ASTM C364 C364M-2007(2012) Standard Test Method for Edgewise Compressive Strength of Sandwich Constructions《夹层结构的抗侧压强的标准试验方法》.pdf

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1、Designation: C364/C364M 07 (Reapproved 2012)Standard Test Method forEdgewise Compressive Strength of SandwichConstructions1This standard is issued under the fixed designation C364/C364M; the number immediately following the designation indicates the yearof original adoption or, in the case of revisi

2、on, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the compressive properties ofstructural sandwich construction in a direction p

3、arallel to thesandwich facing plane. Permissible core material forms includethose with continuous bonding surfaces (such as balsa woodand foams) as well as those with discontinuous bondingsurfaces (such as honeycomb).1.2 The values stated in either SI units or inch-pound unitsare to be regarded sepa

4、rately as standard. Within the text theinch-pound units are shown in brackets. The values stated ineach system are not exact equivalents; therefore, each systemmust be used independently of the other. Combining valuesfrom the two systems may result in nonconformance with thestandard.1.3 This standar

5、d 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 applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM

6、 Standards:C274 Terminology of Structural Sandwich ConstructionsD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD883 Terminology Relating to PlasticsD2584 Test Method for Ignition Loss of Cured ReinforcedResinsD2734 Test Methods for Void Content of R

7、einforced Plas-ticsD3039/D3039M Test Method for Tensile Properties ofPolymer Matrix Composite MaterialsD3171 Test Methods for Constituent Content of CompositeMaterialsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for Moisture AbsorptionProperties and Equilibrium Conditioning of P

8、olymer Ma-trix Composite MaterialsD5687/D5687M Guide for Preparation of Flat CompositePanels with Processing Guidelines for Specimen Prepara-tionE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE122 Practice for Calculating Sample Size to

9、 Estimate,With Specified Precision, the Average for a Characteristicof a Lot or ProcessE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE1012 Practice for Verification of Testing Frame and Speci-men Alignment Under Tensile an

10、d Compressive AxialForce ApplicationE1309 Guide for Identification of Fiber-ReinforcedPolymer-Matrix Composite Materials in DatabasesE1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in DatabasesE1471 Guide for Identification of Fibers, Fillers, and CoreMaterials

11、 in Computerized Material Property Databases3. Terminology3.1 DefinitionsTerminology D3878 defines terms relatingto high-modulus fibers and their composites. TerminologyC274 defines terms relating to structural sandwich construc-tions. Terminology D883 defines terms relating to plastics.Terminology

12、E6 defines terms relating to mechanical testing.Terminolgoy E456 and Practice E177 define terms relating tostatistics. In the event of a conflict between terms, TerminologyD3878 shall have precedence over the other terminologies.3.2 Symbols:b = width of specimenCV = coefficient of variation statisti

13、c of a sample populationfor a given property (in percent)L = length of specimenP = force on specimenSn-1= standard deviation statistic of a sample population fora given propertytc= core thickness1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct

14、 responsibility of Subcommittee D30.09 onSandwich Construction.Current edition approved Aug. 1, 2012. Published December 2012. Originallyapproved in 1955. Last previous edition approved in 2007 as C364/C364M 07.DOI: 10.1520/C0364_C0364M-07R12.1Copyright ASTM International, 100 Barr Harbor Drive, PO

15、Box C700, West Conshohocken, PA 19428-2959, United States.tfs= nominal facesheet thicknessxi= test result for an individual specimen from the samplepopulation for a given propertyx 5 mean or average (estimate of mean) of a samplepopulation for a given property = facesheet compressive stress4. Summar

16、y of Test Method4.1 This test method consists of subjecting a sandwich panelto monotonically increasing compressive force parallel to theplane of its faces. The force is transmitted to the panel througheither clamped or bonded end supports. Stress and strength arereported in terms of the nominal cro

17、ss-sectional area of the twofacesheets, rather than total sandwich panel thickness, althoughalternate stress calculations may be optionally specified.4.2 The only acceptable failure modes for edgewise com-pressive strength of sandwich constructions are those occurringaway from the supported ends. Th

18、e sandwich column, nomatter how short, usually is subjected to a buckling type offailure unless the facings are so thick that they themselves arein the short column class. The failure of the facings manifestsitself by wrinkling of the facing, in which the core deforms tothe wavy shape of the facings

