1、Designation: D7136/D7136M 15Standard Test Method forMeasuring the Damage Resistance of a Fiber-ReinforcedPolymer Matrix Composite to a Drop-Weight Impact Event1This standard is issued under the fixed designation D7136/D7136M; the number immediately following the designation indicates theyear of orig
2、inal adoption or, in the 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 determines the damage resistance ofmultidirect
3、ional polymer matrix composite laminated platessubjected to a drop-weight impact event. The compositematerial forms are limited to continuous-fiber reinforced poly-mer matrix composites, with the range of acceptable testlaminates and thicknesses defined in 8.2.1.1.1 Instructions for modifying these
4、procedures to deter-mine damage resistance properties of sandwich constructionsare provided in Practice D7766/D7766M.1.2 A flat, rectangular composite plate is subjected to anout-of-plane, concentrated impact using a drop-weight devicewith a hemispherical impactor. The potential energy of thedrop-we
5、ight, as defined by the mass and drop height of theimpactor, is specified prior to test. Equipment and proceduresare provided for optional measurement of contact force andvelocity during the impact event. The damage resistance isquantified in terms of the resulting size and type of damage inthe spec
6、imen.1.3 The test method may be used to screen materials fordamage resistance, or to inflict damage into a specimen forsubsequent damage tolerance testing. When the impacted plateis tested in accordance with Test Method D7137/D7137M, theoverall test sequence is commonly referred to as the Compres-si
7、on After Impact (CAI) method. Quasi-static indentation perTest Method D6264/D6264M may be used as an alternatemethod of creating damage from an out-of-plane force andmeasuring damage resistance properties.1.4 The damage resistance properties generated by this testmethod are highly dependent upon sev
8、eral factors, whichinclude specimen geometry, layup, impactor geometry, impac-tor mass, impact force, impact energy, and boundary condi-tions. Thus, results are generally not scalable to otherconfigurations, and are particular to the combination of geo-metric and physical conditions tested.1.5 The v
9、alues 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 result in non-conformancewith the stand
10、ard.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 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 a
11、pplica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD883 Terminology Relating to PlasticsD3171 Test Methods for Constituent Content of CompositeMaterialsD3763
12、 Test Method for High Speed Puncture Properties ofPlastics Using Load and Displacement SensorsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsD5687/D5687M Guide for Preparation of Fl
13、at 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-Static Indentation ForceD7137/D7137M Test Method for Compressive ResidualStrength Properties of D
14、amaged Polymer Matrix Compos-ite PlatesD7766/D7766M Practice for Damage Resistance Testing of1This 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, 20
15、15. Published March 2015. Originallyapproved in 2005. Last previous edition approved in 2012 as D7136/D7136M - 12.DOI: 10.1520/D7136_D7136M-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards vo
16、lume 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 States1Sandwich ConstructionsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to
17、Methods of Mechanical TestingE18 Test Methods for Rockwell Hardness of Metallic Ma-terialsE122 Practice for Calculating Sample Size to Estimate, WithSpecified Precision, the Average for a Characteristic of aLot or ProcessE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 T
18、erminology Relating to Quality and StatisticsE1309 Guide for Identification of Fiber-ReinforcedPolymer-Matrix Composite Materials in DatabasesE1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in DatabasesE2533 Guide for Nondestructive Testing of Polymer MatrixCom
19、posites Used in Aerospace Applications2.2 Military Standards:CMH-17-3G Composite Materials Handbook, Volume3Polymer Matrix Composites Materials Usage, Designand Analysis3MIL-HDBK-728/1 Nondestructive Testing4MIL-HDBK-731A Nondestructive Testing Methods ofComposite MaterialsThermography4MIL-HDBK-732A
20、 Nondestructive Testing Methods ofComposite MaterialsAcoustic Emission4MIL-HDBK-733A Nondestructive Testing Methods ofComposite MaterialsRadiography4MIL-HDBK-787A Nondestructive Testing Methods ofComposite MaterialsUltrasonics4NASA Reference Publication 1092 Standard Tests forToughened Resin Composi
21、tes, Revised Edition, July198353. 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 stati
22、stics. In the event 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
23、 fundamental dimension 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 u
24、sed with square brackets, asthe symbols may have other definitions when used without thebrackets.3.2.2 dent depth, d L, nresidual depth of the depressionformed by an impactor after the impact event. The dent depthshall be defined as the maximum distance in a direction normalto the face of the specim
25、en from the lowest point in the dent tothe plane of the impacted surface that is undisturbed by thedent.3.2.3 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 acceptab
26、le range for the property.3.2.4 principal material coordinate system, na coordinatesystem with axes that are normal to the planes of symmetryinherent to a material.3.2.4.1 DiscussionCommon usage, at least for Cartesianaxes (123, xyz, and so forth), generally assigns the coordinatesystem axes to the
27、normal directions of planes 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
28、the total lack of symmetry, 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
29、“reference coordinate system.”3.2.5 recorded contact force, F MLT-2, nthe force ex-erted by the impactor on the specimen during the impact event,as recorded by a force indicator.3.2.6 reference coordinate system, na coordinate systemfor laminated composites used to define ply orientations. Oneof the
