纤维增强复合材料热隐身斗篷设计

基于变换热动力学原理可获得具有热隐身性能的隐身结构(隐身斗篷)所需要的材料性质的空间分布。但这种材料性质的复杂分布形式以及局部热传导性能无限大等极值性质需求,使得隐身斗篷设计的实现非常困难,需要研究基于常规材料的隐身斗篷设计。本文基于常规材料的热隐身结构实现问题,提出了基于纤维增强复合材料圆环结构的实现热隐身的结构形式。首先,基于变换热动力学原理获得热隐身所需的热传导系数沿半径方向的变化规律;进而,通过设计复合材料不同位置的纤维铺设方式(含量和铺设方向)实现热隐身对材料性能的需求。选择金属银作为纤维,空气作为基体,设计出了具有热隐身性能的复合材料圆环结构纤维含量和铺设方向沿径向的分布方案。对该设计方案进行数值仿真,结果显示所设计的隐身结构具有良好的热隐身性能。由于设计方案基于常规材料,因此具有容易实现的优点。

Thermal invisibility cloak design based on fiber reinforced composite

Although the spatial variation of the material property required for achieving thermal invisibi-lity in the structure,i.e.an invisible cloak for heat flux,can be obtained through transformation thermo-dynamics,the design of the cloak is practically very difficult to be implemented due to the complexity in distribution and local extreme (infinite) in value of the required thermal conductivity of the material.Hence,it is of great engineering significance to explore effective ways to design invisibility cloak for heat by using conventional materials.In this paper,we proposed a way to design annular thermal invisibility cloak by using fiber reinforced composite.The required material property distribution (i.e.thermal conducti-vity) was obtained based on transformation thermodynamics first.Then,through composite microstructure design,the fiber layout (volume fraction and orientation) was determined to match with the required thermal conductivity distribution.Using silver as the reinforcement and air as the matrix,the fiber layout of the annular cloak was obtained,which was easy to be fabricated by ordinary materials.The simulation results showed almost perfect invisible cloak properties,thus validating the proposed design method.