ASTM D3501-2005a Standard Test Methods for Wood-Based Structural Panels in Compression《木基结构板的压缩标准试验方法》.pdf

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1、Designation: D 3501 05aStandard Test Methods forWood-Based Structural Panels in Compression1This standard is issued under the fixed designation D 3501; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu

2、mber in parentheses indicates the year of last reapproval. Asuperscript 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 the determination of thecompre

3、ssion properties of wood-based structural panels.Wood-based structural panels in use include plywood, wafer-board, oriented strand board, and composites of veneer and ofwood-based layers.1.2 Method A, Compression Test for Small SpecimensThismethod is applicable to small specimens that are uniform wi

4、threspect to elastic and strength properties. Two types of com-pression tests are employed: one to evaluate both elastic andcompressive strength properties, and the second to evaluatemaximum compressive strength only.1.3 Method B, Compression Test for Large SpecimensThis method employs large specime

5、ns and responds well tomanufacturing variables and growth characteristics that influ-ence compression properties of structural panels.1.3.1 This method is intended for the following:1.3.1.1 Comparative tests of structural panels,1.3.1.2 Evaluating the effects of moisture content onstrength propertie

6、s of structural panels,1.3.1.3 Determining the strength properties of structuralpanels, and1.3.1.4 Evaluating the effects of raw material and manufac-turing variables on compression properties of structural panels.1.4 The values stated in inch-pound units are to be regardedas standard. The values gi

7、ven in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 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

8、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2395 Test Methods for Specific Gravity of Wood andWood-Base MaterialsD 4442 Test Methods for Direct Moisture Content Measure-ment of Wood and

9、 Wood-Base Materials3. Significance and Use3.1 These methods determine the compressive strength ofstructural panels in response to stresses acting in the plane ofthe panel.3.2 Method AThis method is applicable to structuralpanels of uniform properties within a panel. It is useful forevaluating plywo

10、od of clear, straight-grained veneers, anddetermining the effect of chemical or preservative treatments,construction, principal direction with respect to direction ofstress, and other variables that are expected to uniformlyinfluence the panel.3.3 Method B:3.3.1 The compressive properties obtained b

11、y this methodare a reliable approximation of the strength of a full-size panel,and are intended for use in design.3.3.2 The compressive properties are influenced by buck-ling; however, this effect can be eliminated in this test byrestraining the edges of the specimens.3.4 It is recommended that wher

12、e comparisons are to bemade, that the same method and specimen size be usedthroughout. This is because the volume of material included ina test specimen can influence the compressive strength regard-less of whether the material properties are uniform throughoutthe sheet or vary widely due to the pre

13、sence of growth ormanufacturing features.1These test methods are under the jurisdiction of ASTM Committee D07 onWood and are the direct responsibility of Subcommittee D07.03 on Panel Products.Current edition approved Dec. 1, 2005. Published December 2005. Originallyapproved in 1976. Last previous ed

14、ition approved in 2000 as D 3501 94 (2000).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 standards Document Summary page onthe ASTM website.1Copyright ASTM In

15、ternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Control of Moisture Content4.1 Condition structural panel samples to be tested at aspecific moisture content or relative humidity to approximateconstant weight in controlled atmospheric conditions bef

16、oretesting. For panels used under dry conditions, a relativehumidity of 65 6 2 % at a temperature of 68 6 6F (20 6 3C)is preferred.5. Variables Influencing the Compressive Properties ofStructural Panels5.1 Moisture ContentCut a moisture content sample hav-ing minimum area of 2 in.2(13 cm2) from the

17、clear areas of thespecimen and weigh immediately after each test. Moisturecontent samples from large specimens of Method B shall haveminimum area of 8 in.2(52 cm2). If inspection of the edges ofa plywood panel reveals the presence of a knot in any ply,select a second sample. Moisture content samples

18、 also servingas specific gravity samples shall be free of voids. Moisturecontent determinations shall be made in accordance with TestMethods D 4442.5.2 Specific GravityDetermine specific gravity in accor-dance with Test Methods D 2395. The specimen may be thesame as that for moisture content determi

19、nation but must havevolume of at least 1 in.3(16 cm3) if from small specimens, andat least 3 in.3(49 cm3) if from large specimens, and be free ofvisible knots or voids.METHOD ACOMPRESSION TESTFOR SMALL SPECIMENS6. Direction of Grain, Fibers, or Layers6.1 The direction of the individual plies, lamina

