Danihelová Anna, Vidholdová Zuzana, Gergeľ Tomáš, Spišiaková Kružlicová Lucia, Pástor Michal
Department of Fire Protection, Faculty of Wood Sciences and Technology, Technical University in Zvolen, T. G. Masaryka 24, 960 01 Zvolen, Slovakia.
Department of Wood Technology, Faculty of Wood Sciences and Technology, Technical University in Zvolen, TU in Zvolen, Masaryka 24, 960 53 Zvolen, Slovakia.
Polymers (Basel). 2022 Jul 10;14(14):2813. doi: 10.3390/polym14142813.
This article presents a proposal of thermal modification of Norway spruce and sycamore maple for special wood products, mainly for musical instruments. Selected physical and acoustical characteristics (PACHs), including the density (), dynamic modulus of elasticity along the wood grain (), specific modulus (), speed of sound along the wood grain (), resonant frequency () and acoustic constant (), logarithmic decrement (), loss coefficient (), acoustic conversion efficiency (), sound quality factor (), and the timbre of sound, were evaluated. These two wood species were chosen regarding their use in the production or repair of musical instruments. For the thermal modification, a similar process to the ThermoWood process was chosen. Thermal modification was performed at the temperatures 135 °C, 160 °C and 185 °C. The resonant dynamic method was used to obtain the PACHs. Fast Fourier transform (FFT) was used to analyze the sound produced. The changes in the observed wood properties depended on the treatment temperature. Based on our results of all properties, the different temperature modified wood could find uses in the making of musical instruments or where the specific values of these wood characteristics are required. The mild thermal modification resulted in a decrease in mass, density, and increased speed of sound and dynamic modulus of elasticity at all temperatures of modification. The thermally modified wood showed higher sound radiation and lower loss coefficients than unmodified wood. The modification also influenced the timbre of sound of both wood species.
本文提出了对挪威云杉和梧桐槭进行热改性以用于特殊木制品的方案，主要用于乐器。评估了选定的物理和声学特性（PACHs），包括密度（）、沿木纹方向的动态弹性模量（）、比模量（）、沿木纹方向的声速（）、共振频率（）和声常数（）、对数减量（）、损耗系数（）、声转换效率（）、音质因数（）以及音色。选择这两种木材是考虑到它们在乐器生产或修复中的用途。对于热改性，选择了与ThermoWood工艺类似的过程。热改性在135℃、160℃和185℃的温度下进行。采用共振动态法获取PACHs。使用快速傅里叶变换（FFT）分析产生的声音。观察到的木材性能变化取决于处理温度。基于我们对所有性能的结果，不同温度改性的木材可用于制作乐器或需要这些木材特定性能值的地方。温和的热改性导致在所有改性温度下质量、密度降低，声速和动态弹性模量增加。与未改性木材相比，热改性木材显示出更高的声辐射和更低的损耗系数。改性还影响了这两种木材的音色。
