The Application Of Virtual Laminated Element In Stable Type Suspension Bridge Analysis

In the thesis, to solve static and dynamic problem of the Stable Suspension Bridge (SSB), the computational method with virtual laminated beam and plate elements is used. Virtual laminated element breaks through the restriction of traditional finite element method that the different materials and components should adopt different elements. For the complicated structures such as the cable-tower, stiffening beam of the suspension bridge, it can perform simulation with fewer elements and still be able to closely reflect mechanical characteristics, geometric dimensions, spatials and contributions to system stiffness and quality of various components within them. Then the space nonlinearity analysis of the suspension bridge with computer can be realized. In addition, virtual laminated elements is a kind of Finite Element Method (FEM) which is suitable for the complex spatial structure analysis due to retainning the flexible and unitive features of FEM and being applied to the structured system analysis in arbitrary shape, internal structure and boundary condition.This thesis is based on the engineering background of MoJiang Bridge.It uses the established virtual laminate elements program to analyze mechanical characters of the whole bridge. Main jobs and results are as follows:1. This thesis reviews the development of suspension bridges home and abroad, introduces the characteristics of the SSB and expatiates the three design and calculation theories of the suspension bridge. It must be considered in FEM that the suspension bridge has the characteristics of intensive geometrical nonlinearity, so the Total-Lagrange increment solution is adopted in this thesis.2. Related theories of virtual laminate elements are introduced. According to them,3D Virtual Laminated Plate-Shell Element and 3D Virtual Laminated Beam Element is formed. With finite element language and FEPG system, vbeam and vshell programs are developed, and those correctness are verified by the classical calculation example.3. The virtual laminate element analysis method is introduced in FEM analysis of the SSB firstly. The characteristic that it can be layered and segmented inside the element can avoid the restrict of traditional finite element method that different materials and components should apply different elements.It also can make the spatial structure analysis of bridges become convenient and feasible.4. Virtual laminate element method can reduce elements effectively and improve the efficiency of calculation in solving the analysis problems that are provided with many elements and complex spatial structures in civil engineering.5. According to the actual situation of MoJiang Bridge, the model of the SSB is established. The displacement, internal forces, stresses and others of this bridge under four load cases are calculated by use of the established program. The mechanical characteristics of the SSB are shown after analysing and summarizing the results. Finally, this thesis make model analysis of the bridge preparing for dynamic analysis.In designning, the conclusions made by the static and dynamic study of the SSB can provide reference.