Dynamics of Inflatable Space Structure

提出了一种充气膜结构展开动力学的数值分析方法，并编制了数值程序。提出了膜的自接触数学模型和膜折线的粘弹塑性模型。这些模型的表述被落实到直到去年已经开发的数字代码中。膜起皱问题是近年来最热门的研究课题，本研究分析的问题还没有被其他研究人员研究过。然而。本文的主要研究成果如下：(1)建立了具有部分起皱的膜结构动力学数值方法，并开发了相应的数值程序。这种方法使我们能够进行精确守恒能量、线动量和角动量的数值时间积分，即时间积分是无条件稳定的。这是零重力条件下膜动力学计算的关键数值技术，一直是计算膜动力学的难点。(2)建立了充气与膜管相互作用的数学模型。该模型还能很好地守恒能量，从而实现数值稳定的积分。(3)将膜的自接触效应引入到数值程序中。这也是获得准确模拟结果的关键数值技术。(4)建立了膜折叠的粘弹塑性模型，研究表明膜和充气膜结构的动态行为可以用数值方法来预测，这是不可能的。这是这项研究最重要的结果。

A numerical analysis method of deployment dynamics of inflatable membrane structures is proposed, and the numerical code is developed. A mathematical model of self-contact of the membrane and the visco-elastoplastic model of the fold line of the membrane are proposed. The formulation of these models is implemented into the numerical code that has already been developed until last year. The wrinkling problem f the membrane is the most popular research topics in these years, and the problem analyzed in this research has not investigated by other researchers yet. However. That problem will be the most serious problem to fabricate the large membrane structures in near future.The results of this research are summarized as follows; (1) Numerical method of the dynamics of membrane with partial wrinkling is formulated and a numerical code is developed. This method enables us to perform the numerical time integration that exactly conserves the energy, the linear momentum, and the angular momentum, i.e. the time integration is unconditionally stable. This is the key numerical technology to calculate the dynamics of the membrane in zero-gravity condition that has been quite difficult. (2) A mathematical model of the interaction between the inflation gas and the membrane tube is constructed. This model also conserves the energy exactly, which leads the numerically stable integration. (3) The effect of the self-contact of the membrane is implemented into the numerical code. This is also the key numerical technology to obtain the accurate results of the simulation. (4) A visco-elastoplastic model of the fold of the membrane is constructed, which is necessary to simulate the generation and growth of the fold.The research shows that the dynamic behavior of membranes and inflatable membrane structures can be predicted numerically, which has been understood impossible. That is the most important result of this research.