Research And Optimization Analysis On Vertical Lifting System And Main Girder Torque Oscillation Dynamics Of Bridge Crane

Crane is one of the major transportation tools in material handling industry; it features intermittent, repeating, and circular working characteristics. During working, cranes may frequently start and brake. It need to focus on research in dynamic effects of the impact and vibration in the vertical direction and the reverse direction.Based on the new development projects of crane lifting mechanism and the main beam from the famous German company M2, it proposed the multi-degree freedom lifting system dynamics model and centralized multi-segment quality girder torsional vibration dynamics model. The solution was worked out though the fourth-order adaptive step Runge-Kutta method, and research and optimization analysis of the test on site to lifting system dynamics model and main beam torsional vibration dynamics model.The research results can provide a theoretical basis for the detailed design of the crane key components. Main contents and innovations are as follows:(1) This article established serial lifting system dynamic theoretical models which increased the degree of freedom. The increased degree of freedom included:time-varying stiffness of hoisting rope, the rotational freedom degree of deceleration mechanism, the vertical freedom degree of hook a beam end. Based on the established system dynamics model, it used Simulink tools to build a solving procedures of theoretical model, and took adaptive step size fourth-order Runge-Kutta method to solve. The solving results were compared with the experimental results. The results validate the model is reasonable. Based on the validated model, the dynamic characteristics of lifting system has been researched under different working condition. It worked out dynamic load coefficient reference value of key components under different working condition, and provide important reference to the input load choice of crane key components design. In addition, it researched other factors that influence the lifting dynamics load coefficient under the fixed lifting speed. Under the premise of the not reduced crane operating efficiency, it provided the theoretical basis for reducing vertical lifting dynamic load.(2) It proposed main beam torsion vibration model of multi-segment and three-segment concentrated mass so that the issue of main beam torsion vibration was changed to similar torsion vibration issue of transmission axles. By the Simulink program, the solving model of main beam torsion vibration was established. It validated the test on the test bench built specially and validated the rationality of torsion vibration. Based on the validated torsion vibration, it studied the distribution and attenuation regulation of torsional vibration under the working condition of hoist lifting off the ground and suddenly load shedding, and analyzed the regulation of torsion vibration caused by main beam section, the car counterweight, hook eccentricity and location of the car in the main beam and other factors. It carried out the main factors which can influent main beam torsion vibration. After comparing the torsion vibration characteristics between with beams and welded box girder, it provided the basis for considering torsion vibration dynamics load in the main beam design process and for the failure of the material caused by torsion vibration of the main beam.(3) Multi-objective genetic algorithm optimization model was established by a comprehensive consideration of vertical lift and the main beam torsional dynamic load etc. characteristics. It avoided the design load of other components was too large because the weight of beam was considered only during the the beam optimization. the optimization model used the established lifting system simulation model and the main beam torsional vibration simulation model.Regard5ton single beam crane as the research object, it did the multi-objective optimization according to the working condition of lifting off the ground. The paper did the research for the influence of selected different population size and evolution algebra on optimization results and analyzed the calculated Pareto optimal. By selecting a different amount of dynamic parameters as optimization objective, it studied the reasonable values of selecting optimization model amount in main beam multi-objective optimization model.