Vladimir Glukhikh


According to the basic principles of bionics, internal forces are formed in the tree trunk during its growth; these forces generate the strength and resistance of the tree to influence of wind loads and its own weight. When internal forces appear, the strength of wood cells starts developing. The inflow of nutrients is the most intense in the most strained parts of the trunk. The wood responds to external effects through increasing the thickness of cell walls, their density, the modulus of elasticity, etc. The central part of the trunk starts experiencing internal compressive stresses along fibers and tensile stresses dominate the peripheral areas. The paper substantiates the relationship between the size of the core zone and the stress-strain state of wood.
Under effects of internal forces the wood is formed during the growth of a tree as an anisotropic material having different tensile and compressive strengths along and across fibers. The hypothesis on parabolic distribution of internal forces along fibers is described making possible both determining the dimensions of the core and sap zones, and establishing mathematical correlation between the ultimate stress limits of wood during compression along fibers and under static bending. This was proved in numerous experimental studies made by different Russian and foreign research groups. According to calculations given in the paper, the ratio of the ultimate stress limits of wood of various species under compression along fibers to the ultimate stress limits under static bending depends on the nature of distribution of internal forces along the tree trunk. Application of computer technologies makes it possible to use the results obtained to produce sawn timber having required strength indicators.


Tree growth, internal forces, along-the-fiber compression strength, static bending.

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Ashkenazi, Ye.K. (1978). Anizotropiia drevesiny i drevesnykh materialov [Anisotropy of wood and wood materials]. Moscow: Forest Industry, 224 p. (in Russian)

Belov, S.V. (1974). Veter – glavnyi faktor, opredeliaiushchii formu stvolov derev'ev i ikh ustoichivost' [Wind as the main factor determining the shape of tree trunks and their stability]. Forestry, Forest Cultures, Soil Science, 3, pp. 3–24. (in Russian)

Cucera, B. (1970). Einfluss einiger Fehler auf die Biegefestigkeit von Fichtenholz [Effect of separate errors on bending resistance of the spruce wood]. Holztechnologie [Technology of wood], 11(4), pp. 210–216. (in German)

Glukhikh, V.N., Akopyan A.L. (2013). K voprosu o napriazheniiakh rosta v dereve [On the problem of growth stresses in the tree]. In: proceedings of the International Scientific and Practical Conference “Modern problems of wood processing”. Saint Petersburg: Saint Petersburg Polytechnic University, 185 p. (in Russian)

Glukhikh, V.N., Akopyan, A.L. (2016). Nachal'nye napriazheniia v drevesine [Internal forces in the wood]. Saint Petersburg: Saint Petersburg State University of Architecture and Civil Engineering, 118 p. (in Russian)

Grigorovich, V.K. (1952). O naivygodneishem napravlenii volokon v izdeliiakh iz anizotropnykh materialov [On the most advantageous directions of fibers in products made of anisotropic materials]. Reports of the Academy of Sciences of the USSR, 86(4), pp. 152–160. (in Russian)

Ivanov, L. A. (1934). O vliianii vetra na rost dereva [Effects of wind on wood growth]. Botanical Journal of the USSR, 13(3). (in Russian)

Kollmann, F. (1951). Technologie des Holzes und der Holzwerkstoffe [Processing of wood and wood materials]. Berlin. Springer Publishing House. (in German)

Kübler, H. (1959). Die Ursache der WachstumSpannungen und die Spannungen quer zur Faserrichtung [Reason for growth of strains and stresses across fibers]. Holz als Roh- und Werkstoff [Wood as a raw material and goods], 17(1), pp. 1–9. (in German)

Kufner, M. (1978). Elastizitätsmodul und Zugfestigkeit von Holz verschiedenen Rohdichte in Abhängigkeit vom Feuchtigkeitgehalt [Modulus of elasticity and breaking strength factor of wood of different true specific density, depending on the moisture content]. Holz als Roh- und Werkstoff [Wood as a raw material and goods], 11, pp. 435–440. (in German)

Kuznetsov, A.I. (1950). Vnutrennie napriazheniia v drevesine [Internal forces in the wood]. Moscow: State Publishing House of Forest, Paper, and Wood Processing Industries, 60 p. (in Russian)

Razdorsky, V.F. (1934). Printsipy stroeniia skeleta rastenii [Principles of the structure of the plant frame]. Nature Journal, 9. (in Russian)

Temnov, V.G. (1996). Bionicheskii printsip regulirovaniia parametrov napriazhenno-deformirovannogo sostoianiia konstruktivnykh sistem pri ikh proektirovanii i ekspluatatsii [Bionic principles of regulating parameters of the stress-strain state of structural systems during their design and operation]. In: proceedings of the 53rd scientific conference of professors, teachers, scientists, engineers and post-graduate students of the University. Saint Petersburg: Saint Petersburg State University of Architecture and Civil Engineering. (in Russian)

Temnov, V.G. (2001). Konstruktivnye sistemy v prirode i stroitel'noi tekhnike [Structural systems in nature and construction engineering]. Saint Petersburg: Computerburg, 61 p. (in Russian)

Volynsky, V.N. (2006). Vzaimosviaz' i izmenchivost' fiziko-mekhanicheskikh svoistv drevesiny [Interrelation and variability of physical and mechanical properties of wood]. Arkhangelsk: Arkhangelsk State Technical University, 196 p. (in Russian)

Ylinen, A. (1952). Über die mechanische Schaftformtheorie der Bäume [On the theory of the shape of the tree trunk]. Higher technical school in Finland, vol. 6, 51 p. (in German)

Ylinen, A. (1956). Über den Einfluss des Spätholzteiles und der Rohwichte aus die Elastizitätsmoduln die Poussonischen Konstanten und die Schubmoduln bei Holz mit ausgeprägten Yahrringbau [On the influence of the late wood and true specific density on the elastic modulus, Poisson's ratio and moduli of transverse elasticity in the wood with a pronounced structure of annual rings]. Higher technical school in Finland. (in German)



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