温度及水分状态对美国红松弯曲弹性模量的影响

The influence of temperature and moisture contents on modulus of elasticity of Pinus koraicnsis wood

应用温度控制系统,对美国红松小试样规格材进行测试,检验木材温度及水分状态对木材弯曲弹性模量的影响。结果表明:温度对木材的抗弯性能具有显著影响,随着温度的升高,木材的抗弯性能逐渐减弱;相同承载条件下,含水率越高,冻结木材的抗弯曲性能越强。对于纤维饱和材,冰点以下其弹性模量随着温度的降低而迅速增加,在冰点以上则增加缓慢;对于非纤维饱和材,其弹性模量受温度影响变化幅度在冰点两侧区别不明显。冻结木材弹性模量相对于常温(20℃)情况下(相对弹性模量)受温度和含水率变化的影响十分显著,而非冻结木材的相对弹性模量对温度变化均表现不敏感。通过建立的相对弹性模量-温度试验模型,能较好地预测不同温度及含水率下的木材弯曲弹性模量相对于常温的变化幅度。该研究为不同温度条件下尤其是低温时的木材弹性模量测量结果修正提供了试验依据。

Tests were made in a temperature-controlled environment to investigate the effects of temperature and moisture state on the modulus of elasticity （ MOE ） of Pinus koraicnsis wood. The results showed that the temperature had a significant influence on the MOE of wood, which decreased with temperature rising. Under the same load, frozen wood showed higher stiffness as the moisture content （MC） increased. For wood over fiber saturation point （FSP）, the MOE rose up rapidly with temperature decreasing after the temperature fell below the freezing point while above that point, the increase wilh decreasing of temperature was much slow. When the moisture contents were below FSP, the influence of temperature on MOE change did not exert significant difference at both sides of the freezing point. The relative MOE of frozen wood was significantly affected by both temperature and MC while the relative MOE of non-frozen wood was not sensitive to changes in either temperature or MC. By an experimental model established in this paper, the relative MOE of wood at different temperatures and moisture contents can be better predicted. The results of this study can be used to adjust the data of MOE testing of wood in low temperature conditions.