柔性热防护结构的热力耦合响应研究

Flexible thermal protection structures(FTPS) are intended for light-weight thermal protection design for inflatable space station and lunar habitats. Thermo-mechanical coupling effect of the structures under the severe thermal condition is significant, which is one of the key problems deserving of attention during the thermal protection structural design. This project is to carry out deep studies focusing on key scientific problems in the thermo-mechanical coupling property research of FTPS. Aiming at the complex heat transfer problems including conduction-radiation coupling heat transfer and surface shelter from each other, an analytic strategy of radiation heat exchange for the complex wrinkled membrane structures will be proposed. Then the three-dimensional transient heat transfer analysis method of laminate membranes will be developed. Based on improved spring-mass system, the prediction model of three-dimensional configuration for membrane wrinkling will be established. The wrinkling responses under thermal loading will be analyzed and the generation mechanism of thermally induced wrinkling will be studied. On this basis, a thermo-mechanical coupling analysis workframe will be developed for analyzing temperature distribution, thermal stress, thermal deformation and thermally induced wrinkling of FTPS. Then the interaction rules between the transient heat transfer and the mechanical response of the structures will be drawn. The influences of the design parameters to the performace of the FTPS will be studied and the thermal protection/ structural integrated design will be performed, which provides a technical support for the flexible thermal protection design and engineering application.

柔性热防护结构适用于充气式空间站和月球殖民基地居住舱的轻质热防护设计。结构在严酷热环境下的热力耦合效应显著，是热防护结构设计中值得研究的问题之一。本项目针对目前柔性热防护结构的热力耦合响应研究中的一些关键科学问题开展深入研究。针对柔性热防护结构存在传导-辐射耦合和曲面互相遮挡等复杂传热问题，提出适于出现褶皱的复杂薄膜结构的辐射换热分析策略，进而发展层合薄膜的三维瞬态传热分析方法。基于改进的弹簧质点系统，建立薄膜褶皱的三维形态预测模型。分析热载荷下的褶皱响应，并研究热致褶皱的产生机理。在此基础上，发展完善的热力耦合响应分析框架，用以分析结构温度场分布、热应力、热变形和热致褶皱等，进而揭示瞬态传热和结构力学响应之间的相互影响规律。研究设计参数对柔性热防护结构性能的影响，实现防热/承载一体化设计，为柔性防护结构设计和工程应用提供技术支撑。

柔性热防护结构适用于充气式居住舱和火星着陆器的轻质热防护系统，一般由柔性的多层层合薄膜构成。在严酷的太空热或者气动热环境下，柔性热防护的热力耦合效应显著，是柔性航天器结构设计中亟待解决的关键问题之一。本项目针对目前柔性热防护结构的热力耦合响应研究中的一些关键科学问题开展深入研究。针对柔性热防护结构存在传导-辐射耦合和曲面互相遮挡等复杂传热问题，推导了层合薄膜曲面单元瞬态传热的有限元法求解格式，发展了层合薄膜的三维瞬态传热分析方法，并用于分析抛物面型层合薄膜的在轨瞬态传热过程。改进了现有的弹簧质点系统，建立了薄膜结构褶皱的三维形态预测模型，编制了相应的数值仿真程序。采用非接触测量系统，完成了层合薄膜的褶皱形态实验，进而验证了褶皱预测模型的正确性。基于非线性屈曲理论，实现了层合薄膜在空间热环境下的褶皱三维形态分析，从而揭示了热致褶皱的产生机理。基于顺序耦合分析框架，完成了柔性热防护的热力耦合响应研究。基于商业软件二次开发技术编制了柔性热防护的热力耦合分析程序，分析了太空居住舱柔性热防护在轨运行时的瞬态温度场和热响应（热应力、热变形和热致褶皱等），进而揭示瞬态传热和结构力学响应之间的相互影响规律，从而实现防热/承载一体化设计。本项目的研究成果为充气式居住舱和火星着陆器的柔性防护结构设计和应用提供技术支撑。