Dynamic Optimization Of Bridge Model Based On Improved Genetic Algorithm

Structure at work is affected by vibration and impact loads inescapability. So, dynamic damage and destroy is the primary failure mode of structure. Dynamic optimum design of structure is an effective method to improve the dynamic capability. Dynamic optimum design of structure deals with optimum design , dynamic analysis, finite element method, numerical calculation and program design.On the basis of characteristic of dynamic optimum design of structure, this paper introduced the basic concepts and methods of the optimum design of structure and dynamic analysis.Traditional method of optimization applied to Dynamic optimum design has much shortage. Genetic algorithm is a new method of optimization. Comparing with traditional method of optimization, genetic algorithm is excellent in many domain, as global optimization, complicated accessible area, complicated objective function, and using kind easily. Content of the chapter four includes basic concept, calculation process and characteristic. Aiming at improving the capability of the simple genetic algorithm, this paper put forward an improved genetic algorithm—adaptive micro genetic algorithm. At present, most improvements of simple genetic algorithm depend on large-scale population. In study [17], adaptive mutation probability combined with micro genetic algorithm. And the result proved that the method was effective. In this paper, adaptive recombination probability combined with micro genetic algorithm. This method has the excellence both of micro genetic algorithm and adaptive running parameters. The population size was just 5. So the calculation load was much smaller than the simple genetic algorithm's, and the constringency is more faster. And the method made use of adaptive recombination probability which could change with the fitness. Individuals of higher fitness have lower recombination probability. So these individuals can enter the next generation. Individuals of lower fitness have higher recombination probability. So these individuals can be eliminated. And this method made use of penalty function in dealing with constrained optimization problem.Finally took example for the bridge structure model of the mechanics experiment teaching center in Chang'an University, applied bridge analysis software MIDAS to foundation of the finite element model, and carried on the static and dynamic analysis of the model. Then founded the optimization dynamic model, including sensitivity analysis, choosing design variable, design objective function and restriction conditions. At last, made use of the improved genetic algorithm—adaptive micro genetic algorithm. Compiled calculation program in MATLAB. And the answer proved that the method of adaptive micro genetic algorithm was effective in solving problem about dynamic optimum design of structure.