﻿ 木材干燥应力应变宏观模型的构筑
 林业科学  2005, Vol. 41 Issue (5): 214-218 PDF
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#### 文章信息

Yu Jianfang, Wang Ximing.

The Development of Macroscopic Model on Wood Drying Stress-Strain

Scientia Silvae Sinicae, 2005, 41(5): 214-218.

### 作者相关文章

The Development of Macroscopic Model on Wood Drying Stress-Strain
Yu Jianfang, Wang Ximing
Inner Mongolia Agricultural University Huhhot 010019
Abstract: This paper had developed a theoretical mathematics model of wood drying stress-strain using mathematical and physical theories and taking moisture content (MC) and ratio of every layer into consideration as explicit parameters, predicted the development of stress-strain using MATLAB software, and analyzed the effect of MC and ratio of every layer. The results showed that on the condition of making the basic parameters set, the charts plotted by MATLAB software reflected the effect of MC and ratio of every layer. Total strain changed linearly with MC. The model could be applied to analyze the drying characters of a specimen with symmetric properties through the thickness.
Key words: stress    strain    model    moisture content    earlywood ratio

1 模型的构筑

 图 1 木材多层模型图 Fig. 1 Schematic diagram of a model with a speciman containing several layers of different types of wood

1.1 弹性应变

 (1)

 (2)

1.2 干缩应变

 (3)

 (4)

1.3 机械吸湿应变

 (5)

 (6)

 (7)

 (8)

 (9)

 (10)

2 模型的预测

 图 2 樟子松材总应变与含水率的关系图(v=0.2) Fig. 2 Total strain of Scots Pine vs MC
 图 3 全干时樟子松材总应变与早材率的关系图 Fig. 3 Total strain of Scots Pine vs earlywood ratio
 图 4 樟子松早晚材弦纵向应力与含水率的关系图(v=0.8) Fig. 4 Stress of earlywood and latewood of Scots Pine in longitudinal and tangential directions vs MC
 图 5 全干时樟子松早晚材弦纵向应力与早材率的关系图 Fig. 5 Stress of earlywood and latewood of Scots Pine in longitudinal and tangential directions vs earlywood ratio

3 小结

 李维桔. 1983. 木材弹性及木材干燥应力Ⅱ.木材干燥应力. 南京林产工业学院学报, 2: 107-122. 申宗圻. 1990. 木材学. 北京: 中国林业出版社. 徐芝伦. 1983. 弹性力学. 北京: 人民教育出版社. Martensson A, Svensson S. 1997. Stress-strain relationship of drying wood. Holzforschung, 51: 472-478. DOI:10.1515/hfsg.1997.51.5.472 Pang S. 2000. Modelling of stress development during drying and relief during steaming in Pinus radiata lumber. Drying Technology, 18(8): 1677-1696. DOI:10.1080/07373930008917806 Pang S. 2002. Predicting anisotropic shrinkage of softwood. part 1:theories.Wood Science and Technology, 36: 75-91. DOI:10.1007/s00226-001-0122-4 Ranta-Maunus A. 1993. Rheological behaviour of wood in directions perpendicular to the grain. Materials and Structures, 2: 362-369. Salin J G. 1992. Numerical prediction of checking during timber drying and a new mechamo-sorptive creep model. Holzals Rol-und Werkstoff, 50: 195-200. DOI:10.1007/BF02663286 Skaar C.1988.Wood-water relations.Springer, Berlin Ylinen A, Jumppnen P. 1967. Theory of the shrinkage of wood. Wood Science and Technology, 1: 241-252. DOI:10.1007/BF00349757