Nedestruktivne metode določanja relevantnih gradacijskih lastnosti žaganega lesa : diplomsko delo (univerzitetni študij)

Čepon, Matija (author), Gornik Bučar, Dominika (mentor), Bučar, Bojan (comentor), Gorišek, Željko (reviewer)

Metode določanja mehanskih lastnosti lesa so lahko destruktivne (porušne) in nedestruktivne (neporušne). Ker imamo najpogosteje opravka z žaganim lesom, kasneje uporabljenim v konstrukcijske namene, je treba meritve izvajati tako, da lesne strukture ne poškodujemo. Metode, ki jih je glede na omenjeno zahtevo možno uporabiti, sodijo v skupino nedestruktivnih. Raziskovali smo možnosti uporabe različnih nedestruktivnih metod, njihovo zanesljivost in korelacije testiranih rezultatov. Preučevali smo različne mehanske in vizualne lastnosti žaganega lesa smrekovine (Picea abies L.), ki vplivajo na trdnost lesa. Metode, s katerimi smo preučevali deske (100 preizkušancev) in plohe (100 preizkušancev), so bile izvedene na osnovi vizualnega ocenjevanja lesa po DIN 4074-1, 4- točkovnega upogibnega testa po EN 408 in dinamičnih testov (metoda frekvenčnega odziva). Izkazalo se je, da ja povezava med vizualnimi in dinamičnimi rezultati dokaj šibka in nejasna, dobra pa med statičnimi in dinamičnimi. Koeficient korelacije med MOEs in MOEd je bil v vseh primerih večji od 0,9. Pomembna ugotovitev je, da z dinamičnimi rezultati (MOEd), zaradi specifike merjenja (t = 2s), dobimo za 12 % višje rezultate kot pri ostalih izvedenih metodah (metoda 4-točkovnega upogiba). To pomeni, da so polizdelki po tej metodi bistveno bolje ocenjeni in tako prinašajo višje cenovne vrednosti.

• Language: Slovenian
• Keywords: žagan les, nedestruktivne metode, vizualna metoda, frekvenčna metoda
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [M. Čepon]
• Year: 2006
• Number of pages: X, 43 f., [27 f. pril.]
• PID: 20.500.12556/RUL-105-2e15a239-f848-4cde-352e-e56e584c0ee7
• UDC: 630*812:630*832.181
• COBISS.SI-ID: 1383561
• Publication date in RUL: 11.07.2014

Secondary language

• Language: English
• Title: Non-destructive methods to determine relevant graduation properties of sawn wood : graduation thesis (university studies)

Abstract

The methods to determine mechanical properties of wood can be either destructive or non-destructive. Usually we have to deal with the sawn wood meant to be used for construction purposes, therefore, not to make damage the non-destructive method should be used. Different non-destructive methods, their reliability, and correlations of testing results were researched and compared. Various mechanical and visual properties of pine sawn wood (Picea abies L.) were studied. Visual testing (DIN 4074-1), 4-point bending test (EN 408) and dynamic tests (method of frequency response) were performed. The relationship between visual and dynamic results was found out to be poor. Good correlation was obtained between static and dynamic results. In all the cases the coefficient of the correlation between MOEs and MOEd is higher than 0.9. It should also be noted that the dynamic results (MOEd) are 12 % higher than other results (e.g.: MOEs), because of a different nature of measurement (t = 2s). This means that using a dynamic method the semi-manufactured.

• Keywords: construction wood, non-destructive methods, visual method, frequency method