木材高温干燥过程中的弹性应变

Elasticity Strain of Wood in High Temperature Drying

本文对美洲黑杨 (Populusdeltoides Bartr.)锯材高温干燥过程中的弹性应变进行了研究。结果表明 :高温干燥使得木材表层产生较大的塑化变定 ,并对干燥后期木材内层的正常收缩造成阻碍。心层的拉伸应力与木材内裂有关 ,当心层拉伸应力超过木材横纹拉伸极限强度时 ,木材产生内裂。因此 ,在用高温干燥工艺快速干燥杨木类软阔叶树材时 。

The surface layer of the lumber can be greatly plasticized in the high temperature drying. Th e internal cracking may be produced due to the restraint of regular shrinkage in the internal layer in the later drying period. The internal cracking is related to the tensile stress of the core layer. When the tensile stress of the core layer is bigger than the tensile strength perpendicular to grain of wood, the internal crack will appear. Therefore, when the high temperature drying technology is used to rapidly dry the soft broadleaf lumber such as the poplar( Populus deltoides Bartr.) wood, attention should be paid to the drying defect due to the drying stress reversal in the later drying period.