19、; by dimpling of the facings intothe honeycomb cells; by bending of the sandwich, resulting incrimping near the ends as a result of shear failure of the core;or by failure in the facing-to-core bond and associatedfacesheet buckling.5. Significance and Use5.1 The edgewise compressive strength of shor

20、t sandwichconstruction specimens provides a basis for judging the load-carrying capacity of the construction in terms of developedfacing stress.5.2 This test method provides a standard method of obtain-ing sandwich edgewise compressive strengths for panel designproperties, material specifications, r

21、esearch and developmentapplications, and quality assurance.5.3 The reporting section requires items that tend to influ-ence edgewise compressive strength to be reported; theseinclude materials, fabrication method, facesheet lay-up orien-tation (if composite), core orientation, results of any nonde-s

22、tructive inspections, specimen preparation, test equipmentdetails, specimen dimensions and associated measurementaccuracy, environmental conditions, speed of testing, failuremode, and failure location.6. Interferences6.1 Material and Specimen PreparationPoor materialfabrication practices, lack of co

23、ntrol of fiber alignment, anddamage induced by improper specimen machining are knowncauses of high data scatter in composites in general. Specificmaterial factors that affect sandwich composites include vari-ability in core density and degree of cure of resin in both facingmatrix material and core b

24、onding adhesive. Important aspectsof sandwich panel specimen preparation that contribute to datascatter are incomplete or nonuniform core bonding to facings,misalignment of core and facing elements, the existence ofjoints, voids or other core and facing discontinuities, out-of-plane curvature, facin

25、g thickness variation, and surface rough-ness.6.2 System AlignmentUnintended loading eccentricitieswill cause premature failure. Every effort should be made toeliminate undesirable eccentricities from the test system. Sucheccentricities may occur as a result of misaligned grips, poorspecimen prepara

26、tion, or poor alignment of the loading fixture.If there is any doubt as to the alignment inherent in a given testmachine, then the alignment should be checked as discussed inTest Method D3039/D3039M.6.3 GeometrySpecific geometric factors that affect edge-wise compressive strength of sandwich panels

27、includefacesheet fiber waviness, core cell geometry (shape, density,orientation), core thickness, specimen shape (L/W ratio), andadhesive thickness.6.4 EnvironmentResults are affected by the environmen-tal conditions under which the tests are conducted. Specimenstested in various environments can ex

28、hibit significant differ-ences in both static strength and failure mode. Critical envi-ronments must be assessed independently for each sandwichconstruction tested.7. Apparatus7.1 MicrometersThe micrometer(s) shall use a 4- to 6-mm0.16- to 0.25-in. nominal diameter ball-interface on irregularsurface

29、s such as the bag-side of a facing laminate, and a flatanvil interface on machined edges or very smooth-tooledsurfaces. The accuracy of the instrument(s) shall be suitable forreading to within1%ofthesample length, width andthickness. For typical specimen geometries, an instrument withan accuracy of

30、625 m 60.001 in. is desirable for thickness,length and width measurement. .7.2 Test Fixtures:7.2.1 Spherical Bearing Block, preferably of the suspended,self-aligning type.7.2.2 Lateral End SupportsVia (1) clamps made of rect-angular steel bars fastened together so as to clamp thespecimen lightly bet

31、ween them (the cross-sectional dimensionsof each of these bars shall be not less than 6 mm 0.25 in.,such as that shown in Fig. 1;(2) fitting the specimen snuglyinto a lengthwise slot in a round steel bar, where such bars shallhave a diameter not less than the thickness of the sandwich plus6 mm 0.25

32、in., and are suitably retained on the sphericalbearing block surfaces; or (3) casting the ends of the specimensin resin or other suitable molding material. The cast ends of thespecimen should be ground flat and parallel, meeting orexceeding the specimen end tolerances shown in Fig. 2 andFig. 3.7.3 T

33、esting MachineThe testing machine shall be inaccordance with Practices E4 and shall satisfy the followingrequirements:7.3.1 Testing Machine ConfigurationThe testing machineshall have both an essentially stationary head and a movablehead.7.3.2 Drive MechanismThe testing machine drive mecha-nism shall

34、 be capable of imparting to the movable head acontrolled velocity with respect to the stationary head. TheC364/C364M 07 (2012)2velocity of the movable head shall be capable of beingregulated in accordance with 11.6.7.3.3 Force IndicatorThe testing machine force-sensingdevice shall be capable of indi

