文献类型：期刊文献

英文题名：Time dependence of the orthotropic compression Young's moduli and Poisson's ratios of Chinese fir wood

作者：Jiang, Jiali[1,2] Valentine, Bachtiar Erik[2] Lu, Jianxiong[1] Niemz, Peter[2]

第一作者：Jiang, Jiali;蒋佳荔

通信作者：Jiang, JL[1];Jiang, JL[2]|[a0005c4a974b7fbd344a8]蒋佳荔;

机构：[1]Chinese Acad Forestry, Res Inst Wood Ind, State Key Lab Tree Genet & Breeding, Beijing 100091, Peoples R China;[2]ETH, Inst Bldg Mat, CH-8093 Zurich, Switzerland

年份：2016

卷号：70

期号：11

起止页码：1093-1101

外文期刊名：HOLZFORSCHUNG

收录：;EI(收录号：20164502991547);Scopus(收录号：2-s2.0-84994078652);WOS:【SCI-EXPANDED(收录号:WOS:000385809600011)】；

基金：This research was sponsored by the National Natural Science Foundation of China (No. 31570548). J.J. would like to gratefully acknowledge the financial support from the China Scholarship Council (CSC). A special thanks goes to Franco Michel and Thomas Schnider for their help during specimen preparation and their expert assistance in conducting the measurements.

语种：英文

外文关键词：axial strain; Chinese fir wood; compressive creep test; lateral strain; orthotropic viscoelasticity; Poisson's ratios; stress level; time dependence; Young's moduli

摘要：The time dependency of the orthotropic compliance for Chinese fir wood [Cunninghamia lanceolata (Lamb.) Hook] has been investigated by performing compressive creep experiments in all orthotropic directions. Time evolution of the creep strain in the axial and lateral directions was recorded by means of the digital image correlation (DIC) technique, to determine the diagonal and nondiagonal elements of the viscoelastic compliance matrix. The results reveal the significant influence of time on the mechanical behavior. The orthotropic nature of the viscoelastic compliance is highlighted by the different time dependency of the Young's moduli and the Poisson's ratios obtained for the individual directions. Differences among the time-dependent stress-strain relationship determined at the 25, 50, and 75% stress levels indicate that the viscoelastic behavior of wood is also load-dependent. A Poisson's ratio values, which are increasing with time in nu(LR), nu(LT), nu(RT), nu(TR), and decreasing in nu(RL) and nu(TL), demonstrate that the creep strain is influenced by loading directions. The substantially different time dependency of the nondiagonal elements of the compliance matrix further reveals the orthotropic compliance asymmetry and emphasizes the complexity of the viscoelastic character of wood.