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 3, 2023
CHUNMEI YANG, ZANBIN ZHU, TONGBIN LIU, BO XUE, Wen Qu, and Tingting Wang

Determination of Urea-Formaldehyde Resin Content in Poplar Fiber Based on Hyperspectral Techniques

In this experiment, poplar fibers containing 0%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 25% and 30% of urea-formaldehyde resin were prepared. A model for the detection of urea-formaldehyde resin content in poplar fibers was established by the hyperspectral near-infrared imaging system combined with relevant algorithms. The spectral images of poplar fibers containing different contents of urea-formaldehyde (UF) resin were measured separately using hyperspectral imager. The results of four preprocessing methods, namely mean centering (MC), multiple scattering correction (MSC), standard normal variables (SNV) and first-order derivative (1-Der) were analyzed, and the optimal preprocessing method was selected as SNV. The band combinations with the highest correlation with the urea-formaldehyde resin content were compared and analyzed with the full-band model to establish the partial least squares regression (PLSR) model. The experimental results show that the hyperspectral imaging system combined with the corresponding algorithm can achieve rapid detection of UF resin content in poplar fibers, and the results of this study provide technical support and theoretical reference for determination of resin content in ultra-thin fiberboard production. The method is an innovative model for the determination of UF resin in wood fibers.