WOOD RESEARCH Volume 69, Number 3, 2024
ZANBIN ZHU, CHUNMEI YANG, WENJI YU, BO XUE, JIE YAN, YUCHENG LI, and TONGBIN LIU

FRACTURE MECHANISM ANALYSIS OF HIGH-DENSITY FIBREBOARD BASED ON DIGITAL IMAGE CORRELATION TECHNOLOGY

This paper analyses the scattering images of the bending deformation of high-density fibreboards based on the digital image correlation (DIC) technique, so as to study its mechanical deformation law. Three-point bending tests were carried out on fibreboards using a mechanical testing machine with a non-contact measuring system. The measured values of the displacements of the grid nodes in the region of interest (ROI) were combined with the Moving least squares (MLS) method to construct the strains of the high-density fibreboards at different loading forces, thus deriving the strain values of the fibreboards during the bending deformation process. To further analyze its force deformation mechanism, this paper used a portable electron microscope and scanning electron microscope to analyze the damage situation at the fracture damage, and at the same time, it verified that the constructed strain field model was accurate

WOOD RESEARCH Volume 68, Number 2, 2023
CHUNMEI YANG, ZANBIN ZHU, Jiuqing Liu, BO XUE, and YUCHENG LI

Model construction and microwave preheating experiments using fiberboard

Microwave heating is a new type of pre-heating for fiberboard mats. Compared to conventional heating, microwave heating is faster and the surface and interior are evenly heated, thus avoiding the phenomenon of premature hardening of the surface layer of the fibreboard mats. In this paper, the heat transfer law of microwave preheated fiberboard mats was analyzed, and a thermodynamic model of fiberboard microwave heating was established. Furthermore, a microwave preheating simulation was established through COMSOL software; the temperature distribution of the fiberboard after microwave heating was analyzed and the reliability of the simulation model was verified through experiments. The temperature changes of fibers in the two preheating methods were compared by direct contact preheating experiment and microwave preheating experiment. Microwave preheating is more efficient than direct contact preheating, and more uniform temperature distribution in fiberboard mats. The core layer temperature is higher than the surface layer temperature, which can shorten the preheating time. By comparing the COMSOL model with the test, the model can basically reflect the temperature change law of microwave preheating, and the temperature of each layer of the slab is more uniform in the model simulation process. The heating law of the fiberboard was obtained, which provided a theoretical reference for the industrialized microwave preheating of fiberboard.