Лесотехнически Университет

Summary

Subject of the investigation is the prognostication of the resistance of structural three- and multilayer particleboards (SPB) to continuous static bending load under the conditions of relatively dry environment. The theoretical prerequisites of the development are the rheological model of SPB and the schematic diagram of their deformation during continuous load, the algorithm and the nomogram to determine the stiffness of SPB on the basis of their simulation model of a “double T-beam” and the regression dependences of the moduli of elasticity of SPB with various thicknesses on their volumetric density.

An algorithm and a nomogram to determine the continuous load factor of SPB to prognosticate their resistance as structural elements in furniture and building structures have been proposed. The creep coefficient of composite particleboards under operating conditions has been determined.

Summary

The oriented strand board (OSB) is a relatively modern type of engineered wood product used broadly in construction industry and the furniture production. An essential structural parameter of the OSB plate is the orientation of the layering strands (flakes) in the 3-D space XYZ, which pre-determines significant diversity in the directional strength of the final material. A structural model of a 3-layered OSB is presented and the parameters of the morphological structure are analyzed. Optimal limits of the principal morphology criteria ratios are established and optimized dimensions of the flakes are recommended. An empirical equation for calculating the bending strength of the manufactured composite plates is derived. In conclusion, an average value of the principal ratio RE = Eb׀׀ / Eb⊥= σb׀׀ / σ0⊥= 2,25 is suggested, that could be used in the OSB production.

Summary

Subject of the study is the macrostructure of wood particle based composites (WPBC) and the possible rationalization of their significant structural parameters with the goal of increasing the effectiveness of material’s use in the design practice.

The physical nature of the WPBC can be defined as an anisotropic layered wood-polymeric material, fabricated from adhesively bonded wood particles. The macrostructure characteristics and the physical and mechanical properties of the composite material predetermine it’s broad application in the furniture production.

The rationalized macro structural characteristic of the WPBC is established on the basis of theoretical and experimental studies determining the effective dimensions and dispersion of the wood particles. Structural deformation and strength models are developed and analyzed for short and long-term loading.

The impact of the major structural parameters on the complex qualitative indicator of WPBC is defined using mathematical regression modeling.