1、Designation: D3500 90 (Reapproved 2009)D3500 14Standard Test Methods forStructural Panels in Tension1This standard is issued under the fixed designation D3500; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test methods cover the determination
3、of the tensile properties of structural panels.1.2 Structural panels in use include plywood, waferboard, oriented strand board and composites of veneer, and otherwood-based layers1.3 Test Method A, Tensile Test for Small Specimens:1.3.1 This test method employs small specimens that should have a red
4、uced cross section at the center of their length to avoidfailure in the grip area. The transition from full width of specimen to reduced section at the center should be gradual to minimizestress concentration.1.3.2 When the measurements of elastic properties are to be made, the length of the reduced
5、 cross section at the center shouldbe of sufficient length to accommodate an extensometer.1.4 Test Method B, Tensile Test for Large Specimens:1.4.1 This test method employs large specimens and responds well to manufacturing variables, plywood growthpanel gradecharacteristics, and other defectsvariab
6、les influencing the tensile properties of structural panels.1.4.2 The test specimens are large enough to contain the maximum sized defects grade characteristics found in plywood panels.The test specimens have a constant cross section since the size and location of defects grade characteristics contr
7、ol the locationof failures and the effect of stress concentration at the grips is overshadowed.1.4.3 This test method is recommended for the following:1.4.3.1 Comparative tests of structural panels,1.4.3.2 Determining the influence of any specific strength reducing defectsvariables on the tensile pr
8、operties of structural panels,1.4.3.3 Determination of tensile properties of plywood and composites containing veneer with growth and manufacturingcharacteristics.panels for use in developing structural recommendations.1.5 The values stated in inch-pound units are to be regarded as standard. The val
9、ues given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to e
10、stablish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2395 Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based MaterialsD4442 Test Methods for Direct Moist
11、ure Content Measurement of Wood and Wood-Base Materials3. Significance and Use3.1 These test methods determine the tensile properties of structural panels in response to stresses acting in the plane of thepanel.1 These test methods are under the jurisdiction of ASTM Committee D07 on Wood and are the
12、 direct responsibility of Subcommittee D07.03 on Panel Products.Current edition approved May 1, 2009Oct. 1, 2014. Published June 2009November 2014. Originally approved in 1976. Last previous edition approved in 20032009 asD3500 90 (2003).(2009). DOI: 10.1520/D3500-90R09.10.1520/D3500-14.2 For refere
13、ncedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the
14、 user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standar
15、d as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Test Method AThis test method is suited to material that is uniform with respect to tensile properties. It is normall
16、y appliedto structural panels and plywood of clear, straight-grained veneers. It may also be used to evaluate the strength of scarf and fingerjoints and other manufacturing process variables that can be expected to influence the tensile properties of structural panels in auniform manner across the w
17、idth of the sheet.3.3 Test Method BThis test method employs large test specimens and responds well to all manufacturing variables and growthcharacteristics that affect the tensile properties of structural panels.3.4 It is recommended that where comparisons are to be made that the same test method an
18、d specimen size be used throughout.This is because the volume of material included in a test specimen can influence the tensile strength regardless of whether thematerial properties are uniform throughout the sheet or vary widely due to the presence of growth or manufacturing features.4. Control of
19、Moisture Content4.1 Structural panel specimens to be tested at specific moisture contents or after reaching equilibrium moisture content atspecific temperature and relative humidity conditions shall be conditioned to approximate constant weight in controlledatmospheric conditions. For approximating
20、moisture conditions of structural panels used under dry conditions, a relative humidityof 65 6 2 % at a temperature of (68 6 6F) (20 6 3C) is recommended.5. Variables Influencing Tensile Properties of Structural Panels5.1 Moisture ContentMoisture content shall be determined in accordance with Test M
21、ethod D4442.5.2 Specific GravityDetermine specific gravity in accordance with Test Methods D2395. The specimen may be the same asthat for moisture content determination but must have volume of at least 1 in.3 (16 cm3) if from small specimens (Test MethodA), and at least 3 in.3 (49 cm3) if from large
22、 specimens (Test Method B). Specimens containing veneer shall be free of visible knotsor voids in any ply.TEST METHOD ATENSILE PROPERTIESOF SMALL SPECIMENS6. Test Specimens6.1 Specimens may be of Types A, B, or C in Fig. 1.6.1.1 When the evaluation of elastic properties as well as ultimate tensile s
23、trength is required, the size and shape of the testspecimen shall be selected on the basis of the construction and thickness of the material. For other structural panels, and plywoodor composites with the grain of the individual veneer plies or laminations making grain angles of individual veneer la
24、mina of 0or 90, TypeAshall be used for material over 14 in. (6 mm) in thickness and Type B for material 14 in. (6 mm) or less in thickness.For plywood with an angle other than 0 or 90 between the length of the specimens and the grain orientation, Type C shall be usedregardless of the thickness of th
25、e material. The specimens shall have a thickness equal to that of the material. The thickness andthe width of each specimen at the critical section shall be measured to an accuracy of not less than 60.3 % or 0.001 in. (0.02 mm)whichever is larger.6.1.2 The test specimens shall be properly shaped, us
