Stress Concentration Around Knots in Laminated Beams
Keywords:
Knot effects, orientation of knots, laminated beams, St. Venant's PrincipleAbstract
A formal elastic solution of the stresses and displacements occurring in a laminated beam, with an arbitrarily located elliptic or circular knot, subjected to static bending is presented. The solutions are obtained by using the theory of complex variables in plane elasticity. Numerical examples of the stress concentration are illustrated with graphs in which comparisons are made between the cases of sound knot, decayed knot, knothole, and wooden plug. The effects of size, shape, location, orientation, and material property of the knot on the stress concentrations are discussed.References
Bartolomeo, E. D. 1980. A finite element investigation of the stress distribution around knots in wood. M.S. thesis, SUNY, Syracuse, NY.nFreas, A. D. 1962. Factors affecting strength and design principles of glued laminated construction. USDA For. Prod. Lab. Res. Rep. 2016.nGoodman, J. R., A. Dabholker, and J. Bodig. 1980. Verification of a model for tension behavior of wood with knots. Presented at the 34th FPRS Annual Meeting, Boston.nKoch, P. 1972. Utilization of the southern pines. Vol. 1: The raw material. Agricultural Handbook No. 421.nLekhnitskii, S. G. 1969. Anisotropic plates, Translated by S. W. Tsai and T. Cheron, Gordon and Breach Science Publishers, New York, London.nPhillips, G. E., J. Bodig, and J. R. Goodman. 1981. Flow-grain analogy. Wood Sci.14(2):55-64.nPrice, E. W. 1967. Stress distribution in the vicinity of knot-holes in construction lumber under bending forces. M.S. thesis, College of Forestry, University of Washington.nPugel, A. D. 1980. Evaluation of selected mechanical properties of coniferous knotwood. M.S. thesis, Department of Forest and Wood Sciences, Colorado State University.nSavin, G. N. 1961. Stress concentration around holes. Pergamon Press, London, New York, Paris.nSiimes, F. E. 1944. Mitteilungen über die Untersuchung von Festigkeitseigenschaften der Finnischen Schnittwaren. Silvae Orbis. No. 15. Berlin-Wannsee.nSmith, C. B. 1944. Effect of elliptic or circular holes on the stress concentration in plates of wood or plywood considered as orthotropic materials. USDA For. Prod. Lab. Res. Pre. No. 1510.nTang, R. C. 1968. Boundary value problems in anisotropic elasticity. Ph.D dissertation, North Carolina State University, Raleigh, NC.nUenoya, M., and R. G. Redwood. 1978. Buckling of webs with openings. Computers and Structures9(2):191-199.nUSDA Forest Products Laboratory. 1974. Wood handbook: Wood as an engineering material. USDA Agriculture Handbook No. 72, Rev.nWangaard, F. F. 1950. The mechanical properties of wood. John Wiley & Sons, Inc., New York.n
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