Influence of layered structure of composite timber floor boards on their hardness

The possibility of using composite elements of flooring pine veneers with knotholes for the production of supporting layers has been determined. This assessment was made on the basis of the Brinell hardness measurement of the face layer of five-layer composites with empty spots in their structure imitating knotholes of various diameters (10, 20 and 50 mm). The dependencies obtained from empirical determinations were supported by numerical analysis. It was found that it is possible to use veneers with defects (empty spots) with a diameter of up to 20 mm to produce composites of three and more layers of wood (counting from the face layer). The anatomical section of the exposed wood on the face (radial cross-section, tangential section) of the layered composite does not affect the obtained hardness values.
Ispitivanjem je potvrđena mogućnost uporabe furnira od borova drva s rupama od kvrga kao srednjeg sloja u proizvodnji višeslojnih podnih obloga. Ta je procjena napravljena na temelju mjerenja tvrdoće prema Brinellu gaznog sloja peteroslojne podne obloge s rupama različitih promjera (10, 20 i 50 mm) unutar strukture obloge koje simuliraju rupe od kvrga. Ovisnosti dobivene iz empirijskih rezultata potkrijepljene su računskom analizom. Utvrđeno je da je za proizvodnju podnih obloga od tri i više slojeva (brojeći od gaznog sloja) moguće upotrijebiti furnire s greškama (s neispunjenim rupama) promjera do 20 mm. Anatomski presjek izloženog drva na licu višeslojne podne obloge (radijalni i tangentni presjek) ne utječe na vrijednosti tvrdoće.