结构用重组竹弯曲强度和剪切强度的尺寸效应研究

Size effect of bending strength and shear strength of structural bamboo scrimber

提出材料强度服从对数正态分布的脆性断裂理论,并与材料强度服从威布尔分布的脆性断裂理论相比,用以研究结构用重组竹强度的尺寸效应。再通过弯曲、剪切强度的尺寸效应试验,验证以上两种理论模式用于结构用重组竹弯曲、剪切强度尺寸效应计算的精度。结果表明,材料强度服从威布尔分布的脆性断裂理论精度更高。按弯曲强度标准值统计时,尺寸效应系数s为0. 045;按弯曲强度均值统计时,尺寸效应系数s为0. 043;按剪切强度标准值统计时,尺寸效应系数s为0. 223;按剪切强度均值统计时,尺寸效应系数s为0. 181。所得s值可用于尺寸效应折减系数β值的计算。

This paper presented a study on the size effect on the strength of structural bamboo scrimber by adopting the Logarithmic normal brittle-fracture theory,and compared with the Weibull brittle-fracture theory. Experimental tests were conducted to evaluate the accuracy of the two theoretical models. The results show that the Weibull brittle-fracture theory is more accurate. The size effect coefficient s is 0. 045 when calculated using the characteristic value of bending strength,and is 0. 043 when using the mean value. The s value is 0. 223 when calculated using the characteristic value of shear strength,and is 0. 181 when calculated using the mean value. The s value obtained by the Weibull brittlefracture theory can be used for calculating the β value of the reduction factor for the size effect.