1、Designation: D8066/D8066M 17Standard PracticeUnnotched Compression Testing of Polymer MatrixComposite Laminates1This standard is issued under the fixed designation D8066/D8066M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the y
2、ear 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 practice provides instructions for using the TestMethod D6484 open hole compression test fixture to determ
3、ineunnotched compressive strength of multi-directional laminates.The composite material forms are limited to continuous-fiberreinforced polymer matrix composites in which the laminate isboth symmetric and balanced with respect to the test direction.The range of acceptable test laminates and thicknes
4、ses aredescribed in 8.2.1.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may resu
5、lt in non-conformancewith the standard.1.2.1 Within the text the inch-pound units are shown inbrackets.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, heal
6、th and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Internati
7、onal Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:D695 Test Method for Compressive Properties of RigidPlasticsD792 Test Methods for Density and Specific Gravity (Rela-tive Density) o
8、f Plastics by DisplacementD883 Terminology Relating to PlasticsD3410/D3410M Test Method for Compressive Properties ofPolymer Matrix Composite Materials with UnsupportedGage Section by Shear LoadingD3171 Test Methods for Constituent Content of CompositeMaterialsD3878 Terminology for Composite Materia
9、lsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsD5467/D5467M Test Method for Compressive Properties ofUnidirectional Polymer Matrix Composite Materials Us-ing a Sandwich BeamD6484/D6484M Test Method for Open-Hole Compress
10、iveStrength of Polymer Matrix Composite LaminatesD6507 Practice for Fiber Reinforcement Orientation Codesfor Composite MaterialsD6641/D6641M Test Method for Compressive Properties ofPolymer Matrix Composite Materials Using a CombinedLoading Compression (CLC) Test FixtureD7249/D7249M Test Method for
11、Facing Properties of Sand-wich Constructions by Long Beam FlexureE6 Terminology Relating to Methods of Mechanical TestingE132 Test Method for Poissons Ratio at Room TemperatureE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and Statistics
12、3. Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto high-modulus fibers and their composites, as well as termsrelating to structural sandwich constructions. TerminologyD883 defines terms relating to plastics. Terminology E6 definesterms relating to mechanical testing. Terminology
13、 E456 andPractice E177 define terms relating to statistics. In the event ofa conflict between terms, Terminology D3878 shall haveprecedence over the other standards.3.2 Definitions of Terms Specific to This StandardNOTE 1If the term represents a physical quantity, its analyticaldimensions are stated
14、 immediately following the term (or letter symbol) infundamental dimension form, using the following ASTM Internationalstandard symbology for fundamental dimensions, shown within squarebrackets: M for mass, L for length, T for time, for thermodynamictemperature, and nd for non-dimensional quantities
15、. Use of these1This 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 Aug. 1, 2017. Published September 2017. DOI:10.1520/D8066_D8066M-17.Copyright ASTM Internat
16、ional, 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 established in the Decision on Principles for theDevelopment of International Standards, Gui
17、des and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1symbols is restricted to analytical dimensions when used with squarebrackets, as the symbols may have other definitions when used without thebrackets.3.2.1 nominal value, na value, existing in
18、 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.3.3 Symbols:Across-sectional area of a specimenByface-to-face percent bending in specimenCVsample coefficient of variati
19、on, in percentEclaminate compressive modulusFuncxultimate unnotched compressive strength in the testdirectionhspecimen thicknessPmaxmaximum force carried by test specimen prior tofailureP1load at x1P2load at x2wspecimen widthx1actual measured axial strain value nearest lower end ofstrain range usedx
20、2actual measured axial strain value nearest upper end ofstrain range usedy1actual measured transverse strain value nearest lowerend of strain range usedy2actual measured transverse strain value nearest upperend of strain range usedxg1indicated axial strain from Gage 1 (used in % bendingequation)xg2i
