1、Designation: D 6264 98 (Reapproved 2004)Standard Test Method forMeasuring Damage Resistance of Fiber-Reinforced Polymer-Matrix Composite to Concentrated Quasi-Static IndentationForce1This standard is issued under the fixed designation D 6264; the number immediately following the designation indicate
2、s the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 A quasi-static indentation (QSI) test method
3、is used toobtain quantitative measurements of the damage resistance ofa continuous-fiber-reinforced composite material to a concen-trated indentation force (Fig. 1). The indentation force isapplied to the specimen by slowly pressing a hemisphericalindenter into the surface. Procedures are specified
4、for deter-mining the damage resistance for a simply supported testspecimen and for a rigidly backed test specimen. The damageresistance is quantified in terms of a critical contact forceassociated with a single event or sequence of events to cause aspecific size and type of damage in the specimen. T
5、hese testsmay be used to screen materials for damage resistance or toinflict damage into a specimen for subsequent damage toler-ance testing. This test method is limited to use with compositesconsisting of layers of unidirectional fibers or layers of fabric.This test method may prove useful for othe
6、r types and classesof composite materials. Certain interferences, however, havebeen noted (see 6.7).1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are provided forinformation purposes only.1.3 This standard does not purport to address all of thesafet
7、y 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 883 Terminology Relating to Pla
8、sticsD 2734 Test Methods for Void Content of Reinforced Plas-ticsD 3171 Test Method for Constituent Content of CompositeMaterialsD 3878 Terminology for Composite MaterialsD 5229/D5229M Test Method for Moisture AbsorptionProperties and Equilibrium Conditioning of Polymer Ma-trix Composite MaterialsD
9、5687/D5687M Guide for Preparation of Flat CompositePanels With Processing Guidelines for Specimen Prepara-tionE 4 Practices for Force Verification of Testing MachinesE 6 Terminology Relating to Methods of Mechanical Test-ingE 18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of
10、Metallic MaterialsE 122 Practice for Calculating Sample Size to Estimate,With a Specified Tolerable Error, the Average for aCharacteristic of a Lot or Process3. Terminology3.1 DefinitionsTerminology D 3878 defines terms relatingto high-modulus fibers and their composites. TerminologyD 883 defines te
11、rms relating to plastics. Terminology E 6defines terms relating to mechanical testing. In the event of a1This standard is under the jurisdiction of ASTM Committee D30 on CompositeMaterials and is the direct responsibility of Subcommittee D30.05 on Structural TestMethods.Current edition approved Mar.
12、 1, 2004. Published March 2004. Originallyapproved in 1998. Last previous edition approved in 1998 as D 6264 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the
13、standards Document Summary page onthe ASTM website.FIG. 1 Quasi-Static Indentation Test1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.conflict between terms, Terminology D 3878 shall have prece-dence over the other standards.3.2 Def
14、initions of Terms Specific to This StandardTheterms in this test method may conflict with general usage.There is not yet an established consensus concerning the use ofthese terms. The following descriptions are intended only foruse in this test method.NOTE 1If the term represents a physical quantity
15、, 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: M formass, L for length, T for time, u for thermodynamic temperature, andnd for
16、nondimensional quantities. Use of these symbols is restricted toanalytical dimensions when used with square brackets, as the symbolsmay have other definitions when used without the brackets.3.2.1 contact force, F MLT2,nthe total force appliednormal to the face of the specimen by the indenter.3.2.2 d
17、amage, nin structures and structural materials,astructural anomaly in a material or structure created bymanufacturing or service usage.3.2.3 damage resistance, nin structures and structuralmaterials, a measure of the relationship between the force,energy, or other parameter(s) associated with an eve
18、nt orsequence of events and the resulting damage size and type.3.2.4 dent depth, d L,nresidual depth of the depressionformed by an indenter after removal of load. The dent depthshall be defined as the maximum distance in a direction normalto the face of the specimen from the lowest point in the dent
