网状编织结构力学性能分析

发布时间：2019-06-14 12:21

【摘要】：大功率无源微波部件以及天线中的电磁波干扰问题,严重影响着卫星通信系统的设计、实现及正常稳定的工作。网状反射面天线是移动通信、电子侦察、数据中继、微波遥感等卫星上的关键设备之一,然而,天线上用于反射和接收信号的网状编织结构──金属网,是产生电磁波干扰的关键非线性部件之一。电磁波干扰问题是由网状反射面固有非线性引起的,非线性主要包括接触非线性和材料非线性。接触非线性在金属网结构中不可避免,是产生干扰的主要根源。研究发现,金属网接触结的接触力直接决定了接触非线性。因此,对网状反射面进行力学分析,获得其接触力,具有重要研究意义。另外,本文研究的网状反射面力学分析方法,为网状反射面的精确建模,以及后期的力学分析奠定了基础。本文针对网状天线金属网编织结构复杂、力学建模困难且存在尺寸非线性效应等问题,研究了金属网结构的分形力学方法,主要研究内容为:1.研究小尺寸金属网结构的弹性性能。首先,结合图像测量、样条插值、截面扫描以及编织单元拼接等方法建立金属网结构的几何模型,并获得其力学模型,进而借助仿真分析探究其力学性能,验证网状反射面金属网结构的正交各向异性性能。然后,采用仿真分析与有限元技术研究具有正交各向异性性质的金属网结构,探究其力学等效的方法,利用正交各向异性平面应力结构描述金属网结构的力学性能。最后,建立弹性性能参数识别的数学模型,获得小尺寸金属网的等效弹性性能参数。2.研究金属网结构的分形力学分析方法。以小尺寸金属网参数为基础,研究金属网结构的分形力学分析,揭示其分形特征。首先,研究金属网结构小岛分维和计盒分维的计算方法,并利用这两种分维描述金属网的分形特征。接下来,利用推广的Sierpinski毯描述金属网结构的力学性能,推导金属网结构的刚度矩阵,建立弹性性能参数与金属网尺寸间的关系,基于小尺寸金属网结构参数预测大尺寸金属网的力学参数。最后,通过算例验证了该方法的可行性。3.研究网状反射面金属网接触力的统计分析。从统计学的角度,研究网状反射面上指定区域的接触力统计分布规律。以偏馈环形桁架式网状可展开天线为例,根据网状反射面金属网力学分析的思路,编制应用性强的界面程序,研制网状反射面金属网接触力分析软件,通过图形用户界面呈现分析结果,给出网状反射面指定区域金属网接触力均值的分布云图,以及指定接触结的接触力。
[Abstract]:The problem of electromagnetic wave interference in high power passive microwave components and antennas seriously affects the design, realization and normal stability of satellite communication system. Mesh reflector antenna is one of the key equipment on mobile communication, electronic reconnaissance, data relay, microwave remote sensing and other satellites. However, the mesh braided structure used to reflect and receive signals on the antenna is one of the key nonlinear components to produce electromagnetic wave interference. The electromagnetic wave interference problem is caused by the inherent nonlinear of the reticulated reflector, which mainly includes contact nonlinear and material nonlinear. Contact nonlinear is inevitable in metal mesh structure and is the main source of interference. It is found that the contact force of metal mesh contact junction directly determines the contact nonlinear. Therefore, it is of great significance to analyze the mechanics of the reticulated reflector and obtain its contact force. In addition, the mechanical analysis method of reticular reflector studied in this paper lays a foundation for the accurate modeling of reticulated reflector and the later mechanical analysis. In order to solve the problems of complex braided structure, difficult mechanical modeling and size nonlinear effect, the fractal mechanics method of metal mesh structure is studied in this paper. the main research contents are as follows: 1. The elastic properties of small size metal mesh structure are studied. Firstly, the geometric model of metal mesh structure is established by image measurement, Spline interpolation, cross section scanning and braided element splicing, and its mechanical model is obtained, and then its mechanical properties are investigated by simulation analysis, and the orthotropic properties of reticulated reflector metal mesh structure are verified. Then, the metal mesh structure with orthotropic properties is studied by simulation analysis and finite element technique, and the mechanical equivalent method is explored. The orthotropic plane stress structure is used to describe the mechanical properties of the metal mesh structure. Finally, the mathematical model of elastic performance parameter identification is established, and the equivalent elastic performance parameters of small size metal mesh are obtained. 2. The fractal mechanics analysis method of metal mesh structure is studied. Based on the parameters of small size metal mesh, the fractal mechanical analysis of metal mesh structure is studied and its fractal characteristics are revealed. Firstly, the calculation method of fractal dimension of small island and box with metal mesh structure is studied, and the fractal characteristics of metal mesh are described by using these two fractal dimensions. Then, the mechanical properties of the metal mesh structure are described by using the extended Sierpinski blanket, the stiffness matrix of the metal mesh structure is derived, the relationship between the elastic properties parameters and the size of the metal mesh is established, and the mechanical parameters of the large size metal mesh are predicted based on the structural parameters of the small size metal mesh. Finally, an example is given to verify the feasibility of the method. The statistical analysis of contact force of metal mesh on reticulated reflector is studied. From the point of view of statistics, the statistical distribution of contact force in the specified area on the reticulated reflector is studied. Taking the biased feed ring truss mesh expandable antenna as an example, according to the idea of mechanical analysis of the mesh reflector metal mesh, the interface program with strong application is compiled, and the contact force analysis software of the mesh reflector metal mesh is developed. through the graphical user interface, the distribution cloud diagram of the average contact force of the metal mesh in the designated area of the mesh reflector and the contact force of the specified contact junction are given.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820;TN972

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