Research On Wave Characteristics And Propagation Rules Of Catenary

With the great promoting of train’s running speed in recent years, especially the large-scale construction of high speed railway, the vibration behavior and wave characteristics of high-speed electrified railway catenary have caused high attention. When running at a high speed, the high speed train oscillates the over-head contact line and makes it showing an obvious fluctuation characteristic, like wave propagation and reflection at certain anisotropic medium point, which have a huge influence on the current-collection quality. After a review of related studies on catenary fluctuation overseas, this paper analyzed the fluctuation characteristics of catenary and its propagation regularity. The achievements are as follows:First, by starting with a single beam and a single cable model, the wave velocity expression was conducted based on the beam and cable model. And thereafter, the single span catenary model was developed into multi-span catenary model. Finally, based on the analysis of the difference between the structure models and element types, and the influence of element bending deformation and the supporting stiffness, a suitable model to study the catenary wave characteristics has been established.Second, through the numerical simulation technology, the propagation speeds of the catenary vibration wave were obtained at different locations and train speed levels, and then the reflection coefficient formula at catenary section fixed-end and hanging points was deduced. Furthermre, the catenary wave propagation regularity was presented by the contour plots of catenary displacement simulated solution.Third, for the wave velocity of a real catenary structure the theoretical value was compared with the laboratory test value. Through this difference coefficient, the theoretical wave velocity was modified, which usually was valued by the simplified beam model and other similar catenary models.At last, some developments in identifying the catenary damping parameters were involved, which will contribute to the simulation analysis of pantograph-catenary dynamics. Specifically, based on the test free vibration signal, the amplitude decay theory and some MATLAB programs were used to identify the damping ratio of catenary.