基于ABAQUS有限元法的空洞树干强度分析

树木空洞可能会导致树木的死亡，同时，由于空洞树木抗风雪能力低，易在空洞处断裂，对人身和财物安全具有重大隐患。本研究通过软件Abaqus建立空心树干的三维模型进行有限元模拟分析，探索树干空洞的大小对树木强度和断裂破坏行为的影响。结果表明:1）树木发生弯曲和扭转破坏系数随载荷增加而增大，树干最外层的最大弯曲和扭转剪应力在断裂破坏前随载荷增加呈线性增加；2）当树干空洞发展到树干内外径比（α）为0.7时，随着空洞的继续增大其弯曲和扭转破坏系数会急剧增加，在α小于0.7时，弯曲和扭转破坏系数有一定的增加，但增加幅度较小；3）随着树干空洞造成内外径比的增加，树木发生扭转破坏的偏冠程度会逐渐降低。研究初步探明了树干空洞影响树木破坏行为和方式的力学机理，可为树木安全性评估提供一定的理论支持和依据。

Strength Analysis of Cavity Tree Trunks by Finite Element Method Based on Abaqus

Trees with hollow trunks could result in the death of tree,meanwhile,it would bring serious safety issues to human body and belongs,because it would fracture at hollow trunk for its low resistance to wind and snow.To understand the influence of hollow size of trunk on the strength and fracture behavior of trees,a three-dimensional model of the hollow trunks was established by Abaqus for finite element mechanical analysis.The results showed that 1) the bending and torsional damage coefficients of trees increased with the increase of load,and the maximum bending and torsional shear stresses in the outermost layer of the trunk increased linearly with load before fracture damage.2) When the trunk cavity developed to the trunk inner with an outer diameter ratio (α) of 0.7,its bending and torsional damage coefficient increased sharply as the trunk cavity increased continuously,and when α was less than 0.7,the bending and torsional damage coefficients had a certain increase,but the increment was small.3) With the increase of the inner and outer diameter ratio caused by the trunk cavity,the degree of crown deviation where the tree first underwent torsional damage would gradually decrease.The mechanical mechanism of the influence of trunk cavity to the fracture behavior and pattern of tree was revealed preliminarily by this study.