木材过热蒸汽干燥过程中的收缩应力(Ⅰ)——径向收缩应力特征  

Shrinkage Stress of Wood during Drying under Superheated Steam (Ⅰ): the Characteristics of Radial Shrinkage Stress

作　　者：程万里[1] 刘一星[1] 齐华春[1] 師岡敏朗[2] 則元 京[2] 

机构地区：[1]东北林业大学,哈尔滨150040 [2]京都大学木质科学研究所

出　　处：《东北林业大学学报》2004年第6期32-34,共3页Journal of Northeast Forestry University

基　　金：国家自然科学基金资助项目 (30 4 71 354)

摘　　要：试验研究了日本柳杉在 12 0～ 180℃高温高压过热蒸汽条件下 ,干燥过程中所伴随的收缩应力的发生发展特征 ,以及温度和相对湿度对径向收缩应力的影响。试验采用夹具束缚试件在干燥过程中的收缩变形 ,利用应力传感器连续测定饱水试件在高温高压过热蒸汽条件下 ,从试件达到环境平衡条件开始直到全干状态或明显开裂为止的径向收缩应力。对温度 80～ 180℃ ,相对湿度 0～ 80 %干燥条件下收缩应力的研究结果表明 ,温度 14 0℃、相对湿度 6 0 %以上的条件下 ,收缩应力得到有效抑制。在温度 14 0℃以上的条件下 ,即使相对湿度达到 10 0 %仍然存在收缩应力 ,此收缩应力的发生与木材细胞壁组成的结构变化有关。The changing features of shrinkage stress for Sugi (Cryptomeria japonica D. Don) wood specimens were studied when dried with radial restraint using superheated steam at 120～180 ℃, and the effects of temperature and relative humidity on radial shrinkage stress were analyzed. A load cell was used to bind up the shrinkage distortion of specimens in the course of drying, and the radial shrinkage stress was determined with stress sensor from environmental balance state to entire dry or evident cracking under the condition of superheated steam with high temperature and high press. The shrinkage stress was measured at temperatures from 80 to 180 ℃ and relative humidity from 0 to 80%. The result showed that the shrinkage stress decreased dramatically when drying with temperature above 140 ℃ and relative humidity above 60%. The shrinkage stress when drying temperature above 140 ℃ still occurred even at relative humidity of 100%, which was considered to relate to the structural change of cell wall components.

关 键 词：木材干燥 收缩应力 径切方向 过热蒸汽 饱和蒸汽 

分 类 号：S781.71[农业科学—木材科学与技术]