diplomsko delo
Aljaž Menegatti (Author), Katarina Čufar (Reviewer), Aleš Straže (Mentor)

Abstract

Namesto tradicionalnega vizualnega in čutnega ocenjevanja kakovosti resonančne smrekovine smo v nalogi laboratorijsko analizirali makroskopsko zgradbo ter njene fizikalne, mehanske in akustične lastnosti. Vzorčili smo smrekov les s Pokljuke (1200 m n.v., oddelek 64), z majhnim letnim priraščanjem in jo primerjali s kontrolno smrekovino z nižje ležečega rastišča (Zavratec nad Idrijo, 650 m n.v.). Iz naravno posušenega lesa smo izdelali preizkušance (dimenzij 20 × 20 × 300 mm) za določanje dinamičnih in statičnih mehanskih lastnosti. Dodatno smo izdelali še poliedre (dimenzij 75 × 75 × 75mm) in na njih izmerili hitrosti preleta ultrazvočnega valovanja v vseh anatomskih smereh in ravninah. Strukturne lastnosti smo določili stereo-mikroskopsko, izmerili smo širino branik, delež kasnega lesa ter določili povprečno gostoto lesa. Ugotovili smo, da je smrekov les z dobrimi resonančnimi lastnostmi redek. Le-ta ima nizko gostoto (≤ 400 kg/m3), počasno (do 2 mm) in homogeno priraščanje, z majhnim deležem kasnega lesa (do 23 %). Resonančna smrekovina je vzdolž lesnih vlaken bolj toga in ima značilno manjše dušenje vibracij. Pretvorba mehanske energije v zvočno je pri resonančnem smrekovem lesu boljša kot pri navadni smrekovini.

Keywords

les;smreka;mehanske lastnosti;akustične lastnosti;priraščanje;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [A. Menegatti]
UDC: 630*812.12:630*174.7 Picea abies
COBISS: 123863299 Link will open in a new window
Views: 23
Downloads: 3
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Other data

Secondary language: English
Secondary title: Relevant properties of resonance spruce wood
Secondary abstract: Instead of the traditional visual and sensory evaluation of the quality of resonance spruce wood, we analysed the macroscopic structure and its physical, mechanical and acoustic properties in the laboratory. We sampled spruce wood from Pokljuka (1200 m a.s.l., section 64) with narrow annual rings and compared it with a control spruce from a site at a lower altitude (Zavratec nad Idrijo, 650 m a.s.l.). Test specimens (dimensions 20 × 20 × 300 mm) were made from air-dried wood to determine dynamic and static mechanical properties. Polyhedra (75 × 75 × 75 mm) were also fabricated, on which the velocity of ultrasonic waves was measured in all anatomical directions (R, T, L) and planes. Structural properties were determined by stereomicroscopy; we measured the width of annual rings, the proportion of latewood, and determined the mean wood density. We found that spruce wood with good resonance properties is rare. It has low density (≤ 400 kg/m3), thin (up to 2 mm) and homogeneous annual rings with a low proportion of latewood (up to 23%). Resonance spruce wood is stiffer along the wood grain, and usually has lower vibration damping. The conversion of mechanical energy into sound is better with resonance spruce wood than with conventional spruce wood.
Secondary keywords: wood;spruce;mechanical properties;acoustic properties;growth characteristics;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za lesarstvo
Pages: 1 spletni vir (1 datoteka PDF (VIII, 39 str.))
ID: 16479279