Identification of damping of Spruce wood (Picea abies) under various levels of moisture content using time-scale decomposition

Merhar, Miran (author)

The damping of spruce wood is analysed at different moisture content levels for the first three vibration modes of tangentially and radially vibrating samples. Two methods were used to determine the damping. The first was the vibration envelope fitting as an improved version of the well-known logarithmic decrement, and the second was the newer and recently increasingly used wavelet transform. Both methods showed that the damping of spruce wood first decreases and then increases with moisture content, with the damping in the first vibration mode being about 9% higher in the radial direction than in the tangential direction. In the second and third vibration modes, the damping in the tangential direction was higher than in the radial direction by about 10% and 8.8%, respectively. The measured damping factors from the envelope fitting had, on average, 15.9% higher values than those from the wavelet transform. It can be concluded from the results that the wavelet transform is more accurate for determining the damping factor, as it enables the decoupling of multi-degree of freedom systems if mode coupling is present.

• Language: English
• Keywords: damping factor, wavelet transform, logarithmic decrement, relative humidity, impulse response function, time response, natural frequency, frequency response function, Morlet wavelet, vibration
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.01.2024
• Year: 2024
• Number of pages: 14 str.
• Numbering: Vol. 16, iss. 10, [article no.] 1313
• PID: 20.500.12556/RUL-156191
• UDC: 630*8
• ISSN on article: 2073-4360
• DOI: 10.3390/polym16101313
• COBISS.SI-ID: 194771459
• Publication date in RUL: 13.05.2024

Record is a part of a journal

• Title: Polymers
• Shortened title: Polymers
• Publisher: MDPI
• ISSN: 2073-4360
• COBISS.SI-ID: 517951257

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.

Secondary language

• Language: Slovenian
• Keywords: faktor dušenja, valčna transformacija, logaritmični dekrement, relativna vlažnost, odziv na impulzno vzbujanje, lastna frekvenca, funkcija frekvenčnega odziva, Morletova valčna funkcija, nihanje

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0182
• Name: Razvojna vrednotenja