Vpliv hrupa na meritev dinamičnega modula elastičnosti lesenih elementov

diplomska naloga št.: 440/B-GR

Žiga Krvina (Author), Goran Turk (Mentor), Mitja Plos (Co-mentor)

Abstract

V okviru te diplomske naloge je bil preučen vpliv hrupa na meritev dinamičnega modula elastičnosti z napravo za strojno razvrščanje lesa STIG. Primerjani so bili rezultati, pridobljeni z laserskim digitalnim vibrometrom, in mikrofonom ob različnih okoliščinah zunanjega hrupa. Opravljene so bile meritve v zaprtem in tihem prostoru, nato smo se premaknili na zunanje lokacije, kjer so bile izvedene meritve ob cesti, ob glasbi, ob prižgani krožni žagi ter ob manjšem žagarskem obratu pri različnih jakostih hrupa. Pri izvajanju meritev je bila merjena 1. lastna frekvenca desk. Z njo ob določeni gostoti ter izmerjeni vlažnosti lesa nato določimo dinamični modul elastičnosti. Dinamični modul elastičnosti predstavlja indikativno lastnost (IP), na osnovi katere se razvrsti merjen kos lesa v trdnostni razred. Ugotovili smo, da meritve, izvedene z mikrofonom, ne glede na hrup nekoliko odstopajo glede na meritve, opravljene z vibrometrom. Hrup nam lahko oteži zaznavo prave lastne frekvence preizkušanca. Meritve v različno hrupnih razmerah so pokazale, da lahko razvrščanje opravimo pri različnih nivojih hrupa. Najpomembnejše pri delovanju sistema v hrupnem območju je zadostna bližina mikrofona, dovolj glasen udarec ter pravilno izbrano kladivo.

Keywords

gradbeništvo;diplomske naloge;UNI;GR;B-GR;dinamični modul elastičnosti;vpliv hrupa na meritve;razvrščanje lesa;STIG;lastna frekvenca;mikrofon;

Data

Language:	Slovenian
Year of publishing:	2023
Typology:	2.11 - Undergraduate Thesis
Organization:	UL FGG - Faculty of Civil and Geodetic Engineering
Publisher:	[Ž. Krvina]
UDC:	539.3:691.1:624.07(043.2)
COBISS:	166367747
Views:	169
Downloads:	29
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Influence of noise on the measurement of the dynamic modulus of elasticity of timber elements
Secondary abstract:	The influence of noise on the measurement of the dynamic modulus of elasticity using the timber grading device STIG was examined within this thesis. The results obtained with a laser vibrometer and a microphone were compared under various external noise conditions. Measurements were conducted in a closed, quiet environment, followed by outdoor measurments conducted near a road, with music playing, during the operation of a circular saw and at a small sawmill at different noise levels. During the measurements, the first natural frequency of the boards was measured. Based on this frequency, along with the specific density and measured moisture content of the wood, the dynamic modulus of elasticity is determined. The dynamic modulus of elasticity serves as an indicating property (IP) for classifying the measured piece of wood into a strength class. We have found that measurements taken with a microphone, regardless of the noise, deviate to some extent from the measurements taken with a vibrometer. Noise makes it difficult to detect the true natural frequency of the test subject. The measurements under different noise levels confirmed that strength grading can be performed under different noise conditions. The most important factors in the operation of the system in a noisy environment are sufficient proximity of the microphone, a sufficiently loud impact, and the correct choice of hammer.
Secondary keywords:	graduation thesis;civil engineering;dynamic modulus of elasticity;effect of noise on measurements;wood grading;STIG;natural frequency;microphone;
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo
Pages:	X, 40 str.
ID:	22078991