WOOD RESEARCH Volume 67, Number 3, 2022
EUN-SUK JANG and CHUN-WON KANG

Why the sound-absorbing performance of heartwood and sapwood differs in yellow poplar (Liriodendron tulipifera) cross-sections?

In this study, we investigated why the sound-absorbing performance is different with between heartwood and sapwood of yellow poplar, which are known for their sound-absorbing properties. We performed image observation as well as gas permeability, pore size, and porosity analysis, and measured the sound absorption coefficient of all samples using an impedance tube. We determined that the pores were significantly larger, and the gas permeability and through-pore porosity much higher, in the sapwood than the heartwood. The average sound absorption coefficient of the sapwood at 2000-6400 Hz (0.61 ± 0.04) was 2.7x that of the heartwood (0.23 ± 0.03). The average NRC of the sapwood (0.23 ± 0.01) was 1.9x that of the heartwood (0.12 ± 0.01). This study ultimately determined that the sapwood, as a consequence of its larger pore size and superior through-pore porosity, which thereby improved its gas permeability, outperformed the heartwood in terms of sound-absorption. We also determined that pore size and through-pore porosity were the primary parameters that determined the sound-absorbing performance of yellow poplar cross-sections.

WOOD RESEARCH Volume 61, Number 1, 2016
Limam Amel, Zerizer Abdellatif, and Quenard Daniel

Determination of acoustic parameters of bio-based materials distended for building: Application case to Aleppo pine wood cork and their composites

In this work, we are interested to incorporating acoustic comfort in buildings by using bio-based materials. More specifically, this work aims to determinate experimentally the sound absorption coefficient (α) and the sound reduction index (R) in three different samples. The first sample consists of Aleppo pine wood (Pinus halepensis) with two different configurations (solid wood and laminated timber wood). The second sample consists of a black agglomerated cork (suber) with two different thicknesses. The third sample consists of sandwich assemblies obtained by superimposing two wooden layers (solid or laminated timber wood) bonded with an inter layer cork. In this experimentation, we have used Kundt tube to determine sound absorption coefficient and AcouSYS V2.0 software to predict the sound reduction index. The obtained results showed that the first parameter (α) is influenced by the thickness of material. The second parameter (R) of symmetrical and asymmetrical sandwich assemblies of solid laminated timber wood with an interlayer of black agglomerated cork even shows good performances.

WOOD RESEARCH Volume 63, Number 4, 2018
Bin Na, Haiqing Wang, Tao Ding, and Xiaoling Lu

Study on factors affecting the sound absorption property of magnesia- bonded wood-wool panel

Magnesia-bonded Wood-Wool Panel is a kind of environmentally friendly inorganic material with wood-wool as matrix materials, and magnesium oxychloride cement (MOC) as binder which is also a kind of porous material with nice sound absorption property. In this study, through single factor experiments, it was found that The thickness of the panel, molar ratio of MgO/MgCl2/H2O, wood-wool length influenced material sound absorption performance of the panel significantly. The thickness of the panel was the most significant factor affecting the panell’s sound absoption property, while the effects of density of the panel and weight ratio of magnesia to wood were not significant. The optimal factors were obtained through orthogonal experiments: Thickness of the panel 25 mm, molar ratio of MgO to MgCl2 to H2O 5: 1: 10, density of the panel 0.65 g.cm-3, weight ratio of magnesia to wood 1.25, wood-wool length 200 mm.

WOOD RESEARCH Volume 65, Number 2, 2020
Bin Na, Haiqing Wang, Tao Ding, and Xiaoling Lu

Influence of wet and dry cycle on properties of magnesia-bonded wood-wool panel

In this paper, magnesia-bonded wood-wool panel was subjected to different times of wet and dry cycle to analyze their effects on the physical properties and the sound absorption property of the panel from macro and micro perspective. The results showed that with the increase of the wet and dry circle times, both MOE and thickness swelling decreased and the average absorption coefficient of the specimen increased.