| 摘要: |
| 为了准确预测规格材抗弯强度与木节之间的关系，选取含不同类型、尺寸木节的兴安岭落叶松规格材，分别截取清材试样和足尺试样进行抗弯试验，并对试验数据进行了回归分析.结果表明，对于足尺试样，采用其平均密度ρa和最大降等缺陷处木节截面受拉侧的Ik/Ig来拟合足尺抗弯强度ff效果最佳，相关系数R2为0.753，均方根RMSE为4.71；木节对足尺抗弯强度的影响相对于密度几乎同等重要.建立了足尺抗弯强度、清材抗弯强度和木节信息之间的理论模型. |
| 关键词: 木节 规格材 抗弯强度 理论模型 |
| DOI：10.3969/j.issn.1007 9629.2012.06.028 |
| 分类号: |
| 基金项目:林业公益性行业科研专项（200904016）；竹藤中心科研业务费专项（1632009003） |
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| Experimental Research on the Effects of Knot on theBending Strength of Dimension Lumber |
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ZHONG Yong, REN Hai qing, LOU Wan li
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Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
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| Abstract: |
| Defects, especially for knots, seriously affect the bending strength of wood. Full scale specimens and clear specimens for bending test, cut from dimension lumbers of Larix gmelinii with different kinds of knots, were applied to evaluate the predictive accuracy of the bending strength and to improve the accuracy of the bending strength by multivariate regression analysis with density and knot information. According to the regression analysis results, the knot Ik/Ig of the weakest location for tension side and the average density ρa show the best predictive accuracy of bending strength for full scale specimens（ff）, with 0.753 of R2 and 4.71 of RMSE. Based on the ratio of regression parameter B/A of independent variables for density and knot information, the effect of knot and density are equally important in influencing ff. Finally, a simplified theoretical model that can be used to calculate bending strength for dimension lumber is constructed. |
| Key words: knot dimension lumber bending strength theoretical model |
