天然林落叶松锯材机械应力分等法与四点弯曲性能相关性研究

Study on the Correlation Between Stress Rating Method and Four-Point Bending Performance of Chinese Larch Sawn Lumber Machinery

采用机械应力分等法对天然林落叶松锯材进行动态弹性模量EMSR测定,依据美国标准ASTM D 4761-05测量其四点平弯与侧弯的弹性模量E4f、E4s和抗弯强度(MOR),并分析EMSR与E4f、E4s、MOR的相关性。结果显示,EMSR与E4f、E4s相关性存在较大差异,且后者高于前者。相关系数分别为0.555、0.681。E4f、E4s与MOR相关性高于EMSR与MOR的相关性,E4s与MOR的相关性高于E4f与MOR的相关性。实验表明,采用机械应力分等法提高木材分等准确性还需进一步研究。

Dynamic elastic modulus of Chinese larch （Larix gmelinii） sawn lumber is tested with the machine stress rating method. Based on American standard ASTM D 4761-05, the elastic modulus of its four point flat-wise bending and edge-wise bending E4f,E4s and modulus of rupture （MOR）are measured, with the correlation between E4f,E4s and MOR analyzed. The result shows that there exists a big difference in the correlation between EMSR and E4f＆amp;E4 , with the latter higher than the former, with correlation coefficients being 0.555 and 0.681. The correlation between E4f＆amp;E4s and MOR is higher than that between EMSRand MOR and the correlation between E4s and MOR is higher than that between E4f and MOR. The experiment shows that the improvement of wood rating accuracy with the machine stress rating method requires further research.