| The design of flat-top tower crane, mostly based on traditional analogy and static performance in current, induces some shortages, such as high weight, irrational structure and bad dynamic performance. So, modern optimization method is introduced into the design of tower crane in current thesis to meet the goal of better dynamic performance of crane jib and lighter structural weight, under the condition of structure strength, stiffness and stability.The loads and restrictions of flat-top tower crane are simplified according to ?standard of Crane Design?. Finite element methods ANSYS is utilized to establish the parametric model of crane jib, execute structural analysis, modal analysis and harmonic response analysis, and the state of static force response and the ranks of natural frequency are gained under different work conditions, and the second-class natural frequency is found as the main factor influencing the dynamic performance of crane jib. So, the weight and the second-class natural frequency are selected as the objective of optimization to establish the mathematical model of multi-objective optimization.Because of the big mass of the variables and the most are discrete, the traditional multi-objective method is hard to solve the analytical model, so, the thesis adopts non-dominated sorting multi-objective genetic algorithm (NSGA-â…¡), and iSIGHT multi-objective optimization platform is used to integrated the ANSYS finite element analysis and NSGA-â…¡to automatically gain the Pareto solution Set of the multi-objective optimization in computer. Finally, the solution in Pareto set with good compromise between weight and frequency is selected as the final solution of optimization design, which is coincident with the respected scheme after being validated.
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