Theoretical And Experimental Research On Sunflower-patterned Large-span Spatial Cable-truss Tensile Structures

Cable-strut tensile structure is a modern class of space structures composed of cables and struts and characterized by self-equilibrium prestress. As a new type of cable-strut tensile structures, sunflower-patterned spatial cable-truss tensile structure (SSCTTS) is proposed to improve the mechanical performance of rib-patterned cable-truss tensile structure, which has been erected in large scale buildings recently, by changing the topological relationship of the structural member. Some key problems as morphology analysis, optimal design of cable-strut tensile structure are studied profoundly in this dissertation. Considering its complex geometric topology forms, multi-states of self-equilibrium stress and modes of mechanism displacement, systematical theoretical research and model experimental investigation of SSCTTS are carried out for the first time, on the basis of aforementioned research work on cable-strut tensile structure.Firstly, based on reading many specialty literatures, the developmental history of cable-strut tensile structures and several famous projects are introduced, as well as the statement of its architectural and structural characteristic. After summarizing the investigation actuality about cable-strut tensile structures, the research contents of this thesis are presented.An effective method of tangent stiffness matrix which has more extensive function than the traditional product-force method is applied to judge the geometric stability of hinged truss system, based on the theory of equilibrium matrix and energy criterion. Numerical calculation process to obtain the tangent stiffness matrix of structure is deduced and geometric stability of different types of structures are analyzed.A new method of object-selection optimization with simple format and general utility is proposed to solve feasible prestress distribution of cable-strut tensile structures with multi-overall states of self-equilibrium stress. Program is developed to calculate different types of cable-strut tensile structures and the reliability of the method is verified.Correlative multistage optimal design method of the cable-strut structure considering both the size of cross-section and prestress variables is presented and the related optimization problems are studied deeply. Also, optimal design examples of structure prove the validity of the method and relevant calculating program.Considering diversity of the structural topology, key problems as geometric stability, feasible prestress distribution, optimization of cross-section and prestress variables of SSCTTS are studied bythe means mentioned above. Some conclusions are obtained and the conditions for the future study of mechanical property of the structure are provided.The static properties of multiform structural examples are analyzed and the effect of geometric nonlinearity is taken into account with different prestress levels under the condition of multi load cases and multi-step loading. Some important parameters of SSCTTS, such as prestress levels, structural topology, variable regulation and range of vertical posts, are analyzed. Several conclusions are given out by extrapolating the analytical results.The dynamic properties of eight kinds of examples about SSCTTS are analyzed. The influence of prestress level to the dynamic property is examined. Seismic response analysis of SSCTTS is conducted by time history method and the property of earthquake resistance is evaluated. Some significant conclusions are obtained.Through comparison of the static and dynamic properties between SSCTTS and rib-patterned cable-truss structures, it prove that the mechanical performance of SSCTTS is better than that of the latter type.Based on the studies above, the optimal form of structural system is discussed. Among the multiform structural types of SSCTTS, we find that the EC-type is the preferred type due to its good mechanical property and satisfying economy, and it is worth applying in large-span spatial projects.A structural model with outer diameter of 5 meters, inner oval opening of 3.8...