Abstract
The contact-points information of the large-scaled ballast aggregate model (21.1-million-DOFs) is modeled by using both of the Multi-Point Constraints (MPCs) and the nonlinear contact springs. To introduce the direct solver MUMPS corresponding to the parallel computing of a distributed memory type, the whole model is divided into 24 sub-domains for the large-scale parallel computing of FrontISTR. The finite element transient response analysis reveals that the natural frequency of the 1st order vertical elastic vibration mode of the ballasted track exists around 310 Hz and that the rigid body vibration mode of the sleeper occurs at around 1/3 frequency of the elastic vibration mode. The analytical results coincide substantially with the one obtained by the field measurement and the full-scale experimental one. It is inferred that the occurrence of the ballast resonance modes is the cause of the shift and the flow of the ballast gravel.
