Analysis of the vibration band-gaps of bouble-rail phononic crystal model for ballast track

Existing vibration analysis models for track structure often simplify the dynamic model of the track structure to a single rail based on the symmetry of the track structure for analyzing its frequency dispersion characteristics and vibration attenuation rate. However, the single rail model fails to fully reflect the coupling characteristics of the two rails fixed on the sleepers by fasteners in actual railways, and ignores the differences in vibration wave propagation when waves propagate transversely along the sleepers. To fully consider the effect of the spatial coupling effect between the rail and the sleeper on the vibrational band gap of the ballast track, a double-rail phononic crystal (DRPC) model that consisted of two parallel rails fastened on equally spaced sleepers supported by ballast was proposed. The transfer matrix method was used to simplify the two rails in the ballasted track as Euler beams. The ballast and fasteners as connecting springs, and the sleepers as Winkler foundation beams, and a double rail phononic crystal model (DRPC) of the ballasted track structure were established. A Fortran program was used to analyze the vibration bandgap of the ballasted track, and the results were compared with those of the phononic crystal single rail model (SRPC) that only considers a single rail. The results show that the 6 characteristic waves of the SRPC model are included in the 12 characteristic waves of the DRPC model. The band-gaps of the left rail in DRPC model are basically close to the SRPC model, the central positions, and widths of the band gaps of waves in the right track of the DRPC model are different from the SRPC model. The band gaps related the transverse, torsion and in-plane bending vibration are quite different between the two models. The DRPC model can better analyze the propagation characteristics of various characteristic waves related to the spatial vibration such as the transverse, torsion and in-plane bending vibration. The DRPC model can amend the shortcomings of the spatial simplify of the SRPC model, and it can more accurately considering the propagation characteristics of various characteristic waves related to the spatial effect. © 2023, Central South University Press. All rights reserved.