Research On Wind Induced Effect Analysis And Wind Load Reduction Design Of Large Gantry Crane

As a special high-rise structure,the main girder of large-scale gantry crane usually has large windward area and adopts high-level horizontal installation mode,which makes its structure more sensitive to wind load.Wind load is one of the important loads in crane design.It is not only an important basis for checking the motor power and stability of the crane,but also an important influencing factor for the stress analysis of crane metal structure.The scientificity and accuracy of wind load estimation will greatly affect the safety and economy of crane design.Therefore,the research on wind-induced effect and anti wind load reduction design of crane has high scientific and engineering significance.Around the research objectives of wind-induced response and wind load reduction design of large-scale gantry crane,the wind load of crane is taken as the research object,and the wind load distribution law of main wind resistance components such as crane main beam is studied to explore the wind load reduction design of crane.Taking bionics research as an opportunity,the design method of bionic box girder with low flow resistance is explored to promote the application of structural bionics in the field of construction machinery design and equipment upgrading of crane industry.From the three stages of structural design,site installation and upgrading,the systematic establishment of crane wind load reduction design method can reduce the crane operation energy consumption,achieve the goal of energy saving and consumption reduction,and provide new ideas for crane design.The main contents of this thesis are as follows:(1)According to the unique structural characteristics of large gantry crane,combined with the research results of flow around bluff body at home and abroad,a computational fluid dynamics model suitable for the study of wind-induced effect of crane is explored.By comparing the simulation results of different turbulence models for the flow around bluff body,a turbulence model suitable for the flow characteristics of gantry crane structure is obtained according to the characteristics of ultra-high Reynolds number and multi sharp angle.The accuracy and reliability of simulation results are evaluated and verified by wind tunnel test method.(2)The correlation and coupling mechanism between structural characteristic parameters of box girder and wind-induced load are studied.The aerodynamic parameters,surface pressure distribution and flow field characteristics of the crane structure with different spacing ratio of box girder,width height ratio of box girder and flange plate size were studied.The general rules of wind-induced effect and flow pattern of structure under different structural characteristic parameters are summarized,and the relevant contents in "crane design code" are supplemented and perfected.According to the corresponding relationship between structural characteristic parameters and structural wind load,the parameter setting of low wind resistance crane structure is explored,which can provide reference for the design of crane anti wind load reduction structure.(3)The wind-induced response of large-scale gantry crane structure and the influence of incoming wind direction angle on the wind load distribution of the structure are discussed.The wind-induced response of large gantry crane structure is studied by unidirectional fluid structure coupling method.Firstly,the pressure distribution data of crane structure surface is obtained by computational fluid dynamics method,and then the wind-induced response of the structure is obtained by coupling the data of computational fluid dynamics with the structural mechanics model.Due to the "one rigid and one flexible" outrigger design of gantry crane,resulting in the asymmetry of both sides of the structure,different flow direction has a significant impact on the wind load of gantry crane structure.The influence of incoming wind direction angle on the wind resistance of gantry crane is studied,and the general rule between the maximum or minimum windward resistance angle of the whole machine and the structure is summarized,so as to obtain the load reduction scheme of the gantry crane field installation.(4)Study on bionic box girder with low flow resistance inspired by ostracion cubicus.Inspired by the advantages of low flow resistance of ostracion cubicus,the bionic design method of box girder structure was innovatively proposed by attaching light materials.Firstly,the streamline characteristics of puffer fish were extracted,and the contour equation of bionic attachment structure based on the height of box girder was established.Then,the low flow resistance streamlined box girder was designed by attaching light materials on the windward side of the box girder.Computational fluid dynamics is used to study the flow characteristics of the attached structure,and the load reduction mechanism of the bionic structure is analyzed.(5)Wind tunnel tests were carried out on the flow characteristics of gantry crane and the load reduction effect of bionic box girder.Based on the results of computational fluid dynamics simulation,the wind tunnel test of crane is designed.The results of computational fluid dynamics are compared and verified by extracting the surface pressure distribution and the three component forces of the whole machine under different wind directions of the scaled wind tunnel model.At the same time,the scale-up model of the crane is attached,and the load reduction effect of bionic attached box girder is verified and analyzed through the change of three components of the whole machine.Wind tunnel test of crane structure is helpful to obtain the flow characteristics of crane in wind field accurately and intuitively.In this paper,computational fluid dynamics simulation and wind tunnel test are used to systematically study the structural flow characteristics,wind-induced response and wind load reduction design of large gantry crane.The research in this paper complements and perfects the relevant contents of wind load in the code for crane design,forms a relatively complete wind load reduction design method for large gantry crane,and further deepens the lightweight design method of crane.The results of wind tunnel test and CFD simulation are compared and analyzed.