Regularities process of the waste wood destruction

This article deals with the problem of using wood raw material complex processing for the new raw materials production. The article describes the use of new materials based on long-fiber fractions and division of waste wood harvesting process fragments in the following ways: compression and impact, as well as the process of degradation of wood in transverse loading. The article describes stages of the waste wood material model destruction under compressive load across the grain. The test samples are cut from the branches and twigs. Several assumptions are being introduced: the process of destruction has a multistage character; samples are uniform in structure and have transverse isotropy; relationship between stress and strain are linear up to the moment of occurrence of cracks; samples have cylindrical shape with a radius of a circle in cross section, equal to the average radius of sample in its cross section. A model of a multistage fracture is proposed in this article. The first stage lasts from the load application to the specimen until the occurrence of the first crack. The second stage lasts from the moment of cracks occurrence until the loss of the sample integrity. The third stage lasts from full disclosure of the initial crack until the load carrying particles. To describe the first stage author suggests using the theory of elasticity. It should be noted that the maximum normal tensile stresses are formed along the direction of diameter, i. e. initial crack occurs in this direction. Factors of a fracture are: medullary rays; core (the weakest element of the timber). The author proposes to use methods of fracture mechanics in the mathematical study of the second phase.