ASTM D7137 D7137M-17 Standard Test Method for Compressive Residual Strength Properties of Damaged Polymer Matrix Composite Plates.pdf

1、Designation: D7137/D7137M 17Standard Test Method forCompressive Residual Strength Properties of DamagedPolymer Matrix Composite Plates1This standard is issued under the fixed designation D7137/D7137M; the number immediately following the designation indicates theyear of original adoption or, in the

2、case of revision, the year 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 compression residual strengthproperties of multidirectional poly

3、mer matrix composite lami-nated plates, which have been subjected to quasi-static inden-tation per Test Method D6264/D6264M or drop-weight impactper Test Method D7136/D7136M prior to application ofcompressive force. The composite material forms are limited tocontinuous-fiber reinforced polymer matri

4、x composites withmultidirectional fiber orientations, and which are both symmet-ric and balanced with respect to the test direction. The range ofacceptable test laminates and thicknesses is defined in 8.2.NOTE 1When used to determine the residual strength of drop-weightimpacted plates, this test met

5、hod is commonly referred to as theCompression After Impact, or CAI, method.1.2 The method utilizes a flat, rectangular composite plate,previously subjected to a damaging event, which is testedunder compressive loading using a stabilization fixture.NOTE 2The damage tolerance properties obtained are p

6、articular to thetype, geometry and location of damage inflicted upon the plate.1.3 The properties generated by this test method are highlydependent upon several factors, which include specimengeometry, layup, damage type, damage size, damage location,and boundary conditions. Thus, results are genera

7、lly notscalable to other configurations, and are particular to thecombination of geometric and physical conditions tested.1.4 This test method can be used to test undamaged polymermatrix composite plates, but historically such tests havedemonstrated a relatively high incidence of undesirable failure

8、modes (such as end crushing). Test Method D6641/D6641M isrecommended for obtaining compressive properties of undam-aged polymer matrix composites.1.5 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 eq

9、uivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.5.1 Within the text the inch-pound units are shown inbrackets.1.6 This standard does not purport to address all of thesafety concerns, if a

10、ny, 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.1.7 This international standard was developed in accor-dance with internatio

11、nally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D792 Test

12、Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD883 Terminology Relating to PlasticsD3171 Test Methods for Constituent Content of CompositeMaterialsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equili

13、brium Conditioning of Polymer MatrixComposite MaterialsD5687/D5687M Guide for Preparation of Flat CompositePanels with Processing Guidelines for Specimen Prepara-tionD6264/D6264M Test Method for Measuring the DamageResistance of a Fiber-Reinforced Polymer-Matrix Com-posite to a Concentrated Quasi-St

14、atic Indentation ForceD6641/D6641M Test Method for Compressive Properties ofPolymer Matrix Composite Materials Using a CombinedLoading Compression (CLC) Test Fixture1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommitte

15、e D30.05 onStructural Test Methods.Current edition approved Oct. 15, 2017. Published October 2017. Originallyapproved in 2005. Last previous edition approved in 2012 as D7137/D7137M-12.DOI: 10.1520/D7137_D7137M-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM C

16、ustomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was de

17、veloped in accordance with internationally recognized principles on standardization established 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.1D7136/D7136M Tes

18、t Method for Measuring the DamageResistance of a Fiber-Reinforced Polymer Matrix Com-posite to a Drop-Weight Impact EventE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE122 Practice for Calculating Sample Size to Estimate, WithSpecified

19、 Precision, the Average for a Characteristic of aLot or ProcessE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and Statistics2.2 Military Standards:NASA Reference Publication 1092 Standard Tests forToughened Resin Composites, Revised Edit

20、ion, July198333. Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto composite materials. Terminology D883 defines termsrelating to plastics. Terminology E6 defines terms relating tomechanical testing. Terminology E456 and Practice E177define terms relating to statistics. In the eve

21、nt of a conflictbetween terms, Terminology D3878 shall have precedenceover the other standards.3.2 Definitions of Terms Specific to This Standard:3.2.1 If the term represents a physical quantity, its analyticaldimensions are stated immediately following the term (or lettersymbol) in fundamental dime

22、nsion form, using the followingASTM standard symbology for fundamental dimensions,shown within square brackets: M for mass, L for length, Tfor time, for thermodynamic temperature, and nd fornon-dimensional quantities. Use of these symbols is restrictedto analytical dimensions when used with square b

23、rackets, asthe symbols may have other definitions when used without thebrackets.3.2.2 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 propert

24、y.3.2.3 principal material coordinate system, na coordinatesystem with axes that are normal to the planes of symmetryinherent to a material.3.2.3.1 DiscussionCommon usage, at least for Cartesianaxes (123, xyz, and so forth), generally assigns the coordinatesystem axes to the normal directions of pla

25、nes of symmetry 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 symmet

26、ry, while, 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 sy

27、stem.”3.2.4 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 lamin

28、ateis referenced relative to the reference axis to define the plyorientation for that ply.3.2.5 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 symme

29、tric laminate of the 0i/90jnsfamily as viewed from the reference 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

