| As a new type of high-rise building structure,the diagonal grid structure mainly consists of intersecting diagonal columns and horizontal ring beams.The high-rise diagonal grid structure system has the structural forms of diagonal grid cylinder and diagonal grid cylinder-core cylinder,etc.This structural system has been widely used at home and abroad in recent years because of its unique architectural form and good lateral resistance performance,and its application has become more and more widespread.The oblique grid cylinder-core cylinder structure to be studied in this dissertation is a new cylinder-in-cylinder structural system consisting of an oblique grid cylinder and a reinforced concrete core cylinder with openings,in which the oblique grid cylinder mainly bears the vertical and lateral loads through the axial tension and compression of the oblique columns.Although many research results have been achieved,there is relatively little research on the theoretical aspects of its simplified calculation compared to finite element analysis and experimental research,and the existing theoretical analysis is mainly based on the variational method.Based on this,this dissertation presents a synergetic force analysis and second-order effect analysis of the diagonal grid cylinder-core structure under the Hamiltonian mechanics solution system,taking into account the shear lag effect.The first-order Hamiltonian canonical equations for the oblique intersecting grid cylinder-core cylinder structure are obtained by introducing the Lejeune transformation,which gives the generalised forces in the dual variables of the generalised displacements,and realises the order reduction of the control differential equations.The fine integration method with high computational accuracy is used for the solution,which can quickly solve the internal forces and deformations of the structure.The method is highly accurate and efficient,and can be used for rapid mechanical analysis in the early stages of engineering design,providing a new way of thinking about the mechanics of these structures.The main work is as follows:(1)It is proposed to use the equivalent continuity method to equate the oblique intersecting grid cylinder structure as a thin-walled cylinder with a solid web enclosed by four orthogonal anisotropic continuous slabs,and to simplify the reinforced concrete core cylinder with openings as a double-limb shear wall model.Considering the shear lag effect of the outer cylinder structure and the bending and shear deformation of the inner and outer cylinder structures,simplified computational models for diagonal grid cylinder-core cylinder structure synergy analysis and second-order analysis were established respectively.(2)Under the Hamiltonian dual solution system,the synergistic force performance of the diagonal grid cylinder-core cylinder structure and the shear lag effect are analysed.The solution is compared with a finite element calculation example to verify the correctness and numerical accuracy of the method in this dissertation.On this basis,the axial forces of the inclined columns are solved and the influencing factors of the synergistic force performance are analysed.(3)On the basis of the synergistic force analysis,the second-order effect of the diagonal grid cylinder-core cylinder structure is analysed by means of Hamiltonian mechanics,and the Hamiltonian dual solution system for the second-order analysis of the diagonal grid cylinder-core cylinder structure is established.It is proposed to compare and analyse the results with the finite element calculations to verify the correctness and accuracy of the calculation method in this dissertation.Based on this method,the force performance of the second-order analysis of the diagonal grid cylinder-core cylinder structure is compared with that of the synergetic analysis,and the effect of different loads on the second-order effect of the diagonal grid cylinder-core cylinder structure is analysed. |
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