Research On The Dynamic Characteristics Of Catenary Droppers In High-speed Railway

Dropper is a key component of the catenary,and is a bridge connecting the load-bearing cable and the contact line.It not only transmits the vibration and force between the two,but also bears the role of current-carrying.In recent years,high-speed rail catenary dropper breaking accidents have occurred from time to time,causing the pantograph network system to malfunction and seriously endangering the safety of train operations.Therefore,analyzing the dynamic characteristics of the hanging string when the pantograph slides over the catenary and the impact of current carrying on the dropper,and exploring the reasons for the breakage of the dropper in service are of great significance to the safety of high-speed railway operations.This paper takes catenary droppers in high-speed railways as the research object,and mainly studied the following:Firstly,a ternary reduction quality model of the pantograph is established,and the fitting formula of the catenary variable stiffness is obtained using the principle of least squares;Based on the analysis of the pantograph-net coupling dynamics,the pantograph-net coupling dynamics model is established to solve the pantograph-net contact force and lift changes under the six current driving conditions of my country’s current high-speed rail,providing loads for subsequent pantograph-net coupling transient dynamics simulation Incentive input.Studies have shown that as the train speed increases,the pantograph-net contact force fluctuates more and more severely,and the contact environment between the two becomes more and more unstable.Secondly,the initial geometric form of the catenary is solved by the method of torque balance,and the finite element model of the pantograph and net coupling is established through software named ANSYS Workbench,the modal analysis of the catenary and the transient dynamics analysis of the pantograph and net coupling are carried out to study the pantograph slip vibration behavior of outdated droppers when the train speed is 300km/h.Studies have shown that the vibration characteristics of the hanging string at different positions within the span are different,and the hanging string at the mid-span position has the largest vibration amplitude,the largest impact,and the most vulnerable to damage.Thirdly,the feeder current of the traction network of a high-speed rail power supply section was monitored,and the current input data of the catenary within a day was obtained,and the actual instantaneous input current of the string was obtained by analysis and solution.A solid model of the stranded wire body of the dropper was established,and the electro-thermal coupling field analysis of the dropper was established.The actual instantaneous maximum current carrying current of the dropper was used as the input value to study the effect of the duration of power on the temperature rise of the dropper.Studies have shown that: under the actual current-carrying strength of the hanging string,the internal temperature of the wire body rises with the increase of the duration of energization.Finaly,according to the energized tensile experiment of the dropper,the material property change data of the dropper is obtained,and the transient dynamics simulation of the pantograph-net coupling under the current action is carried out to analyze the influence of the force and electricity coupling on the dynamic characteristics of the dropper and compare and analyze with the previous article.Studies have shown that under the action of electric current,the ability of the hanging string to resist its own deformation is reduced,and the vibration amplitude is increased.Under the excitation of the pantograph head load,it is more prone to large deformation.