Analysis Of Dynamic Characteristics Of Flat-top Tower Crane Based On ANSYS

Flat-top tower cranes are typital steel structure,which are important lifting and transportation equipment in construction industry.In the process of lifting and transporting cargoes,the impact loads generated by the frequent starting and braking of the lifting transportation and rotation mechanisms cause the whole structural vibration of the flat-top tower crane.The alternating stresses produced by the structural vibration inevitably cause fatigue failure of the steel structure and reduce service life of the cranes.In this paper,the finite element model is set up for solving the whole structural vibration problem of the flat-top tower crane,the low order vibration modes of the whole structure are extracted.The vibration response of the whole structure under lifting,translation,rotation and compound working conditions was explored,and the effect law of the dynamic parameters,such as the cargo mass and the mechanism running speed,on the structural vibration response was analyzed.The main research was as follows:(1)Based on the principle that the model structural deformation is closed to the real structural deformation,the finite element model was set up for the QTZ5613 flat-top tower crane.The natural frequency and mode shape of the first 10 orders were extracted and the effect law of the inertia force,centrifugal force and Coriolis force induced by the three mechanism motion on the structural vibration are summaried for the crane.(2)The vibration responses of the whole structure under the single working condition of lifting,translation and rotating were simulated on the finite element model.And the effect laws of the parameters,such as the cargo mass,the distance between the trolley and the tower body,and the mechanism running speed,on the whole structural vibration were analyzed.The vibration period and the amplitude of the whole structure increase as the cargo mass,the distance between the trolley and the tower body and the mechanism running speed increase.(3)The vibration response of the whole structure under the compound working condition of lifting translation,lifting rotation and lifting rotating and translation was simulated on the finite element model.And the effect law of parameters,such as the cargo mass,the distance between the trolley and the tower body,and the mechanism running speed,on the whole structural vibration were investigated.The vibration period and the amplitude of the whole structure increase as the cargo mass,the distance between the trolley and the tower body,and the mechanism running speed increase.(4)The testing platform of measuring mechanism motion and the whole structural vibration was set up on the QTZ5613 flat-top tower crane.The effect law of the three mechanism motions on the whole structural vibration was studied under the condition of lifting,translation,rotation and compound working conditions for the flat-top tower crane.The test error source and the simulation error source were analyzed by comparing the test data with the simulation data that proves the correctness of the simulation research.The test also provides the data for further studying the coupling mechanism between the whole structural vibration and the cargo swing.