| As an important material loading and unloading mechanism,the gantry crane’s structure tends to be "larger" and "flexible" with the development of port economy and railway freight yard,and the overall structure usually has a high center of gravity and a large windward area.In the wind load environment,the crane structure is more and more sensitive to the wind load.Therefore,in the crane structure wind engineering,it is of great practical significance to study the coupling mechanism between the main beam structure and wind load,to fully explore the aerodynamic characteristics of the main beam of the crane and to establish the design method of anti-wind load reduction of the crane,which can improve the anti-overturning capacity of the gantry crane.In this paper,the crane structure is taken as the research object,and the coupling mechanism between the structural characteristics of the main beam and the wind load is explored through the numerical simulation of the wind-retaining component by using Fluent.The correlation between the flow characteristics of the crane double beam structure and the wind-retaining reduction coefficient is comprehensively analyzed.The bionic attached box girder in the design of wind resistance and load reduction is extended to analyze and evaluate the load reduction effect of the streamline shape of the main girder structure,and a comprehensive design method for the wind resistance and load reduction of the main girder of the crane is established.The main research contents of this paper are as follows :(1)The accuracy and reliability of simulation analysis results of crane solved by different turbulence models were verified by combining the wind tunnel tests and academic research results at home and abroad for the main girder structure type of gantry crane.The windinduced effect phenomenon of I-beam and composite beam under high Reynolds was numerically simulated by CFD,the flow characteristics around the boundary layer of the two main beams were analyzed,the coupling mechanism of the main beam structure type pair and wind load was discussed,and the aerodynamic characteristics of the main beam structure were obtained.parameters,vortex shedding frequency and surface wind pressure coefficient distribution law,so as to explore the structural parameter design of gantry crane I-beam and composite beam.(2)According to the design specification of main beam spacing ratio of gantry double beam crane,referring to three flow modes of flow around the flow form of tandem structure,numerical simulation of flow around the double beam structure with different characteristic parameters(box beam spacing ratio,box beam height to width ratio)is carried out to study the coupling mechanism between characteristic parameters of double beam structure and wind load.The aerodynamic parameters such as drag coefficient,lift coefficient and surface pressure distribution of double beam structure under different characteristic parameters are simulated,and the law of change of drag coefficient of double beam structure with the space ratio of main beam is discussed,which provide reference for the wind-shielding reduction coefficient spectrum of double-girder structure in "Design rules for cranes".The correlation between double beam structure and wind-induced load is summarized to provide reference for load reduction design of crane double beam structure.(3)Aiming at the research on the wind resistance and load reduction of the crane main girder,based on the low flow resistance bionic box girder structure design idea,without affecting the bearing capacity of the main girder,a variety of attached expansion structures are established,and the computational fluid dynamics software is used for different attachments.The load shedding mechanism of the structure is numerically simulated,and the wind-induced effect of different streamlined structures on the main beam of the crane is comprehensively evaluated.The results show that the low flow resistance windward shape can reduce the separation scale of the fluid around the flow,which not only effectively reduces the operating load of the crane structure,but also greatly reduces the oscillation amplitude of the main girder structure with the reduction of the wake vortex scale.In this paper,the double beam structure of large gantry crane with different main beam structure types and different characteristic parameters is systematically studied,which complements and provides a reference for the description of wind loads of related components in "Crane Design Code",and further expands the related research of attached structure in crane wind resistance and load reduction... |
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