Analysis of cold temperature effect on stress wave velocity in green wood

作者：Xu Huadong; Wang Lihai^*

来源：Holzforschung, 2014, 68(6): 693-698.

DOI：10.1515/hf-2013-0151

• stress wave velocity
• temperature' moisture content
• water phase

The objective of this study was to investigate the effect of temperature on stress wave velocity (SWV) in green wood below zero degress centigrade (0 degrees C). Both field and laboratory tests were conducted on standing Korean pine trees and small wood samples to study the effects of low temperature at various moisture content (MC) on SWV. As expected, SWV in wood increased with decreasing temperature. However, near 0 degrees C, the SWV increment was not linear but showed disproportional high increments at MCs above 50%. To explain this phenomenon, differential scanning calorimeter (DSC) measurements were performed at various MCs and temperatures, i.e., the interrelation between the state of water aggregation and SWV was analyzed. The explanation of the irregular behavior of SWV as a function of temperature is straightforward: free water and a small portion of bound water in green wood are transformed from water to ice below zero degrees (0 inverted perpendicular inverted perpendicular C) centigrade. Thus the disproportional high SWV increment below 0 degrees C reflects the aggregation change of water because the SWV in ice is higher than that in liquid water.

• 出版日期2014-8
• 单位东北林业大学