Reaserch On The Structural Morphology And Quadrangle Mesh Of Single-Layer Lattice Shell

Spatial structure is widely used in large marketplace, gymnasium, hangar, exhibition center, natatorium and industrial buildings because of its good spatial stress characteristics. In recent years, new progress has been made in the morphological research of spatial structures with the development of computer technology, which can perfectly combine the structure form and reasonable stress. Single-layer lattice shell is a kind of spatial structure that estabilished along curved surface, which can cover a large space with a small surface area. It is favored by architects and engineers with its beautiful shape and reasonable stress.Compared with the international design level, the development of space structure in our country is seriously affected by the structure form. Some lattice shell structures pay little attention to the conceptual design and structural morphology in order to ensure the safety of structures, as a result, usually lack of creativity and the structure form of diversity. Structural engineers tend to be passively to satisfy the architecture model proposed by architects, rather than actively participate in the determination of structure form in the initial stage, which likely to cause the problems of unreasonable structure and the reduction of artistic value.This thesis attempts to find the shell with high bearing capacity and architectural aesthetics value, and expect to achieve the harmony of both, so we can find the roof structure both light and transparent.The thesis mainly studies the structural morphology of single-layer lattice shell, and quadrangle mesh of lattice shells. The main works is as follows:(1)According to the optimization goal of’light’, this thesis attempts to find more reasonable form of single-layer lattice shells. Taking Kiewitt lattice spherical shell as an example, we compared the effect of form-finding using both Nonlinear Finite Element Method and the Force Density Method, then, static and stability behaviors of traditional spherical shell and form-fingding spherical shell are compared, and the effect of form-finding is comfirmed. At last, the morphology of aptimazation analysis of a comlex roof lattice shell is made.(2)According to the optimization goal of ’transparent’, for quadrangle mesh net shells, meshing method and mechanical performance optimization method is studied and analyzed. Compared with the common triangular grid, quadrilateral grid single-layer lattice shells are brighter and more transparent on the vision, to meet the requests of more harmonious and close relationship between human and nature. This thesis uses both modified planar quadrangle mesh and surface translation mesh to creat a spherical lattice shell, and a comparision of the form and mechanical property between these two mesh methods is made. At the same time, considering the quadrilateral mesh is poorer in the shear properties, prestressed cable is applied to improve the created shell.(3)Based on the research above, this thesis explores the structural form and design idea of a pratical engineering of quadrilateral grid single-layer lattice shell. And mechanical property analysis of the shell created by surface translation mesh is performed(4)This thesis sums up joint forms commonly used in single-layer lattice shell glass roof, and briefly describes advantages and disadvantages of either. Taking welded hollow spherical joint as an example, one kind of method is introduced in order to consider the stiffness of joint. The influence of the stiffness of welded hollow spherical joint on the integral stiffness and stability of reticulated shell is discussed. Moreover, the influence of the computational accuracy of beam element on the result is also discussed. At last, suggestions about considering the equivalent stiffness of welded hollow spherical joint in structure design are offered.