Strain analysis of lumber containing a knot during tensile failure
Strain analysis of lumber containing a knot during tensile failure
复制标题
拉伸破坏期间含有结的木材的应变分析
DOI：
10.1007/s10086-010-1154-x
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发表时间：
2011
影响因子：
2.9
通讯作者：
T. Nakano
中科院分区：
文献类型：
--
作者：
H. Nagai;K. Murata;T. Nakano
分析了含节材在拉伸载荷作用下的应变分布。采用数字图像相关法测量了节点附近的局部拉应变。断裂通常发生在结附近，那里的纤维取向以三维方式变化。该区域的纤维方向与透明部分的纤维方向不同，与样品的厚度方向一致，而不是与样品的纵向一致。我们的结果不同意那些以前的模型，假设木材的纵向作为裂纹扩展的方向。应变分析表明，在最终断裂发生之前，节点周围存在一个非线性区域。结果表明，尽管宏观上的脆性断裂，但非线性表征对于确定含节材的破坏机理是必要的。
We analyzed the strain distribution of lumber containing a knot under a tensile load. The local tensile strain near the knot was measured using the digital image correlation method. Fracture often initiated near the knot where the fiber orientation changed in a three-dimensional manner. The fiber direction in this zone was different from that in the clear part, coinciding with the thickness direction and not with the longitudinal direction of the specimen. Our results disagree with those of previous models that assumed the longitudinal direction of lumber as the direction of crack propagation. Strain analysis showed that a nonlinear region existed around the knot just before ultimate fracture occurred. The results indicated that nonlinear characterization is necessary to determine the failure mechanism of lumber containing a knot, despite the brittleness fracture at the macroscopic scale.