1、Designation: D 5961/D 5961M 08Standard Test Method forBearing Response of Polymer Matrix Composite Laminates1This standard is issued under the fixed designation D 5961/D 5961M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the bearing response of pinnedor fastened joints using multi-directional polymer matrixc
3、omposite laminates reinforced by high-modulus fibers bydouble-shear tensile loading (ProcedureA), single-shear tensileor compressive loading of a two-piece specimen (ProcedureB), single-shear tensile loading of a one-piece specimen(Procedure C), or double-shear compressive loading (Proce-dure D). St
4、andard specimen configurations using fixed valuesof test parameters are described for each procedure. However,when fully documented in the test report, a number of testparameters may be optionally varied. The composite materialforms are limited to continuous-fiber or discontinuous-fiber(tape or fabr
5、ic, or both) reinforced composites for which thelaminate is balanced and symmetric with respect to the testdirection. The range of acceptable test laminates and thick-nesses are described in 8.2.1.1.2 This test method is consistent with the recommendationsof MIL-HDBK-17, which describes the desirabl
6、e attributes ofa bearing response test method.1.3 The multi-fastener test configurations described in thistest method are similar to those used by industry to investigatethe bypass portion of the bearing bypass interaction responsefor bolted joints, where the specimen may produce either abearing fai
7、lure mode or a bypass failure mode. Note that thescope of this test method is limited to bearing and fastenerfailure modes. Use Test Method D 7248/D 7248M for by-passtesting.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. Within the text theinch
8、-pound units are shown in brackets. The values stated ineach system are not exact equivalents; therefore, each systemmust be used independently of the other. Combining valuesfrom the two systems may result in nonconformance with thestandard.1.5 This standard does not purport to address all of thesaf
9、ety 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.2. Referenced Documents2.1 ASTM Standards:2D 792 Test Methods for Density
10、and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD 883 Terminology Relating to PlasticsD 953 Test Method for Bearing Strength of PlasticsD 2584 Test Method for Ignition Loss of Cured ReinforcedResinsD 2734 Test Methods for Void Content of Reinforced Plas-ticsD 3171 Test Methods fo
11、r Constituent Content of CompositeMaterialsD 3410/D 3410M Test Method for Compressive Propertiesof Polymer Matrix Composite Materials with UnsupportedGage Section by Shear LoadingD 3878 Terminology for Composite MaterialsD 5229/D 5229M Test Method for Moisture AbsorptionProperties and Equilibrium Co
12、nditioning of Polymer Ma-trix Composite MaterialsD 5687/D 5687M Guide for Preparation of Flat CompositePanels with Processing Guidelines for Specimen Prepara-tionD 7248/D 7248M Test Method for Bearing/Bypass Interac-tion Response of Polymer Matrix Composite LaminatesUsing 2-Fastener SpecimensE4 Prac
13、tices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical Test-ingE83 Practice for Verification and Classification of Exten-someter SystemsE 122 Practice for Calculating Sample Size to Estimate,With Specified Precision, the Average for a Characteristicof a Lot
14、or ProcessE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 238 Test Method for Pin-Type Bearing Test of MetallicMaterials1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.05 onStruct
15、ural Test Methods.Current edition approved Sept. 15, 2008. Published November 2008. Originallyapproved in 1996. Last previous edition approved in 2005 as D 5961/D 5961M 051.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For A
16、nnual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E 456 Terminology Relating to Quality and StatisticsE 691 Practice for Co
17、nducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 1309 Guide for Identification of Fiber-ReinforcedPolymer-Matrix Composite Materials in DatabasesE 1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in DatabasesE 1471 Guide for Identific
18、ation of Fibers, Fillers, and CoreMaterials in Computerized Material Property Databases2.2 Other Document:MIL-HDBK-17, Polymer Matrix Composites, Vol 1, Sec-tion 733. Terminology3.1 DefinitionsTerminology D 3878 defines terms relatingto high-modulus fibers and their composites. TerminologyD 883 defi
19、nes terms relating to plastics. Terminology E6defines terms relating to mechanical testing. TerminologyE 456 and Practice E 177 define terms relating to statistics. Inthe event of a conflict between terms, Terminology D 3878shall have precedence over the other documents.NOTE 1If the term represents