30、property (in percent)D = damage diameterECAI= effective compressive modulus in the test directionFCAI= ultimate compressive residual strength in the testdirectionh = specimen thicknessl = specimen lengthn = number of specimens per sample populationN = number of plies in laminate under testPmax= maxi

31、mum force carried by test specimen prior tofailureSn-1= 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 sample popu-lation for

32、 a given property4. Summary of Test Method4.1 A uniaxial compression test is performed using abalanced, symmetric laminated plate, which has been damagedand inspected prior to the application of compressive force.The damage state is imparted through out-of-plane loadingcaused by quasi-static indenta

33、tion or drop-weight impact.4.1.1 Quasi-Static IndentationThe rectangular plate isdamaged due to application of an out-of-plane static indenta-tion force in accordance with Test Method D6264/D6264M.4.1.2 Drop-Weight ImpactThe rectangular plate is dam-aged due to application of an out-of-plane drop-we

34、ight impactin accordance with Test Method D7136/D7136M.4.2 The damaged plate is installed in a multi-piece supportfixture, that has been aligned to minimize loading eccentricitiesand induced specimen bending. The specimen/fixture assemblyis placed between flat platens and end-loaded under compres-si

35、ve force until failure. Applied force, crosshead displacement,and strain data are recorded while loading.4.3 Preferred failure modes pass through the damage in thetest specimen. However, acceptable failures may initiate awayfrom the damage site, in instances when the damage producesa relatively low

36、stress concentration or if the extent of damage3Available from National Aeronautics and Space Administration (NASA)-Langley Research Center, Hampton, VA 23681-2199.D7137/D7137M 172is small, or both. Unacceptable failure modes are those related to load introduction by the support fixture, local edge

37、supportFIG. 1 Schematic of Compressive Residual Strength Support Fixture with Specimen in PlaceFIG. 2 Support Fixture AssemblyD7137/D7137M 173conditions, and specimen instability (unless the specimen isdimensionally representative of a particular structural applica-tion).5. Significance and Use5.1 S

38、usceptibility to damage from concentrated out-of-planeforces is one of the major design concerns of many structuresmade of advanced composite laminates. Knowledge of thedamage resistance and damage tolerance properties of alaminated composite plate is useful for product developmentand material selec

39、tion.5.2 The residual strength data obtained using this testmethod is most commonly used in material specifications andresearch and development activities. The data are not intendedfor use in establishing design allowables, as the results arespecific to the geometry and physical conditions tested an

40、d aregenerally not scalable to other configurations. Its usefulness inestablishing quality assurance requirements is also limited, dueto the inherent variability of induced damage, as well as thedependency of damage tolerance response upon the pre-existent damage state.5.3 The properties obtained us

41、ing this test method canprovide guidance in regard to the anticipated damage tolerancecapability of composite structures of similar material,thickness, stacking sequence, and so forth. However, it must beunderstood that the damage tolerance of a composite structureis highly dependent upon several fa

42、ctors including geometry,stiffness, support conditions, and so forth. Significant differ-ences in the relationships between the existent damage stateand the residual compressive strength can result due todifferences in these parameters. For example, residual strengthand stiffness properties obtained

43、 using this test method wouldFIG. 3 Support Fixture Base Plate (Inch-Pound Version)FIG. 4 Support Fixture Base Plate (SI Version)D7137/D7137M 174FIG. 5 Support Fixture Angles (Inch-Pound Version)FIG. 6 Support Fixture Angles (SI Version)D7137/D7137M 175more likely reflect the damage tolerance charac

44、teristics of anun-stiffened monolithic skin or web than that of a skin attachedto substructure which resists out-of-plane deformation.Similarly, test specimen properties would be expected to beFIG. 7 Support Fixture Side Plates and Base Slideplates (Inch-Pound Version)FIG. 8 Support Fixture Side Pla

45、tes and Base Slideplates (SI Version)D7137/D7137M 176similar to those of a panel with equivalent length and widthdimensions, in comparison to those of a panel significantlylarger than the test specimen.5.4 The reporting section requires items that tend to influ-ence residual compressive strength to

46、be reported; theseinclude the following: material, methods of materialfabrication, accuracy of lay-up orientation, laminate stackingsequence and overall thickness, specimen geometry, specimenpreparation, specimen conditioning, environment of testing,void content, volume percent reinforcement, type,

47、size andlocation of damage (including method of non-destructiveinspection), specimen/fixture alignment and gripping, time attemperature, and speed of testing.5.5 Properties that result from the residual strength assess-ment include the following: compressive residual strengthFCAI, compressive force

48、as a function of crossheaddisplacement, and surface strains as functions of crossheaddisplacement.6. Interferences6.1 The response of a damaged specimen is dependent uponmany factors, such as laminate thickness, ply thickness, stack-ing sequence, environment, damage type, damage geometry,damage loca

49、tion, and loading/support conditions.Consequently, comparisons cannot be made between materialsunless identical test configurations, test conditions, and lami-nate configurations are used. Therefore, all deviations from thestandard test configuration shall be reported in the results.Specific structural configurations and boundary conditionsmust be considered when applying the data generated usingthis test method to design applications.6.2 Material and Specimen PreparationPoor material fab-rication practices, lack of control of fiber alignment, anddama