轻质多孔智能材料与结构的力-电-磁耦合性能分析及优化设计

This project aims to design a kind of intelligent and flexible microstructure with the self-adaptive adjustment for band width and location which is used in the radoms and the structural absorbing materials. The main research contents are as follows. Firstly, the homogenization method and the finite element technique are applied to achieve the effectvie electromageticelastic properties prescribed within the bound limit. Design variables are assigned to each element as pseudo-densities. Combined the sensitivity analysis with the globally convergent method for moving asymptotes(GCMMA), the topology optimization of the flexible microstructure is performed to find the optimum coupled properties under the displacement constraint in the design of the compliant micro-mechanism. Secondly, the optimum flexible microstructure is regarded as the compliant micro-mechanism. Driven by the coupled thermo-mechanical load, the compliant micro-mechanism is moving. Corresponding with the different locations, the effective electromagneticelastic properties are varied. The mechanical, transmission and absorption properties are also different. After the effective values are calculated at a number of different locations, the discrete data are obtained. The function expression between the driving load and effective electromagneticelastic properties of the flexible microstructure is built by using the fitting method. And then, the corresponding thermo-mechanical loads are designed in order to meet the demand of the broadband transmission or absorption. So the CMS can self-adjusted to meet the need of band width and location when the environment temperature and load change. Thus, the adaptive controls for the wave transmission or absorption are achieved. This research is very valuable for the design of the intelligent materials and structures in the aerospace industry.

本项目以实现天线罩和结构型隐身材料的宽频可控特性为研究背景，旨在设计一种满足不同频段条件下具有力-电-磁耦合性能自适应功能的智能柔性微结构。主要研究内容包括：在分析计算多孔材料与结构的多场耦合等效性能的基础上，以输出位移为约束条件，建立以力-电-磁耦合性能为设计目标的的优化模型，采用灵敏度分析技术和全局收敛多目标优化算法，实现柔性微结构的拓扑优化设计；作为一种柔顺微机构,在热力耦合载荷驱动下，计算不同变形状态下的等效耦合性能，采用数据拟合的方法，建立热力耦合驱动载荷与柔性微结构的力-电-磁耦合性能间的函数关系；以满足宽频透波或吸波等性能要求，开展热力耦合载荷的逆向设计，使多孔材料与结构根据环境温度及载荷的变化，自适应于频带宽度及位置要求，达到对透波或吸波性能的智能控制。研究成果对航空航天领域中智能材料结构的设计具有重要的理论意义和应用价值。

本项目从航空航天工程领域中对结构隐身、轻质的性能需求出发，以天线罩和结构型隐身材料的频带可控性为应用背景，开展具有力-电-磁耦合性能自适应功能的智能柔性微结构的结构电磁性能分析和设计方面的基础理论和方法研究，主要研究内容和成果包括：.（1）考虑了蜂窝结构（正六边形和手征性蜂窝）孔壁微元体伸缩变形，推导出了一种分析柔性蜂窝结构大变形情况下面内等效弹性性能的改进计算方法，并分别采取基于大变形仿真计算的直接等效方法和实验测试手段，验证了该方法更适用于低刚度大变形条件下柔性蜂窝夹芯结构的等效弹性模量的计算。.（2）针对带吸波涂层的柔性蜂窝夹芯结构，深入研究了其等效介电性能的计算机理，为了反映出等效介电常数的色散效应，基于波导结构传输原理，研究采用改进的强扰动理论。计算结果表明，随着频率升高，色散效应逐渐减弱；并根据传输线理论计算反射率，以此为指标作为衡量材料的吸波性能，在指定频段范围内以结构参数为变量，实现了柔性蜂窝夹芯结构吸波性能的优化设计。.（3）采用旋转对称设计域和变量关联技术，实现了极化不敏感性完美吸波超材料的优化设计，在特定频段下，结构的表面阻抗与自由空间阻抗达到了完美匹配，实现了在宽角度下对斜入射TE 和TM 极化电磁波的高效吸收；并研究发现多层结构的吸收效果是单层结构吸波特性相互耦合的结果，在整体厚度许可范围内，通过多层超材料设计，拓宽了吸波带宽。.（4）利用柔性导电橡胶的温度敏感电阻特性和电磁波屏蔽效能及较好的拉伸强度，研究设计温度可调的电磁超材料和力可调的吸波超材料；并利用静电场下液晶分子取向变换，设计电可重构开口环谐振器电磁超材料。研究结果揭示了介电颗粒的电、磁谐振调控机理，以及电磁-热学、电磁-力学等物理场耦合对电磁谐振的影响规律，以实现对柔性超材料结构电磁性能的智能控制。.本项目发表SCI检索论文9篇，获授权国家发明专利2项。