落叶松规格材足尺弯曲性质研究

Full-size bending mechanical properties of Dahurian larch dimension lumber

参照GB 50329-2002《木结构试验方法标准》对经过目测分级的2种尺寸(截面尺寸为40 mm×90 mm和40 mm×140 mm,长度均为4 000 mm)兴安落叶松规格材进行了静态弯曲试验,测试了其抗弯弹性模量(MOE)和抗弯强度(MOR)。结果表明:40 mm×90 mm和40 mm×140 mm两种规格材Ⅰc、Ⅱc和Ⅲc等级的MOE平均值分别为15.0、13.0、13.2和15.7、14.0、15.6 GPa;40 mm×90 mm规格材Ⅰc、Ⅱc和Ⅲc等级MOR的特征值(5%分位值)分别为37.5、26.72和24.85 MPa,40 mm×140 mm规格材Ⅰc、Ⅲc等级MOR的特征值(5%分位值)为27.95和24.2 MPa;Ⅰc等级的力学强度特征值明显高于Ⅱc和Ⅲc等级;落叶松规格材的MOR、MOE的相关性较好。落叶松规格材足尺弯曲力学性质研究可以为国产结构材的分级技术提供依据,也为国产结构材的设计应用提供参数。

Two groups of full-size Dahurian larch（Larix gmelinii） dimension lumber,which were visually graded,with different dimensions of 40 mm×90 mm×4 000 mm and 40 mm×140 mm×4 000 mm,had been edge-wise bending tested to get the modulus of elasticity（MOE） and modulus of rupture（MOR） according to Chi-nese Standard GB 50329-2002.The results showed that： 1） the MOE average values of 40×90 and 40×140 dimen-sion lumberⅠc,Ⅱc and Ⅲc were 15.0,13.0,13.2 and 15.7,14.0,15.6 GPa;the MOR characteristic values of 40×90 dimension lumberⅠc,Ⅱc and Ⅲc were 37.5,26.72 and 24.85 MPa;the MOR characteristic values of 40×140 dimension lumber Ⅰc and Ⅲc were 27.95 and 24.2 MPa;2）Ⅰc grade presented higher mechanical proper-ties as compared with other grades;3） The results showed a good relationship between MOR and MOE.The study of full-size larch dimension lumber bending mechanical properties provided a basis for the grading technology of domestic structural materials;it also provided parameters for structural material design applications.