An Analysis Of Flexural Elastic Behavior Of 3-PLY Southern Pine Plywood
AbstractTwo methods for predicting deflections of 3-ply plywood have been verified experimentally and compared. Both methods can predict accurately the total deflection, pure bending deflection and shear deflection even at a span-to-depth ratio 14:1 of 3-ply southern pine plywood. The approximate method predicts deflections with as much accuracy as the exact theoretical method. The approximate method has the advantage of being simpler in application, and it does not require the knowledge or determination of Poisson's ratios and values of pure modulus of elasticity for the core (ETR) required by the exact method. Both methods require accurate values of modulus of rigidity in "rolling shear" and/or an accurate value of the ratio GTR/GLR. It is suggested that values of GTR for all commercial species, used for production of structural plywood, be determined by an accurate method.
American Plywood Association. 1966. Plywood design specifications. Tacoma, Wash.nAmerican Society For Testing And Materials. ASTM Standards, Part 16. D805-63, 1968. Philadelphia, Pa.nBlblis, E. J. 1969. Flexural rigidity of southern pine plywood. In print, Forest Prod. J.nBlblis, E. J., and J. D. Fitzgerald. 1969. Shear properties of loblolly pine growth zones. Submitted for publication in Forest Prod. J.nBlblis, E. J. 1967. Shear deflection of two species wood beams. Wood Science and Technology, 1(3): 231-238.nBlblis, E. J. 1966. Design considerations for laminated wood beams composed of two species. Forest Prod. J., 16(7): 39-51.nBlblis, E. J. 1965. An analysis of wood-fiberglass composite beams within and beyond the elastic region. Forest Prod. J., 15(2): 81-88.nDoyle, D. V., J. T. Drow, and R. S. McBurney. 1962. Elastic properties of wood. U. S. Forest Prod. Lab. Rpt. No. 1528.nFitzgerald, J. D. 1968. Shear properties of earlywood and latewood of loblolly pine. Master Thesis, Dept. of Forestry, Auburn Univ., Auburn, Ala.nMarch, H. W., and C. B. Smith. 1944. Flexural rigidity of a rectangular strip of sandwich construction. U. S. Forest Prod. Lab. Rpt. No. 1505.nMarch, H. W. 1936. Bending of a centrally loaded rectangular strip of plywood. Physics, 7(1): 32-41.nMunte, B. P., and R. L. Ethington. 1968. Method for evaluating shear properties of wood. U. S. Forest Prod. Lab. R. Note V-PL-0195.nNewlin, J. A., and G. W. Trayer. 1924. Deflection of beams with especial reference to shear deformations. National Advisory Committee for Aeronautics Rpt. No. 180. Washington, D. C.nPalka, L. C. 1967. Loading methods on rolling shear. Forest Prod. J., 17(3): 30-36.nPreston, S. 1954. Effect of synthetic resin adhesives on the strength and physical properties of wood veneer laminates. Yale Univ. School of Forestry Bull. No. 60. New Haven, Conn.nU. S. Forest Products Laboratory. 1964. Bending strength and stiffness of plywood. Research Note FPL-059.nWangaard, F. F. 1950. The mechanical properties of wood. John Wiley and Sons, Inc., New York.n
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.