| The flat-top tower crane has abroad application in city construction and industry lifting these years. The design of flat-top tower crane, mostly based on traditional analogy and static performance in current, induces some shortages, for example, high weight and bad dynamic characteristic. The bad performance will affect both efficiency of flat-top tower crane and physical health of manipulator. Research show that dynamic rigidity of flat-top tower crane is the most important parameter, which affects dynamic characteristic of flat-top tower crane structure significantly, Usually, it is described in terms of the structure's natural frequency.The mechanic properties of mechanical systems include two aspects of static and dynamic characteristics. The paper aims to process optimum design of flat-top tower crane structure based on dynamic characteristic, and finite element analysis software ANSYS is utilized to establish the parametic modal of flat-top tower crane. This paper presents the static analysis and dynamic analysis. Through the modal analysis on the structure of flat-top tower crane, the first twelfth natural frequency and vibration mode are calculated when the trolley with full load. The fact affecting the dynamic characteristics of the flat-top tower crane belongs to low-frequency vibration.Through the harmonic response analysis, the ranks of natural frequency are gained, and the second-class natural frequency is found as the main factor influnencing the dynamic characteristics.The optimum design of flat-top tower crane based on dynamic characteristic is accomplished by ANSYS, considering the dynamic stiffness of system structure as dynamic optimization objective. Before the optimum, sensitivity analysis has been done to determine the dynamic optimum design variables. After the optimization analysis all of analysis results were analyzed. |
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