Research On Optimization Design Of Prestressed Steel Structure Based On Improved PGSA And Cable Force Identification Method

Prestressed steel structures can offset the load effect, adjust the internal force peak value, enhance structural stiffness, stability and other performance by applying prestress. Based on the achievements of predecessors, this paper studies the optimization design of prestressed steel structures and the method of cable force identification, aiming at further promoting application of prestressed steel structures in engineering practice.Based on investigating a large amount of documents, research status and problems about the optimization design of prestressed steel structures and the method of cable force identification are summarized. The theoretical and practical significance about the optimization design research of prestressed steel structures based on Plant Growth Simulation Algorithm(PGSA) and static equilibrium method of cable force identification.The basic principle of PGSA is analyzed,then the limitations of PGSA are pointed out and verified. According to these, three improvement strategies are proposed: elitist strategy of morphactin concerntration’s calculation, strategy of intelligent variable step size, selection strategy of the initial point base on GA(Genetic Algorithm). Through typical examples, all improvement strategies have positive effect on optimizing efficiency and global search ability of PGSA.Comprehensive the above improved strategies, a new hybrid intelligent algorithm, improved plant growth simulation- genetic hybrid algorithm(PGSA- GA) is proposed. The optimization algorithm process of PGSA-GA is given. And the paper adopts the secondary development language-APDL of ANSYS and MATLAB to compile optimization design program. Through the analysis of two examples of verification, it comes to the results that compared with genetic algorithm, 2-level optimization algorithm, relative difference quotient algorithm and continuous variation method, this algorithm has obvious advantages on optimization effect.The paper conducts analyses the characteristics and difficulties of the mixed variables optimization analysis of suspend-dome. the advantages of PGSA-GA are pointed out. An optimal design process is, further on, programmed to optimally design the suspend-dome based on PGSA-GA, whose results further validate feasibility and effectiveness of the algorithm.The static equilibrium method of cable force identification is studied. On the one hand, the key part of the cable force identification equipment, new composite cable clip with soft metal liner, is researched and designed. The friction law of cable clip has carried on the theoretical analysis and experimental verification. The result show that the composite cable clip is able to meet the demand of the cable force identification. On the other hand, the formula and solving method of cable force identification considering the effects of flexural rigidity are given. Through the cable force identification test reflects the formula and test results are consistent and high precision, accord with the actual stress state of cable. The the accuracy and feasibility of cable force identification method considering the effects of flexural rigidity are verified.