编织防扭钢丝绳拉伸载荷作用下应力分布研究

发布时间：2018-11-04 10:37

【摘要】：随着国家电网事业的快速发展,编织防扭钢丝绳因其高强度、高防扭特性在电缆张力架设工程中被大量且反复使用。由于施工环境较为恶劣,且编织钢丝绳服役过程承载复杂,钢丝绳的疲劳、断丝等现象屡见不鲜。编织钢丝绳在载荷作用下的应力分布对钢丝绳的使用寿命和强度有着极大影响,其力学建模和失效机理分析越来越受到重视。由于其结构复杂,目前国内外对编织钢丝绳的力学研究甚少。因此有必要建立编织钢丝绳的力学计算模型,研究其在载荷作用下的应力分布规律,为该类钢丝绳的失效机理分析及结构优化等研究提供理论基础。本文针对四方八股编织钢丝绳,通过几何参数关系研究、力学建模、仿真模拟及拉伸试验、断丝及断股试验等研究,探索其在拉伸载荷作用下的应力分布规律,具体研究内容如下:(1)根据编织钢丝绳的结构特点及参数方程,建立其几何模型并进行修正;对修正后的几何模型中绳股的中心线进行投影,借助四心圆近似椭圆法,获得绳股的展开线;在此基础上推导出编织钢丝绳基本几何参数之间的关系,借助CAD软件及拉伸试验,获得该类钢丝绳基本几何参数值和弹性模量;分析绳股曲率、挠率随离心角和节距的变化曲线,进一步研究编织钢丝绳的几何特性,为其力学分析奠定理论基础。(2)基于弹性理论及Love曲杆理论,研究绳股在平直状态下承受拉伸载荷时的力学响应,获得绳股轴向总拉力与芯丝及内、外侧丝应变等的关系式,建立绳股平直状态力学模型;根据绳股展开线,分析四方八股编织钢丝绳平直状态下承受拉伸载荷时绳股受力及变形特点,推导出钢丝绳拉伸载荷与绳股应力、应变关系式,从而建立编织钢丝绳平直状态力学分析模型;以YS9-8×19编织钢丝绳为例,借助Matlab进行了数值计算,并分析应变和应力随载荷的变化规律。(3)借助数值模拟软件,建立无摩擦和不同摩擦系数的YS9-8×19编织钢丝绳有限元模型,通过仿真分析揭示其相应的应力应变分布规律,探讨摩擦力对编织钢丝绳受力的影响;开展不同拉伸载荷作用下编织钢丝绳的有限元仿真,并将仿真结果与力学模型理论计算结果对比分析,从定性的角度佐证所建力学模型的有效性;对相同载荷下不同节距的编织钢丝绳有限元模型进行仿真,分析其应力和变形随节距的变化规律,进而优选出节距范围,为工程应用提供理论指导。(4)以YS9-8×19编织钢丝绳为例,进行不同载荷下的拉伸试验,获得钢丝绳位移量随载荷的变化曲线,并与理论计算值进行对比分析,验证了力学模型的合理性;对钢丝绳试样进行断丝及断股试验,分析断丝和断股的特点及位置,探讨其危险截面存在位置,与理论及仿真结果进行综合分析比对,验证了钢丝绳拉伸载荷作用下应力分布规律的可靠性。
[Abstract]:With the rapid development of the State Grid, the braided torsion resistant wire rope has been widely and repeatedly used in cable tension erection engineering because of its high strength and high torsion resistance. Because the construction environment is relatively bad, and the service process of braided wire rope is complex, the fatigue of wire rope and broken wire are common phenomena. The stress distribution of braided wire rope under load has a great influence on the service life and strength of the wire rope. More and more attention has been paid to the mechanical modeling and failure mechanism analysis of the wire rope. Because of its complex structure, there are few researches on the mechanics of braided wire rope at home and abroad. Therefore, it is necessary to establish a mechanical calculation model of braided wire rope and study its stress distribution under load, which provides a theoretical basis for the analysis of failure mechanism and structural optimization of this kind of wire rope. In this paper, through the research of geometric parameter relation, mechanical modeling, simulation and tensile test, broken wire and broken strand test, the stress distribution law of square eight strands braided wire rope under the action of tensile load is explored. The specific research contents are as follows: (1) according to the structural characteristics and parameter equations of the braided wire rope, the geometric model is established and modified; Based on the projection of the central line of the rope in the modified geometric model, the unfolding line of the rope is obtained by using the four-center circle approximate ellipse method. On this basis, the relationship between the basic geometric parameters of braided wire rope is deduced, and the basic geometric parameters and elastic modulus of this kind of wire rope are obtained by means of CAD software and tensile test. The curves of curvature and torsion of rope with centrifugal angle and pitch are analyzed, and the geometric characteristics of braided wire rope are further studied. (2) based on elastic theory and Love bent rod theory, the geometric properties of braided wire rope are studied. The mechanical response of rope strands under tensile load is studied. The relationship between the total axial tensile force of rope strands and the strain of core wire, inner and outer wire is obtained, and the mechanical model of the straight state of rope strands is established. According to the development line of wire strands, the stress and deformation characteristics of wire strands under tensile load are analyzed, and the relationship between tensile load and stress and strain of wire strands is deduced. Thus the mechanical analysis model of braided wire rope is established. Taking YS9-8 脳 19 braided wire rope as an example, the numerical calculation is carried out with the aid of Matlab, and the variation of strain and stress with load is analyzed. (3) with the aid of numerical simulation software, The finite element model of YS9-8 脳 19 braided wire rope without friction and different friction coefficient is established. The distribution of stress and strain is revealed by simulation analysis, and the influence of friction on the force of braided wire rope is discussed. The finite element simulation of braided wire rope under different tensile loads is carried out, and the simulation results are compared with the theoretical results of mechanical model, which proves the validity of the established mechanical model from the qualitative point of view. The finite element model of braided wire rope with different pitch under the same load is simulated, the variation of stress and deformation with pitch is analyzed, and the range of pitch is selected. (4) taking YS9-8 脳 19 braided wire rope as an example, the tensile test under different loads is carried out, and the displacement curve of wire rope with load is obtained, and compared with the theoretical calculation value. The rationality of the mechanical model is verified. The characteristics and position of broken wire and broken strands are analyzed, and the location of dangerous cross section is discussed, and compared with the theoretical and simulation results, the test results of broken wire and broken strands of steel wire rope are carried out, and the characteristics and positions of broken wires and broken strands are analyzed and compared. The reliability of stress distribution under tensile load of wire rope is verified.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG356.45

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