19、 tothe plane of the indented surface that is undisturbed by thedent.3.2.5 F1force, F1 MLT2,ncontact force at which theforce/indenter displacement curve has a discontinuity in forceor slope.3.2.6 indenter displacement, d L,nthe displacement ofthe indenter relative to the specimen support.3.2.7 maximu
20、m force, FmaxMLT2,nthe maximumcontact force a laminate will resist. This force is obtained fromthe F/d curve after a point is reached where the contact forcedoes not increase with increasing indenter displacement.3.3 Symbols:d = dent depth (see 3.2.4).F = contact force (see 3.2.1).F1= F1force (see 3
21、.2.5).Fmax= maximum force (see 3.2.7).N = number of ply groups in a laminates stackingsequence.d = indenter displacement (see 3.2.6).4. Summary of Test Method4.1 The quasi-static indentation (QSI) test is used to mea-sure the damage resistance of a uniform-thickness laminatedcomposite specimen. An i
22、ndentation force is applied slowly bypressing a displacement-controlled hemispherical indenter intothe face of the specimen. The displacement is increased untilthe desired damage state is reached. Procedures are specifiedfor determining the damage resistance for a simply supportedtest specimen and f
23、or a rigidly backed test specimen. Thedamage response is a function of the test configuration.4.2 A record of the applied contact force/indenter displace-ment (F/d) is recorded on either an X-Y recorder, an equivalentreal-time plotting device, or stored digitally and postprocessed.5. Significance an
24、d Use5.1 Susceptibility to damage from concentrated indentationforces is one of the major weaknesses of many structures madeof advanced laminated composites. Knowledge of the damageresistance of a laminated composite material subjected to aconcentrated indentation force is useful for product develop
25、-ment and material selection.5.2 The QSI test method can serve the following purposes:5.2.1 To establish quantitatively the effects of stackingsequence, fiber surface treatment, variations in fiber volumefraction, and processing and environmental variables on thedamage resistance of a particular com
26、posite laminate to aconcentrated quasi-static indentation force.5.2.2 To compare quantitatively the relative values of thedamage resistance parameters for composite materials withdifferent constituents. The damage response parameters included, F1, and Fmax, as well as the F/d curve.5.2.3 To place a
27、controlled amount of damage in a specimenfor subsequent damage tolerance tests.5.2.4 To isolate and measure the indentation response of thespecimen without bending (rigidly backed configuration).6. Interferences6.1 The QSI test simulates the force/displacement relation-ships of many impacts governed
28、 by boundary conditions(1-7).3These are typically relatively large-mass low-velocityhard-body impacts on plates with a relatively small unsup-ported region. This test method does not address wave propa-gation and vibrations in the specimen, time-dependent materialbehavior, or inertia-dominated impac
29、t events.6.2 The damage response of a specimen is dependent onmany factors, including the indenter geometry and specimensupport conditions. Consequently, comparisons cannot bemade between materials unless identical test configurations,identical test conditions, and identical laminates are used.There
30、fore, all deviations from the standard test configurationshould be reported in the results.6.3 Force F1does not represent the initiation of damage, butgenerally represents when the displacement of the indenter isaffected by large-scale damage formation. Typically, matrixcracks and small delamination
31、s form before this force.6.4 The dent depth may “relax” or reduce with time or uponexposure to different environmental conditions.6.5 Treatment and interpretation of delamination growth arebeyond the scope of this test method.6.6 Material and Specimen PreparationPoor materialfabrication practices, l
32、ack of control of fiber alignment, anddamage induced by improper coupon machining are knowncauses of high material data scatter in composites.6.7 Application to Other Materials, Lay-Ups, and Architec-tures:3The boldface numbers in parentheses refer to the list of references at the end ofthis standar
33、d.D 6264 98 (2004)26.7.1 The QSI test primarily has been used for testingcarbon-fiber-reinforced tape and fabric laminates with polymermatrices. For other materials, a quite different response mayoccur.6.7.2 Nonlaminated, 3D fiber-reinforced, or textile compos-ites may fail by different mechanisms t
34、han laminates. The mostcritical damage may be in the form of matrix cracking or fiberfailure, or both, rather than delaminations.7. Apparatus7.1 Testing MachineThe testing machine shall be inconformance with Practices E 4 and shall satisfy the followingrequirements:7.1.1 Testing Machine HeadsThe tes
