1、Designation: D 7332/D 7332M 07Standard Test Method forMeasuring the Fastener Pull-Through Resistance of aFiber-Reinforced Polymer Matrix Composite1This standard is issued under the fixed designation D 7332/D 7332M; the number immediately following the designation indicates theyear of original adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method determines the fastener pull-throughresistance of multid
3、irectional polymer matrix composites rein-forced by high-modulus fibers. Fastener pull-through resis-tance is characterized by the force-versus-displacement re-sponse exhibited when a mechanical fastener is pulled througha composite plate, with the force applied perpendicular to theplane of the plat
4、e. The composite material forms are limited tocontinuous-fiber or discontinuous-fiber (tape or fabric, or both)reinforced composites for which the laminate is symmetric andbalanced with respect to the test direction. The range ofacceptable test laminates and thicknesses is defined in 8.2.1.2 Two tes
5、t procedures and configurations are provided.The first, Procedure A, is suitable for screening and fastenerdevelopment purposes. The second, Procedure B, isconfiguration-dependent and is suitable for establishing designvalues. Both procedures can be used to perform comparativeevaluations of candidat
6、e fasteners/fastener system designs.1.3 The specimens described herein may not be representa-tive of actual joints which may contain one or more free edgesadjacent to the fastener, or may contain multiple fasteners thatcan change the actual boundary conditions.1.4 This test method is consistent with
7、 the recommendationsof CMH-17, which describes the desirable attributes of afastener pull-through test method.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. Within the text theinch-pound units are shown in brackets. The values stated ineach sys
8、tem are not exact equivalents; therefore, each systemmust be used independently of the other. Combining valuesfrom the two systems may result in nonconformance with thestandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsi
9、bility 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 and Specific Gravity (Rela-tive Density) of Plastics by Displace
10、mentD 883 Terminology Relating to PlasticsD 3171 Test Methods for 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
11、Test Method for Moisture AbsorptionProperties and Equilibrium Conditioning of Polymer Ma-trix Composite MaterialsD 5687/D 5687M Guide for Preparation of Flat CompositePanels with Processing Guidelines for Specimen Prepara-tionE4 Practices for Force Verification of Testing MachinesE6 Terminology Rela
12、ting to Methods of Mechanical Test-ingE18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of Metallic MaterialsE 122 Practice for Calculating Sample Size to Estimate,With a Specified Tolerable Error, the Average for aCharacteristic of a Lot or ProcessE 177 Practice for Use of the
13、 Terms Precision and Bias inASTM Test MethodsE 456 Terminology Relating to Quality and StatisticsE 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 Databases2.2 I
14、ndustry Documents:1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.05 onStructural Test Methods.Current edition approved March 15, 2007. Published April 2007.2For referenced ASTM standards, visit the ASTM web
15、site, 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, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Sta
16、tes.CMH-17-1F Composite Materials Handbook, Volume1Polymer Matrix Composites Guidelines for Character-ization of Structural Materials33. Terminology3.1 DefinitionsTerminology D 3878 defines terms relatingto composite materials. Terminology D 883 defines termsrelating to plastics. Terminology E6defin
17、es terms relating tomechanical testing. Terminology E 456 and Practice E 177define terms relating to statistics. In the event of a conflictbetween terms, Terminology D 3878 shall have precedenceover the other standards.NOTE 1If the term represents a physical quantity, its analyticaldimensions are st
18、ated 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, u for thermodynamic temperature,and nd for non-dimensional quantities. Use
19、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 diameter-to-thickness ratio, D/h nd, nthe ratio ofthe hole diameter to the specimen
20、thickness.3.2.1.1 DiscussionThe diameter-to-thickness ratio may beeither a nominal value determined from nominal dimensions oran actual value determined from measured dimensions.3.2.2 failure force, nthe maximum force magnitudeachieved prior to the first significant (greater than 10 %) dropin applie
21、d force, as observed in force versus displacement data.3.2.3 initial sub-critical failure, ndiscontinuity observedin force versus displacement data prior to attaining the failureforce. Sub-critical failures are characterized by minor (lessthan 10 %) drops in applied force, or by compliance changes(g
22、reater than 10 % change in slope), prior to attaining thefailure force.3.2.4 nominal value, na value, existing in name only,assigned to a measurable property for the purpose of conve-nient designation. Tolerances may be applied to a nominalvalue to define an acceptable range for the property.3.2.5 p
23、rincipal material coordinate system, na coordinatesystem with axes that are normal to the planes of symmetryinherent to a material.3.2.5.1 DiscussionCommon usage, at least for Cartesianaxes (123, xyz, and so forth), generally assigns the coordinatesystem axes to the normal directions of planes of sy
24、mmetry inorder that the highest property value in a normal direction (forelastic properties, the axis of greatest stiffness) would be 1 orx, and the lowest (if applicable) would be 3 or z. Anisotropicmaterials do not have a principal material coordinate systemdue to the total lack of symmetry, while
25、, for isotropic materials,any coordinate system is a principal material coordinatesystem. In laminated composites, the principal material coor-dinate system has meaning only with respect to an individualorthotropic lamina. The related term for laminated compositesis “reference coordinate system.”3.2
26、.6 reference coordinate system, na coordinate systemfor laminated composites used to define ply orientations. Oneof the reference coordinate system axes (normally the Carte-sian x-axis) is designated the reference axis, assigned aposition, and the ply principal axis of each ply in the laminateis ref
27、erenced relative to the reference axis to define the plyorientation for that ply.3.2.7 rupture, nseparation of the fastener and test lami-nate, caused by failure of the fastener, the composite plate, orboth. Rupture is characterized by an extreme force drop, suchthat the specimen is incapable of car
