| The dropper is an important component of the suspension part of the catenary.It is the transmission of vibration and force between the contact wire and the messenger cable,which guarantees the sag of the contact wire and the flow quality of the bow.which guarantees the relaxation of contact wire and the current-collecting quality of pantograph and catenary.The failure of the dropper will seriously endanger the traffic safety and current-collecting quality..With the continuous improvement of train speed,the reliability of the whole dropper is also put forward higher requirements.During pantograph-catenary operation,the pantograph sliding through the catenary will cause the vibration of the catenary,and then cause the compression and tension of the whole dropper and the change of its internal load.The dynamic characteristics of the dropper are the main parameters affecting the fatigue life.The dynamic characteristics of dropper are the main parameters affecting its fatigue life.It is very important to master the dynamic characteristics of the dropper for analyzing the causes of dropper failure and improving the safety and efficiency of railway transportation.Firstly,the dynamic uplifting amount of the dropper under actual service conditions is obtained by means of field measurement.The vibration of the dropper of different train speeds,different catenary parameters and different suspension positions is analyzed and compared;The results show that the dynamic characteristics of droppers at symmetrical positions within a span are identical,and the compression amplitude of the two droppers installed on the elastic suspension cable is the smallest,and the working environment is good.The compression amplitude of the two droppers installed near the elastic suspension cable is the largest and the working environment is worse.The compression amplitude of the dropper increases with the increase of train speed and decreases with the increase of catenary tension.Then,the pantograph-catenary system model with integral dropper structure is established by finite element simulation method,and the simulation analysis under actual working conditions is carried out.The simulation results are compared with the field measurement data to verify the validity of the simulation results.Then,the dynamic force and compression amplitude of the dropper are extracted,and the dynamic characteristics of the whole dropper under typical working conditions are studied and analyzed.It is found that the maximum dynamic force of the dropper occurs at the moment when the dropper changes from bending state to tension state after the pantograph passes by;in the same span catenary,the dynamic force of the two droppers in the middle position is the largest;in the same dropper,the dynamic force of the position near the upper and lower ends of the compression nozzle and the middle position of the strand is the largest,which makes the dropper more prone to fracture.Finally,the dynamic response of dropper under different pantograph-catenary parameters is simulated and analyzed,and the influence of pantograph-catenary parameters on the dynamic characteristics of dropper is studied.The results show that the maximum dynamic force decreases with the increase of contact line tension,and the compression amplitude decreases and increases with the increase of cable tension.The average dynamic force is mainly affected by the number of droppers.It is found that the non-standard installation of dropper will significantly increase the dynamic force of dropper and increase the risk of dropper rupture.The influence of the combination of tension of messenger wire,contact line tension and number of droppers on the dynamic characteristics of dropper is studied by orthogonal experimental design and simulation method.The results show that increasing the tension of messenger wire properly and reducing the tension of contact line are more conducive to reducing the compression amplitude and dynamic force of dropper.The optimum combination which can improve the dynamic performance of dropper is obtained after comprehensive analysis. |
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