ASTM_D_3044_-_94_2011.pdf

Designation:D304494(Reapproved 2011)Standard 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 number 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 the 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 elastic properties,the method gives the effectiveshearing modulus.Wood-based structural panels in use includeplywood,waferboard,oriented strand board,and composites ofveneer and of wood-based layers.NOTE1This test method is primarily designed for material in whichthe grain or orientation of the individual plies,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 elastic-ity moment of inertia)values along both diagonals shall be equal.1.2 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 limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D2395 Test Methods for Specific Gravity of Wood andWood-Based MaterialsD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base Materials3.Summary of Test 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 plate.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 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 appearsin the equation governing the bending of a plate.This is themodulus that is needed in discussing the deflection andbuckling of plates.5.Control of Moisture Content5.1 The structural 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 temperature 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 the length and widthnot less than 25 nor more than 40 times the thickness.Thethickness,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 specimens with initial curvature.7.Loading Procedure7.1 Support the test specimen on supports having a radius ofcurvature not greater than14in.(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 the corners,first attach metal plates as shown in Fig.1This 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 Nov.1,2011.Published November 2011.Originallyapproved in 1972.Last previous edition approved in 2000 as D3044 94(2006).DOI:10.1520/D3044-94R11.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 1.Fig.1 also shows sugges