21、ndicated axial strain from Gage 2 (used in % bendingequation)vxycCompressive Poissons ratio4. Summary of Practice4.1 In accordance with Test Method D6484/D6484M, per-form a uniaxial compression test of a balanced, symmetriclaminate without a hole.5. Significance and Use5.1 This practice provides sup
22、plemental instructions for theuse of Test Method D6484/D6484M to determine unnotchedcompressive strength data for material specifications, researchand development, material design allowables, and qualityassurance. Factors that influence compressive strengths andshall therefore be reported include th
23、e following: material,methods of material fabrication, accuracy of lay-up, laminatestacking sequence and overall thickness, specimen preparation,specimen conditioning, environment of testing, specimenalignment and gripping, speed of testing, time at temperature,void content, and volume percent reinf
24、orcement. Compositeproperties in the test direction that may be obtained from thistest method include:5.1.1 Unnotched compressive (UNC) strength, Fxunc,5.1.2 Ultimate compressive strain,5.1.3 Compressive (linear or chord) modulus of elasticity,Ec, and5.1.4 Poissons ratio in compression.5.2 This prac
25、tice provides a compression test method forlaminates containing fibers in multiple fiber directions, particu-larly those combining axial (0 degree) fibers and off-axis (6 degree) fibers. Other compression strength test methods in-clude SACMA SRM-1 (also known as the modified D695),D3410/D3410M, D546
26、7/D5467M, D6641/D6641M, andD7249/D7249M. The SRM-1 test uses 12.6 mm 0.50 in. widespecimens, which is only appropriate for unidirectional tape,cross-ply 0/90ns tape, or small unit-cell-size fabrics (e.g.3K-70-P). Larger cell-size fabrics (e.g., spread-tow 12K fab-rics) should be tested with wider sp
27、ecimens. The standardD3410/D3410M and D6641/D6641M test fixtures do permitthe use of wider specimens, e.g., 25.4 mm 1.0 in. wide, andthus can be used to test laminates containing both axial andoff-axis fibers; however their gage lengths are relatively short.Test Method D5467/D5467M is intended to ob
28、tain the com-pressive strength of unidirectional laminates, but is expensivedue to the sandwich beam configuration. Test Method D7249/D7249M is intended to obtain the compressive strength ofsandwich facesheets.5.2.1 Advantages of this practice include:5.2.1.1 Avoiding the use of tabs, which are typi
29、cally re-quired with the end-loaded SRM-1 specimen, which are oftenrequired with the shear loaded Test Method D3410/D3410Mspecimen, and sometimes required with the Test MethodD6641/D6641M test specimen, in order to obtain valid failuremodes, and5.2.1.2 Longer and wider gage section imposing less con
30、-straint on in-plane transverse displacement.5.2.2 Disadvantages of this practice include:5.2.2.1 Longer and wider specimen, thus consuming morematerial than other standards noted above6. Interferences6.1 EnvironmentResults are affected by the environmentalconditions under which the tests are conduc
31、ted. Laminatestested in various environments can exhibit significant differ-ences in both failure force and failure mode. Experience hasdemonstrated that elevated temperature, humid environmentsare generally critical for compressive strength. However,critical environments must be assessed independen
32、tly for eachmaterial system and stacking sequence tested.6.2 Material OrthotropyThe degree of laminate orthot-ropy strongly affects the failure mode and measured strengths.Valid strength results should only be reported when appropriatefailure modes are observed, according to Section 12.6.3 Thickness
33、 ScalingThick composite structures do notnecessarily fail at the same strengths as thin structures with thesame laminate orientation (that is, strength does not alwaysscale linearly with thickness). Thus, data gathered using thetest method described in this practice may not translate directlyinto eq
34、uivalent thick-structure properties.6.4 Support FixtureResults are affected by the amount oflateral pressure applied to the test specimen by the supportfixture. Sources of variation in this lateral pressure includefixture grip surface, fixture bolt torque, hydraulic grippingD8066/D8066M 172pressure,
35、 and fixture shimming choices, and should be con-trolled and reported as required in Section 11, Procedure, andSection 14, Report. Testing unnotched specimens in the TestMethod D6484/D6484M support fixture is very sensitive tofixture gaps, tolerances, and alignment; the fixture can becomebent due to
