张拉导线应力及刚度的研究

发布时间：2019-06-01 16:34

【摘要】：张拉载荷下导线的应力分布以及拉伸刚度的变化情况体现了导线的力学性能。本文采用理论计算方法、有限元仿真方法以及试验测量方法,以LGJ-300/25型钢芯铝绞线固定端情况为例,对张拉载荷下导线的应力及刚度进行研究。理论计算部分,建立股线的受力平衡方程,得到张拉导线的载荷、应力分布情况以及截面拉伸刚度理论值;在此基础上,考虑导线温度变化对导线线材变形的影响,得出不同条件下温度对导线应力、应变及载荷的影响。有限元仿真部分,利用导线的螺旋对称特点,建立导线单股线模型,根据模型中相应节点的位移关系,建立节点组之间的约束方程,并根据约束方程施加边界条件及载荷,从而缩小模型的计算规模,节约计算时间。试验测量部分,根据钢芯铝绞线拉伸刚度的测量原理,设计安装了导线拉伸试验测量装置,给出了拉伸刚度的具体试验测量方法,完成了导线的拉伸试验测量,并对试验操作的过程进行了详细的描述,得到导线的载荷-应变曲线。研究结果表明:(1)导线中心直钢线与6根层钢线为线接触,接触面积大,挤压应力最小,其他各层股线之间的接触区域为点接触,挤压应力由内而外逐渐减小;导线横截面上各层股线承受的载荷及应力呈现由内而外减小趋势;随着导线温度的升高,铝股线承受的载荷相对减小,最内层铝股线的载荷及应力最先减小为零。(2)在拉伸载荷作用初期,导线截面拉伸刚度略微增加,随着载荷增大,铝股线发生塑性变形,导线截面拉伸刚度开始急剧减小。
[Abstract]:The stress distribution and tensile stiffness of conductors under tension load reflect the mechanical properties of conductors. In this paper, the stress and stiffness of conductors under tension load are studied by using theoretical calculation method, finite element simulation method and experimental measurement method, taking the fixed end of LGJ-300/ 25 steel core aluminum strand as an example. In the part of theoretical calculation, the stress balance equation of the strand is established, and the load, stress distribution and the theoretical value of the tensile stiffness of the section are obtained. On this basis, considering the influence of wire temperature change on wire rod deformation, the influence of temperature on conductor stress, strain and load under different conditions is obtained. In the finite element simulation part, according to the spiral symmetry characteristics of the conductor, the single strand model of the conductor is established. According to the displacement relationship of the corresponding nodes in the model, the constraint equation between the node groups is established, and the boundary conditions and loads are applied according to the constraint equation. Thus, the calculation scale of the model is reduced and the calculation time is saved. In the part of test and measurement, according to the measuring principle of tensile stiffness of steel core aluminum strand, a measuring device for conductor tensile test is designed and installed, the concrete test and measurement method of tensile stiffness is given, and the tensile test measurement of conductor is completed. The process of test operation is described in detail, and the load-strain curve of conductor is obtained. The results show that: (1) the straight wire in the center of the conductor is in contact with six steel wires, the contact area is large, the extrusion stress is the smallest, the contact area between the other strands is point contact, and the extrusion stress decreases gradually from inside to outside; The load and stress of each layer of strands on the cross section of the conductor show a decreasing trend from inside to outside. With the increase of conductor temperature, the load of aluminum strand decreases relatively, and the load and stress of innermost aluminum strand decrease to zero at first. (2) in the initial stage of tensile load, the tensile stiffness of conductor section increases slightly, and with the increase of load, The plastic deformation of aluminum strand occurs, and the tensile stiffness of wire section begins to decrease sharply.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM751

【参考文献】