塔式起重机金属结构的振动模态校核与非接触测量

塔式起重机的结构特点和使用要求决定了它不可避免产生振动。详细介绍了使用有限元法求解塔机的振动模态的步骤。使用非接触法测量塔机的振动频率,给出塔机振动的架构、算法设计、数据结果及处理。试验证实,使用有限元法可以对塔机的金属结构振动进行有效分析和计算,与非接触法测量的结果接近,误差在15%以内。通过对非接触测量的结果分析可以得到塔机金属结构不同部件间刚度强弱的关系。

Vibration mode check and non-contact measurement on metallic structure of tower crane

The structure features and operating requirements of tower crane produce inevitable vibration.Nevertheless,people usually pay more attentions on the static strength,static stiffness and stability in the crane designs and examinations.The research on vibration becomes a vital aspect of modern tower crane.The paper introduces the finite element method in solving the vibration modes.Beam element,bar element and plate element are used to model the complex metallic structure.Load combination under different work conditions are used in the loading of structure according to the national standard.The solving and the post-processing are the typical methods used in FEM vibration analysis.To note,tower crane vibration measurement is difficult and complicated to be practiced in common method.A non-contact method is applied to dynamically measure the frequency of metallic structure vibration.A new architecture of the non-contact vibration measurement for metallic structure is shown.Following the introduction of some algorithms used in the object tracking,a simple and effective algorithm that used in the target tracking is adopted in image processing.The data obtained from the image processing are processed in time-frequency domain.The results of non-contact measurement are compared in detail with the FEM method.The test confirms that the vibration modes of the tower crane could be effectively acquired by using finite element method and the results are partially close to the non-contact method.The error is less than 15%.Briefly,through the analysis of finite element method and non-contact measurement;the stiffness relationship of metallic structural components of tower crane can be obtained.