Svojstva i mogućnost upotrebe kombinovanog LVL-a topole i bukve za izradu prozorskih okvira

Abstract

Predmet ovog rada je ispitivanje fizičkih i mehaničkih svojstava topolovih LVL ploča spolja dodatno ojačanih bukovim furnirom, kao i ispitivanje čvrstoće ugaonih elemenata veze za prozor izrađenih od ovog materijala. Ploče su presovane suvim vrućim postupkom u industrijskim uslovima, a kao vezivno sredstvo korišćen je FF fenol - formaldehidni lepak. Uzorci za ispitivanje čvrstoće ugaonih spojeva spajani su dvostrukim prizmatičnim čepom i prorezom pomoću PVA-c lepka klase D4. Statistička analiza pokazala je da postoji značajna razlika u vlažnosti i gustini ploča po debljinama dok kod tvrdoće ploča značajnost razlike ne postoji. Rezultati smicajne čvrstoće u sloju lepka pokazali su da su i FF i PVA-c D4 lepak ispunili uslove propisane standardom. Podaci dobijeni ispitivanjem elementa veze za prozor pokazali su da spoj dvostruki čep i prorez spojen pomoću PVA-c lepka tip D4, u potpunosti može primeniti u proizvodnji i eksploataciji prozora pojačane nosivosti.

The subject of this paper was a research of physical and mechanical properties of LVL composed of peeled poplar veneers in core layers and only outer layers of beech peeled veneers, so as the examination of window frame glue joint strength produced of this material. LVL boards have been hot pressed in industrial conditions, using appropriate phenol formaldehyde (PP) adhesive. Samples for corner window frame glue joint strength testing were glued with PVAc D4 class adhesive. Statistical analysis showed that there were significant differences both in moisture content and density of LVL boards regarding their thickness, while in the case of hardness this difference did not exist. Examinations of LVL glue line shear strength showed that both phenol formaldehyde (PP) and PVAc D4 class adhesives fulfilled standard requirements. The results of corner window frame double tenon glue joint strength produced from combined poplar-beech veneer LVL indicated that such material could be used to produce window frame corner joint, strong enough to withstand the additional load, without an increase of the cross section.