High Precision Simulation of Large Deployable Membrane Space Structure and Formulation of Similarity Rule

薄膜作为可展开的轻型结构具有优良的性能，被认为是大型可展开空间结构。如果将膜应用于大型可展开空间结构，存在以下几个结构设计问题：(A)膜很小的皱纹和塑性折叠线，膜的摩擦自碰撞可能会对大型膜的动力学产生不良影响，(B)膜展开后的动力稳定性得不到保证，(C)飞行模型(~100m)与地面(~20m)的实验模型之间没有合适的膜动力学相似准则。本研究旨在提出定量获取这三个问题中有价值的知识的方法。研究结果总结如下：(1)相似准则的建立：建立了考虑了轨道上或地面实验中的扰动对薄膜的影响的运动方程。利用该方程，推导出了相似准则。实验结果验证了所提出的相似准则的有效性。(2)膜运动的参数研究：研究人员开发了一个高精度的有限元程序NEDA来模拟膜的展开。研究人员利用商业软件ABAQUS以及NEDA进行了模拟，评估了膜的质量分布、折叠方式对展开的影响以及展开后的稳定性。(3)褶皱模型的验证：研究人员提出了褶皱的数值模型，使我们能够对膜进行有效的模拟。通过与壳元模型的比较，验证了所提出的褶皱模型的有效性。(4)折叠展开方法的评价：针对折叠展开方法，提出了综合评价方法。

Membrane has excellent property for deployable light structure, and has been expected as large deployable space structure. If membrane is applied to the large deployable space structure, there are several structural design problems as follows; (a) very small wrinkles and plastic fold lines, and the frictional self-impact of the membrane will be possibly give undesirable influence on the dynamics of the large membrane, (b) the dynamic stability of the membrane after the deployment is not guaranteed, (c) there is no appropriate similarity rule on the dynamics of membrane between the flight model (〜100m) and the experimental model that is available on the ground (〜20m). This research has aimed at proposing the method to get the valuable knowledge quantitatively about these three problems. The research results are summarized as follows;(1) Formulation of similarity rule : The equation of motion is formulated which includes the effect of the disturbances applied to the membrane on orbit or in the ground experiment. Using the equation, the similarity rule was derived. The validity of the formulated similarity rule was shown by the experimental results.(2) Parametric study of the membrane motion : The investigator had developed a highly precise FEM code "NEDA" to simulate the deployment of membranes. The investigator conducted the simulation by using the commercial software "ABAQUS" as well as "NEDA", and evaluated the influence of the mass-distribution, fold-pattern on the deployment and the stability after the deployment.(3) Verification of the wrinkle model: The investigator proposed the numerical model of the wrinkle that enables us the efficient simulation of the membrane. The validity of the proposed wrinkle model is shown by comparing the proposed model and the shell element model.(4) Evaluation of the folding and deploying method : The synthetic evaluation method was proposed concerned with the folding and deploying method.