28、rying significant appliedforce.3.2.8 specially orthotropic, adja description of an ortho-tropic material as viewed in its principal material coordinatesystem. In laminated composites, a specially orthotropic lami-nate is a balanced and symmetric laminate of the 0i/90jnsfamily as viewed from the refe
29、rence coordinate system, suchthat the membrane-bending coupling terms of the laminateconstitutive relation are zero.3.3 Symbols:A = cross-sectional area of a specimenCV = coefficient of variation statistic of a sample populationfor a given property (in percent)d = fastener or pin shank diameterdcsk=
30、 countersink depthD = specimen hole diameterh = specimen thicknessl = specimen lengthn = number of specimens per sample populationN = number of plies in laminate under testPf= failure forcePi= force carried by test specimen at initial failurePm= maximum force carried by test specimen during testsn-1
31、= standard deviation 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 samplepopulation for a given propertydi= displacement at initial failuredr=
32、displacement at rupture4. Summary of Test Method4.1 Procedure A, Compressive-Loaded Fixture:4.1.1 Two flat square, constant rectangular cross-sectioncomposite plates, each containing a centrally located fastenerhole, are placed in a multi- piece fixture that has been alignedto minimize loading eccen
33、tricities. Each plate contains fouradditional holes on the periphery to accommodate the testfixture components. The two plates are joined together by thefastener, with one plate being rotated 45 with respect to thesecond plate.4.1.2 The plates are pried apart by the application ofcompressive force t
34、ransmitted through the fixture, producing atensile loading through the fastener and a compressive loadingthrough the composite plates. Force is applied until failure ofthe composite specimen, the fastener, or both occurs. Appliedforce and crosshead displacement are recorded while loading.3Available
35、from U.S. Army Research Laboratory, Materials Directorate, Aber-deen Proving Ground, MD 21001.D 7332/D 7332M 0724.2 Procedure B, Tensile-Loaded Fixture:4.2.1 A flat square, constant rectangular cross-section com-posite plate containing a centrally located fastener hole isplaced in a multi-piece fixt
36、ure that has been aligned tominimize loading eccentricities. The plate is joined by thefastener to a yoke, which is designed to rotate as to avoidimparting a moment to the fastener.4.2.2 A uniaxial tensile force is applied to the yoke, impart-ing a tensile loading on the fastener and an out-of-plane
37、compressive loading on the composite plate. Force is applieduntil failure of the composite specimen, the fastener, or bothoccurs. Applied force and crosshead displacement are recordedwhile loading.4.3 For both procedures, preferred failure modes are thoseassociated with failure of the composite at t
38、he fastener hole.Unacceptable failure modes include those associated with thefastener (such as head, shank or thread failure) or failure of thecomposite away from the fastener hole.5. Significance and Use5.1 This test method is designed to produce fastener pull-through resistance data for structural
39、 design allowables, re-search and development. The procedures may be used to assesspull-through resistance for a variety of composite laminatethicknesses, fastener diameters, and fastener head styles. How-ever, the flexibility of test parameters allowed by the variantsmakes meaningful comparison bet
40、ween datasets difficult if thedatasets were not generated using identical test parameters.5.2 Early composite pull-through tests using fasteners com-mon to metal structures led to premature joint failures, andresulted in the development of fasteners specific for compositeapplications. These fastener
41、s have larger heads and tails toreduce through-thickness compression stresses on the compos-ite laminate.5.3 General factors that influence the mechanical responseof composite laminates and should therefore be reportedinclude the following: material, methods of material prepara-tion and lay-up, spec
42、imen stacking sequence, specimen prepa-ration, specimen conditioning, environment of testing, speci-men alignment, speed of testing, time at temperature, voidcontent, and volume percent reinforcement.5.4 Specific factors that influence the pull-through resis-tance of composite laminates and should t
43、herefore be reportedinclude the following: hole diameter, fastener diameter, fas-tener head diameter, loading bar spacing to fastener holediameter ratio (Procedure A), clearance hole diameter tofastener hole diameter ratio (Procedure B), diameter to thick-ness ratio, fastener torque, fastener or pin
44、 material, fastener orpin clearance, countersink angle and depth of countersink, typeof grommet (if used), and type of support fixture. Fastenerpull-through resistance properties which may be determinedfrom this test method include initial sub-critical failure force/displacement, failure force, maxi
45、mum force, and rupture dis-placement.6. Interferences6.1 Material and Specimen PreparationPoor materialfabrication practices, lack of control of fiber alignment, anddamage induced by improper specimen machining are knowncauses of high material data scatter in composites in general.Important aspects
46、of specimen preparation that contribute todata scatter include thickness variation, out-of-plane curvature,surface roughness, and failure to meet the dimensional toler-ances specified in 8.2.2.6.2 Hole PreparationBecause of the dominating presenceof the filled hole, results from this test method are
47、 relativelyinsensitive to parameters that would be of concern in anunnotched tensile, compressive or flexural property test. How-ever, since the filled hole dominates the strength, consistentpreparation of the hole, without damage to the laminate, isimportant to meaningful results. Damage caused by
48、holepreparation will affect strength results and can reduce thecalculated strength.6.3 Fastener Head Style and CountersinkResults areaffected by the head style of the fastener utilized. In general,specimens containing protruding head fasteners exhibit thehighest pull-through resistance forces, follo
49、wed by (in order ofdecreasing pull-through resistance forces) 100 tension headfasteners, 100 shear head fasteners, and 130 shear headfasteners. Results may also be affected by the ratio of counter-sunk (flush) head depth to thickness; the preferred ratio is therange from 0.0 to 0.7 unless the experiment is investigating theinfluence of this ratio.6.4 Fastener-Hole ClearanceResults are affected by theclearance arising from the difference between hole and fastenerdiameters. Excess clearance can change the observed specimenbehavior by promoting the onset
