1、Designation: D3044 16Standard Test Method forShear Modulus of Wood-Based Structural Panels1This standard is issued under the fixed designation D3044; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers determination of the shearmodulus of wood-based structural panels associated with sheardistortion in the plane of t
3、he panels. The method is applicableto all types of wood-based structural panels. The grain direc-tion or orientation of the individual plies, laminations, or layersshall be parallel or perpendicular to the edge of the testspecimen. If the plies, laminations, or layers are of differentmaterial or ela
4、stic properties, the method gives the effectiveshearing modulus. Wood-based structural panels in use includeplywood, oriented strand board, and composites of veneer andof wood-based layers.NOTE 1This test method is primarily designed for material in whichthe grain or orientation of the individual pl
5、ies, laminations, or layers isparallel or perpendicular to the edge of the specimen. It may be used,however, for plywood specimens in which the grain is at 45 to thespecimen edges if a four-ply panel with all plies of the same thickness isused. The controlling condition is that the EI (modulus of el
6、astic-ity moment of inertia) values along both diagonals shall be equal.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This stan
7、dard 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 A
8、STM Standards:2D2395 Test Methods for Density and Specific Gravity (Rela-tive Density) of Wood and Wood-Based MaterialsD2718 Test Methods for Structural Panels in Planar Shear(Rolling Shear)D4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Based Materials3. Summary of Test
9、 Method3.1 The test consists of twisting a square plate of material byapplying loads at the ends of one diagonal and supporting theplate at the ends of the other diagonal. From theory on theflexure of flat plates the deflections of the plate under thisloading is related to the shear modulus of the p
10、late. Deflectionsof the plate at points on the diagonal are measured relative toits center. The shear modulus of the specimen is determinedfrom load-deflection data. The shear modulus obtained is thatassociated with shearing distortion in the plane of the plate. Aphotograph of testing apparatus and
11、a deflection measuringdevice is given in Fig. 1.4. Significance and Use4.1 This test method is most useful for determining themoduli of rigidity of orthotropic materials for which moduli ofrigidity cannot be computed from elastic moduli and Poissonsratios. The shear modulus determined by this method
12、 appearsin the equation governing the bending of a plate. This is themodulus that is needed in discussing the deflection andbuckling of plates.NOTE 2Test Methods D2718 describes a plate method for determi-nation of modulus of rigidity of structural panels.5. Control of Moisture Content5.1 The struct
13、ural panel samples to be tested at specificmoisture contents or equilibrium relative humidities shall beconditioned to approximately constant mass in controlledatmospheric conditions. For approximating moisture condi-tions of panels used under dry conditions, a relative humidityof 65 6 2 % at a temp
14、erature of 68 6 6F (20 6 3C) isrecommended. Specimens shall be tested without undue delayafter conditioning. Testing in similarly controlled atmosphereis recommended whenever possible.6. Test Specimen6.1 The test specimen shall be square, with the thicknessequal to the thickness of the material, and
15、 the length and widthnot less than 25 nor more than 40 times the thickness. The1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.03 on Panel Products.Current edition approved June 1, 2016. Published July 2016. Originally app
16、rovedin 1972. Last previous edition approved in 2011 as D3044 94 (2011). DOI:10.1520/D3044-16.2For 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
17、 Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1thickness, length, and width of each specimen shall be mea-sured to an accuracy of not less than6 0.3 %. Care shall betaken to avoid obtaining test speci
18、mens with initial curvature.7. Loading Procedure7.1 Support the test specimen on supports having a radius ofcurvature not greater than14 in. (6 mm) on the opposite endsof a plate diagonal, and loaded in a similar manner on theopposite ends of the other diagonal. In order that the loads areapplied at
19、 the corners, first attach metal plates as shown in Fig.1. Fig. 1 also shows suggested apparatus for applying load andmeasuring deflection. Apply the load with a continuous anduniform motion of the movable head at a rate of 0.012 timesthe length of the plate in inches or millimetres, expressed ininc
20、hes or millimetres per minute, within a permissible variationof 625 %.7.2 The load applied shall be accurate to within 1 %.8. Deflection Measurements8.1 Measure the deflections to the nearest 0.001 in. (0.02mm) of points on each diagonal relative to the center of theplate. These measurements prefera
21、bly shall be made near thequarter-points of the diagonals, and if other points than theseare chosen, take care to avoid locations near the concentratedloads at the plate corners. Apparatus used to measure the platedeflection should be supported on the plate to ensure accuratemeasurements. Do not str
22、ess the plate beyond its elastic range,and choose increments of load so that not less than 12 andpreferably 15 load-deflection readings are taken. To eliminatethe effects of slight initial curvature obtain two sets of data, thesecond set with the panel rotated 90 about an axis through thecenter of t
23、he plate and perpendicular to the plane of the panel.Average the two results to obtain the shear modulus for theplate.Asatisfactory arrangement for measuring relative deflec-tions is indicated in Fig. 1; the dial readings in this case givetwice the average deflections relative to the panel center of
24、 thefour points at which the dial and dial stem supports touch thepanel.9. Calculation9.1 Calculate the shearing modulus of elasticity as follows:G 5 3u2P/2h3where:G = shearing modulus, psi (or MPa),P = load applied to each corner, lbf (or N),h = thickness of the plate, in. (or mm), = deflection rel
25、ative to the center, in. (or mm), andu = distance from the center of the panel to the point wherethe deflections are measured, in. (or mm).NOTE 3The value of P/ is generally taken as the slope of theload-deflection curve.10. Variables Influencing Shear Modulus10.1 Moisture ContentCut a moisture cont
26、ent samplehaving minimum area of 4 in,2(26 cm2) from the clear areas ofthe specimens and weigh immediately after each test. Whereadditional tests are to be made on the plate, a satisfactorymoisture content specimen may be provided at the time thespecimens are originally cut, in which case subject th
27、esespecimens to the same conditioning as the plate. If inspectionof the edges reveals the presence of a knot in any ply of aplywood panel, select a second specimen. Moisture contentspecimens also serving as specific gravity specimens shall befree of voids. Moisture content determinations shall be ma
28、de inaccordance with Test Methods D4442.10.2 Specific GravitySpecific gravity determination shallbe made in accordance with Test Methods D2395. The speci-men may be the same as that for moisture content determina-tion but must be at least 2 in.3(33 cm3) in volume, and be freeof visible knots or void
29、s.FIG. 1 Shear Modulus Test of Structural Panel Showing Method of Loading and Observing the Deflections Along the DiagonalsD3044 162NOTE 4The moisture content and specific gravity as determinedabove are the average values. In plywood made up of thin veneers, theglue may constitute a significant part
30、 of the total mass, and as a result thecalculated specific gravities and moisture contents may vary substantiallyfrom the true values for the veneers. In some instances it may be desirableto take this into account.11. Report11.1 The structural panel specimen shall be described as tospecies, construc
31、tion, and adhesive type used in its manufac-ture. Data for individual specimens and specimen averagesshall include:11.1.1 Panel thickness,11.1.2 Moisture content,11.1.3 Specific gravity,11.1.4 Modulus of rigidity, and11.1.5 Load-deflection diagrams.11.2 When specified, additional data shall include,
32、 but arenot limited to the maximum applied load, grade, ProductStandard, span rating, Performance Category, bond classifica-tion and manufacturing characteristics which may influenceresults.12. Precision and Bias12.1 The precision and bias of this test method have not yetbeen determined, but when da
33、ta are available, a precision andbias statement will be included.13. Keywords13.1 shear modulus; structural panel; woodASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressl
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36、nd. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. I
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