Topology Optimization And Robustness Analysis Of Space Grid Structure

Currently, grid structures recommended by specification have the same topology from the geometric edge of the grid to the central region. Due to the big difference of stress at different grid region, the material underutilized in the view of structural optimization. At the same time, because of having features like great span, to many bars and serious damage consequences, disproportionate damage resistance ability of grid structure becomes increasingly important as frequent accidents having occurred in recent years. So this paper study on grid structure from two aspects of topology optimization and robustness.Topology optimization was the leading subject of research in the structure optimization field recent years. This paper summarized the structure optimization methods and discussed implementation methods of topology optimization methods like variable thickness method, homogenization method, variable density method and evolutionary structural optimization method. Last, combined with evolutionary structural optimization method, this paper designed peripheral tangential constraint and four-point constraint grid structure topology. To obtain cross-sectional dimensions of the rods, make full stress design to the optimized grid structure, and compare the existing grid structures of the same constraints forms and designed under the same load conditions with performance. Compare metric are steel consumption, robustness and ultimate bearing capacity.Selecting pyramid space grid, diagonal square pyramid grids, evacuated quadrangular pyramid grids, checkerboard square pyramid grids, orthogonal space Truss grid, three-way cross truss grid and using H_∞ structural robustness index, studied the robustness influence of structural geometric parameters and grid form to the structure through parametric analysis. And then, make the appropriate changes to the topology of the grid through empirical analysis to improve the robustness of the structure. Selecting the same form grid structure as the above-mentioned and using four-point constraint of different locations, conduct structural robustness comparison to grid structures obtained by full stress design. And then, find out the most suitable location of four-point constraint from the view of robustness.According to these research, evolutionary structural optimization is effective for optimization of grid structure and can generally save steel consumption by ten percent. At the same time, disproportionate damage resistance ability, reasonable topology improvement, suitable span and best restraint position of the grid structure can be obtained by calculating robustness evaluation of different grid structure of grid structure...