桉木制单板层积材的抗压强度预测模型

Predicting Model for Compressive Strength of Eucalyptus Laminated Veneer Lumber

为了研究桉木制单板层积材的抗压强度预测模型,进行了342个试件的抗压试验,分析了试件纹理角度、胶层角度对其抗压强度、弹性模量和破坏模式的影响.采用指数模型拟合试件抗压强度,并通过卡方(χ2)检验来验证该指数模型和Hankinson公式、Norris公式以及GB 50005—2003规范公式对抗压强度的拟合度.结果表明:随着试件纹理角度、胶层角度的增加,其抗压强度和弹性模量均显著下降;抗压试件的破坏模式有3种,为纤维褶皱破坏、剪切破坏和压溃破坏;指数模型、Hankinson公式和Norris公式均能较好地拟合抗压强度,而GB 50005—2003规范公式拟合的抗压强度值偏高.

A total of 342 specimens of eucalyptus laminated veneer lumber were tested in static compression to study the predicting model for compressive strength. The effects of an angle to grain and an angle to glue line were also investigated. The compressive strengths of specimens were fitted by exponential model, Hankinson formula, Norris formula and GB 50005-2003 formula, and the fitting degree of 4 used models was compared by chi-square test. The results indicate that both compressive strength and elastic modulus significantly decrease with the increase of an angle to grain or an angle to glue line. Three kinds of failure modes with compressive test are wood fiber fold, shear failure and crushing failure. Exponential model, Hankinson formula and Norris formula fit the measured compressive strength better. On the contrary, the compressive strength measured is far less than that fitted by GB 50005-2003 formula.