文献类型：期刊文献

英文题名：The formation mechanism of microcracks and fracture morphology of wood during drying

作者：Gao, Yufa[] Fu, Zongying[] Fu, Feng[] Zhou, Yongdong[1,2] Gao, Xin[] Zhou, Fan[]

第一作者：Gao, Yufa;周永东;Zhou, Yongdong

通信作者：Zhou, YD[1];Zhou, YD[2]

机构：[1]Chinese Acad Forestry, Res Inst Wood Ind, Beijing 100091, Peoples R China;[2]Natl Forestry & Grassland Adm, Key Lab Wood Sci & Technol, Beijing 100091, Peoples R China

年份：0

外文期刊名：DRYING TECHNOLOGY

收录：;EI(收录号：20224513063087);Scopus(收录号：2-s2.0-85141142587);WOS:【SCI-EXPANDED(收录号:WOS:000876871400001)】；

基金：This work was supported by the National Natural Science Foundation of China (No. 31890772).

语种：英文

外文关键词：Wood drying; microcracks; fracture morphology; shrinkage behavior; moisture content gradient

摘要：The surface checks or internal cracks from drying could significantly affect the processing and utilization of the wood. Therefore, it is of great significance to investigate the formation mechanism of cracks and reduce its occurrence. In this work, the development of cracking was quantified and its relationship with moisture content (MC) gradient and anisotropic shrinkage was analyzed. Results showed that the slight shrinkage occurred at the MC of 40%, and the shrinkage ratio at the end of drying was about 7.38% in the tangential (T) direction and 4.35% in the radial (R) direction. The shrinkage ratio of T/R in the MC range of 30%-15% was about 1.8, which was higher than that (1.65) in the MC range of 15%-5%. Cracks initiation was observed at average MC of 45%. The area and number of cracks reached a maximum at 15% MC. During the late stage of drying, the drying stress of the surface layer was reversed from tensile to compressive, which leads to the narrowing or closure of the cracks. Moreover, the fracture morphology of wood cells was observed at the microscopic level, indicating that the failure firstly occurred in the intercellular layer between the ray tissue and the tracheid in the latewood. The ray cells presented intact, and the lamellar structure between ray tissues and between the ray cells and the tracheids were the weak points of wood during drying. The results would contribute to keeping in minimum drying defects and improving the drying quality of wood.