兴安落叶松目测等级锯材抗拉强度的宽度尺寸效应

以兴安落叶松锯材作为研究对象,研究了不同目测等级下锯材试材宽度与其顺纹抗拉强度之间的依存性。选取3种宽度尺寸的目测等级锯材,分成高、低目测等级组,按照相同的测试跨度测试锯材顺纹抗拉强度,并利用斜率法和形状参数法估计高、低目测等级试材顺纹抗拉强度5%分位值的宽度尺寸效应。结果表明：1）落叶松锯材宽度增加,其顺纹抗拉强度下...

Size effects of width on tensile strength of visually-graded Chinese larch lumber

The dependence between tensile strength and width of Chinese larch visually-graded dimension lumber was investigated.Three different width dimension lumbers were parted into two groups:high visual grade and low visual grade.The ultimate tensile strength parallel to grain was tested under same test span.The width size effects of 5th percentile of tensile strength were estimated by the slope method and the parametric method.The results were as the followings:1) Increasing the lumber width lowered the ultimate tensile strength parallel to grain.2) The estimated width effect parameters were 0.29 in high and 0.33 in low for the 5th percentile of the ultimate tensile strength parallel to grain.3) The parametric method could estimate the width size effects of the ultimate tensile strength parallel to grain.