Optimization Design And Wind Environment Impact Analysis Of X-Y Towing Carriage Main Girder In Wind Tunnel

The deep-water engineering innovation experiment base of Dalian University of Technology is an important platform for the country to carry out scientific research,technology development,test verification and personnel training in the field of deep-water engineering.In order to meet the requirements of installation,measurement and towing of the test model,X-Y towing carriage is planned to be installed on the upper part of the deep basin.The design requirements of X-Y towing carriage for this deep basin is extremely strict because there is a large wind tunnel in the upper part of the deep basin and the space in the wind tunnel is narrow,the design requirements include such as,low height,long span,high stiffness,small wind resistance and so on.In view of these conditions,the paper gives two design schemes for the X-Y towing carriage truss girder by adjust the layout of girders and section optimization then carries out the static and dynamic analysis especially considering the frequent starting and braking of towing carriage equipment and fan,these conditions will have strong impact and vibration effect on the main girder.The dynamic characteristics of the main girder structure have great influence on the dynamic strength stiffness and accuracy of the whole equipment.Finally select a better solution based on the results to optimize the design and wind field analysis.According the issues above,the specific contents of this paper include these followings:(1)The paper gives half-through towing carriage scheme and through towing carriage scheme by comprehensive consideration the narrow space environmental conditions,,both schemes of towing carriage main girder are truss structure in order to avoid the problem that the front resistance of the structure to the wind field is too large like box girder,which increase the wind resistance that seriously affects the accuracy of the measurement results.(2)The stress,deformation distribution,dynamic analysis,modal analysis and transient dynamic analysis when the fan starts up of the main girder structure under different working conditions are studied by using the finite analysis software ANSYS and then compared with the theoretical analysis,check whether the stiffness and strength meet the requirements of the standard?(4)The parameters of truss cross-section dimensions were defined as optimization variables.The strength and stiffness conditions were defined as constraint condition and the volume of the model was defined as objective function then optimized the girder structure.(5)The wind field environment of the trailer is analyzed,and the wind load on the towing carriage is analyzed and calculated by the method of computational fluid dynamics.The CFD software FLUENT is used to establish two cases of the empty wind tunnel and the towing carriage in the wind tunnel,and the influence of the trailer girder on the aerodynamic performance of the wind tunnel is compared and analyzed.Through the static analysis,modal analysis and transient dynamic analysis of two kinds of towing carriage main girder structure schemes,it can be seen that both schemes are within the acceptable range,but by comparing and analyzing the quality,the mechanical property,structure size and economic benefits which is the through towing carriage scheme is more in line with the requirements,after optimized design structure get a better scheme.The research results of this paper provide a useful reference for the scheme selection of deep-water engineering innovation experiment base of Dalian University of Technology.