Shape Optimization Analysis For Stable Type Suspension Bridge

The stable type suspension bridge with ordinary suspension bridge as the basic form, increase the inverse-tensional system in the bridge below (including inverted Inverse-tensional cabled and pull rod). So as to make the bridge be pre tensioned structure. The bridge was relatively were "cured" and stiffness is also improved. However, different load and the effect location will appear the following phenomenons (1) Because the bridge by the apparent effects of local load deformation, pour pull rod will appear relaxation phenomenon, axial force decreases obviously, and even the emergence of zero tension or pressure situation. So when the live load on the bridge, down the rods can be changed into zero bar, reduces the pre tensioning effect, stability of suspension bridge with the whole affected;(2) Because loading local initial design tension mode and bridge, rod back rod of the uneven stress, difference is bigger. Some rod tension is too large, affect the service life and safety, and some down rod tension is too small, does not have what effect. The overall stiffness was influenced by the suspension bridge;(3) Because the bridge is pre tensioned structure, after loading of any component stress change will cause the redistribution of stress of each member, the tensioning state changed.Therefore it is necessary to find a way which can guarantee the axle load transfer function and ensure the realization of the stiffness of the bridge and makes each member’s force reasonable tensile state. This requires the stability of suspension bridge tensioning scheme optimization, find the optimal tension scheme.In view of the above problems, this paper mainly research contents include:(1) The system combs and elaborates the theory of nonlinear finite element for the stable type suspension bridge, the hands of the relevant Fortran program.(2) According to the state changes affect the overall distribution characteristics of the stress component of stable type suspension bridge prestressing structure, proposed by adjusting down rod length, and verified in various load conditions, then adjust the tension of the optimization criterion and optimization scheme.(3) Composite structure finite element application of stable type suspension bridge cable, rod, beam calculation procedures, structure according to the optimized scheme design of a stable type suspension bridge forming optimized calculation. Comparison and analysis of the bridge shape before and after optimization, rod force, main cable, spring force, suspender tension. Summarizes the reasonable tension linear inverted cable. Summarizes the reasonable tension linear inverted cable. Research results show that the optimization method is correct, the optimization of the expected, and provide reference for bridge design.(4) Intelligent control method into the stable type suspension bridge to maintain control of the mechanical properties. The development of the overall scheme of intelligent control system to maintain the mechanical properties of the bridge, in contrast to the strain criterion is proposed based on the performance of a large amount of computation to maintain the bridge. The controller to actuator, sensor, such as the choice of the formation, the intelligent control system.