Mjerenje i modeliranje mehaničkih svojstava drvene vune

undergraduate thesis

• Title (english): Measurement and modeling of mechanical properties of wood wool
• Author: Tena Krnić
• Mentor: Juraj Šipušić (mentor)
• Committee member: Juraj Šipušić (predsjednik povjerenstva)
• Committee member: Krunoslav Žižek (član povjerenstva)
• Committee member: Vanja Kosar (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-09-17, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Mehanička svojstva drvene vune iznimno su bitna pri izradi izolacijskih kompozitnih ploča drvene vune i cementa. U ovom radu mjeren je prvenstveno modul elastičnosti uzorka jelovog drveta kako bi se usporedila svojstva drveta sa svojstvima kompozitnog materijala kojemu je glavna sastavnica jelovo drvo. Mjerenja su provedena u laboratoriju koristeći statičke i dinamičke metode mjerenja prema ASTM C 1259^10 standardu mjerenja. U eksperimentalnom dijelu ovoga rada konstruirano je mjerilo frekvencije titranja pomoću fotosenzora, laboratorijskog izvora napona i digitalnog osciloskopa povezanog s računalom. Rezultati mjerenja dobiveni su kao krivulje vremenske ovisnosti napona odnosno amplitude prigušenog titranja. Eksperimentalni podaci (prigušeno titranje mehanički pobuđenog uzorka) utočnjeni su prema modelu prigušenog harmonijskog oscilatora: 𝑈(𝑡)=𝐴∙𝑠𝑖𝑛(𝜔𝑡+𝜑)∙𝑒^(−𝑡/𝜏). Na taj način uklonjen je šum i određena vlastita frekvencija titranja uzorka potrebna za određivanje modula elastičnosti ispitivanog uzorka. Dobivena vrijednost modula elastičnosti ukazuje na sličnost elastičnih svojstava jelovog drva i kompozitne ploče drvene vune i cementa, što ukazuje na minimalnu promjenu svojstava drva prilikom prerade u kompozitnu ploču, te ta kompozitna ploča svoju elastičnost duguje upravo drvu.

Abstract (english)

The mechanical properties od wood wool are extremely important in the production of insulating composite boards of wood wool and cement. In this paper, the modulus of elasticity of a fir tree sample was measured primarily in order to relate the properties of wood to the properties of wood wool composite board whose main component is fir wood. Measurements were preformed in the laboratory using static and dynamic measurement methods according to ASTM C 1259^10 measurement standard. In the experimental part of this paper, a vibration frequency meter was constructed using a photosensor, a laboratory voltage source and a digital osciloscope connected to a computer. The results were obtained as time-dependent curves of voltage or amplitude of damped oscillation. Experimental data (damped oscillation of a mechanically excited sample) were refined according to the damped harmonic oscillator model: 𝑈(𝑡)=𝐴∙𝑠𝑖𝑛(𝜔𝑡+𝜑)∙𝑒^(−𝑡/𝜏). In this way, the noise was removed and the natural oscillation frequency of the sample required to determine the modulus of elasticity of the tested sample was determined. Result indicates the similarity of elastic properties of fir wood and composite board of wood wool and cement, which indicates a minimal change in the properties of wood during processing into composite board, and this composite board ows its elasticity to wood.

• Keywords: drvena vuna; mehanička svojstva; modul elastičnosti; kompozitna ploča
• Keywords (english): wood wool; mechanical properties; modulus of elasticity; composite board
• Language: croatian
• URN:NBN: urn:nbn:hr:149:616944
• Study programme: Title: Materials Science and Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-04-06 09:16:45