Research On Cooperative Effect Performance Of Large-Span Complex Lattice Shell And Substructure

Large-span complex lattice shell structure, as its beautiful appearance, reasonable mechanical performance, flexible and diversity of structure, mechanism and factory-like, has become the most develop spatial structure. With the wide application of large-span complex lattice shells in engineering, the mechanical properties of the structures were more and more paid attention to. Because there are shortcomings in analysis of large-span complex lattice shell, in this passage, take Qing yang gymnasium in Gansu province as study background. Nonlinear finite element method is applied. A system composed by large-span complex lattice shell and sub-structure will be analyzed by using finite software of MIDAS and ANSYS programs. Two key problems as boundary circumstances and the global damping radio of such structures are analyzed in this paper for reference for the calculation and analysis in practical project.The mainly work in this paper as follows:(1) The text analyzes bearing reaction forces, internal forces and node displacements of the overall structure of the large-span complex lattice shell considering the different boundary conditions. The results show that the support should be consistent with the calculation assumes, and the border bearing stiffness should be based on the stiffness of sub-structure and the stiffness of bearing. So effects of the boundary conditions should be considered to large-span complex lattice shell structural performance in the actual engineering.(2) To study the vibration characteristics of the overall structure, the text analyses the modal using MIDAS and ANSYS software respectively. The natural frequencies will be obtained in order to study the dynamic characteristics.(3) The text obtained the different modes of damping ratios of the combined structures of steel lattice shell and concrete supports according to the damping ratio group in the MIDAS program. Then discuss on the damping ratio of the structure according the reliability analysis and the damping ratio is between 0.033 and 0.049.(4) Using software of ANSYS program, through the dynamic time interval analysis about complex spatial shell structure with two calculative models, which were with sub-structure or not. Compared the node displacement and rod axial force of the overall structure, and traced out node time-displacement curve and the rod dynamic internal force-time curve, thus research seismic performance of the large-span complex lattice shell and sub- structure considered cooperative effects. At the same time, this paper selected different damping ratios and different seismic waves to study the seismic performance of the overall structure.