in reamed hole.6Test specimen.NOTE 1Critical dimensions are as follows:TypeBearing HoleDiameter, mm (in.)Bearing Pin Diameter, mm(in.)Thickness ofSpacer Plate,mmA(in.)I 3.175 + 0.025 3.150 + 0.000 3.2 0.000 0.025(0.125 + 0.0010 (0.124 + 0.0000 (18 ) 0.0000) 0.00
33、10)II 6.350 + 0.025 6.325 + 0.000 6.3 0.000 0.025(0.250 + 0.0010 (0.249 + 0.0000 (14 ) 0.0000) 0.0010)AThe spacer plate shall be shimmed to a thickness of 0.025 to 0.125 mm (0.001to 0.005 in.) greater than the specimen under test.FIG. 1 Steel Tension Loading FixtureD953 182with so the sample can be
34、supported flush to the surface of theangle and align without any angularity. This fixture willsupport and align the sample normal to the loading ram. It isallowed to use C-clamps to provide lateral support to thesample against the fixture as shown in Fig. 5 (B). The nominalbearing pin diameter shall
35、 be the same as the thickness of thesample.7. Test Specimens7.1 The test specimens for Procedures A and B shallconform to the dimensions shown in Fig. 6. A size of testspecimen shall be chosen that most nearly conforms toproduction requirements of the material and the type of loadingunder considerat
36、ion. It is permitted to machine the specimenfrom sheet or molded to finished size. The bearing hole shall belocated as shown in Fig. 6. It shall be drilled undersized andreamed to size as indicated. The hole shall be clean and smoothwith sharp edges but not polished. The reaming operation shallbe do
37、ne in the drill press by hand without the use of a jig.NOTE 2The thicker specimens with the larger pin-bearing hole arelikely to give the more precise results, although it is advantageous to usethe thinner specimens with the smaller pin-bearing hole in testing certainrelatively brittle plastics beca
38、use they are less likely to fail prematurely.7.2 The test specimens for procedure C shall conform to thedimensions shown in Fig. 7. The test specimen shall be a 76.2mm by 76.2 mm (3 in. by 3 in.) sample machined from a partthat mostly nearly conforms to the production requirements ofthe material und
39、er consideration. The specimen shall be clearlymarked to identify the orientation of the material. The pin-bearing hole shall be located at a distance of 15.88 mm (0.625in.) from the one edge of the sample in the direction of theloading.The hole shall be drilled undersized and reamed to sizeas indic
40、ated in Fig. 7. The hole shall be clean and smooth withsharp edges but not polished. The reaming operation shall bedone in the drill press by hand without the use of a jig. Thesample with pin-bearing hole shall be carefully machined at themid-section of the hole to present half of the hole as shown
41、inFig. 7.7.3 The dimensions given in Fig. 7 applies to holes up to25.4 mm (1 in.). For pin-bearing holes bigger than 25.4 mm (1in.) an edge distance (B) of 3 times the diameter of thepin-bearing pin shall be considered.7.4 Oversized Holes for Engineering DesignsTo deter-mine the pin-bearing strength
42、 of oversized holes for engineer-ing design purpose, it is allowed to use the compression fixtureand the compression sample, prepared as described in 7.2except that it is not required to clean or ream the hole. Whiledetermining the pin-bearing stress of an oversized hole, notethat the values obtaine
43、d for a particular combination of holesize, pin size, thickness, and material is acceptable only for thatcombination.1Spacer plate.2Dial gauge.3Double foot ring mounted on spindle of dial gauge.4Bearing pin.5Yoke mounted on specimen.6Test specimen.7Plan view of yoke.FIG. 2 Tension Loading Assembly1T
44、est specimen.2Hardened steel pin.3Hardened thrust bushing.NOTE 1Critical dimensions are as follows:TypeBearing HoleDiameter,mm (in.)Bearing Pin Diameter,mm (in.)MinimumClear-ance Be-tweenBushings,mm (in.)I 3.175 + 0.025 3.150 + 0.000 2.8 0.000 0.025(0.125 + 0.0010 (0.124 + 0.0000 (7/64) 0.0000) 0.00
45、10)II 6.350 + 0.025 6.325 + 0.000 6.0 0.000 0.025(0.250 + 0.0010 (0.249 + 0.0000 (15/64) 0.0000) 0.0010)FIG. 3 Steel Compression Loading FixtureD953 1838. Number of Test Specimens8.1 At least five specimens shall be tested for each sample inthe case of isotropic materials.8.2 Ten specimens, five per
46、pendicular to and five parallelwith the principal axis of anisotropy, shall be tested for eachsample in case of anisotropic materials.1Test specimen. 6Dial gauge.2Bearing pin. 7Pedestal support.3Thrust bushings. 8Clamp for cheek blocks.4Hanger for dial gauge. 9Hard maple cheek blocks to stabilize te
47、st specimen.5Spring-supported thrust member of transfer deforma-tion of specimen to dial gauge foot.FIG. 4 Compression Loading AssemblyFIG. 5 Compression Loading Fixture for Procedure C (With Picture of Sample Under Pin-Bearing Load)D953 184NOTE 3If the intent of the testing is to obtain the charact
48、eristic valuein accordance with Practice D7290, the sample numbers have to be aminimum of ten samples per direction of principal axis.8.3 Specimens that break at some obvious flaw that is notnaturally formed by the material processing method shall bediscarded and retests made, unless such flaws cons
49、titute avariable the effect of which is being studied.9. Conditioning9.1 ConditioningCondition the test specimens in accor-dance with Procedure A of Practice D618, unless otherwisespecified by contract or the relevant ASTM material specifica-tion. Conditioning time is specified as a minimum. Tempera-ture and humidity tolerances shall be in accordance withSection 7 of Practice D618 unless specified differently bycontract or material specification.9.2 Test ConditionsConduct tests at the same temperatureand humi
