股线及多级绞缆结构力学分析方法与行为研究

发布时间：2018-05-22 19:20

本文选题：绞缆的多层级结构 + 力学性能分析　；参考：《兰州大学》2017年博士论文

【摘要】：股线和线缆结构在众多工程领域应用广泛,基于其内部复杂的相互接触力学行为和几何上的分级分层结构使得绞缆具有一些丰富而优越的力学特性。围绕现代高新技术和大科学工程关联的超大型超导磁体中的CICC多级线缆结构的应用,针对股线和线缆的多级复杂结构有效性质和力学行为预测等基础力学问题,本论文进行了较为系统的理论建模和数值分析,探讨了股线和多级线缆结构性能和外载荷下结构的力学行为,进而揭示股线间局部接触等效应对结构整体性能的影响规律等,为优化线缆的设计提供理论支持和参考。论文主要进行了以下几个方面的研究工作:首先,针对线缆结构的基本组成单元——单根复合股线的基本力学属性和多场有效性能预测开展了研究。单根股线一般为多相复合材料,基于细观力学的理论方法,提出了股线复合材料在力、热、电磁多场复杂环境中有效性质的广义Mori-Tanaka方法,给出了相应的等效性质预测公式。进一步建立了纤维夹杂复合材料结构的有限元数值模型,采用Comsol有限元软件进行求解并给出预测结果。结果表明:所建立的广义Mori-Tanaka模型可以较好地预测复合股线的力学、热学和电磁学等有效特性,并获得不同夹杂相体积分数下的有效性能依赖关系,理论模型预测结果和有限元结果吻合良好。其次,围绕多根股线螺旋绞扭而成的一级绞缆结构,考虑股线间局部接触变形和接触摩擦等效应,开展了绞缆力学性能与行为分析研究。针对该一级绞缆(1×3)结构的复杂非线性力学方程的求解,提出了分步加载的力学分析方法,逐次考虑局部接触变形和摩擦效应的影响并获得绞缆和各个股线力学响应的解析解答;文中所建模型和结果可适应于股线螺旋角(从55o到90o)的更大范围。在此基础上,本文详细分析并获得了螺旋股线间的摩擦力分布特征,以及接触摩擦对股线性能和整体绞缆行为的影响;获得了不同螺旋角下股线间接触和摩擦对绞缆结构轴向拉伸和扭转变形下的等效刚度、内力分量等的影响特征。结果表明:股线间局部接触变形和摩擦均会对绞缆力学性能产生影响,接触变形对绞缆结构整体力学性能的影响更为显著。为了验证理论模型与解析结果的可靠性,将相关结果与ABAQUS有限元数值模拟的结果进行了对比,二者吻合良好,特别是在股线螺旋角较大变化范围内,均能给出较好预测结果。再次,针对一级绞缆结构通过螺旋绞扭而成的复杂二级绞缆结构(3×3),考虑其局部接触变形,并对此进行力学行为分析与研究。在二级绞缆结构中两种不同的接触形式,忽略股线间接触摩擦效的情形下,建立了二级绞缆结构力学行为分析的两级等效模型。结合二级绞缆内部不同接触形式,提出了二级绞缆内部接触和接触变形的计算方法,详细分析了接触变形对绞缆整体变形的影响,并获得绞缆各层级中的应变以及内力分布的解析表达。模型不仅从理论上解释了二级绞缆各局部接触变形对绞缆结构的影响原理,并且定量分析了接触变形对二级绞缆力学性能的影响。结果表明:绞缆内部子缆的局部接触变形,对小螺旋角下绞缆的整体力学性能和股线内力均有着显著的影响,是影响绞缆力学性能的重要因素。该模型可退化为已有文献中不考虑接触变形的传统模型,在较大螺旋角的情形下两者预测结果相近。最后,围绕具有多层级复杂几何特征的多级绞缆(3N)结构,本文提出了一种分析多层级线缆力学性能的分(跨)级分析模型,实现了对多级绞缆结构力学性能的理论分析。在忽略股线泊松效应和线缆内部接触变形的假设前提下,基于对各层级中心线位移和变形的逐级递推关系,建立了从最低层级股线变形到最高级层绞缆变形之间的联系。在小变形条件下,根据变形前后股线的截面主轴坐标架的旋转关系,获得了股线上任意点处的应变解析表达式,从理论上建立了股线应变和各级绞缆变形的严格依赖关系;进一步通过解析逐级递推,我们可得到绞缆各级中心线的变形情况,通过等效方法得到了线缆在变形时的整体力和扭矩等基本力学特征与响应。该多级绞缆结构的一般分析方法用于退化后的一级股线结构二级绞缆结构(3×3),分析并给出了结构有效性质并和力学响应,结果吻合良好,验证了该多级结构分析方法的有效性。
[Abstract]:The strands and cable structures are widely used in many engineering fields. Based on their internal complex contact mechanical behavior and geometric hierarchical structure, the cable has some rich and superior mechanical properties. The structure of CICC multistage cable in superlarge superconducting magnets associated with modern high technology and large scientific engineering In this paper, a systematic theoretical modeling and numerical analysis are carried out to discuss the structural properties of the strands and multistage cables and the mechanical behavior of the structures under external loads. In order to provide theoretical support and reference for optimizing the design of cable, the main research work in the following aspects is carried out in the following aspects: firstly, the basic components of the cable structure, the basic mechanical properties and the multi field effective performance pre measurement, are studied. The single strand is generally multiphase composite. Materials, based on the theoretical method of meso mechanics, a generalized Mori-Tanaka method for the effective properties of a strand composite in a complex environment of force, heat and electromagnetic fields is proposed. The corresponding prediction formula of the equivalent properties is given. The finite element numerical model of the structure of fiber inclusion composite is further established, and the Comsol finite element software is used to obtain the finite element model. The results show that the generalized Mori-Tanaka model can well predict the effective properties of the mechanics, thermal and electromagnetics of the composite strands, and obtain the effective performance dependence under the volume fraction of the different inclusions. The prediction results of the theoretical model are in good agreement with the finite element results. Secondly, around the multiple strand lines. The mechanical properties and behavior of the cable are studied in consideration of the effect of the local contact deformation and contact friction between the strands. The mechanical analysis method of the step loading is put forward to solve the complicated nonlinear mechanical equation of the first class stranded cable (1 x 3). The effect of the rubbing effect is obtained and the analytical solutions of the mechanical response of the strands and the strands are obtained. The model and the results in this paper can be adapted to the greater range of the helix angle of the strand (from 55o to 90o). On this basis, the