【作者】 李鹏；

【导师】 段宝岩；

【作者基本信息】 西安电子科技大学 ， 机械电子工程， 2010， 博士

【摘要】 电子装备是机电结合的系统,机电耦合问题已成为制约电子装备性能提高并影响下一代装备研制的一个瓶颈。因而在多个国家重点项目的支持下,基于前人的工作,本文以电子装备的典型案例—反射面天线和高密度机箱为研究对象,针对其存在的场耦合问题进行了深入研究与探索。在前人提出的反射面天线机电耦合模型的基础上,针对耦合模型综合考虑随机误差与系统误差,导致计算工作量大的问题,提出了新的耦合模型求解方法。首先基于结构分析的变形网格推导了结构与电磁网格转换矩阵,用于得到电算网格和内部计算点,以内部点代替细化网格,保证精度的同时降低计算工作量;其次利用有限元单元形函数插值,计算内部点的变形,可提高高频时的计算精度;再次根据结构网格的具体形式推导了不同单元的数值积分公式,拓展了适用范围;最后通过数值算例和工程实验表明了该求解方法的正确性和有效性。针对耦合模型系统误差中的太阳辐射热变形影响面天线电性能的问题,首先研究天线受到太阳照射的热流密度;其次以热流密度为载荷,分析了天线的温度分布,并通过实验验证了分析结果;最后研究了温度导致的结构变形对天线电性能的影响。针对耦合模型随机误差中通常忽视表面加工质量的问题,利用分形函数建立天线面板表面纹理的数学模型,将表面纹理引入面天线机电耦合模型中计算电性能。得出了表面加工质量的纹理幅度、密度和粗糙程度对电性能影响的初步规律。相关结论可供工程实践参考。针对面天线结构设计中的机电分离问题,在面天线机电耦合模型的基础上,建立了反射面天线的机电集成优化模型,进行反射面天线机电集成优化设计。同时将天线整体建模,在设计变量中包含馈源(副面)支撑结构的参数,能够将天线的主面和馈源(副面)支撑结构作为一个整体进行设计。通过典型8m口径抛物面天线的机电集成优化实例表明,与传统结构优化和单纯考虑主面的机电集成优化相比,考虑整体的机电集成优化能够取得更好的效果。最后将机电集成优化应用于某工程的40m口径反射面天线,获得的改进设计方案可供工程参考。针对高密度机箱电磁兼容性分析的问题,从多场耦合的角度,综合考虑了孔缝等结构参数、接触缝隙等因素,同时还考虑了实际工作中机箱的结构变形和温度对电磁器件的影响等实际因素,提出了高密度机箱的机电热三场耦合模型。对于接触缝隙或导电衬垫,通过转移阻抗得到其等效的电磁参数,可进入场耦合模型,提高了实际机箱电磁屏效分析的准确性。说明了耦合模型求解的具体步骤。最后不但进行了数值算例仿真还设计了实物实验,通过仿真数据与实验数据的对比表明了所提场耦合模型的正确性与有效性。针对高密度机箱设计中存在的机电热分离问题,在高密度机箱机电热三场耦合模型的基础上建立了多场耦合的集成优化模型,分析了优化模型的特点,提出优化求解的思路与流程。并将优化模型应用于某实际工程案例,通过对结构参数进行优化设计,获得的改进设计方案在结构强度、通风散热和电磁屏效三个方面都有明显的改善,体现了集成优化的优势。更多还原

【Abstract】 Electronic equipment is a kind of electromechanical system, and the electromechanical coupling problem is the bottleneck which constrains the improvement of existing electronic equipment and the development of the next generation equipment. With the support of several national key projects, based on the previous work, this paper researches the coupled multifield problem and integrated optimization design on the study of reflector antenna and electronic equipment enclosure, which are two kinds of typical electronic equipments.Based on the electromechanical coupling model of reflector antenna proposed by previous scholars, for the problem of large computation in analysis of the coupling model, a new solution is proposed which could improve analysis efficiency and precision. Firstly, the transformation matrix between structures grid and electromagnetic grid is derived. Secondly, the finite element shape function of the structure grid is used to interpole phase difference of aperture surface. Thirdly, different formulas of different structure grid for numerical integration are derived. Finally, the correctness and effectiveness of the new solution is proved by some numerical simulations and experiments.For the problem of thermal deformation of ground reflector antenna due to solar radiation , which is a kind of system error, the heat flux from solar on antenna surface is calculated firstly. Secondly, the temperature distribution of antenna is obtained by FEM, and a temperature experiment proved the temperature results. Thirdly, thermal-structure analysis was proceeded by FEM. Finally, electronic parameters of the antenna were calculated by coupling model. Another surface quality problem of reflector machining, is a kind of random error. Fractal function is used to model surface texture. Microscopic surface texture is introduced to the coupling model and then calculates electronic performance. The effects of different amplitude, density and roughness of the reflector texture to antenna’s far field patterns are studied. These results could be referenced in engineering practice.For the separation problem of electromagnetic and structure design of reflector antenna, based on the coupling model, a new electromechanical integrated optimization model of reflector antenna is established. The structure parameters include feed support structure, so the antenna structure could be designed as a entirety. The examples of tipical 8m and 40m antennas in some project show that the electromechanical integrated optimization results are much better than the tradition structure design, and the results indicate the rationality and effectiveness of the integrated optimization.Address to numerical simulation of shielding effectiveness and leakage electromagnetic field of electronic equipment enclosure, server influence factors are researched in the view of multifield coupling, including structure parameters(holes, slots and so on), contact seam/conductive rubber, structure deformation and temperature. In consideration of the enclosure which will deform due to impact and vibration, and temperature will affect the features of electromagnetic components in practical working, the three fields coupled model of electronic equipment enclosure is established. Transfer impedance is used to compute electromagnetic parameters of contact seam/conductive rubber during solving the coupled model. The comparison between simulation data and the experiment data shows that the three fields coupled model is correct.Against the separation problem of electromagnetic, structure and thermal design of enclosure, basis on the three fields coupled model, a integrated optimization model is proposed. Finally, the optimization method is applied to an engineering case, to optimize the structural parameters, and the designed scheme is greatly improved in structure strength, ventilation and shielding effectiveness, and the results indicate the advantage of the integrated optimization.更多还原