WOOD RESEARCH Volume 61, Number 2, 2016
Rongrong Li, Xiaolei Guo, Pingxiang Cao, and Xiaodong (Alice) Wang

Optimization of laser cutting parameters for recombinant bamboo based on response surface methodology

A means for selecting the optimal process parameters for the laser cutting of recombinant bamboo, based on the design of experiments (DOE) approach, was presented. Recombinant bamboo with thicknesses of 5, 10, and 15 mm was cut by a CO2 laser. The parameters investigated were the laser power, air pressure, and cutting speed. The results were compared using a number of process responses which define the efficiency of the cutting, including the upper kerf (UK) width, lower kerf (LK) width, and the ratio of upper-to-lower kerfs. Mathematical models were developed to establish the relationship between the process parameters and response parameters; special graphs were drawn for this purpose. Finally, a numerical optimization was performed to find out the optimal process settings to achieve a minimumupper-to-lower kerf ratio.

WOOD RESEARCH Volume 62, Number 5, 2017
Rongrong Li, Wei Xu, Lu Fang, Pingxiang Cao, Xiaolei Guo, and Mats Ekevad

Short Note: Non-standard test method for glue line shear strength

The relevant standards for glueline shear strength testing were summarized and analyzed in this paper. Depending on these existing test standards, the resulting stress in glueline is not pure shear stress, but a combination of shear and normal stresses. In order to overcome this deficiency, a symmetrical structure was proposed for making samples. Some comparative testing was accomplished by using these symmetrical samples, the results showed that the normal stress could be avoided during testing. These results were also confirmed by finite element method (FEM), the simulation results showed that the shear stress in glueline was uniform.

WOOD RESEARCH Volume 64, Number 1, 2019
Chuangui Wang, Rongrong Li, Chengqian Liu, and Xiaodong (Alice) Wang

Effects of medium-low temperature hydrothermal treatment on microstructure and dimensional stability of chinese sweetgum wood

To investigate the changes of microstructure and dimensional stability during hydrothermal treatment, the Chinese sweetgum (Liquidambar formosana Hance) wood samples were treated in a numerical show constant temperature water bath with temperature of 60, 80 and 100°C for 4 h. The dry shrinkage rate and water absorption of untreated and treated samples were measured. Scanning electron microscopy (SEM) was selected to observe and investigate the changes of wood microstructure, which caused by hydrothermal treatment. The results showed that dry shrinkage rate increased from 4.92% to 7.00% and 9.62% to 10.12% in tangential direction and radial direction, respectively. However, the shrinkage rate difference (SRD) as an index to evaluate possibility of wood deformation, decreased from 1.96 to 1.45, which meant the shape stability of treated samples improved. The water absorption increased from 93.15% to 112.11%. From the results of SEM, the most sediment on aspirated pits were removed and pit membrane was ruptured after treatment. It had positive effect on moisture migration and wood permeability. It is maybe the reason of the variation of water absorption and dry shrinkage rate.