Analysis And Research Of Dynamic Structure Of Tower Crane

The tower crane is a kind of machine widely used in construction industry. It possesses complex coupling movement due to frequent starting and braking during operation. Precise description and calculation of the dynamic corresponding process of tower crane structure system under the outside force will be both practically and theoretically instructive for the design and production of the tower crane. Research methods formerly used for the dynamic property of tower cranes mainly include dynamic ratio method, finite element method, mode analysis method, mode synthesis method based on dynamic substructure, subspace iterative method, direct calculation method via less freedom establishment, etc. However, some disadvantages still exist of these methods. This dissertation is mainly aimed at the precise and detailed description of the typical working process of tower cranes based on the structure system of existing tower cranes. Distinctively affected working state is chosen so as to calculate the biggest corresponding dynamic force so that differential equation concerning the movement of the structure system of tower cranes could be induced and the method to find the solution will be suggested, thus providing the theoretical base and feasible method for describing the dynamic process of the structure system of tower cranes. QT20, a new-type folded-arm tower crane with variable trolley range, is used as an example to establish the finite analytic mode and analyze its dynamic property. Furthermore, via the analysis of the calculated result, the structure features of dynamic tower cranes are discovered, which gives instruction to the design of similar tower cranes. Instead of tow-dimensional finite element mode, three-dimensional mode in truss structure is established based on the actual structure. The way to impose one-way force has been altered. When the excitation force is calculated , suspended weight lift off the ground, the trolley accelerative start or weight lift off the ground and crane arm accelerative slew should be considered, as well as the single state of suspended weight lift off the ground and the braked drop, so as to make the...