1、Designation:D349911Standard Test Method forToughness of Wood-Based Structural Panels1This standard is issued under the fixed designation D3499;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 pare
2、ntheses 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 Department of Defense.1.Scope1.1 This test method for toughness of wood-based structuralpanels covers the
3、 determination of energy necessary to causefailure by impact loading of a beam specimen which is simplysupported and loaded at midspan.Wood-based structural pan-els in use include plywood,waferboard,oriented strand board,and composites of veneer and of wood-based layers.1.2 The values stated in inch
4、-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 standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theres
5、ponsibility 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:2D143 Test Methods for Small Clear Specimens of TimberD2395 Test Methods for Specific Gravit
6、y of Wood andWood-Based MaterialsD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base Materials3.Significance and Use3.1 The failure of wood-based materials with impact loadsis sometimes an important criteria in design considerations.Inaddition,some effects on the mechan
7、ical properties of wood,such as decay,are best evaluated by measuring its toughness.This test method serves to evaluate the toughness of structuralpanel products while Methods D143 can be used to measurethe toughness of solid clear wood specimens.4.Apparatus4.1 The toughness testing machine(Note 1)s
8、hall consist ofa frame supporting a pendulum,being so arranged that ameasured amount of the energy from the fall of the pendulummay be applied to a test specimen.The pendulum shall consistof a bar to which is fastened a weight adjustable to differentpositions and shall carry at its upper end a drum
9、or pulleywhose center provides the axis of rotation.The force shall beapplied to the specimen by means of a flexible steel cablepassing over the drum.A stationary graduated scale or dial anda vernier operated by the moving drum shall be provided forreading the angles through which the pendulum swing
10、s.Themachine shall be adjusted before test so that the pendulumhangs truly vertical and adjusted to correct for friction.Thecable shall be adjusted so that the load is applied to thespecimen when the pendulum swings to within approximately15 of the vertical so as to produce complete failure by the t
11、imethe downward swing is completed.NOTE1The set-up shown in Fig.1 has been found to give satisfactoryresults.5.Test Specimen5.1 The toughness test specimen to be used in conjunctionwith the Forest Products Laboratory toughness testing machineshall be58in.(16 mm)in width for material less than58in.(1
12、6mm)in thickness,and the thickness of the specimen shall beequal to that of the material.For material more than58in.(16mm)in thickness,the width shall be equal to the thickness ofthe material,thus making the specimen square in cross section.The length shall be determined from the thickness of themat
13、erial in accordance with Table 1.The actual cross-sectionaldimensions,and the specimen and span length shall be mea-sured to an accuracy of not less than 60.3%or 0.001 in.(0.02mm)whichever is larger.6.Control of Moisture6.1 Panel specimens to be tested at specific moisture con-tents or after reachin
14、g equilibrium moisture content at specifictemperature and relative humidity conditions shall be condi-tioned to approximate constant weight in controlled atmo-spheric conditions.For approximating moisture conditions ofpanels used under dry conditions,a relative humidity of 65 62%at a temperature of
15、68 6 6F(20 6 3C)is recommended.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 May 1,2011.Published June 2011.Originallyapproved in 1976.Last previous edition approved in 2000
16、as D3499 94(2005).DOI:10.1520/D3499-11.2For 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 7.Span and Supports7.1 The test specimen shall be supported as a beam on twovertical pins,which exert reactions that
