Research On Mechanics Characteristics And Temperature Effect Of Medium And Low Speed Maglev Turnout Beam

At present,China’s medium and low speed maglev transportation system is in the golden age of development.The medium and low speed maglev transportation system has high development potential and great promotion value in urban rail transit due to its unique advantages.As an indispensable part of the medium and low speed maglev traffic system,maglev turnout system is an important infrastructure to give full play to the line passing capacity.Medium and low speed maglev train runs through rail-holding mode,which makes the structure of maglev turnout very different from that of traditional railway turnout.In essence,it is a continuous box-shaped steel structure beam with huge structure,complex crosssection and elastic bending.Due to the special working principle and structure of medium and low speed maglev turnout,the design of maglev turnout beam structure is difficult.In order to meet the high precision requirement of maglev train,the maglev turnout beam must keep high precision.The maglev turnout beam will produce a certain degree of deformation under the effect of temperature,which will affect the accuracy level of the line.Therefore,optimizing the design of maglev turnout beam structure and studying its temperature effect are of great significance to the efficient operation and management of maglev transportation system.In this paper,medium and low speed maglev turnout is taken as the main object.The general structure of maglev turnout,the common types of turnout and the working principle of various system devices are briefly introduced.The structural characteristics of the steel frame structure of turnout are analyzed.On this basis,the mechanical analysis model of the maglev turnout beam structure is established by simplifying the structural characteristics.The deformation and stress characteristics of the maglev turnout beam under different working conditions are calculated.The training samples of the neural network are established by uniform experiment method,the results of mechanical analysis model are used as the constraints of the neural network model,the corresponding volume is calculated as the output variable of the neural network,and the genetic algorithm is used to optimize the neural network.Compared with the volume before optimization,the weight of the maglev turnout beam is reduced by 5.85%.The structural responses of the optimized maglev turnout beam under the same conditions are calculated and compared with those of the model before optimization.The results show that the deformation of the optimized turnout beam model is less than that before optimization,and the maximum stress amplitude also decreases.The mechanical properties of the optimized maglev turnout beam model are analyzed: the structural responses under other working conditions are checked,and the mode calculation of maglev turnout beam structure is carried out by using block Lanczos method,and the vibration characteristics of maglev turnout beam under free state and actual constraints are analyzed.Based on the theory of temperature field analysis,the temperature distribution of the medium and low speed maglev turnout beam under different temperature loads in the different fields is analyzed by using means of steady state analysis.The thermal-structural coupling method is used to study the temperature deformation of the maglev turnout beam structure.The results show that under the transverse and vertical temperature differential loads,the temperature in the maglev turnout beam distributes approximately linearly along the width or height of the beam,when the temperature difference increases,the temperature gradient increases accordingly.Vertical temperature differential loads have little effect on the deformation,while transverse temperature differential loads have the most significant effect.In addition,the influence of ambient temperature on temperature distribution and temperature deformation of the maglev turnout beam is also considered.In the calculation results of this paper,when the temperature difference between the left and right webs exceeds 15°C,the transverse deflection of the maglev turnout beam will exceed the temperature deformation limit in the relevant regulations.Therefore,it is necessary to clarify the temperature effect of the turnout beam under practical conditions in the structural design of medium and low speed maglev turnout beam.