Static Mechanical Property And Construction Simulation Of Grid Shells

Grid shell structure is a kind of light structures. It is suitable for the free surface glass-covered skylight structure. Grid shell usually uses the plane quadrilateral or triangle grid units. The prestressed cables are arranged by the diagonal direction in the each cell plane, thereby enhancing the grid plane lateral stiffness of the structure. The prestressed cables and the bars form mixed prestressed structure together.Because of its lightweight and good permeability, Grid shell has broad application prospects. Grid shell structure in some developed countries such as Europe and America has some engineering applications, but the domestic research on Grid shell is just at the initial stage. In order to grasp the basic mechanical characteristics of Grid shell and promote its further development and application, In this paper, modeling technique of Grid shell is researched combined with CATIA software. Focus on single-layer cylindrical Grid shell with better prospects static performance and stability of performance, and stability of the structure in the different construction process during prestressed tension, the systematic analysis is carried out to provide a theoretical basis for practical applications and technical support in the future.First of all, considering Grid shell structural characteristics, combined with finite element software ANSYS and CAE / CAD software CATIA, numerical models of Grid shell were established with interface program, using surface translation method. The technology of Grid shell with free surface modeling based on CATIA-ANSYS is controlled.Secondly, by using ANSYS software system parameters analysis of cylindrical Grid shells is carried out. Taking into account the initial prestress level of cable, span ratio, the form of uneven loading, initial geometric defect, cable prestress loss in a variety of factors, the nodal displacement in the structure, member forces in response, ultimate bearing capacity of structural stability, buckling mode and so on are investigated. The results showed that: the initial prestress is to ensure that an important condition for the establishment of structural system, but too much prestress will be burden on the structure, resulting in reduced ultimate bearing capacity; uneven load distribution barely affect the stability of the structure, Grid shell is sensitive to initial geometric defect, the presence of initial geometric defect will cause that the limit load is significantly reduced.Finally, five different programs prestressing construction of single-layer cylindrical Grid shell are simulated. Considering prestress loss of the cable, the deformation construction of the structure in various stages, load and displacement control values are analysised. The results show that: one end cable tension will cause one side bias transformation, asymmetric deformation is not easy to control displacement. In the scheme of side to the other side tension, the ultimate bearing capacity of the structure is very low in the early stages. Deformation of structural displacement is reach the L/400. the scheme of alternative from the middle to both sides tension is recommended. The ultimate bearing capacity of the structure steady increases, the deformation is regular. the displacement and cable tension are relatively easy to controlled.