特高压输电塔半刚性连接节点受力性能及结构非线性分析研究

发布时间：2018-05-03 21:42

本文选题：特高压输电塔 + 半刚性节点　；参考：《重庆大学》2014年博士论文

【摘要】：特高压输电塔结构特点是塔身高、所受风荷载、覆冰荷载和自重大，尤其是大跨越塔，塔身往往达到300米甚至更高，，结构形式十分复杂。在输电塔设计中，现有的设计软件一般采用整体空间桁架模型进行计算，即认为节点属于铰接连接，没有考虑杆端因弯矩产生的的弯曲应力对输电塔结构的影响。现有研究表明，传统的按铰接或刚接对输电塔结构进行内力计算和构件及节点设计可能和实际情况差别较大，从而留下安全隐患。因此对半刚性输电塔结构的研究迫在眉睫。本文首先针对角钢塔中常见的角钢-节点板连接节点进行了试验研究，接着在此基础上提出了此类节点弯矩转角全过程曲线的理论计算方法，然后通过大量的非线性有限元分析系统全面地研究了此类节点的半刚性特性，并给出了节点半刚性设计建议公式。对比表明，试验、理论和有限元结果吻合很好。最后将半刚性节点引入输电塔结构体系，详细研究了输电塔结构的半刚性受力性能。本文主要研究内容如下： 1）进行了五个角钢-节点板连接节点的足尺试验。试验结果表明：此类节点具有典型的半刚性特性。此类节点通常因连接主角钢和节点板的螺栓被剪断而达到极限弯矩。角钢规格、节点板厚度、螺栓强度等级、螺栓直径、螺栓个数、螺栓间距以及钢材强度等级等因素对节点的弯矩-转角曲线都有影响。 2）运用组件法并结合虚功原理建立了角钢-节点板连接节点初始转动刚度的计算模型，考虑了主角钢受剪、螺栓受剪、孔壁变形对节点转动刚度的影响；在考虑材料塑性变形的基础上进一步推导了计算节点弯矩-转角全过程曲线的理论方法，该方法能够较好地分析节点转动变形的组成，包括主角钢剪切变形、螺栓剪切变形、螺栓孔挤压变形。理论结果和试验结果吻合较好，该理论方法填补了输电塔半刚性节点研究上的理论空白。 3）建立了精细化的非线性有限元模型，与试验结果对比表明，该模型能较准确地反映此类节点的受力及变形特点。在实用范围内，通过变化节点的角钢肢宽和肢厚、螺栓直径、螺栓间距、螺栓个数、节点板厚以及钢材强度等级来考察各因素对节点极限弯矩、初始转动刚度以及弯矩-转角曲线的影响。校核确定了节点的刚度系数。运用最小二乘法拟合出Kishi-Chen幂函数模型各参数的建议公式。对比表明：按建议公式确定的Kishi-Chen幂函数曲线能够准确地预测此类节点的弯矩-转角关系，可以作为工程设计的参考。 4）采用Hermite插值多项式及最小势能原理推导了考虑节点连接刚度的薄壁杆件单元的刚度矩阵。将节点的弯矩-转角关系引入输电塔结构，考虑几何和材料非线性，运用有限元软件ANSYS对体系进行弹塑性全过程分析。研究了节点刚度大小、主斜材夹角、主斜材线刚度比、节间数、结构高度、初始缺陷等因素对半刚性塔腿结构的受力性能的影响，同时研究了各种因素下结构半刚性性能的敏感性规律。为输电塔结构的半刚性设计提供了指导建议。
[Abstract]:The structure characteristic of UHV transmission tower is tower height, wind load, ice load and self important, especially large span tower, the tower body often reaches 300 meters or even higher, the structure form is very complex. In the design of the transmission tower, the existing design software generally uses the whole space truss model to calculate, that is to say, the node belongs to articulated connection. The influence of bending stress on the transmission tower structure is considered. The existing research shows that the internal force calculation and the design of the structure of the transmission tower by hinged or rigid connection may differ greatly from the actual situation, thus leaving the hidden danger. Therefore, it is imminent to study the structure of the semi-rigid transmission tower.
In this paper, the experimental research on the common angle steel joint plate joint in the diagonal steel tower is studied. On the basis of this, the theoretical calculation method of the full process curve of the bending moment angle of this kind of node is put forward, and then the semi-rigid characteristics of this kind of node are thoroughly studied by a large number of nonlinear finite element analysis systems, and the nodes are given. The semi rigid design formula. The comparison shows that the experiment, the theory and the finite element results are in good agreement. Finally, the semi-rigid joints are introduced into the transmission tower structure system and the semi-rigid behavior of the transmission tower structure is studied in detail. The main contents of this paper are as follows:
1) full scale test of five angle steel joint plate joints. Test results show that such joints have typical semi-rigid characteristics. This kind of node usually reaches the limit bending moment because the bolts connecting the leading steel and the joint board are cut. Angle steel specifications, plate thickness, bolt strength grade, bolt diameter, bolt number, bolt spacing And the strength grade of steel will affect the moment rotation curve of the joints.
2) using the component method and combining the principle of virtual work, the calculation model of the initial rotational stiffness of the angle steel joint plate joint is established. The influence of the leading steel shear, the bolt shear and the hole wall deformation on the rotational stiffness of the node is considered, and the theory of the bending moment full process curve of the joint is further derived on the basis of the plastic deformation of the material. The method can well analyze the composition of the rotational deformation of the node, including the shear deformation of the leading steel, the shear deformation of the bolt and the extrusion deformation of the bolt hole. The theoretical results are in good agreement with the experimental results. The theoretical method fills the theoretical blank in the study of the semi-rigid joints of the transmission tower.
3) a fine nonlinear finite element model is established. Compared with the experimental results, the model can accurately reflect the stress and deformation characteristics of this kind of node. In the practical range, the parameters of the angle steel limb width and limb thickness, bolt diameter, bolt spacing, bolt number, joint plate thickness and steel strength grade are investigated. The stiffness coefficient of the node is determined by checking the influence of the ultimate bending moment, the initial rotational stiffness and the bending moment curve. The proposed formula of the parameters of the Kishi-Chen power function model is fitted by the least square method. The comparison shows that the Kishi-Chen power function curve determined by the proposed formula can accurately predict the bending moment of this kind of node. The angle of rotation can be used as a reference for engineering design.
4) using the Hermite interpolation polynomial and the minimum potential energy principle, the stiffness matrix of the thin-walled member element, considering the joint stiffness of the node, is derived. The relationship between the bending moment and corner of the node is introduced into the transmission tower structure. Considering the geometric and material nonlinearity, the whole process of elastoplastic process is analyzed with the finite element software ANSYS. The stiffness of the node is studied. The influence of the angle of main inclined material, the stiffness ratio of the main inclined material line, the number of internodes, the height of the structure, the initial defect on the stress performance of the semi-rigid tower leg structure, and the sensitivity law of the semi-rigid structure under various factors are also studied. It provides guidance for the semi-rigid design of the transmission tower structure.

【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU347

【参考文献】