Tower Crane Dynamic Analysis And Application Study On Structural Damage

Tower crane is a construction machinery which is widely used in construction, mine, industry and other areas. As mechanism frequently starting or braking, this will cause the strong vibration and impact of the structure, the vibration makes the serious influence on tower work performance, which can cause structural fatigue damage. According to the research of the predecessor, the most dangerous condition is rapidly lifting heavy objects from the ground, which would cause greater power load. Aiming at the process of heavy objects lifting from the ground, analysed dynamic property under the incentive of the hoisting dynamic load.Tower crane is a mechanical equipment with high risk and high accident rate. Metal structure is the main component of tower crane, which decides tower cranes’work safety and reliability. Nearly half cases of tower crane accidents are caused by metal structure damage. Therefore, how to avoid, to discover in time and get rid of tower crane fault or hidden trouble make tower crane the ability to perceive and process information, perform tower crane’s fault and safety problems to automatic alarm, so as to improve the reliability of its operation, this has become the focus problem of the attention.This paper took tower structure as research object, studied the establishing method of finite element model, established the whole finite element model of tower crane by ANSYS according to the characteristics of the tower crane structure, simulated structure in the good and damage condition, determined the vibration characteristics of tower crane structure in good conditon and damage status through modal analysis, compared the natural frequency and vibration modes in good condition and damage status.Researched the load hoisting process from the ground, firstly analysed the dynamic process and deformation under hoisting dynamic load excitation and established the dynamic model of tower crane according to mechanical dynamics theory, solved the dynamic excitation in the process of lifting from the ground, then imposed the excitation on the tower crane, carried out transient analysis of the tower crane in good condition and damage status, understood the dynamic characteristics of tower crane under the two states.Studied the support vector machine theory and the theory of wavelet analysis, put forward feature extration method based on wavelet packet energy, input the feature vectors into support vector machines, used in the state recognition and damage alarming of tower crane structure. Studied the dynamics results under different structural condiations, the results show this method make a good effect in small sample case.Design the single limb experimental method of tower crane, established an experiment model, measured the experimental data, test that the wavelet packet analysis and support vector machine method is feasible to be applied to structure damage warning by the single limb experiment, this method provides a new way by online monitoring the health diagnosis state of tower crane structure.