Study Of Computer-Aided Design System In Space Grid Structure

Now space grid structure is becoming a popular construction, and it is very important in theory and practicality to workout the CAD software that is used for space grid structure. The thesis deals with computer-aided design system in space grid structure.The thesis workouts the CAD software based on Windows System, which called SGSCAD used for Space Grid Structure. The analytic model of the SGSCAD is based on finite element method and the experimental results that have been provided. To calculate correctly space grid structure, the SGSCAD utilizes the element of 3D bar or 3D beam that is distinguished by the mode of linking among the members of the structure to simulate varied types of the space grid structure. The thesis provides some samples to prove the SGSCAD, and studies the behavior of space grid structure under static. Moreover, the thesis puts forward the issues in practice calculating through results that have been calculated.By the method of optimizing node number, the storage technology of one-dimension changing bandwidth and the solver utilizing block-to-block technology, the SGSCAD has a high speed of calculating and efficiently reduces the size of memory requested.By the means of Lanczos in dynamics analysis of large space grid structure, the thesis workouts inherent frequency and models. This method can solve eigenvalue more fast than that of means called subspace iteration, and can reduce the possibility of losing eigenvalue. The thesis also studies the rule of space grid structure's internal force under the effect of earthquake by the mode-superposition in response spectrum.And the thesis investigates the optimum design of Space Grid Structure by means of modified full stress method, and it is obvious that it can getgood effect. Furthermore, the thesis introduces the design of the members and joints in Space grid structure, and gives the flowcharts of program.The SGSCAD consist of pre-processing module, structure analysis module and post-processing module. The article introduced design of each module and design of data structure and data files. At last, the operation guide of the SGSCAD software is briefly introduced.