30、 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 referenced relative to the reference axis to define the plyorientation for that ply.3.2.7 striker tip, nthe portion or com
31、ponent of the impac-tor which comes into contact with the test specimen first duringthe impact event.3.3 Symbols:A = cross-sectional area of a specimenCE= specified ratio of impact energy to specimen thicknessCV = coefficient of variation statistic of a sample populationfor a given property (in perc
32、ent)D = damage diameter (see Fig. 11)d = dent depthE = potential energy of impactor prior to dropE1= absorbed energy at the time at which force versus timecurve has a discontinuity in force or slopeEa= energy absorbed by the specimen during the impacteventEi= actual impact energy (incident kinetic e
33、nergy)Emax= absorbed energy at the time of maximum recordedcontact force3Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,PA 15096-0001, http:/www.sae.org.4Available from U.S. Army Materials Technology Laboratory, Watertown, MA02471.5Available from National Aeronautics and Sp
34、ace Administration (NASA)-Langley Research Center, Hampton, VA 23681-2199.D7136/D7136M 152F = recorded contact forceF1= recorded contact force at which the force versus timecurve has a discontinuity in force or slopeFmax= maximum recorded contact forceg = acceleration due to gravityh = specimen thic
35、knessH = impactor drop heightl = specimen lengthm = impactor massmd= impactor mass for drop height calculationmdlbm= impactor mass in standard gravity for drop heightcalculationn = number of specimens per sample populationN = number of plies in laminate under testSn-1= standard deviation statistic o
36、f a sample population fora given propertyt = time during impactor drop and impact eventti= time of initial contacttT= contact duration (total duration of the impact event)w = specimen widthv = impactor velocityvi= impactor velocity at time of initial contact, tiW12= distance between leading edges of
37、 the two flag prongson velocity indicatorxi= 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 property = impactor displacement4. Summary of Test Method4.1 A drop-weight impact test is perfo
38、rmed using abalanced, symmetric laminated plate. Damage is impartedthrough out-of-plane, concentrated impact (perpendicular tothe plane of the laminated plate) using a drop weight with ahemispherical striker tip. The damage resistance is quantifiedin terms of the resulting size and type of damage in
39、 thespecimen. The damage response is a function of the testNOTE 1Clamp tip centered 0.25 in. from edge of cut-out.FIG. 1 Impact Support Fixture (Inch-Pound Version)NOTE 1Clamp tip centered 6 mm from edge of cut-out.FIG. 2 Impact Support Fixture (SI Version)D7136/D7136M 153configuration; comparisons
40、cannot be made between materialsunless identical test configurations, test conditions, and so forthare used.4.2 Optional procedures for recording impact velocity andapplied contact force versus time history data are provided.4.3 Preferred damage states resulting from the impact arelocated in the cen
41、ter of the plate, sufficiently far from the plateedges such that the local states of stress at the edges and at theimpact location do not interact during the damage formationevent.5. Significance and Use5.1 Susceptibility to damage from concentrated out-of-planeimpact forces is one of the major desi
42、gn concerns of manystructures made of advanced composite laminates. Knowledgeof the damage resistance properties of a laminated compositeplate is useful for product development and material selection.5.2 Drop-weight impact testing can serve the followingpurposes:5.2.1 To establish quantitatively the
43、 effects of stackingsequence, fiber surface treatment, variations in fiber volumeFIG. 3 Representative Rigid Base (Inch-Pound Version)FIG. 4 Representative Rigid Base (SI Version)D7136/D7136M 154fraction, and processing and environmental variables on thedamage resistance of a particular composite la
44、minate to aconcentrated drop-weight impact force or energy.5.2.2 To compare quantitatively the relative values of thedamage resistance parameters for composite materials withdifferent constituents. The damage response parameters canFIG. 5 Impact Device with Cylindrical Tube Impactor Guide MechanismF
45、IG. 6 Impact Device with Double Column Impactor Guide MechanismD7136/D7136M 155include dent depth, damage dimensions, and through-thicknesslocations, F1, Fmax, E1and Emax, as well as the force versustime curve.5.2.3 To impart damage in a specimen for subsequentdamage tolerance tests, such as Test Me
46、thod D7137/D7137M.FIG. 7 Drop-Weight Impact Test Specimen (Inch-Pound Version)FIG. 8 Drop-Weight Impact Test Specimen (SI Version)D7136/D7136M 1565.3 The properties obtained using this test method canprovide guidance in regard to the anticipated damage resistancecapability of composite structures of
47、 similar material,thickness, stacking sequence, and so forth. However, it must beunderstood that the damage resistance of a composite structureis highly dependent upon several factors including geometry,thickness, stiffness, mass, support conditions, and so forth.Significant differences in the relat
48、ionships between impactFIG. 9 Representative Impactor Force versus Time HistoryFIG. 10 Impactor Force versus Time History with Harmonic ResonanceD7136/D7136M 157force/energy and the resultant damage state can result due todifferences in these parameters. For example, properties ob-tained using this
49、test method would more likely reflect thedamage resistance characteristics of an unstiffened monolithicskin or web than that of a skin attached to substructure whichresists out-of-plane deformation. Similarly, test specimen prop-erties would be expected to be similar to those of a panel withequivalent length and width dimensions, in comparison tothose of a panel significantly larger than the test specimen,which tends to divert a greater proportion of the impact energyinto elastic deformation.5.4 The standard impactor geometry has a blunt, he