20、tions, orlayers shall be parallel, perpendicular, or inclined at any otherrequired angle to the length of the test specimen.7. Test Specimen7.1 The test specimen shall be rectangular in cross section.The thickness, width, and length of each specimen shall bemeasured to an accuracy of not less than 6

21、0.3 % or 0.001 in.(0.02 mm), whichever is larger.7.2 When tests to evaluate both elastic and compressivestrength properties are required, the size of the specimens shallbe as follows:7.2.1 For Material Over14 in. (6 mm) in Thickness, thespecimens shall have a thickness equal to that of the materiala

22、nd the width shall be a minimum of 1 in. (25 mm), but not lessthan the thickness. The length shall be not greater than seventimes the least cross-sectional dimension.7.2.2 For Material14 in. (6 mm) or Less in Thickness, thespecimen shall have the following dimensions: thickness equalto that of the m

23、aterial; the width nominally 1 in. (25 mm), anda length of 4 in. (100 mm). Such specimens shall be supportedlaterally throughout the test.7.2.3 When tests to evaluate maximum compressivestrength only are required, an alternative type of specimen 4 in.(100 mm) in width and a length equal to six times

24、 the thicknessmay be used.7.2.4 The end surfaces of the specimen shall be smooth andparallel to each other and at right angles to the length.8. Evaluation of Both Compressive Strength and ElasticProperties8.1 Support laterally test specimens14 in. (6 mm) or less inthickness intended for use in obtai

25、ning load deformation datato prevent buckling during the test, but do not exert unduepressure against the sides of the specimen. This support shallnot measurably restrain the normal compressive deformationunder load. A satisfactory method of providing lateral supportis illustrated in Fig. 1, and a d

26、etailed design of this apparatusis shown in Fig. 2.9. Loading Procedure9.1 Apply the load through a spherical bearing block pref-erably of the suspended, self-aligning type.Apply the load witha continuous motion of the movable head so as to cause failurewithin 3 to 10 min after initiation of loading

27、. A rate of 0.003in./in. (mm/mm) of length of the specimen per minute within apermissible variation of 625 % has usually proved satisfac-tory.9.2 Measure the elapsed time from initiation of loading tomaximum load and record to the nearest12 min.10. Load-Deformation Curves10.1 Take data for load-defo

28、rmation curves to determine themodulus of elasticity and the proportional limit. Chooseincrements of load so that not less than 12 readings of load anddeformation are taken to the proportional limit. Read thedeformation to the nearest 0.0001 in. (0.002 mm). Attachcompressometers over the central por

29、tion of the length of thespecimen with the points of attachment not less than34 in. (18mm) from the specimen ends. Fig. 3 shows a type of Lambsroller compressometer, with a 2-in. (50-mm) gage length issuitable for specimens 312 to 6 in. (90 to 150 mm) in length. Asuitable arrangement of a Martins mi

30、rror having a 2-in.(50-mm) gage length for measuring deformations of laterallysupported specimens is illustrated in Fig. 1.11. Alternative Test for Evaluation of MaximumCompressive Strength Only11.1 In the alternative test for the evaluation of maximumcompressive strength only, apply the load throug

31、h a sphericalloading block with a continuous rate of cross-head movementso as to produce failure within 3 to 10 min after initiation ofloading. A loading rate of 0.003 in./in. (mm/mm) of length perminute is suggested. The loading rate shall be modified if timesfall outside the 3 to 10-min range. Rec

32、ord the maximumcrushing force and calculate the maximum crushing stress.METHOD BCOMPRESSION TESTFOR LARGE SPECIMENS12. Test Specimens12.1 Specimens shall be precisely cut with all adjacentedges at right angles. The dimension of the specimen shall be712 in. (190 mm) wide by 15 in. (381 mm) long measu

33、red to anaccuracy of not less than 60.3 %.12.2 To eliminate buckling, the following length-to-thickness ratios shall be used:D 3501 05a212.2.1 A ratio of 20 or less, if data are to be recorded up tothe proportional limit only, and12.2.2 A ratio of 10 or less, if strength data only arerequired.12.3 I

34、n order to obtain the specified length-to-thicknessratios, it is necessary, in some cases, to glue two or morespecimens face to back.13. Loading Procedure13.1 Apply the load through a hinged connection on theupper head of the testing machine to allow for any deviationsfrom parallel of the ends of th

35、e specimens, and permitadjustment to the end of the specimen in one direction.Specimen buckling can be restrained by use of optionalhardware shown in Fig. 4. If restraint is used, hold thespecimen loosely by the side restraining rail. Apply the loadcontinuously throughout the test at a rate of movab

36、le headmotion that will produce failure within 3 to 10 min afterinitiation of loading. A head speed rate of 0.035 in./min (0.9mm/min) 625 % is suggested. This gives a strain rate ofapproximately 0.002 in./in.min (0.002 mm/mmmin). Typicalloading hardware is shown in Fig. 5 and Fig. 4.14. Load-Deforma

37、tion Curves14.1 Take data for load-deformation curves to determinemodulus of elasticity and the proportional limit. Chooseincrements of load so that not less than 12 readings of load anddeformation are taken to the proportional limit. Take deforma-tion readings to the nearest 0.0001 in. (0.002 mm).

