ASTM D3499-1994(2005) Standard Test Method for Toughness of Wood-Based Structural Panels《木基结构板韧性的标准试验方法》.pdf

1、Designation: D 3499 94 (Reapproved 2005)Standard Test Method forToughness of Wood-Based Structural Panels1This standard is issued under the fixed designation D 3499; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last

2、revision. A number 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 This test method for toughness of wood-ba

3、sed structuralpanels covers the 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 la

4、yers.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. Referen

5、ced Documents2.1 ASTM Standards:2D 143 Method of Testing Small Clear Specimens of TimberD 2395 Test Methods for Specific Gravity of Wood andWood-Base MaterialsD 4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base Materials3. Significance and Use3.1 The failure of wood-ba

6、sed materials with impact loadsis sometimes an important criteria in design considerations. Inaddition, some effects on the mechanical 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 M

7、ethods D 143 can be used to measurethe toughness of solid clear wood specimens.4. Apparatus4.1 The toughness testing machine (Note 1) shall 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. T

8、he pendulum shall consistof a bar to which is fastened a weight adjustable to differentpositions and shall carry at its upper end a drum 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 stationar

9、y graduated scale or dial anda vernier operated by the moving drum shall be provided forreading the angles through which the pendulum swings. 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

10、 load is applied to thespecimen when the pendulum swings to within approximately15 of the vertical so as to produce complete failure by the timethe downward swing is completed.NOTE 1The set-up shown in Fig. 1 has been found to give satisfactoryresults.5. Test Specimen5.1 The toughness test specimen

11、to be used in conjunctionwith the Forest Products Laboratory toughness testing machineshall be58 in. (16 mm) in width for material less than58 in. (16mm) in thickness, and the thickness of the specimen shall beequal to that of the material. For material more than58 in. (16mm) in thickness, the width

12、 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 thematerial in accordance with Table 1. The actual cross-sectionaldimensions, and the specimen and span length shall be mea-sured to an accuracy of n

13、ot 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 reaching equilibrium moisture content at specifictemperature and relative humidity conditions shall be condi-tioned to approximate constant wei

14、ght in controlled atmo-spheric conditions. For approximating moisture conditions ofpanels used under dry conditions, a relative humidity of 65 62 % at a temperature of 68 6 6F (20 6 3C) is recommended.1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsi

15、bility of Subcommittee D07.03 on Panel Products.Current edition approved Oct. 1, 2005. Published October 2005. Originallyapproved in 1976. Last previous edition approved in 2000 as D 3499 74 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service

16、at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Span and Supports7.1 The test specimen shall

17、be supported as a beam on twovertical pins, which exert reactions that are perpendicular to theplane of the panels or laminations. These pins shall be adjustedto the span length taken from Table 1 which provides for aspecimen overhang of 1 in. (25 mm) at each end.8. Loading Procedure8.1 Apply the lo

18、ad at the center of the span perpendicular tothe plane of the plies. Apply the load through a tup, attached toa flexible cable, having a radius of curvature approximatelyequal to one and one-half times the depth of the test specimen.Choose the weight position and initial angle of the pendulumso that

19、 complete failure of the specimen is obtained on onedrop. Most satisfactory results are obtained when the differencebetween the initial and final angle is at least 10.NOTE 2In order to satisfy these conditions properly, it will benecessary to use a toughness testing machine of proper capacity for th

20、especimens being tested. The larger size specimens can be tested in thelarge size Forest Products Laboratory toughness machine which has amaximum capacity of 673 inlbf (76 J), while tests of smaller specimenscan be made in the 20 inlbf (2.3 J), capacity intermediate size machine.9. Calculation9.1 Re

21、ad the initial and final angle to the nearest 0.2 bymeans of the attached vernier. Calculate the toughness asfollows:T 5 wL cos A22 cos A1! (1)where:T = toughness (work per specimen), inlbf (or J),w = weight of the pendulum, lbf (or kgf),L = distance from the center of the supporting axis to thecent

22、er of gravity of the pendulum, in. (or mm),A1= initial angle (Note 3), deg, andA2= final angle the pendulum makes with the verticalafter failure of the test specimen, deg.NOTE 3Since friction is compensated for in the machine adjustment,the initial angle may be regarded as exactly 30, 45, or 60, as

23、the case maybe.10. Moisture Content and Specific Gravity10.1 Moisture ContentCut a moisture content samplewhich is full width and at least 1 in. (25 mm) in length from thespecimen and weigh immediately after each test. If inspectionof the edges of a plywood specimen reveals the presence of aknot in

24、any of the inner plies, select a second sample. Moisturecontent samples also serving as specific gravity samples shallbe free of voids. Moisture content determinations shall bemade in accordance with Test Method D 4442.10.2 Specific GravityDetermine the specific gravity inaccordance with Test Method

25、s D 2395. The specimen may bethe same as that for moisture content determination but musthave volume of at least 0.2 in.3(3 cm3), and be free of visibleknots or voids.11. Report11.1 The specimen shall be described as to species, con-struction, and adhesive type used in its manufacture.11.2 Data for

26、individual specimens and specimen averagesshall include:11.2.1 Specimen thickness,11.2.2 Length,11.2.3 Span length,11.2.4 Moisture content,FIG. 1 Toughness Test of Structural Panel Showing Load Applied to Specimen When Pendulum is Approximately 15 from the VerticalTABLE 1 Length of Toughness Test Sp

27、ecimensPanel Thickness, in. (mm)Span Length Specimen Lengthin. mm in. mmup to18 (3), incl 2 50 4 100Over18 (3) to14 (6), incl 3 75 5 125Over14 (6) to38 (9), incl 5 125 7 175Over38 (9) to12 (12), incl 6 150 8 200Over12 (12) to58 (16), incl 8 200 10 250Over58 (16) to34 (18), incl 9 230 11 275Over34 (1

28、8) to 1 (25), incl 12 300 14 350D 3499 94 (2005)211.2.5 Specific gravity, and11.2.6 Toughness (work per specimen), inlbf (or J).12. Precision and Bias12.1 The precision and bias of this test method have not yetbeen determined, but when data are available, a precision andbias statement will be includ

29、ed.13. Keywords13.1 plywood; structural panels; 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 expressly advised that determination of the validity of any such patent rig

30、hts, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for

31、 revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing

32、 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. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 3499 94 (2005)3