Določanje kakovosti hlodovine iglavcev z nedestruktivnimi metodami

diplomsko delo

Laura Krančič (Author), Bogdan Šega (Reviewer), Aleš Straže (Mentor), Dominika Gornik Bučar (Co-mentor)

Abstract

Smrekovi hlodovini (Picea abies) z žagarskega obrata (n = 15), in z domače dražbe vrednejših sortimentov lesa (n = 15) smo kakovost določali vizualno, skladno z veljavno domačo metodologijo. Na hlodovini smo vzporedno, pri vzdolžnem nihanju z metodo frekvenčnega odziva, določali še hitrost preleta zvoka in dušenje v prvih treh nihajnih načinih. Licencirana hlodovina je bila večjih premerov, med 51 in 79 cm, in je spadala v A – kakovostni razred. Hlodi z žagarskega obrata so bili manjših premerov (27 – 59 cm), in smo jih uvrstili v B (47 %) in C kakovostni razred (53 %). Hitrost zvoka je bila značilno nižja le v 2. in 3. nihajnem načinu pri hlodovini C kakovosti (v < 4000 m/s) od hlodovine iz A in B kakovostnih razredov. Rezultat sovpada z večjo pojavnostjo notranjih strukturnih anomalij, zlasti grč in naraščanja njihove velikosti, ki smo jih največ evidentirali v hlodovini najslabše kakovosti (C). Dušenje zvoka ni bilo značilno povezano s kakovostjo smrekove hlodovine. Ugotovili smo, da čelne razpoke na hlodih značilno povečajo dušenje zvoka v 2. in 3. vzdolžnem nihajnem načinu.

Keywords

les;smreka;hlodovina;kvaliteta lesa;akustične lastnosti;nedestruktivno merjenje;

Data

Language:	Slovenian
Year of publishing:	2024
Typology:	2.11 - Undergraduate Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[L. Krančič]
UDC:	630*832.181:812.12
COBISS:	206730243
Views:	18
Downloads:	1
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Determination of the quality of softwood logs by non-destructive methods
Secondary abstract:	Spruce logs (Picea abies) from the sawmill (n = 15) and from the domestic auction of more valuable wood (n = 15) were visually assessed for quality using standard domestic methods. The sound velocity and damping in the first three vibration modes of the logs were determined in parallel using the longitudinal vibration resonance method. The auctioned logs had a larger diameter (between 51 and 79 cm) and belonged to quality class A. The logs from the sawmill had a smaller diameter (27-59 cm) and were classified in quality classes B (47 %) and C (53 %). The speed of sound was significantly lower (v < 4000 m/s) in the grade C logs than in the grade A and B logs, and only in the second and third vibration modes. This result is consistent with the greater occurrence of internal structural anomalies, particularly knots and their increasing size, observed mainly in the worst grade (C) logs. Vibration damping was not significantly related to the quality of the spruce logs. Cracks at the ends of the logs were found to significantly increase vibration damping in the second and third vibration modes.
Secondary keywords:	wood;spruce;logs;wood quality;acoustic properties;non-destructive testing;
Type (COBISS):	Bachelor thesis/paper
Study programme:	0
Thesis comment:	Univ. v Ljubljani, Biotehniška fak., Oddelek za lesarstvo
Pages:	1 spletni vir (1 datoteka PDF (VII, 40 str.))
ID:	24956240