Morphological Analysis And Stability Properties Study Of Cable-stiffened Space Latticed Shells

At present,with the extensive use of high-strength prestressed cables in longspan space structures,new structure systems such as suspen-domes and cable domes are emerging.Among them,space grid structures supported by multiple flexible cables have gradually gained the favor of architects because of the regular grids and standardized construction.Although several engineering applications have been conducted abroad,there is still a lack of systematic study on the morphological analysis theory,prestress optimization method,stability analysis,and calculation methods for such a structure system,which greatly limits its wide application in architectural engineering.For this reason,this paper considers the synergy between the latticed shell and cables,then proposes a variety of cable-stiffened latticed shells with light weight,high strength,and economic rationality.For the large number of cables and discontinuous forces in structures,the applicative methods of morphological analysis and prestress optimization are proposed,which can improve the structural mechanical properties on the basis of quickly achieving the initial designed state.A practical and reliable stability analysis method is established through numerical analysis and experimental research,considering the geometric defects,cable force defects,and joint stiffness defects.The main research work is as follows:1.The research on the novel cable-stiffened latticed shells’ fabrication and performance evaluation method.A combination method of the single-layer latticed shells and cable-strut systems is proposed.The collaborative work between them is revealed by studying the influences of shell shapes,grid divisions,and cablestrut layouts on the structural performances.From aspects of structural stiffness,bearing capacity,and cable reinforcement efficiency,a multi-attribute evaluation method is established for the comprehensive performance of the cable-stiffened latticed shell system,which can provide a quantitative standard for structure selection and make the structure system design reasonable.2.The research on the morphological analysis and cable force optimization of the cable-stiffened latticed shells with multiple self-internal force modes.Through the block processing of the equilibrium matrix and the least square solution of the over-fixed self-equilibrium equations,a general morphological analysis method is proposed for the cable-stiffened latticed shells,which can quickly realize the designed initial state of the structure with multiple self-internal force modes.Then,the multi-objective optimization model of initial cable forces is established,which takes the cable relaxation coefficient and the maximum bending moment as the objectives.The stability of cable-stiffened latticed shells can be greatly improved by a dimensionality reduction solution strategy based on the hybrid evolutionary algorithm,and the structural ultimate bearing capacity is increased by 20% at least.3.The research on the simulation methods of the multiple initial defects in cable-stiffened latticed shells.According to the structural mechanical properties,an eigenvalue buckling analysis method considering the influences of initial prestress and cable relaxation is proposed,and the modified lowest buckling mode is obtained.On this basis,the most unfavorable distribution of initial geometric defects can be determined.Besides,through the equivalence and mapping of the geometric defect mode,the most unfavorable distribution of initial cable force defects and joint stiffness defects can be further obtained.The reliability of the multiple most unfavorable defect simulation methods is verified through the bearing capacity results of a large number of random defect examples.4.The research on the stability analysis method considering the multi-defects coupling effects.Based on the morphological analysis and the initial defect simulation,a stability analysis method considering the multi-defects coupling effects is established.With this approach,the adverse influences of initial joint position errors,the curvature of members,the cable force deviations,and the joint stiffness loss on the stability of cable-stiffened latticed shells are investigated.The change rule of the structural ultimate bearing capacity with initial defect amplitudes is summarized.And it is recommended that the structural bearing capacity reduction factor of the cylindrical cable-stiffened latticed shells with four-side supported should be 0.568 to 0.642.5.The research on the cable-stiffened latticed shells’ tension forming test and the static stability test.The test specimens and multi-point synchronous loading equipment are designed for the elliptic parabolic latticed shells with an out-ofplane cable-strut system.Then,the tension forming test and the stability test are carried out in the different initial cable force schemes.The shape-forming process,static responses,final failure modes,and the bearing capacity sensitivity to initial defects are mainly investigated.Finally,the correctness of the stability analysis method proposed in this paper is illustrated by comparing the experimental data with numerical simulation results.