1、Designation: C 366/C 366M 05Standard Test Methods forMeasurement of Thickness of Sandwich Cores1This standard is issued under the fixed designation C 366/C 366M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These test methods cover plant manufacturing
3、proce-dures for measuring the thickness of flat sandwich cores.Permissible core material forms include those with continuousbonding surfaces (such as balsa wood and foams) as well asthose with discontinuous bonding surfaces (such as honey-comb). The two test methods covered include the following:1.1
4、.1 Test Method ARoller-Type Thickness Tester.1.1.2 Test Method BDisk-Type Thickness Tester.NOTE 1These test methods are designed for measuring thickness ofcore as it is produced and are not intended for use in determiningdimensions of core specimens for other tests.1.2 The values stated in either SI
5、 units or inch-pound unitsare to be regarded separately 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
6、 nonconformance with thestandard.1.3 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 applica-bility of regulatory limitat
7、ions prior to use.2. Referenced Documents2.1 ASTM Standards:2C 274 Terminology of Structural Sandwich ConstructionsD 883 Terminology Relating to PlasticsD 3878 Terminology for Composite MaterialsD 5229/D 5229M Test Method for Moisture AbsorptionProperties and Equilibrium Conditioning of Polymer Ma-t
8、rix Composite MaterialsE 122 Practice for Calculation of Sample Size to Estimate,Within a Specified Tolerable Error, the Average for Char-acteristic of a Lot or ProcessE 171 Specification for Standard Atmospheres for Condi-tioning and Testing Flexible Barrier MaterialsE 177 Practice for Use of the T
9、erms Precision and Bias inASTM Test MethodsE 456 Terminology Relating to Quality and StatisticsE 1309 Guide for Identification of Fiber-ReinforcedPolymer-Matrix Composite Materials in DatabasesE 1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in DatabasesE 1471
10、Guide for Identification of Fibers, Fillers, and CoreMaterials in Computerized Material Property Databases3. Terminology3.1 DefinitionsTerminology D 3878 defines terms relatingto high-modulus fibers and their composites. TerminologyC 274 defines terms relating to structural sandwich construc-tions.
11、Terminology D 883 defines terms relating to plastics.Terminology E 456 and Practice E 177 define terms relating tostatistics. In the event of a conflict between terms, TerminologyD 3878 shall have precedence over the other terminologies.3.2 Symbols:CV = coefficient of variation statistic of a sample
12、 populationfor a given property (in percent)Sn-1= standard deviation statistic of a sample population fora given propertyXi= 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 property4. Summa
13、ry of Test Methods4.1 These test methods consist of environmentally condi-tioning a sandwich core specimen, zeroing a thickness tester,placing the core underneath the tester, and measuring the core1These test methods are under the jurisdiction of ASTM Committee D30 onComposite Materials and is the d
14、irect responsibility of Subcommittee D30.09 onSandwich Construction.Current edition approved April 1, 2005. Published April 2005. Originallyapproved in 1955. Last previous edition approved in 1999 as C 366 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom
15、er Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.thickness by sliding the core underne
16、ath the tester. Proceduresare provided for thickness measurement using both roller-typeand disk-type thickness testers.5. Significance and Use5.1 Normally, a close tolerance is desirable for core thick-ness so that sandwich panels may be manufactured with all thesandwich components fitting properly
17、and without crushing thecore.5.2 These test methods are designed for measuring thick-ness of core as it is produced and are not intended for use indetermining dimensions of core specimens for other tests.5.3 These test methods provide standard methods of obtain-ing the core thickness of flat sandwic
18、h core materials, andprovide a basis for determining average thickness dimensions.The thickness properties derived may be used in designproperties, material specifications, research and developmentapplications, and quality assurance.5.4 Factors that influence core thickness measurement andshall ther
19、efore be reported include the following: core materialthrough-thickness rigidity, surface roughness, specimen geom-etry (including warpage), specimen preparation, methods ofdimensional measurement, specimen conditioning, and mois-ture content during dimensional measurements.6. Interferences6.1 Mater
20、ial and Specimen PreparationPoor materialfabrication practices and damage induced by improper speci-men machining are known causes of high data scatter incomposites and sandwich structures in general. Importantaspects of sandwich core specimen preparation that contributeto data scatter include the e
21、xistence of joints, voids or othercore discontinuities, out-of-plane curvature/warpage, and sur-face roughness.6.2 Measurement Equipment and ProceduresResults areaffected by the method of thickness measurement, use ofpressure to flatten warped core, and the distance along whichthickness is measured.
