Shohei KAJIKAWA (梶川 翔平)

Abstract. Conventional injection cannot adequately fill wood powder in the mold due to the intergranular friction. To solve these problems, we proposed an injection compression molding technique for wood powder with a natural binder composed of sucrose and citric acid. The effect of the additional pressure from the rear on the moldability and the mechanical properties of the molded product was investigated. By applying pressure from the rear, the molded product became darker in appearance, and its density increased by approximately 20%, approaching the true density of wood. Furthermore, its hardness reached a level comparable to that of polyvinyl chloride (PVC). This result indicated that the rear pressure is effective in improving the moldability and mechanical properties of the molded product.

Abstract. Simulating large deformations of wood is difficult because the deformation of wood is complex, owing to the hierarchical structure of cells and annual rings. This study presents a finite element method (FEM) analysis that uses a lattice model to reproduce large wood deformations. The proposed lattice model comprises earlywood and latewood cells. The appropriate lattice geometry, considering the cell wall thickness and earlywood volume fraction, is investigated by comparing FEM analysis results with experimental results obtained via a lateral compression test. Consequently, the deformed shape and load–displacement (F–δ) diagram varied, depending on the annual ring tilt angle to the compression direction in the experiment. This anisotropy of the deformed shape was reproduced by the FEM analysis via a lattice model with an appropriate cell wall thickness and earlywood volume fraction. The F–δ diagram of the FEM was similar to that of the experiment.