20、a physical quantity, its analyticaldimensions are stated immediately following the term (or letter symbol) infundamental dimension form, using the following ASTM standard sym-bology for fundamental dimensions, shown within square brackets: Mfor mass, L for length, T for time, 1 for thermodynamic tem
21、perature,and nd for nondimensional quantities. Use of these symbols is restrictedto analytical dimensions when used with square brackets, as the symbolsmay have other definitions when used without the brackets.3.2 Definitions of Terms Specific to This Standard:3.2.1 bearing area, L2, nthe area of th
22、at portion of abearing specimen used to normalize applied loading into aneffective bearing stress; equal to the diameter of the loadedhole multiplied by the thickness of the specimen.3.2.2 bearing chord stiffness, EbrML-1T-2, nthe chordstiffness between two specific bearing stress or bearing strainp
23、oints in the linear portion of the bearing stress/bearing straincurve.3.2.3 bearing force, P MLT2, nthe total force carried bya bearing specimen.3.2.4 bearing strain, ,brnd, nthe normalized hole de-formation in a bearing specimen, equal to the deformation ofthe bearing hole in the direction of the b
24、earing force, dividedby the diameter of the hole.3.2.5 bearing strength, FxbrML-1T-2, nthe value of bear-ing stress occurring at a significant event on the bearingstress/bearing strain curve.3.2.5.1 DiscussionTwo types of bearing strengths arecommonly identified, and noted by an additional superscri
25、pt:offset strength and ultimate strength.3.2.6 bearing stress, FbrML-1T-2, nthe bearing forcedivided by the bearing area.3.2.7 countersink depth to thickness ratio, dcsk/h nd,theratio of the countersunk depth of a hole to the specimenthickness.3.2.7.1 DiscussionThe countersink depth to thickness ra-
26、tio is typically a nominal value determined from nominalhole-drilling dimensions and tolerances.3.2.8 diameter to thickness ratio, D/h nd, nin a bearingspecimen, the ratio of the hole diameter to the specimenthickness.3.2.8.1 DiscussionThe diameter to thickness ratio may beeither a nominal value det
27、ermined from nominal dimensions oran actual value determined from measured dimensions.3.2.9 edge distance ratio, e/D nd, nin a bearing speci-men, the ratio of the distance between the center of the hole andthe specimen end to the hole diameter.3.2.9.1 DiscussionThe edge distance ratio may be either
28、anominal value determined from nominal dimensions or anactual value determined from measured dimensions.3.2.10 nominal value, na value, existing in name only,assigned to a measurable quantity for the purpose of conve-nient designation. Tolerances may be applied to a nominalvalue to define an accepta
29、ble range for the quantity.3.2.11 offset bearing strength, FxbroML-1T-2, nthe valueof bearing stress, in the direction specified by the subscript, atthe point where a bearing chord stiffness line, offset along thebearing strain axis by a specified bearing strain value, inter-sects the bearing stress
30、/bearing strain curve.3.2.11.1 DiscussionUnless otherwise specified, an offsetbearing strain of 2 % is to be used in this test method.3.2.12 width to diameter ratio, w/D nd, nin a bearingspecimen, the ratio of specimen width to hole diameter.3.2.12.1 DiscussionThe width to diameter ratio may beeithe
31、r a nominal value determined from nominal dimensions oran actual value, determined as the ratio of the actual specimenwidth to the actual hole diameter.3.2.13 ultimate bearing strength, FxbruML-1T-2, nthevalue of bearing stress, in the direction specified by thesubscript, at the maximum force capabi
32、lity of a bearingspecimen.3.3 Symbols:A = minimum cross-sectional area of a specimenCV = coefficient of variation statistic of a sample populationfor a given property (in percent)d = fastener or pin diameterD = specimen hole diameterdcsk= countersink depthdfl= countersink flushness (depth or protrus
33、ion of the fas-tener in a countersunk hole)e = distance, parallel to force, from hole center to end ofspecimen; the edge distanceExbr= bearing chord stiffness in the test direction specifiedby the subscriptf = distance, parallel to force, from hole edge to end ofspecimenFxbru= ultimate bearing stren
34、gth in the test direction speci-fied by the subscriptFxbro(e %) = offset bearing strength (at e % bearing strainoffset) in the test direction specified by the subscriptg = distance, perpendicular to force, from hole edge toshortest edge of specimenh = specimen thickness3Available from Standardizatio