35、ting machine shallhave both an essentially stationary head and a movable head.7.1.2 Drive MechanismThe testing machine drive mecha-nism shall be capable of imparting to the movable head acontrolled velocity with respect to the stationary head. Thevelocity of the movable head shall be capable of bein
36、gregulated as specified in 11.6.7.1.3 Load IndicatorThe testing machine load-sensingdevice shall be capable of indicating the total load beingcarried by the test specimen. This device essentially shall befree from inertia lag at the specified rate of testing and shallindicate the load with an accura
37、cy over the load range(s) ofinterest of within 61 % of the indicated value.7.1.4 GripsThe top head of the testing machine shallcarry a grip to hold the indenter such that the direction of loadapplied to the specimen is coincident with the axis of travel.The grip shall apply sufficient pressure to pr
38、event slippage ofthe indenter. The lower head shall have a means of attaching aflat rigid support.7.2 Flat Rigid SupportA flat rigid surface shall be at-tached to the lower head and used to support the specimen ortest fixture. The support surface shall be normal to the axis oftravel of the testing m
39、achine head and have a large enoughsurface to support completely the specimen or test fixture. Aconvenient means of providing this surface is through the useof a metal “T” in which the lower part of the “T” is clampedin the lower grips and the top part of the “T” provides thesupport surface. If the
40、rigidly backed configuration is to beused, this support shall be made from steel with a minimumthickness of 12.7 mm (0.5 in.).7.3 IndenterThe indenter shall have a smooth hemispheri-cal tip with a diameter of 12.7 6 0.1 mm (0.500 6 0.003 in.)and a hardness of 60 to 62 HRC as specified in Test Method
41、sE 18. If a different indenter is used as part of the testing, theshape and dimensions shall be noted.7.4 Indenter Displacement IndicatorThe axial displace-ment of the indenter relative to the support fixture may beestimated as the crosshead travel, provided the deformation ofthe testing machine and
42、 support fixture is less than 2 % of thecrosshead travel. If not, the indenter displacement shall beobtained from a properly calibrated external gage or transducerlocated between the indenter and the support fixture or the rigidsupport surface. The displacement indicator shall indicate thedisplaceme
43、nt with an accuracy of 61 % of the thickness of thespecimen.7.5 Load Versus Indenter Displacement (F Versus d)RecordAn X-Y plotter, or similar device, shall be used tomake a permanent record during the test of load versus indenterdisplacement. Alternatively, the data may be stored digitallyand postp
44、rocessed.7.6 Specimen SupportThe damage resistance may bedetermined for a specimen that is simply supported or rigidlybacked. For both configurations, the specimens face shall beheld normal to the axis of the indenter.7.6.1 Simply Supported ConfigurationThe fixture shallconsist of a single plate wit
45、h a 127.0 6 2.5 mm (5.00 6 0.10in.) diameter opening made from a structural metal such asaluminum or steel. The top rim of the opening shall be roundedwith a radius of 0.75 6 0.25 mm (0.03 6 0.01 in.). The plateshall be sufficiently large to support the entire lower surface ofthe specimen, excluding
46、 the circular opening. The thickness ofthe plate shall be a minimum of 25 mm (1.0 in.) and greaterthan the expected maximum indenter displacement. A typicalsupport fixture is shown in Fig. 2.7.6.2 Rigidly Backed ConfigurationThe specimen shall beplaced directly on the flat rigid support that is moun
47、ted in thelower head of the testing machine. For this configuration, thesupport shall be made from steel with a minimum thickness of12.7 mm (0.5 in.).7.7 MicrometersThe micrometer(s) shall use a suitablesize diameter ball-interface on irregular surfaces such as thebag-side of a laminate, and a flat
48、anvil interface on machinedor very smooth tooled surfaces. The accuracy of the instru-ments shall be suitable for reading to within 1 % of the samplewidth and thickness. For typical specimen geometries, aninstrument with an accuracy of 62.5 m 60.0001 in. isdesirable for thickness measurement, while
49、an instrument withan accuracy of 625 m 60.001 in. is desirable for widthmeasurement.7.8 Dent Depth IndicatorThe dent depth can be measuredusing a dial depth gage, a depth gage micrometer, or a properlycalibrated displacement transducer. The measuring probe shallhave a hemispherical tip with a diameter between 1.5 and 5.0mm (0.06-0.20 in.). An instrument with an accuracy of 625 m60.001 in. is desirable for depth measurement.8. Sampling and Test Specimens8.1 SamplingTest at least five specimens per condition,unless valid resul