38、Takedeformation over the central portion of both sides of thespecimen with a gage length of 5 in. (127 mm). Use theaverage of the two readings in calculation of the modulus ofelasticity. A suitable arrangement is shown in Fig. 4 withdeformation measured by transducers mounted on oppositesides of the

39、 specimen. Record the load and deflection electri-cally and display continuous data on a suitable device.15. Calculation of Results15.1 Calculate Results:15.1.1 Compressive modulus of elasticity shall be calcu-lated as follows:Ec5 P/d!L!/A see Note1! (1)where:Ec= Compressive modulus of elasticity (p

40、si)P/d = slope of the linear portion of load-deformation curve(lb/in.) (see Note 2)L = deformation gage length (in.)A = cross-sectional area (in.2)NOTE 1Reporting compressive stiffness on a capacity basis (such asEAc(lb) or EAc/width (lb/ft) is an acceptable alternative.NOTE 2Normal techniques to de

41、termine the slope of the load-deformation curve, such as measuring the maximum slope below theproportional limit, are often difficut to apply to compressive stiffness testsdue to absence of a readily identifiable linear portion or proportional limit,or both. One suitable technique to determine the s

42、lope is to determine thebest linear fit in the range of 5 to 35% of the ultimate load. In any case,data covering a range of at least 20% of the ultimate load and includingloads up to and including applicable design stress should be used.15.1.2 Compressive strength shall be calculated as follows:FIG.

43、 1 Compression Test of Thin Structural Panel Supported Laterally Showing Martens Mirror Compressometer for MeasuringDeformations on Two Opposite FacesD 3501 05a3Fc5 Pmax/A see Note3! (2)where:Fc= Compressive strength (psi)Pmax= maximum load (lb)A = cross-sectional area (in.2)NOTE 3Reporting compress

44、ive stress on a capactiy basis (such as FcAor FcA/width) are acceptable.TABLE 2U.S. CustomaryUnits, in.Metric Equivalents,mmU.S. CustomaryUnits, in.Metric Equivalents,mm0.024 0.61 1316 3018 3112 3838 10 21932 6612 13 22532 7158 16 3916 901116 17 378 981332 18 41516 125FIG. 2 Apparatus for Lateral Su

45、pport for Compression TestD 3501 05a4REPORT16. Report16.1 The structural panel specimen, shall be described as tospecies, construction, and adhesive type used in its manufac-ture, and the principal direction with respect to load direction,and16.2 Description of compressive test method used, includ-i

46、ng whther optional restraining device is used (for Method B),and deformation gauge.16.3 Data for individual specimens and specimen averageswhere applicable shall include the following:16.3.1 Thickness of panel,16.3.2 Construction and veneer thicknesses (plywood pan-els),16.3.3 Veneer or furnish spec

47、ies,16.3.4 Moisture content,16.3.5 Specific gravity,16.3.6 Elapsed time to failure,16.3.7 Load-deflection curve or ultimate load,16.3.8 Description of failure,16.3.9 Compressive stiffness and compressive strength, and16.3.10 Elastic modulus and ultimate compressive strength.17. Precision and Bias17.

48、1 The bias of these test methods have not yet beendetermined due to lack of an applicable standard referencematerial.17.2 The precision of these test methods has not yet beendetermined.17.3 Based on an interlaboratory study of compressivestiffness of plywood and OSB using Method B, the reproduc-ibil

49、ity standard deviation was found to vary between 173 000lb/ft and 1 870 000 lb/ft for panels with compressive stiffnessranging between 3 940 000 lb/ft and 7 950 000 lb/ft.18. Keywords18.1 compression; structural panels; woodFIG. 3 Compression Test of Plywood Prism Showing RollerCompressometer Attachment (2-in. Gage Length) AffordingAverage Deformation for Two Opposite FacesD 3501 05a5FIG. 4 Method B, Loading Hardware Showing a Specimen Mounted with Transducers for Deformation MeasurementD 3501 05a6ASTM International takes no position