ASTM C364 C364M-2016 Standard Test Method for Edgewise Compressive Strength of Sandwich Constructions《夹层结构侧向压缩强度的标准试验方法》.pdf

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1、Designation: C364/C364M 16Standard 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 revision, the year of la

2、st 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 parallel to thesand

3、wich 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 separately as standard

4、. 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 standard does not purport

5、 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 Standards:D792 Te

6、st 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 Reinforced PlasticsD3039/D3039M Test Method for Tensile Properties of Po

7、ly-mer Matrix Composite MaterialsD3171 Test Methods for Constituent Content of CompositeMaterialsD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equilibrium Conditioning of Polymer MatrixComposite MaterialsD5687/D5687M Guide for Preparation of

8、 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 Estimate, WithSpecified Precision, the Average for a Characteristic of

9、 aLot 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 and Compressive AxialForce Application3. Terminology3.1 DefinitionsTermin

10、ology D3878 defines terms relatingto high-modulus fibers and their composites, as well as termsrelating to sandwich constructions. Terminology D883 definesterms relating to plastics. Terminology E6 defines termsrelating to mechanical testing. Terminolgoy E456 and PracticeE177 define terms relating t

11、o statistics. In the event of aconflict between terms, Terminology D3878 shall have prece-dence over the other terminologies.3.2 Symbols: b = width of specimenCV = coefficient of variation statistic of a sample populationfor a given property (in percent)L = length of specimenP = force on specimenSn-

12、1= standard deviation statistic of a sample population fora given propertytc= core thicknesstfs= nominal facesheet thicknessxi= test result for an individual specimen from the samplepopulation for a given propertyx5 mean or average (estimate of mean) of a samplepopulation for a given property = face

13、sheet compressive stress1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.09 onSandwich Construction.Current edition approved April 1, 2016. Published April 2016. Originallyapproved in 1955. Last previous edit

14、ion approved in 2012 as C364/C364M 07(2012). DOI: 10.1520/C0364_C0364M-16.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 This test method consists of subjecting a sandwich panelto monotonically increasing

15、 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 cross-sectional area of the twofacesheets, rather than total sandwich panel thickness, althoughalternate s

16、tress 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. The sandwich column, nomatter how short, usually is subjected to a buckling type offailure unless the fac

17、ings 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; by dimpling of the facings intothe honeycomb cells; by bending of the sandwich, resulting incrimping

18、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 short sandwichconstruction specimens provides a basis for judging the load-carrying capacity of the constru

19、ction 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, research and developmentapplications, and quality assurance.5.3 The reporting section requires items tha

20、t 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-structive inspections, specimen preparation, test equipmentdetails, specimen dimensions and associated m

21、easurementaccuracy, environmental conditions, speed of testing, failuremode, and failure location.6. Interferences6.1 Material and Specimen PreparationPoor material fab-rication practices, lack of control of fiber alignment, anddamage induced by improper specimen machining are knowncauses of high da

22、ta 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 bonding adhesive. Important aspectsof sandwich panel specimen preparation that contribute to datascatt

23、er 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, facing thickness variation, and surface rough-ness.6.2 System AlignmentUnintended loading eccentricitieswi

24、ll 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 preparation, or poor alignment of the loading fixture.If there is any doubt as to the alignment inherent in

25、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 includefacesheet fiber waviness, core cell geometry (shape, density,orientation), core thickness, spe

26、cimen shape (L/W ratio), andadhesive thickness.6.4 EnvironmentResults are affected by the environmentalconditions under which the tests are conducted. Specimenstested in various environments can exhibit significant differ-ences in both static strength and failure mode. Critical envi-ronments must be

27、 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 irregularsurfaces such as the bag-side of a facing laminate, and a flatanvil interface on machined edges or very smooth

28、-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 625 m 60.001 in. is desirable for thickness,length and width measurement. .7.2 Test Fixtures:7.2.1 Sphe

29、rical 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 between them (the cross-sectional dimensionsof each of these bars shall be not less than 6 mm 0.25 in.,suc

30、h 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 in., and are suitably retained on the sphericalbearing block surfaces; or (3) casting the ends of the s

31、pecimensin 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 Testing MachineThe testing machine shall be in ac-cordance with Practices E4 and shall satisfy the follo

32、wingrequirements: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 be capable of imparting to the movable head acontrolled velocity with respect to the stationary head

33、. Thevelocity 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 indicating the total force beingcarried by the test specimen. This device shall be essentiallyfree from inertia lag at the spe

34、cified rate of testing and shallC364/C364M 162indicate 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 strain to at least0.0001 mm/mm 0.0001 in./in. and having a gage length notgreater than two thirds of the un

35、supported 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-laboratory environments, a temperature/vapor-levelcontrolled environmental conditioning chamber is required that

36、shall 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 continuous basis or on a manual basis atregular intervals.7.5 Environmental Test ChamberAn environmental testc

37、hamber is required for test environments other than ambienttesting laboratory conditions. This chamber shall be capable ofmaintaining the entire test specimen at the required testenvironment during the mechanical test.8. Sampling and Test Specimens8.1 SamplingTest at least five specimens per test co

38、ndi-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 inPractice E122. Report the method of sampling.8.2 GeometryThe test specimens shall be as shown in Fig.2 (inch-po

39、und 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 particular notein this end-loaded compression test is the machining qualityand dimensional accuracy of the loaded en

40、ds, 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 traceable back to the panel oforigin, and will neither influence the test nor be affected by it.9. Calibration9.1

41、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 ef-fective moisture equilibrium at a specific relative humidity asestablished by Test Method D5229/D5229M;

42、however, it thetest requester does not specify a pre-test conditioningenvironment, conditioning is not required and the test speci-mens may be 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 liquidits

43、elf in large quantities, as for immersion.FIG. 1 Edgewise Compression Test SetupC364/C364M 16310.2 The pre-test specimen conditioning process, to includespecified environmental exposure levels and resulting moisturecontent, shall be reported with the data.10.3 If there is no explicit conditioning pr

44、ocess, 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 sampling method, specimen geometry,and conditioning travelers (if required).11.1.2 The properties and data reporting

45、 format desired.NOTE 2Determine specific material property, accuracy, and datareporting requirements prior to test for proper selection of instrumentationand data recording equipment. Estimate the specimen strength to aid intransducer selection, calibration of equipment, and determination ofequipmen

46、t 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 volume.11.2 General Instructions:11.2.1 Report any deviations from this test method, whetherintentional or inadver

47、tent.11.2.2 If specific gravity, density, facing reinforcementvolume, or facing void volume are to be reported, then obtainthese samples from the same panels being tested. Specificgravity and density may be evaluated in accordance with TestMethods D792. Volume percent of composite facing constitu-en

48、ts 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 voidcontent equations of Test Method D2734 are applicable to bothTest Meth

49、od D2584 and the matrix digestion procedures.11.2.3 Following final specimen machining, but beforeconditioning and testing, measure the specimen length andwidth. The accuracy of these measurements shall be within 1 %of the dimension. Measure the overall specimen thickness; theaccuracy of this measurement shall be within 625 m 60.001in. Record the dimensions to three significant figures in unitsof millimeters inches.Dimension Recommended RangeLength, L (in.) L # 8tWidth, W (in.) 2.00 # W # L; W $ 2t;W$ 4 cell widths (honeycomb only)t,