diplomsko delo
Žan Kavčič (Author), Željko Gorišek (Reviewer), Aleš Straže (Mentor)

Abstract

Raziskali smo gostoto ter nekatere mehanske lastnosti, povezane s staranjem lesa. Vzorčili smo hrastov (Quercus spp.) konstrukcijski les starosti od 4 let do 512 let z znanimi dendrokronološkimi podatki. Na 31 izbranih kolutih stare hrastovine smo v laboratorijskih pogojih izmerili v vseh anatomskih smereh lesa hitrost preleta ultrazvoka ter togost lesa. S statističnimi testi smo preverili še trdoto prečno na vlakna ter strižno trdnost vzporedno z vlakni. Glede na starost lesa smo ugotovili neznačilne spremembe gostote lesa, strižne trdosti lesa, hitrosti ultrazvoka ter dinamične togosti v vseh anatomskih smereh hrastovine. Največjo togost hrastovega lesa smo določili vzporedno z vlakni, 4-krat manjšo pa v radialni in tangencialni smeri. Trend počasnega zmanjševanja vrednosti s staranjem hrastovine, vendar statistično neznačilen, smo ugotovili pri trdoti lesa prečno na vlakna, v radialni in tangencialni smeri. Tudi specifična trdota, kot razmerje trdote in gostote lesa, je bila pri stari hrastovini nekoliko nižja kot pri recentnem hrastovem lesu.

Keywords

les;hrast;staranje;mehanske lastnosti;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [Ž. Kavčič]
UDC: 630*812
COBISS: 3027849 Link will open in a new window
Views: 656
Downloads: 181
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Other data

Secondary language: English
Secondary title: Mechanical properties of oak wood from historical constructions
Secondary abstract: The density and some mechanical properties associated with the ageing of wood were investigated. We have sampled oak construction wood (Quercus spp.) from four years to 512 years old with known dendrochronological data. On 31 selected discs of old oak, the speed of ultrasound and the stiffness of the wood in all anatomical directions of wood were measured in laboratory conditions. With static tests, the hardness transverse to the grain and the shear strength parallel to the grain were tested as well. Depending on the age of the wood, uneven changes in the density of wood, shear strength of the wood, the speed of ultrasound and dynamic stiffness in all anatomical directions of wood have been observed. The highest stiffness of oak wood was determined parallel to the grain. Similar results, but four times smaller, were determined in the radial and tangential directions. The trend of a slow decrease in value with oak aging that is statistically insignificant was found in the hardness of the wood transverse to the grain, and in radial and tangential directions. The ratio of hardness and density of the wood, known as the specific hardness, was somewhat lower in the old oak than the recent oak wood.
Secondary keywords: wood;oak;ageing;mechanical properties;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za lesarstvo
Pages: VIII, 24 f.
ID: 11109025