PREDICTING WOOD STRENGTH UPON COMPRESSION ALONG FIBERS

Vladimir Glukhikh, Anna Okhlopkova

Abstract


According to the basic principles of bionics, internal forces are formed in the tree stem during its growth. Appearance and development of such forces are mainly caused by external effects, where the main external effect is a wind load. Internal forces develop in response to the powerful effect of the wind load on tree stems. Such forces ensure the resilience of tree stems. They prevent the tree stem from breaking and falling together with the roots.
The established system of internal forces does not disappear upon log sawing. All sawn-timber pieces obtained after log sawing are stressed to various extents. This affects the natural curvature and wood strength upon compression along fibers and static bending. The established mathematical relationship between the size of the core zone and the value of internal forces makes it possible to analyze changes in the wood strength upon compression along fibers along the board. The wood strength depends on the log taper, relative size of the core zone, and distribution of internal forces over the tree stem volume.
According to the obtained data, the ratio of wood ultimate strengths upon compression along fibers and static bending depends on the nature of internal forces' distribution over the tree stem section. The paper presents the results of theoretical studies on the wood strength upon compression along fibers under various laws of internal forces' variation along the length of the log.

Keywords


Internal forces, wood strength upon compression along fibers, ultimate strength, wood strength, log taper

Full Text:

PDF

References


Banks, C.H. (1966). Sawing and stacking timber to reduce warp. Timber technologie, 3.

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)

Glukhikh, V., Okhlopkova, A. (2017). Formirovanie karmashkov v stvolakh derevev listvennitcy daurskoi [Formation of pockets in the trunks of larch trees of the Dahurian]. Lesnoy zhurnal [Forestry journal], 5, pp. 35–52. DOI: 10.17238/issn0536-1036.2017.5.35 (in Russian)

Glukhikh, V., Okhlopkova, A. (2017). Numerical analysis of softwood sawn timber. In: proceedings of Springer Lecture notes in computer science. Bulgaria: Sozopol.

Glukhikh, V. (2017). Change in wood strength under static bending and compression along fibers in the process of tree growth. Architecture and Engineering, 2 (1), pp. 24-31. DOI: 10.23968/2500-0055-2017-2-1-24-31

Kontek, W., Paprzycki, O. (1968). Wplyw wymiarow probek i ukladu slojow rocznych na sile paczenia sie drewna [Effect of sample sizes and annual growth system on the strength of wood joining]. Prace komisyi technologie drewna. Poznan. (in Polish)

Kubler, 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)

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

Okura, S., Ozawa, K., Takagaki, K. (1967). Twisting warp of boards in relation to fiber direction. Japan Wood Res. Soc., 9 (4).

Rodionov, S.V., Maiatin, A.A., Zonov, E.G. (1956). Profilograf dlia izucheniia velichiny korobleniia zagotovok [Prophylograph for studying the value of warping of blanks]. Derevoobrabativaushaya promishlennost’ [Woodworking industry], 11, pp. 10–13. (in Russian)

Stevens, W.C., Mech, E. (1960). Twist in sitka Spruce. Timber trade journal, 2.

Strikha, I.A. (1954). Prichina deformatcii detalei iz drevesiny i sposoby ee umensheniia [The cause of deformation of wood components and ways to reduce it]. Derevoobrabativaushaya promishlennost’ [Woodworking industry], 7. (in Russian)




DOI: https://doi.org/10.23968/2500-0055-2018-3-1-3-6

Refbacks

  • There are currently no refbacks.




     

ISSN: 2500-0055