22、6.3 EnvironmentResults are affected by the environmen-tal conditions under which specimens are conditioned, as wellas the conditions under which the tests are conducted. Speci-mens tested in various environments, with different ambientmoisture contents, can exhibit significant differences in mea-sur
23、ed thickness.7. Apparatus7.1 Test Method ARoller-Type Thickness Tester:7.1.1 Roller-Type Thickness TesterThe tester shall consistof a flat table with a rigid yoke framework attached, as shownin Fig. 1. Two rollers shall be mounted on this yoke, one fixedin position and one movable in the vertical di
24、rection. Thevertical movement of the upper roller shall be translated to adial gage, calibrated in 0.01 mm 0.001 in. increments, thatregisters the amount of variation above or below a presetnominal dimension. The lower roller shall be fixed in positionso that it projects 6 mm 0.25 in. above the meas
25、urementsurface. The upper roller shall exert a force of 18 N 4 lbf onthe core material.7.2 Method BDisk-Type Thickness Tester:7.2.1 Disk-Type Thickness TesterThe tester shall consistof a flat table with a rigid yoke framework attached, as shownin Fig. 2. A 25 mm 1 in. diameter presser disk movable i
26、n avertical direction shall be mounted on the yoke. The verticalmovement of the disk shall be translated to a dial gage,calibrated in 0.01 mm 0.001 in. increments, that registers theamount of variation above or below a preset nominal dimen-sion. The disk shall exert a force of 24 N 5.5 lbf on the co
27、rematerial.7.3 Measurement SurfaceA flat, rigid surface shall bepositioned such that the specimen can be supported underneaththe thickness tester without bending or warping.8. Sampling and Test Specimens8.1 SamplingTest at least five specimens per test condi-tion, or take five readings from alternat
28、ive locations on a singlelarge specimen, unless valid results can be gained through theuse of fewer specimens, as in the case of a designed experi-ment. For statistically significant data, consult the proceduresoutlined in Practice E 122. Report the method of sampling.8.2 GeometryTest specimens shal
29、l be flat but otherwisemay be any length, width, and thickness consistent with thelimits of the measuring apparatus.FIG. 1 Roller-Type Thickness TesterC 366/C 366M 0528.3 Specimen Preparation and MachiningEnsure the testspecimens are flat, and that the facing plane surfaces areparallel to each other
30、. Take precautions when cutting speci-mens to avoid notches, undercuts, and rough or unevensurfaces which can affect the measured thickness due toinappropriate machining methods. Record and report the speci-men cutting preparation method.8.4 LabelingLabel the test specimens so that they will bedisti
31、nct from each other and traceable back to the sheet 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 As the physical
32、dimensions of the core materials areaffected by moisture, subject the test specimens to standardASTM atmospheric conditions (Specification E 171)of2363C 73 6 5F and 50 6 5 % relative humidity, in accordancewith Procedure C of Test Method D 5229/D 5229M.NOTE 2If a conditioning chamber is not availabl
33、e, record the actualtemperature and humidity at the time of measurement.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 format desired.NOTE 3Determine spe
34、cific material property, accuracy, and datareporting requirements prior to test for proper selection of apparatus.11.1.3 The environmental conditioning test parameters.11.1.4 The method of thickness measurement (Method A orB) and accuracy of thickness tester.11.2 General Instructions:11.2.1 Report a
35、ny deviations from this test method, whetherintentional or inadvertent.11.2.2 Condition the specimens as required. Store the speci-mens in the conditioned environment until test time, if the testenvironment is different than the conditioning environment.11.3 Method ARoller-Type Thickness Tester:11.3
36、.1 Place a spacer bar of a thickness equal to the desirednominal core thickness between the rollers on the measurementsurface, and zero the dial gage.11.3.2 Remove the spacer bar and insert the core material tobe measured.11.3.3 Move the core through the rollers back and forth andobserve the dial ga