35、cating the total force beingcarried by the test specimen. This device shall be essentiallyfree from inertia lag at the specified rate of testing and shallindicate the force with an accuracy over the force range(s) ofinterest of within 61 % of the indicated value.7.3.4 Strain GageCapable of measuring

36、 strain to at least0.0001 mm/mm 0.0001 in./in. and having a gage length notgreater than two thirds of the unsupported length of thespecimens to be tested, nor less than three unit cells if thefacesheet is a composite fabric material form.7.4 Conditioning ChamberWhen conditioning materialsat non-labo

37、ratory environments, a temperature/vapor-levelcontrolled environmental conditioning chamber is required thatshall be capable of maintaining the required temperature towithin 63C 65F and the required relative humidity levelto within 63 %. Chamber conditions shall be monitored eitheron an automated co

38、ntinuous basis or on a manual basis atregular intervals.7.5 Environmental Test ChamberAn environmental testchamber is required for test environments other than ambienttesting laboratory conditions. This chamber shall be capable ofmaintaining the entire test specimen at the required testenvironment d

39、uring the mechanical test.8. Sampling and Test Specimens8.1 SamplingTest at least five specimens per test condi-tion unless valid results can be gained through the use of fewerspecimens, as in the case of a designed experiment. Forstatistically significant data, consult the procedures outlined inPra

40、ctice E122. Report the method of sampling.8.2 GeometryThe test specimens shall be as shown in Fig.2 (inch-pound units) and Fig. 3 SI units.8.3 Specimen Preparation and MachiningGuide D5687/D5687M provides recommended specimen preparation prac-tices and should be followed where practical. Of particul

41、ar notein this end-loaded compression test is the machining qualityand dimensional accuracy of the loaded ends, and the overallflatness and parallelism of the sandwich panel, as denoted inFig. 2 and Fig. 3.8.3.1 LabelingLabel the test specimens so that they willbe distinct from each other and tracea

42、ble back to the panel oforigin, and will neither influence the test nor be affected by it.9. Calibration9.1 The accuracy of all measuring equipment shall havecertified calibrations that are current at the time of use of theequipment.10. Conditioning10.1 The recommended pre-test specimen condition is

43、 ef-fective moisture equilibrium at a specific relative humidity asFIG. 1 Edgewise Compression Test SetupC364/C364M 07 (2012)3established by Test Method D5229/D5229M; however, it thetest requester does not specify a pre-test conditioning environ-ment, conditioning is not required and the test specim

44、ens maybe tested as prepared.NOTE 1The term moisture, as used in Test Method D5229/D5229M,includes not only the vapor of a liquid and its condensate, but the liquiditself in large quantities, as for immersion.10.2 The pre-test specimen conditioning process, to includespecified environmental exposure

45、 levels and resulting moisturecontent, shall be reported with the data.10.3 If there is no explicit conditioning process, the condi-tioning process shall be reported as “unconditioned” and themoisture content as “unknown.”11. Procedure11.1 Parameters to be Specified Before Test:11.1.1 The specimen s

46、ampling method, specimen geometry,and conditioning travelers (if required).11.1.2 The properties and data reporting format desired.NOTE 2Determine specific material property, accuracy, and datareporting requirements prior to test for proper selection of instrumentationand data recording equipment. E

47、stimate the specimen strength to aid intransducer selection, calibration of equipment, and determination ofequipment settings.11.1.3 The environmental conditioning parameters.11.1.4 If performed, sampling method, specimen geometry,and test parameters used to determine facing density andreinforcement

48、 volume.11.2 General Instructions:11.2.1 Report any deviations from this test method, whetherintentional or inadvertent.11.2.2 If specific gravity, density, facing reinforcement vol-ume, or facing void volume are to be reported, then obtainthese samples from the same panels being tested. Specificgra

49、vity and density may be evaluated in accordance with TestMethods D792. Volume percent of composite facing constitu-ents may be evaluated by one of the matrix digestion proce-dures of Test Method D3171, or, for certain reinforcementmaterials such as glass and ceramics, by the matrix burn-offtechnique in accordance with Test Method D2584. The voidDimension Recommended RangeLength, L (in.) L # 8 3 tWidth, W (in.) 2.00 # W # L; W $ 2 3 t;W$ 4 3 cell widths (honeycomb only)t, total panel thickness (in.) As required, in order to be representative of in