distribution characteristics of the friction force between the spiral strands are analyzed and obtained in detail, as well as the contact friction on the properties of the strand and the whole cable line. The effects of the contact and friction of the strands under the different helix angle on the equivalent stiffness and the internal force components of the cable structure under axial tension and torsion are obtained. The results show that the local contact deformation and friction between the strands will affect the mechanical properties of the cable, and the effect of contact deformation on the mechanical properties of the cable structure. In order to verify the reliability of the theoretical model and the analytical results, the correlation results are compared with the results of the ABAQUS finite element numerical simulation. The two are in good agreement, especially in the large variation range of the helix angle of the strand, and the better prediction results are given. Again, the needle is complicated by twisted twisted structure of the first class stranded cable. The structure of two stage cable (3 x 3), considering its local contact deformation, has been analyzed and studied on the mechanical behavior. In the case of two different contact forms in the two grade cable structure, the two equivalent model of the mechanical behavior analysis of the two grade cable structure is established under the circumstances of neglecting the indirect contact friction effect of the strands. The calculation method of internal contact and contact deformation of two grade cable is put forward. The influence of contact deformation on the overall deformation of the cable is analyzed in detail, and the analytical expression of strain and internal force distribution in the various layers of the cable is obtained. The model not only explains the influence principle of the contact deformation on the structure of the stranded cable in theory, but also explains the influence principle of the contact deformation on the stranded cable structure in theory. The effect of contact deformation on the mechanical properties of the two grade cable is quantitatively analyzed. The results show that the local contact deformation of the cable inner cable has a significant influence on the mechanical properties and the internal force of the strand, which is an important factor affecting the mechanical properties of the cable. In the case of large spiral angle, the prediction results are similar in the case of large spiral angle. Finally, based on the multi-layer complex geometric characteristics of the multilevel cable (3N) structure, this paper presents a sub (cross) level analysis model for analyzing the mechanical properties of multi-layer cable, and realizes the theoretical analysis of the mechanical properties of the multistage cable structure. On the premise of line Poisson effect and cable internal contact deformation, based on the progressive recurrence relation of the displacement and deformation of the central line of each level, the connection between the deformation of the lowest level strands and the most advanced layer cable is established. Under the condition of small deformation, the rotation relation of the main axis coordinate frame of the cross section of the strands before and after the deformation is obtained. The analytical expression of strain analysis at any point on the femoral line is used to establish the strict dependence relation between the strained strain and the deformation of the twisted cable at all levels. Further, by analyzing the step by step recurrence, we can get the deformation of the central line at all levels of the cable, and get the basic mechanical characteristics of the whole force and torque of the cable in the change of the shape by the equivalent method. The general analysis method of the multistage cable structure is used for the degenerated first grade strand structure two grade cable structure (3 x 3). The effective properties of the structure and the mechanical response are given. The results are in good agreement, and the effectiveness of the multistage structure analysis method is verified.
【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O342

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