| 摘要: |
| 选取了不同类型、不同尺寸木节的兴安落叶松规格材，分别截取清材试样和足尺试样进行抗弯测试.通过对试验数据回归分析，足尺抗弯弹性模量Ef采用其平均密度ρa和测试跨距内所有木节信息拟合效果最佳，R2为0.674，均方根RMSE为1.15.根据足尺抗弯弹性模量中独立变量密度和木节信息拟合参数值的分析，相对于密度的影响，木节对足尺抗弯弹性模量的影响较小.建立了足尺抗弯弹性模量、清材抗弯弹性模量和木节信息之间的理论模型. |
| 关键词: 木节 落叶松规格材 抗弯弹性模量 理论模型 |
| DOI：10.3969/j.issn.1007 9629.2012.04.016 |
| 分类号: |
| 基金项目:林业公益性行业科研专项（201104027）；林业新技术所专项（CAFINT2010K01）；竹藤专项（1632009003） |
|
| Effect of Knots on Bending Modulus of Elasticity of Larch Dimension Lumber |
|
ZHONG Yong, SUN Hua lin, LOU Wan li, REN Hai qing, LI Xia zhen
|
|
Research Institute of Woos Industry, Chinese Academy of Forestry, Beijing 100091, China
|
| Abstract: |
| The defects, especially for knots, seriously affect the bending properties of wood. Full scale specimens and clear specimens for bending test, cut from larch dimension lumbers with different kinds of knots, were applied to predict the accuracy of the modulus of elasticity(MOE) in bending and to improve the accuracy of MOE by multivariate regression analysis with density and knots information. According to the regression analysis results, the∑［(Ik/Ig)·(Mk/Mo)］ of all knots and the average density ρa showed the best predictive accuracy of MOE for full scale specimen(Ef), with 0.674 of R2 and 1.15 of RMSE. Based on the ratio of regression parameter of independent variables for density and knots information, the knots were less influential than density on influencing Ef. Finally, a simplified theoretical model that can be used to calculate MOE for larch dimension lumber, was defined as Ef/Ec=0.96-0.47∑［(Ik/Ig)·(Mk/Mo)］. |
| Key words: knots larch dimension lumber modulus of elasticity(MOE) theoretical model |
