Variability of Young's Modulus and Wood Tensile Strength in the Work Cycle

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Abstract

The article describes the process of allocating each of the distributions of mechanical properties and calculates integral distributions of wood tensile strength in cutting areas and saw timber. We established a previously unknown pattern of distribution of Young's modulus and tensile strength as a sum of four normal distributions with their arithmetic means and estimation of quadratic means. The original, natural distribution of Young's modulus and tensile strength of wood logs steadily deteriorated as a result of long-term storage of raw materials in piles in industrial depots, on sawmills in winter stocks, in interoperation stocks after log sorting by size and, finally, in stocks for drying and finished product stocks. Sampling was done at the stage of saw timber length formation, so that the samples contained the entire information about their mechanical properties. Nondestructive testing of mechanical properties allowed us to sort saw timber by strength and rational use of wood in durable structures.

Authors

V.F. Dounaev, Candidate of Engineering

Northern (Arctic) Federal University named after M.V. Lomonosov

Affiliation

Northern (Arctic) Federal University named after M.V. Lomonosov

Keywords

Young's modulus, tensile strength, equivalent time of loading, cutting area, saw timber bundle, normal distribution, arithmetic mean, estimation of standard deviation.

References

1. Borovikov A.M., Ugolev B.N. Handbook on Wood. Moscow, 1989. 296 p. 2. Dounaev V.F. Sawmilling: from Geometry to Physics, Mechanics and Technology. Lesnoy zhurnal, 2008, no. 1, pp. 90–100. 3. Dounaev V.F. Melekhov V.I. Pattern Changes of Wood Mechanical Properties in Time Under Deformation. Lesnoy zhurnal, 2010, no. 3, pp. 101–109. 4. Sobolev Y.S. Wood as a Construction Material. Moscow, 1979. 248 p. (in Russian).