36、 high unnotched compressive failure forces, there-fore the fixture dimensions should be periodically checked.The support fixture can inhibit the growth of delaminationdamage by inhibiting out-of-plane deformation, and by reliev-ing force from the specimen via friction effects.NOTE 2It has been found
37、 for at least one carbon tape material that thethermal-spray gripping surface on the Test Method D6484/D6484M testfixture (see Flagnote 2 in Test Method D6484/D6484M Figures 5 to 8) canlead to premature failures at the ends of the gripped areas, and that smoothgrip surfaces (no thermal spray) yield
38、superior strength results (1).26.5 Type of LoadingDifferences in force versus crossheaddisplacement and force versus extensometer strain responsemay be observed when comparing hydraulic grip-loaded speci-mens with end-loaded specimens. Hydraulic grip-loaded datatypically exhibit linear behavior at t
39、he onset of loading.At highforce levels, some nonlinear behavior may be observed due togrip slippage. End-loaded data typically display some initialnonlinear behavior at low force levels, due to seating of thespecimen/fixture assembly underneath the load platens, butthen exhibit linear behavior to f
40、ailure. The use of specimen endloading is not allowed by this standard for unnotched specimentesting, as it often leads to end brooming/crushing failures inunnotched compression specimens.7. Apparatus7.1 General ApparatusGeneral apparatus shall be in ac-cordance with Test Method D6484/D6484M.7.2 Str
41、ain-Indicating DeviceWhen required by the testrequestor, longitudinal strain shall be either a) simultaneouslymeasured using strain gages on opposite faces in the center ofthe specimen (so as to be within the support fixture opening) toallow for a correction as a result of any bending of thespecimen
42、, b) measured by use of edge mounted extensometers,or c) suitable non-contact strain measurement devices. WhenPoissons ratio is to be determined, the specimen shall be straingaged instrumented to measure strain in the lateral directionusing the same type of transducer. The same type of straintransdu
43、cer shall be used for all strain measurements on anysingle coupon.Attachment of the strain-indicating device to thecoupon shall not cause damage to the specimen surface. Referto Test Method D3410/D3410M for additional requirementsfor strain measurement on compression specimens.7.3 Data Acquisition E
44、quipmentEquipment capable ofrecording force and strain data is required.8. Sampling and Test Specimens8.1 Samplingshall be in accordance with Test MethodD6484/D6484M.8.2 Geometry:8.2.1 Stacking SequenceThe standard laminates shallhave multidirectional fiber orientations (fibers shall be orientedin a
45、 minimum of two directions) and balanced and symmetricstacking sequences. Nominal thickness shall be 4 mm0.160 in., with a permissible range of 3 to 5 mm 0.125 to0.200 in., inclusive. Fabric laminates containing satin-typeweaves shall have symmetric warp surfaces, unless otherwisespecified and noted
46、 in the report.NOTE 3Typically, a 45i/45i/0j/90kns tape or 45i/0jns fabriclaminate should be selected such that a minimum of 5 % of the fibers layin each of the four principal orientations. This laminate design has beenfound to yield the highest likelihood of acceptable failure modes. Notethat testi
47、ng 0i/90jns tape or fabric laminates can result in acceptablefailure modes (see also Section 5). Consult Practice D6507 for informa-tion on fiber orientation codes.8.2.2 Specimen ConfigurationThe test specimen configu-ration shall be in accordance with Test Method D6484/D6484M. No hole, notch or dam
48、age shall be introduced intothe specimen.8.3 Specimen PreparationSpecimens shall be prepared ingeneral accordance with Test Method D6484/D6484M, withthe omission of the hole.9. Calibration9.1 The accuracy of all measuring equipment shall havecertified calibrations that are current at the time of use
49、 of theequipment.10. Conditioning10.1 The recommended pre-test condition is effective mois-ture equilibrium at a specific relative humidity as establishedby Test Method D5229/D5229M; however, if the test requestordoes not explicitly specify a pre-test conditioning environment,no conditioning is required and the test specimens may betested as prepared.10.2 The pre-test specimen conditioning process, to includespecified environmental exposure levels and resulting moisturecontent, shall be reported with the test d
