落叶松规格材机械应力分等方法的研究

Mechanical Stress Grading of Larch Dimension Lumber from Northeastern China

对东北人工林落叶松规格材机械分等方法及其特征值进行了研究。结果表明，抗弯弹性模量与抗弯强度相关性较好，纵向振动法可作为落叶松规格材机械分等的有效方法。按照我国GB50005-2003《木结构设计规范》的规定，落叶松规格材可归类为M14-M35之间的等级；通过机械分等，大大提高了落叶松规格材的强度设计值。

In this research, the vibration method was used to evaluate the mechanical properties of dahurian larch （ Larix gmelini）, a major softwood species that grows in the Northeastern China. The results showed a good relationship between bending strength and modulus of elasticity（MOE）. The good correlation of dynamic （from the vibration test） and static MOE indicated that vibration could be used as an effective mechanical stress grading tool for larch lumber. Lumber was sorted into four grades： M22, M26, M30, and M35 using mechanical stress grading. The grades were equivalent to the European machine grade of C22, C26, C30, and C35, respectively. It was found that through mechanical grading; the graded lumber had a higher design value than the existing general design value of domestic larch according to GB 50005-2003.