The objective of this study was to determine normal impedance on the surface as well as sound absorption coefficients for several wood species from Europe and from the tropical zone. The mathematical models of Miki, Attenborough, and Allard – dealing with acoustic properties of porous materials – have also been compared. The air flow resistivity exhibits a distinct link between fiber dimensions and wood porosity. The highest sound absorption coefficient was found for oak, ash, sapeli, and pine woods at 2 kHz frequency. The Attenborough model provides results closest to laboratory measurements, although it still requires significant improvements. The Miki and Allard models have some drawbacks and should be applied with reservation for the determination of wood acoustic properties.

From modern buildings to public spaces are made of concrete, steel, and glass. These materials increase propagation of sound and the reverberation time. Therefore, furniture should be good sound absorbers in such places. The objective of this study was to ascertain acoustic properties of wood-based materials by determining normal acoustic impedance on the surface and sound absorption coefficients. Experiments were carried out on 17 types of wood-based materials commonly employed in furniture design and manufacture. Investigations were conducted based on the transferfunction method. It was demonstrated that for frequencies between 125 and 500 Hz, the highest capability of sound absorption was determined of low surface layer density and high porosity. Honeycomb panels with paper core absorbed better sounds in the range between 1 and 2 kHz. Panels of considerable external surface irregularities were characterized by the most favorable acoustic properties for the frequency of 4 kHz.

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The development of both light and strong wood-derived materials is an interesting research area, particularly in terms of usability in, e.g., furniture constructions. Honeycomb panels being current industry standard are relatively thick (32 mm and 40 mm), thus their attractiveness in designing furniture is limited. In a few studies, it has been shown that honeycomb panels with paper cores are characterized by unsatisfactory mechanical properties, especially when the composite thickness is less than 20 mm. From the literature, it is also evident that mechanical properties might be improved by introducing auxetic features into the core structure. Even though it is a concept with great potential, there are a few studies dealing with honeycomb panels with auxetic cores made of paper. Furthermore, there is no research on the corner joints made from such material. For this reason, the aim of the study was to test the bending behavior of the corner adhesive joints made of honeycomb panels with double arrow-shaped auxetic cores. Within the research, the core cell was adopted based on literature and preliminary studies, paper auxetic cores were produced by the use of the designed and 3d printed device, and joints stiffness and strength were calculated analytically based on the experiment results. Evaluated corner joints stiffness, both in compression and tension test, is greater for samples made of panels with designed auxetic cores. Surprisingly, in the analyzed range of elasticity, it was statistically proved that the values of joint stiffness coefficient K did not vary significantly between compared joints pairs.

So far, no coherent and comprehensive method has been elaborated allowing investigation of tensile strength of upholstery seams dedicated to upholstered furniture. Producers of this type of furniture are interested in the assessment of the quality of upholstery material joints, which seems to be particularly important for ensuring the appropriate quality of products. Therefore, the objective of this research was to investigate the influence of the type of material used and the direction of the fabric cut on the strength of upholstery covers. Static tensile testing of selected upholstery fabric samples was performed, and an attempt was made to identify the most optimal fabric–seam joints. It was stated as a conclusion that the fabric tensile strength was the highest for Secret 10 fabric. In addition, the strength of upholstery covers is not influenced by the direction of the fabric die cut. For each fabric, a different configuration is preferable, as shown by results (Power 13: A-B, Secret 10: B-B, Soft 10: A-A). The method, implemented for upholstered furniture, allows for an objective assessment of the strength of upholstery covers and the selection of the most advantageous fabric–seam combination for future furniture designs.