26、ing a template in conjunction with a vertical-spindle wood-working shaperor any other method that will give equally satisfactory results.7. Loading Procedure7.1 Hold the specimen in wedge-type self-tightening and self-aligning grips. Rate of crosshead motion shall be constantthroughout the test such
27、 that the specimen breaks within 3 to 10 min after initiation of loading. A crosshead motion rate of 0.035in./min (0.9 mm/min) is usually satisfactory. If failure does not occur within the desired 3 to 10-min time span, adjust the loadingrate.7.2 Measure the elapsed time from initiation of loading t
28、o maximum load and record to the nearest 12 min.8. Load-Deformation Curves8.1 Take data for load-deformation curves to determine the modulus of elasticity and the proportional limit. Choose incrementsof load so that not less than 12 and preferably 15 or more readings of load and deformation are take
29、n to the proportional limit.Attach the deformation apparatus at the center of the specimens length and width. Take deformation readings to the nearest 0.0001in. (0.002 mm). Fig. 2 and Fig. 3 show 2-in. (51-mm) gauge length Tripolitis extensometers that have been found satisfactory forthis test.TEST
30、METHOD BTENSILE STRENGTH OF LARGE SPECIMENS9. Apparatus9.1 Hold the structural panel specimen in grips that apply the required forces to the specimen without influencing load at, orlocation of, failure. Such devices shall not apply a bending moment to the test section, allow slippage under load, or
31、inflict damageor stress concentrations to the test section. Figs. 4 and 5 illustrate the test set-up and grips.D3500 1429.2 Grip AlignmentFor ideal test conditions, the grips should be self-aligning, that is, they should be attached to the forcemechanism of the machine in such a manner that they wil
32、l move freely into axial alignment as soon as the load is applied and thusapply uniformly distributed forces along and across the test cross section. When self-aligning grips are not available, the specimenmay be clamped in the heads of a universal-type testing machine with wedge-type jaws.9.3 Conta
33、ct SurfaceThe contact surface between grips and test specimen shall be such that slippage does not occur. It isrecommended that 11-in. (279-mm) long gripping area be used (measured parallel to direction of force). Large projections thatdamage the contact surface of the wood should be avoided. Grips
34、that have been used successfully include: diamond floor plate,grips surfaced with coarse emery paper, and urethane friction padding.10. Test Specimens10.1 Specimens shall be precisely cut with all adjacent edges at right angles. The dimension of the specimen shall be at least6 in. (152 mm) wide by 4
35、8 in. (1219 mm) long. The thickness and width shall be measured to an accuracy of not less than 60.3 %or 0.001 in. (0.02 mm), whichever is larger.11. Loading Procedure11.1 Apply the load continuously throughout the test at a uniform rate of moveable crosshead motion that will produce failureof the s
36、pecimen within a 3 to 10-min time period after initiation of loading. A strain rate of 0.001 in./in.min (0.001 mm/mmmin)6 25 % has been found to give satisfactory results. This rate corresponds to a crosshead motion of approximately 0.025 in./min(0.625 mm/min) for a net specimen length of 26 in. (60
37、0 mm). Widely varying material properties or deformation of loadingequipment may cause failure times to fall outside this range, requiring an adjustment of loading rate.11.2 Measure the elapsed time from initiation of loading to maximum load and record to the nearest 12 min.U.S. CustomaryUnits, in.M
38、etric EquivalentsmmU.S. CustomaryUnits, in.Metric Equivalentsmm14 6 378 9812 13 418 1051 25 414 108178 48 16 406212 64 20 503258 67 25 635278 73 30 762NOTE 1A generous radius of curvature at the minimum section as provided in this specimen is highly desirable.FIG. 1 Dimensions and Details of Tension
39、 Test SpecimensD3500 14312. Load-Deformation Curves12.1 When deformation measurements are needed for determining elastic properties mount a pair of transducers on the oppositefaces of the specimen to minimize the effect of bending. Attach the transducers at the mid length and width of the specimen.
40、Itis recommended that the deflection be measured over a gauge length of at least 5 in. (127 mm) and deformations measured to thenearest 0.0001 in. (0.002 mm). It is recommended that an X-Y recorder be used to obtain a continuous load-deformation curve.Otherwise choose the increments of load so that
41、not less than 12 and preferably 15 or more readings of load and deformation aretaken to the proportional limit.13. Report13.1 The structural panel specimen shall be described as to size, species, construction, and adhesive type used in itsmanufacture, and (where applicable) direction of the face gra
42、in or orientation with respect to load direction. The test method shallbe identified.13.2 Data for individual specimens and, where applicable, specimen averages shall include:FIG. 2 Tension Test of Thick Plywood Showing Nonaveraging Type of Extensometer (2-in. Gauge Length)D3500 14413.2.1 Thickness,
43、13.2.2 Width,13.2.3 Specific gravity,13.2.4 Moisture content,13.2.5 Elapsed time to failure,13.2.6 Tensile stiffness (cross-sectional area modulus of elasticity),13.2.7 Maximum load,13.2.8 Maximum tensile strength,13.2.9 Load-deflection diagrams, and13.2.10 Description of failure.13.3 It may also be
44、 desirable to include additional data that may influence results such as, for plywood, cross-sectional area ofparallel and perpendicular plies, thickness of individual plies, and natural and manufacturing features present relating to panelgrade or thought to influence test results.13.4 A description
45、 of the test method shall include equipment used to apply loads to the specimen, deformation measuringequipment, and geometry of deformation measured.14. Precision14.1 The precision of these test methods has not yet been determined, but when data are available a precision statement willbe included.F
46、IG. 3 Tension Test of Plywood with Extensometer Attachment Showing Specimen Used When Load is Applied at an Angle Other than0 or 90 to the Direction of the Grain of the PliesD3500 14515. Keywords15.1 panels; structural panels; tensile properties; wood-basedFIG. 4 Test Method B Tension Test Set-UpD35
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