The Research On Analysis And Optimization Of Dynamic Stiffness Of Large Span Double Beam Bridge Crane

In recent years,the demand of the bridge crane of large tonnage and large span in our country is increasing day by day.The lightweight design of the structure is the inevitable requirement with the huge increasing of the material strength of the crane.At the same time in order to improve the comfortable feeling of crane operators that exposed under vibration and improve the operation efficiency,the crane design process must control the vibration amplitude and vibration attenuation,therefore the modern crane dynamic stiffness analysis and optimization is particularly important.In this article,3D modeling software AutoCAD was used to establish an all steel structure model for double beam of large span single trolley of bridge crane,namely Hypermesh grid generation platform for precision mesh topology reasonable of crane based on the simplified geometric model.Based on the script language Python,the Abaqus was developed two times to realize the parametric modeling of the crane bridge structure.The finite element simulation model of main girder of long-span bridge crane is established and the simulation model is checked;Secondly,the static of the large span bridge crane stiffness strength and dynamic stiffness were analyzed,and the factors that mainly influence the dynamic stiffness of bridge crane were analyzed:Based on Frequency Abaqus,the modal characteristics and modal frequency of car position and the end effect of beam bracing stiffness under the crane's six order is further analyzed.The paper analyzes the value of crane dynamic stiffness and the influence mechanism of each factor;Then the mathematical model of bridge crane dynamic stiffness optimization was established:Based on Python scripting language of Abaqus,girder parametric modeling and dynamic static characteristic calculation was operated for the analysis and the results of system selection and extraction,the ultimate success of the optimization design of crane girder size integrated multidisciplinary design ISight platform is achieved in multi Island genetic algorithm.ISight platform was chosen for optimization of the optimization mathematical model;Finally,based on the ISight platform,double objective optimization of dynamic stiffness and quality of a 48m span double beam bridge crane is achieved,through the establishment of objective function and constraint conditions and multi Island genetic algorithm parameters.The automatic solution of the optimization mathematical model and the optimal solution of the sectional dimension is achieved,so as to improve the dynamic performance of the lightweight and the structure of the target.The final optimization results show that the dynamic stiffness of the system is increased from 2.27Hz to 2.67Hz,and the amplitude is increased to 17.62%,the structure weight is reduced from 55.88ton to 52.58ton,and the reduction range is up to 5.91%.The results obtained for the crane in this article can satisfy the strength,rigidity and dynamic characteristic and lightweight demand as an optimal solution,that could provide support for the optimization design method for the static and dynamic characteristics of girder bridge crane,and that finally realizes the dynamic stiffness for the purpose of reducing the weight of crane and the improvement of system.