Definition of the Strength Assessment of the Extension of Wooden Elements with Knots

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UDС

624.00

DOI:

10.17238/issn0536-1036.2015.1.103

Abstract

Wood belongs to the materials with the considerable anisotropic qualities. These qualities have influence to the strained-deformed characteristics of material. Besides, the real wood construction has such defects of structure as knots. To calculate the theoretical definition of the strained state of the element with a knot the design model is developed. The paper considers the anisotropic plate with two anisotropic axises: longitudinal and lateral. The extension of the plate is plankwise with the spreaded load. To make the calculations easier it’s better to change a knot by a hole and calculate wood element with a hole. The tensile stress is calculated after the theory of elasticity of the anisotropic body. The stress concentration factors and the step-down ratio were calculated. To verify the calculations the tensile strength was determined experimentally. The plates of 400?50?5 mm with and without knots were tested by tense.

Authors

L.A. Gubenko1, Candidate of Engineering, Associate Professor M.G. Khandov2, Engineer

Affiliation

1Northern (Arctic) Federal University named after M.V. Lomonosov, Naberezhnaya Severnoy Dviny, 17, Arkhangelsk, 163002, Russia; е-mail: gubenko-L@mail.ru  2Building Mounting Company no.1, Timme, 26, Arkhangelsk, 163061, Russia; е-mail: egick@list.ru

Keywords

knot, hole, stress, tensile strength, stress concentration, anisotropy.

References

1. Lehnitskii S.G. Teorija uprugosti anizotropnogo tela [Theory of Elasticity of the Anisotropic Body]. Moscow, 1977. 416 p. 2. Savin G.N. Koncentracija naprjazhenij okolo otverstij [Stress Concentration Near the Holes]. Moscow, 1951. 496 p.