Jaša Saražin (Author), Milan Šernek (Author), Miha Humar (Author), Aleš Ugovšek (Author)

Abstract

Cilj raziskave je bil definirati in razviti lesni kompozit z majhnim presekom, ki bo lepljen pri sobni temperaturi in bo lahko uporabljen kot ojačitveni material v lesenih okenskih profilih velikih dimenzij. Na osnovi pregleda objav je bil kot najprimernejši kompozit izbran slojnat furnirni les (LVL). Izbran material za njegovo izdelavo je bil rezan 0,5 mm debel bukov (Fagus sylvatica L.) furnir, ki je bil zlepljen s poliuretanskim lepilom (Purbond HB 440) v 20 mm debel LVL. Ker je bil proučevan tudi učinek termične modifikacije, je bilo pol preizkušancev narejenih iz termično modificiranega furnirja, pol pa iz nemodificiranega. Upogibna trdnost in togost preizkušancev sta bili določeni s tritočkovnim upogibnim testom. Termično modificirani preizkušanci so dosegli 19 % nižjo upogibno trdnost kot nemodificirani, medtem ko se upogibni modul elastičnosti (togost) ni značilno spremenil. Povprečne upogibne trdnosti do 150 MPa so bile zadovoljive, upogibni moduli elastičnosti okoli 13 GPa pa so bili bistveno pod želenimi vrednostmi, kar je bilo pripisano izboru pretankega furnirja in lepljenju pri sobni temperaturi, ki ne omogoča zgoščevanja lepljenca

Keywords

bukev;furnir;LVL;modul elastičnosti;termična modifikacija;upogibna trdnost;

Data

Language: Slovenian
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL BF - Biotechnical Faculty
UDC: 630*832.286:812.71
COBISS: 2846857 Link will open in a new window
ISSN: 0024-1067
Views: 531
Downloads: 121
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Other data

Secondary language: English
Secondary title: Bending strength and stiffness of laminated veneer lumber (LVL) made from thermally modified and unmodified beech veneer
Secondary abstract: The aim of the research was to define and develop a wooden composite with a thin cross-section and which could be used as reinforcement material in oversized wooden window profiles. An additional limitation was to bond the composite at room temperature. Based on a review of the literature, laminated veneer lumber (LVL) was chosen as the best option. The researched LVL samples were made of 0.5 mm thick, cut, beech (Fagus sylvatica L.) veneer, bonded with polyurethane adhesive (Purbond HB 440). Half of the samples were made of thermally modified veneers, and other half of unmodified. Bending strength and stiffness were determined with a three-point bending test. Thermally modified samples had on average 19 % lower bending strength compared to the unmodified samples, but the modulus of elasticity (stiffness) did not change significantly. The bending strength of up to 150 MPa was satisfactory, but the modulus of elasticity of 13 GPa was far below expectations. This is attributed to the selection of too thin veneer and too low bonding temperature, which does not enable densification of the composite
Secondary keywords: beech;veneer;LVL;modulus of elasticity;thermal modificaton;bending strength;
Type (COBISS): Article
Pages: str. 29-36
Volume: ǂLetn. ǂ66
Issue: ǂšt. ǂ2
Chronology: 2017
DOI: 10.26614/les-wood.2017.v66n02a03
ID: 13708084