基于绝对坐标与SPH方法的充气薄膜空间结构展开动力学研究

Under the framework of multibody system dynamics, this study deals with the modeling of rigid (rigid-body motion) -flexible-gas coupled dynamics mentioned in the deployment process of a kind of large-scale inflatable membrane space structures and predicts the deployment dynamics of these structures with a satellite body, in order to meet the major requirements of the nation in future space technology. The theoretical models and numerical results will be validated and amended via the ground-deployment experiments. These researches can be used to predict the theoretical framework of deployment dynamics of inflatable membrane space structures and to provide the fundamental basis for the design and application of inflatable deployment structures and so on, which also offers an accurate dynamic model and an efficient computational strategy for the control system. The major studies of the project include (1) the modeling of the deployment dynamics of inflatable membrane space structures based on Absolute Coordinate Based (ACB) method and Smoothed Particle Hydrodynamics (SPH) method, (2) the parallel solution of a huge set of dynamics equations of motion, (3) the analysis of deployment dynamics for a coupled system including a satellite body and inflatable membrane space structures, (4) the ground-deployment experiments for inflatable membrane space structures. The project will focus on solving the following open problems, such as how to simulate the wrinkling of large-scale membrane structures efficiently, how to describe the rigid-flexible-gas coupled dynamic characteristics in the framework of multibody system dynamics, and how to solve a huge set of dynamic equations of motion in parallel.

以我国未来航天科技迫切需求的大尺度充气空间结构为背景，在多体系统动力学理论体系下，研究一类大型充气薄膜空间结构展开过程中所涉及的刚（刚体运动）-柔-气耦合动力学建模问题，预测此类结构与航天器本体系统整体展开动力学规律。通过开展地面实验以验证与改进理论模型及数值仿真结果，完善充气薄膜空间结构的展开动力学理论体系框架，为此类充气展开空间结构的设计、展开动力学分析等方面提供理论依据，并进一步为充气展开过程的控制研究奠定精确建模与高效求解的理论基础。主要研究内容包括：基于绝对坐标（ACB）方法与光滑粒子流体动力学（SPH）方法的充气薄膜空间结构展开动力学建模、大规模系统动力学方程的并行求解、充气薄膜空间结构―航天器本体系统整体展开动力学分析及地面实验研究。重点解决以下科学问题：大面积薄膜结构皱曲现象的高效模拟问题；充气展开中的刚―柔―气耦合多体动力学建模问题；大规模系统动力学方程并行求解问题。

大型充气空间结构因其质量轻、折叠体积小等优点在航天领域具有广泛应用前景。本项目主要研究大型充气薄膜空间结构展开过程中所涉及的刚（刚体运动）−柔−气耦合动力学建模问题。本项目主要成果如下：提出了基于图形学Bézier三角形描述的绝对节点坐标三角形板、壳以及薄膜单元；考虑薄膜结构非线性本构关系，提出了一种新的超弹性绝对节点坐标方法薄壳/薄膜单元，推导了此类单元的弹性力及其切线刚度矩阵；采用弧长控制法、伴随特征值分析以及模态注入法，建立了一种薄膜空间结构充气屈曲分析方法以及高效降阶方法；基于多层区域分解方法，采用MPI技术提出了一种高效求解大规模柔性多体系统动力学方法的并行算法。同时，为了模拟薄膜结构与气体间相互耦合效应，提出一种虚拟SPH粒子嵌入薄膜单元建模方法，模拟气固柔性边界，并采用广义alpha方法与预估校正方法交替求解薄膜动力学方程与气体N−S方程；基于层次包围盒技术，给出了一种高效模拟薄膜空间结构展开过程涉及的自接触动力学建模方法。最后，将理论成果成功应用于卷曲式充气薄膜管的展开动力学问题研究，获得了系统关键的展开动力学特性。通过研究在著名期刊上共发表SCI文章5篇，完成了课题拟定的研究内容，实现了研究目标。