空间薄膜结构动态测试研究最新进展

New Progress in Dynamic Measurement of Space Based Membrane Structure

空间薄膜结构是一种主要由薄膜材料制成的新型大型轻量化结构,在深空探测中可用于构建大型天线、太阳帆、太阳能集中器等新概念飞行器。它具有超低频率、密集模态、局部模态、几何大变形、高柔性、低密度、强非线性、以及承载能力随充气压力改变等一系列特点,传统的实验模态分析方法已经不满足此类结构的测试要求。同时在地面测试时容易受空气附加质量、地球重力及温度、湿度环境影响,这给动态测试带来很大困难。本文首先总结了适合薄膜空间结构的动态测试技术如新型智能传感器,激光测量和数字图像测量等非接触测试方法最新进展,并比较分析各测试方法优缺点。此外对微重力、真空、交变温度等空间环境对动态测试结果的影响进行总结,存在缺陷对动态测试结果的影响进行评述,最后针对目前空间薄膜结构动态测试中存在的问题进行探讨并指出未来发展方向。

Space membrane structure mainly made of membrane materials is a new kind of ultra large-scale lightweight structure and is used in new concept space-based structures such as large antenna,solar sail,solar energy concentrators etc.Its intrinsic characteristics are ultra-low natural frequency,dense modes,local modes,large deformation,high flexibility,low density,strong non-linear as well as bear capacity highly depended on internal pressure.Traditional experimental modal analysis method cannot meet the analysis requirement for this kind of structure.Moreover,these membrane structures are easily affected by added mass of air,earth＇s gravity,environmental temperature and humility in ground experimental analysis,which bring very difficult problems in dynamic analysis.In this paper,progress of new technology suitable for membrane structure,such as non-contact measuring methods,including smart sensors,laser measurement as well as digital image measurement etc.is reviewed firstly;their benefits and weakness are evaluated.Besides the effect of micro-gravity,vacuum,alternating temperature in space environment,the effect of existed imperfection on result of dynamic measurement is also commented.Finally,potential solutions are discussed and future research endeavors are also suggested based on problems emerged in current dynamic measurement of space membrane structure.