35、n Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.D 5961/D 5961M 082k = calculation factor used in bearing equations to distin-guish single-fastener tests from double-fastener testsK = calculation factor used in bearing equations to distin-guish single-
36、shear tests from double-shear tests in a singlebearing strain equationLg= extensometer gage lengthn = number of specimens per sample populationP = force carried by test specimenPf= force carried by test specimen at failurePmax= maximum force carried by test specimen prior tofailuresn-1= standard dev
37、iation statistic of a sample population fora given propertyw = specimen widthxi= test result for an individual specimen from the samplepopulation for a given propertyx= mean or average (estimate of mean) of a sample popu-lation for a given propertyd = extensional displacement = general symbol for st
38、rain, whether normal strain or shearstrainbr= bearing strainsbr= bearing stress4. Summary of Test Method4.1 Procedure A, Double Shear, Tension:4.1.1 Aflat, constant rectangular cross-section test specimenwith a centerline hole located near the end of the specimen, asshown in the test specimen drawin
39、gs of Figs. 1 and 2, is loadedat the hole in bearing. The bearing force is normally appliedthrough a close-tolerance, lightly torqued fastener (or pin) thatis reacted in double shear by a fixture similar to that shown inFigs. 3 and 4. The bearing force is created by loading theassembly in tension in
40、 a testing machine.4.1.2 Both the applied force and the associated deformationof the hole are monitored. The hole deformation is normalizedby the hole diameter to create an effective bearing strain.Likewise, the applied force is normalized by the projected holeFIG. 1 Double-Shear and Single-Shear On
41、e-Piece Test Specimen Drawing (SI)D 5961/D 5961M 083area to create an effective bearing stress. The specimen isloaded until a maximum force has clearly been reached,whereupon the test is terminated so as to prevent masking ofthe true failure mode by large-scale hole distortion, in order toprovide a
42、more representative failure mode assessment. Bear-ing stress versus bearing strain for the entire loading regime isplotted, and failure mode noted. The ultimate bearing strengthof the material is determined from the maximum force carriedprior to test termination.4.1.3 The standard test configuration
43、 for this procedure doesnot allow any variation of the major test parameters. However,the following variations in specimen and test fixture configu-ration are allowed, but can be considered as being in accor-dance with this test method only as long as the values of allvariant test parameters are pro
44、minently documented with theresults:Parameter Standard VariationLoading condition: double-shear noneMating material: steel fixture noneNumber of holes: 1 noneCountersink: none noneFit: tight any, if documentedFastener torque: 2.2-3.4 Nm 20-30 lbf-in. any, if documentedLaminate: quasi-isotropic any,
45、if documentedFastener diameter: 6 mm 0.250 in. any, if documentedEdge distance ratio: 3 any, if documentedw/D ratio: 6 any, if documentedD/h ratio: 1.2-2 any, if documented4.2 Procedure B, Single Shear, Two-Piece Specimen:4.2.1 The flat, constant rectangular cross-section test speci-men is composed
46、of two like halves fastened together throughone or two centerline holes located near one end of each half,as shown in the test specimen drawings of Figs. 5-8. Theeccentricity in applied force that would otherwise result isminimized by a doubler bonded to, or frictionally retainedagainst each grip en
47、d of the specimen, resulting in a forceline-of-action along the interface between the specimen halves,through the centerline of the hole(s).4.2.1.1 Unstabilized Configuration (No Support Fixture)The ends of the test specimen are gripped in the jaws of a testmachine and loaded in tension.4.2.1.2 Stab
48、ilized Configuration (Using Support Fixture)The test specimen is face-supported in a multi-piece boltedsupport fixture, similar to that shown in Fig. 9. The testspecimen/fixture assembly is clamped in hydraulic wedge gripsand the force is sheared into the support fixture and thensheared into the spe
49、cimen. The stabilized configuration isprimarily intended for compressive loading, although thespecimen/fixture assembly may be loaded in either tension orcompression.4.2.2 Both the applied force and the associated deformationof the hole(s) are monitored. The deformation of the hole(s) isnormalized by the hole diameter (a factor of two used to adjustFIG. 2 Double-Shear and One-Piece Single-Shear Test Specimen Drawing (Inch-Pound)D 5961/D 5961M 084for hole deformation occurring in the two halves) to result in aneff
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