Computer Simulation Of Inflating Process Of Pneumatic Membrane Structure

Membrane structure is a new kind of space structure styles appeared in the middle period of the 20th century. It can create lots of colorful outer architecture shapes which are quite different from other structure styles. Therefore, since membrane structure has been acquainted and develops into a kind of structure style, it has been widely used by lots of architects and civil engineers in the space structure buildings such as large gymnasiums, stadiums, exhibition halls and etc. Although pneumatic membrane structures, as one form of that, have some irrevocable shortcomings, its advantage in certain field is obvious. Developing with the progress of the level of technology and successive improvement of inflation equipment, it is believed that air-supported structures will be rapidly developed in our country during the next few years.For the inflating process of pneumatic membrane structures, this paper analyses the characteristic of structural style and material and mechanics in membrane structure, and simulates the entire process from little puffed to totally inflated in three-dimensions. Based on two different theories, simulation technique is presented and deeply expatiated.Firstly, the inflating process of pneumatic membrane structure is simulated with the pole inertia conception. Considering the section feature of pneumatic membrane structure, the membrane section is partitioned into finite elements and is predigested to a mechanical model which is formed of finite poles jointed by hinges. In order to acquire the real-time state of every node on the model, we regard forces on the ends of pole as unknown quantities of general dynamical equation. Using the dynamical laws of pole unit in dynamics and corresponding conditions, the general dynamical equation of the mechanical model can be founded. Then by solving the founded matrix equation, nodes' positions and the real-time moving states of model are all obtained. Therefore, the simulation of entire process in which pneumatic membrane structure is inflating, can be achieved in this way. The general dynamical equation which is acquired in this theory has three characteristic, that is muti-unknowns, scrambling and sparsely. Considering this and comparative analysis, orthogonal list is used to storage coefficient matrix, and Improving Gaussian Elimination Method is used to numerically calculate dynamical equation. Therefore, nodes' positions and the real-time moving states of model can be obtained in this way.Moreover, after the survey of cloth modeling methods in geometry and physics, mass-spring model based in elasticity theory is proposed to the inflating process simulation of pneumatic membrane structure. This paper expatiate the loads supported on mass-spring model, and then analyze particles in classical dynamics. In addition, some hyper-elasticity phenomena, such as, over-pull of structural springs and unstably shake of membrane surface etc. Some methods will be proposed to solve these problems and be proved.The author gives some examples to prove the methods above and program in visual C++. Two model system is constructed based in inertia and elastic theory. Besides, construction and gridding meshing of Mass-Spring model is solved by ANSYS modules. After programming data interface and constructing model originally, realistic simulation of inflating process is completed by OpenGL for two models.