单层马鞍形无内环交叉索网结构受力性能研究

Mechanical behavior of single-layer saddle-shape crossed cable net without inner-ring

为提升内环索网结构抗连续倒塌能力与经济性,提出一种单层马鞍形无内环交叉索网。该新型索网具有抗连续倒塌能力强、鲁棒性好等优势。首先介绍了单层马鞍形无内环交叉索网的结构形式并给出了该结构的数学表达式;然后采用大型通用有限元软件ANSYS对单层马鞍形无内环交叉索网进行参数化建模、找形分析和结构设计,并采用生死单元法对该索网断索后的受力行为进行了非线性分析;最后研究了矢跨比、外环节点数和间隔数三个关键几何参数对结构静力性能的影响规律。研究结果表明:单层马鞍形无内环交叉索网单根或少数拉索破断不会引起结构的连续倒塌;随着矢跨比的减小,索网变扁平,最大应力与位移均逐渐增大;随着外环节点数的增加,索网变密,最大应力与位移均逐渐减小;随着间隔数的增加,索网中央多边形开口缩小,最大应力在间隔数由2增至4时增长迅速,在间隔数由4增至7时增长缓慢,最大位移则出现先增大后减小的趋势。

To improve the progressive-collapse resistance and the cost effectiveness,a new structure,i. e. single-layer saddle-shape crossed cable net without inner-ring was proposed. The new cable net has the advantages of strong resistance to progressive collapse and high robustness. Firstly,the structure form of the single-layer saddle-shape crossed cable net without inner-ring was introduced and the corresponding mathematical expressions were given. Then the finite element software ANSYS was used to perform parametric modeling,form-finding analysis,and structural design of a single-layer saddle-shape crossed cable net without inner-ring. And‘Birth and Death’method was used to calculate the nonlinear behavior of the cable breaking. Finally,the influence of three key geometric parameters,i. e.the rise-span ratio,the number of outer-ring nodes and the number of intervals,on the static characteristics of the structure was investigated. The results show that the breakage of single or several cables does not cause progressive collapse of the single-layer saddle-shape crossed cable net without inner-ring. As the rise-span ratio decreases,the cable network becomes flat,and the maximum stress and displacement increase. With the increase of the number of outer-ring nodes,the cable net becomes denser,and the maximum stress and displacement decrease. With the increase of the interval number,the size of the central polygonal opening of the cable net reduces,and the maximum stress increases rapidly when the number of intervals increases from 2 to 4,and increases slowly when the number of intervals increases from 4 to 7,while the maximum displacement first increases and then decreases.