不确定条件下机械结构电磁屏蔽特性建模与分析方法研究

The electromagnetic shielding performance of mechanical structures is an important technical indicator of electronic equipment. Shielding analysis technologies are primary means for pre-evaluating the shielding performance of mechanical structures. The existing technologies predict the output of the system based on the specified knowledge of the input parameters, which cannot meet the requirement of analysis under uncertainty in real life. This project is proposed to conduct a series of fundamental research on modeling and analysis methods for electromagnetic shielding properties of mechanical structures under uncertainty. Considering the multiscale and highly resonant nature in modeling and analysis process of the shielding performance, equivalent modeling methods for coupling channels of electromagnetic energy that are independent of numerical methods and extrapolation method for time-domain response of highly resonant structures are studied first to enhance the computational efficiency of the shielding effectiveness, and thus provide sample data for statistical analysis. Subsequently, in order to obtain the calculation method of statistical moments of the shielding effectiveness, the relationship between random input parameters and output shielding effectiveness and the sensitiveness of input parameters are studied extensively based on statistical electromagnetic. Finally, the proposed methods will be verified by applying them to analyze the shielding performance of servers and comparing the results with measurement. This is an interdisciplinary project that involves mechanical engineering and electromagnetics since it investigates the mutual coupling effects between mechanical structure and electromagnetic field. The achievements are expected to provide methods for the shielding properties analysis and design of mechanical structures under uncertainty, and will be widely employed in the future.

机械结构的电磁屏蔽性能是电子设备的重要技术指标，屏蔽分析技术是屏蔽性能预测的重要手段。现有分析技术主要是在输入已知的条件下求系统输出，无法满足现实中广泛存在的输入不确定的分析需求。本项目基于电磁学对不确定条件下机械结构屏蔽特性的建模与分析方法展开基础研究。首先针对屏蔽建模与分析中的“多尺度”和“强谐振”问题，系统研究电磁能量耦合通道等效建模方法和强谐振结构时域响应外推方法，提高屏蔽效能的计算效率，为统计分析提供样本数据。进而基于统计电磁学对输入随机变量与输出屏蔽效能之间的关系进行研究，考察输入随机变量的敏感度，建立屏蔽效能统计量的求解方法。最后针对屏蔽性能要求很高的服务器进行分析和测试，验证所提出方法的有效性。本项目研究机械结构与电磁场之间的相互作用，涉及机械工程与电磁学的交叉，研究成果有望为机械结构的电磁屏蔽特性分析与设计提供方法与手段，具有重要的理论价值和应用前景。

机械结构的电磁屏蔽性能是电子设备的重要技术指标，屏蔽分析技术是屏蔽性能预测的重要手段。项目以电子设备的机械结构为对象，研究不确定条件下电磁屏蔽特性的建模与分析方法，并取得了可观的成果：基于电磁场孔缝耦合理论、波导理论及场线耦合理论，研究了机械结构的电磁耦合机理，探索了各种结构因素对机械结构电磁屏蔽性能的影响规律；基于电磁场孔缝耦合理论与传输线理论，建立了带孔缝腔体结构屏蔽效能的解析计算方法，并将其适用范围扩展至高频段；基于多导体传输线理论，研究了复杂线缆结构的等效建模方法，提高了带线缆屏蔽结构屏蔽效能的计算效率；基于Bethe小孔耦合理论与波导理论，研究了带孔缝腔体结构的电磁谐振特性，提出了特定干扰源特性下腔体结构谐振频率和谐振模式的预测方法；基于Prony理论，建立了强谐振结构晚期时域响应外推方法，显著提高了机械结构屏蔽效能的数值计算效率；基于统计多极展开法与混沌多项式法研究了机械结构的屏蔽效能统计量与输入随机变量统计量之间的关系，提出了屏蔽效能统计量的高效计算方法。项目成果可为机械结构电磁屏蔽性能的高效预测提供解析和数值计算方法，进而为电子设备的电磁屏蔽特性分析与设计提供方法与手段，具有重要的理论价值和应用前景。