The Main Girder Of QD400t Double-girder Bridge Crane Structure Design And Optimization

With the development of society and the advancement of science and technology,the market competition of bridge crane is increasingly competitive.How to reduce the price of the product is the main problem that the bridge crane manufacturers face to improve the viability of the enterprise in the case of performance and safety performance.According to the needs of QD400 t electric double girder bridge crane in workshop of Shandong Dachi Electric Co.,Ltd,the main girder is preliminary designed,then analyzed and optimized to make the structure more reasonable,the material consumption is educed,the height of the whole machine is reduced.The work of this project is importance to reduce the cost of crane and the construction.Aiming at the working environment and working condition of QD400 t bridge crane,the double girder with box girder structure is selected,the end girder was connected with the main girder in the form of butt joint,the layout and technical parameters of Bridge Crane are designed preliminarily.Analyze the stress condition of the preliminarily selected form of the main girder,according to the requirements of design standards,use the classic strength,stiffness and stability calculations,and complete the structural design of the main girder.The three-dimensional modeling and two-dimensional drawing of the bridge crane are carried out by SolidWorks software.The static analysis of primary girder with ANSYS Workbench shows that the stiffness and strength of the primary girder are designed to meet the requirement of steel.Based on the linear buckling analysis of the main girder used ANSYS Workbench,the first six-order buckling deformation and the buckling load factor are obtained.The result shows the most easy instability parts of the main girder.Strengthen easily instability parts to improve the local stability of the main girder.The modal analysis of the main girder by ANSYS Workbench gives the natural frequencies and the first six-order vibration characteristics of the main beam.The natural frequencies of the first six-order mode are all small,it is meets the requirement of ergonomics,the driver in the operation process will not be fatigue,dizziness and other discomfort,caused by vibration.It is very important to prevent the crane from resonating and improve the life of the main girder.It provides a basis for further dynamic analysis.Through static analysis and dynamic analysis of the primary girder,it is shown that the main girder satisfies the requirements of Static stiffness,strength and dynamic stiffness,and has enough rich amounts.On this basis,an optimization model of the structural size of the main girder is established,and the section height of the main girder is optimized,the design variable,objective function and constraint condition are determined.Use VB programming language to find the optimal solution.And the main girder of the optimal solution is analyzed by mechanical analysis.The results show that,the weight of the main girder and the height of the end part are greatly improved on the premise that the main girder meets the requirements of the stiffness and strength.