WOOD RESEARCH Volume 67, Number 6, 2022
HONGHAI LIU, XIAOKAI ZHANG, and Jingwen Zhang

Study of dewatering characteristics of eucalyptus wood by supercritical CO2

Wood collapse is a major defect for their applications in solid wood production. Supercritical CO2 (ScCO2) dewatering can quickly remove water in wood and effectively reduce the capillary tension leading to collapse of wood structure. In this study, Eucalyptus exserta F.V. Muell wood was dewatered using ScCO2 at 35, 45, 55°C and 15, 20, 25 MPa, separately. The dewatering characteristics and wood deformation were statistically analyzed and compared after dewatering. The results show that the dewatering rate of ScCO2 is affected by moisture content (MC) of wood, showing the higher the MC, the faster the dewatering. It is also affected significantly by pressure, indicating increased dewatering rate with the pressure. The effect of temperature on dewatering rate is not apparent as the pressure is less than 25 MPa, but it becomes significant at 25 MPa condition, showing an increased dewatering rate with temperature. In this experiment, the greatest dewatering rate was 19.8%·h-1 at 55°C and 25 MPa. The transversal shrinkage of all specimens after 5 cycles dewatering was lower than 1.5%, indicating the ScCO2 dewatering could effectively inhibit collapse of eucalyptus wood structure. The transversal shrinkage decreases with the pressure, and is not affected significantly by temperature.

WOOD RESEARCH Volume 67, Number 3, 2022
Bo Li and Yuan An

Deformation behavior of circular saw blades with different body structures after roll tensioning

A roll tensioning process for circular saw blades with four typical body structures was built with the finite element method. After roll tensioning, the elastoplastic deformation behaviors of the four blades were simulated and tested and the effects of roll reduction displacement on flatness were analyzed. The abilities of the blades to withstand cutting temperature load after the roll tensioning process were compared. The theoretical results showed that each of the four circular saw blades with unique body structures had different process parameters in an appropriate tensioning state. Circular saw blades with different body structures showed variation in improvements of their ability to withstand cutting temperature load after an appropriate tensioning process.

WOOD RESEARCH Volume 62, Number 4, 2017
Miroslav Gašparík, Milan Gaff, and Babiak Marian

Tension stress simulations of layered wood using a finite element method

This article investigates the material thickness of the individual layer composition influence on the stresses under tension loading. The SolidWorks application was used for tension stress simulations. This simulated course of tensions was carried out for soft and hard materials as a function of their thicknesses. Hard material was represented by beech wood and soft material by aspen wood. Subsequently, the tensile stress and deformation of various two- and three-layered compositions of these materials were analyzed. Based on our results, the soft material was the weakest link; therefore, the ultimate tensile strength of the entire layered material is directly dependent on it. Hard material can withstand greater tensile stress and deformation without breaking, as soft material does.