This paper investigated the bending moment of chair base joints. The ultimate bending moments (maximum moment), calculated on the base of the measured maximum applied loads (maximum force), were compared for the front leg and rear leg joints of a cha...

This paper explores the possibility of using recycled seashells from marine coasts of the Mali Ston Bay in Dubrovnik-Neretva County, Croatia, to create a novel bio material derived from waste seashells. In this research, two types of waste seashells, mussel (Mytilus galloprovincialis) and oyster...

The scarcity of high-quality wood encouraged the development of various technological processes for joining wood. The finger joint is one of the most widespread technological processes for wood joining. This study aimed to determine the effect of steaming and heat modification of beech wood, as well as the type of adhesive, on the mechanical characteristics of finger joints. Samples made from un-modified beech, steamed-treated, and heat-treated beech wood were bonded with polyvinyl acetate (PVAC), non-structural, and structural polyurethane (PUR) adhesives. Compressive tests on wood materials were used to evaluate their mechanical performance. The finger joint samples were tested for their bending performance. Modulus of rupture, modulus of elasticity, and compressive strength were calculated. An analysis of variance (ANOVA) was conducted to evaluate the impact of wood modification type and adhesive used on the mechanical characteristics of the finger joints. According to the results of this study, it can be concluded that the steaming process does not influence changes in the mechanical characteristics of the finger joints. Heat treatment of beech and the type of adhesive used significantly influence the tested mechanical characteristics of the finger joints and beech wood. Heat-treated beech had lower values of modulus of rupture (70 MPa) and density (690 kg/m³) and higher values of compression strength (59 MPa) in relation to un-modified (780 kg/m³) and steamed-treated (800 kg/m³) beech wood.

In this paper, the stress and strain analysis of common laminated wood seat shell is performed. Experimental stiffness evaluation is conducted by measuring displacement of the point on the backrest, and experimental stress analysis is carried out by tensometric measuring at the critical transition area from the seat to the backrest. Finite element analysis is carried out layer by layer with a “2D linear elastic model” for orthotropic materials. Good matching is found between numerical and experimental results of displacement. It is also shown that the results of the principal stress in the measurement points of the seat shell compare favourably with experimental data. The applied in-plane stress analysis of each individual veneer is not applicable for interlaminar stress calculations that are a significant factor in curved forms of laminated wood. Curved forms of laminated wood products require more complex numerical analysis, but the method can be used to achieve approximate data in early phase of product design.

This study examines the physical and mechanical properties of pedunculate oak (Quercus robur L.) wood samples taken from historical trabaccolo ship Carmen during restoration. The research is based on a methodological approach typical of conservation–restoration practice, in which only a limited number of samples can be taken to preserve the authenticity and integrity of the original material. Two groups of samples were analyzed visually: preserved (bright) wood and wood showing cross-sectional discoloration (dark). Physical properties (color, moisture content, density, porosity and swelling) and mechanical properties (compressive strength, bending strength and modulus of elasticity) were determined according to relevant ISO standards and chemical changes in the wood structure (FT-IR). FT-IR analysis revealed progressive degradation of hemicelluloses and oxidative modification of lignin, which was particularly significant in dark wood samples. The results of tests of physical properties indicate that dark samples exhibit higher moisture content (13%), lower density (about 7%) and greater porosity compared to preserved samples (bright wood). The compressive strength of the bright specimens was 38.3% higher than that of the dark specimens, suggesting reduced mechanical performance of the altered wood. The bending strength and modulus of elasticity of the preserved samples (bright wood) corresponded to literature data for recent oak wood.