Dynamic Response Analysis And Multi-objective Optimization Design Of Unconventional Dedicated Tower Crane

Unconventional Dedicated Tower Crane is a new kind of integrated lifting equipment which was designed and trial manufactured by Institute of Building Mechanization China Academy of Building Research. It is mainly used for the construction of high-rising buildings, such as cooling tower, cable bent tower and chimney which with unconventional appearance. Tower cranes of traditional structure shows many questions during the construction of these buildings because of the restricted working scope and low availability, while the new equipment not. Nevertheless, the new structure also exist some problems. For example, there are no inclined web members on the cross section of tower body, which results in a lack of structural stability. In addition, with the increase in height of the bridge, the windward area of the crane becoming larger, that would leads to strong impacts and vibrations. This article mainly talks about the structural response and the working stability of the crane under the dynamic load. Then, a multi-objective optimization design of the crane was down based on the FEA results.Under the foundation of the analysis of the basic composition of the Unconventional Dedicated Tower Crane, and following the size of each metallic structure, a parametric FEA model of the metal structure was built by APDL. Then the static analysis focus on the dangerous conditions, the modal analysis and the harmonic response analysis were conducted by ANSYS.In the traditional structure design, wind load usually be equal to static load, which neglect the dynamical characteristic of turbulent wind load. This article uses linear filter method to simulate turbulent wind velocity and then get wind loads at different heights. On the basis of this, the transient dynamic analysis was conducted by ANSYS to explore the working stability of the crane that under these loads. Furthermore, the tower body was equivalent to mage-frame structure by the equivalent inertia moment method, so that the buckling critical load of the tower body with different heights could be calculated. Then the results were compared with the ANSYS-based results and a set of suitable values were given.A multi-objective optimization model was established in order to find the maximal key modal frequency, minimal dynamic load coefficient and less mass, which based on the integration function and optimization function of platform i SIGHT that integrating ANSYS and Multi-objective Genetic Algorithm NSGA-II. Sensitivity analysis was done based on a parametric finite element model in ANSYS for all structural parameters to decide the optimum design variables. The work provides the Pareto optimal solution set which shows the influence relation among optimization objectives. It can be for a reference of the design of cranes with good static and dynamic characteristics.