37、ge readings. Record the maximum variationin readings on the dial gage to three significant figures in unitsof millimetres inches (with an accuracy of 625 mm 60.001in.), plus and minus, along with the distance traversed underthe rollers. Take care not to exert hand pressure on the corenear the roller
38、s, as this will affect the dial gage readings.11.4 Method BDisk-Type Thickness Tester:11.4.1 Place a spacer bar of a thickness equal to the desirednominal core thickness on the measurement surface beneaththe disk and zero the dial gage.11.4.2 Remove the spacer bar and insert the core material tobe m
39、easured.11.4.3 With the disk automatically reciprocating vertically,move the core in a saw tooth pattern along the length of thespecimen and observe the dial gage readings. Record themaximum variation in readings on the dial gage to threeFIG. 2 Disk-Type Thickness TesterC 366/C 366M 053significant f
40、igures in units of millimetres inches (with anaccuracy of 625 mm 60.001 in.), plus and minus, along withthe distance traversed under the disk.11.4.4 If the specimen is excessively warped and the weightof the presser disk is not sufficient to straighten it, use anadditional adjustable pressure ring c
41、oncentric with the 25 mm1 in. diameter disk presser foot to force the specimen to lieflat on the measurement surface. The outside diameter of thisring shall be 115 mm 4.5 in.12. Validation12.1 Property values shall not be calculated for any speci-men that contains some obvious flaw described in 6.1,
42、 unlesssuch flaw constitutes a variable being studied. Retests shall beperformed for any specimen on which values are not calcu-lated.13. Calculation13.1 StatisticsFor each series of tests calculate the aver-age value, standard deviation, and coefficient of variation (inpercent) for the maximum vari
43、ation in dial gage readings, bothplus and minus:x5 (i51nxi!/n (1)Sn215(i51nxi22 nx2!/n 2 1! (2)CV 5 100 3 Sn21/x(3)where:x= sample mean (average),Sn-1= sample standard deviation,CV = sample coefficient of variation, %,n = number of specimens, andxi= measured or derived property.14. Report14.1 Report
44、 the following information, or references point-ing to other documentation containing this information, to themaximum extent applicable (reporting of items beyond thecontrol of a given testing laboratory, such as might occur withmaterial details or panel fabrication parameters, shall be theresponsib
45、ility of the requestor):NOTE 4Guides E 1309, E 1434 and E 1471 contain data reportingrecommendations for composite materials and composite materials test-ing.14.1.1 The revision level or date of issue of this test method.14.1.2 The name(s) of the test operator(s).14.1.3 Any variations to this test m
46、ethod, anomalies noticedduring testing, or equipment problems occurring during testing.14.1.4 Identification of all the materials constituent to thesandwich core specimen tested, including for each: materialspecification, material type, manufacturers material designa-tion, manufacturers batch or lot
47、 number, source (if not frommanufacturer), date of certification, and expiration of certifi-cation.14.1.5 Description of the fabrication steps used to preparethe sandwich core including: fabrication start date, fabricationend date, process specification, and a description of theequipment used.14.1.6
48、 Method of preparing the test specimen, includingspecimen labeling scheme and method, specimen geometry,sampling method, and specimen cutting method.14.1.7 Results of any nondestructive evaluation tests.14.1.8 Calibration dates and methods for all measurementsand test equipment.14.1.9 Type of thickn
49、ess tester and method used (Method Aor B).14.1.10 Conditioning parameters and results.14.1.11 Relative humidity and temperature of the testinglaboratory.14.1.12 Number of specimens (or measurements taken froma single large specimen) tested.14.1.13 Nominal core thickness.14.1.14 Prescribed or recommended thickness tolerance,plus or minus.14.1.15 Distance over which thickness measurements areobserved and recorded.14.1.16 Individual maximum positive (plus) variation ofdial gage reading from zero, along with average value, s
