Uncertainty and sensitivity analysis for train-ballasted track-bridge system

This paper is devoted to present an integrated uncertainty and sensitivity procedure for use in performance assessments for train-bridge interactions. Firstly, a train-ballasted track-bridge dynamic model with proper consideration of the nonlinear wheel-rail contact geometries is constructed in three-dimensional space; and then the uncertainties related to this system are illustrated, in which the material, geometry, structural damping of bridge superstructure and the temporal-spatial ergodic properties of track irregularities are highlighted; and furthermore, the probability density evolution method accompanied with an advanced number theoretical method is introduced to describe the transmission of probability from excitation input to response output for the uncertainty analysis; finally, the key factors affecting the dynamic behaviours of system components are clarified by the variance-based global sensitivity analysis which has taken the interactions between factors into account. Numerical examples show that the uncertainty analysis algorithm is of high efficiency and accuracy by comparing with the robust Monte-Carlo simulation method; the variability of bridge parameters and track irregularities show remarkable effects on the dynamic indices; and the most sensitive factors are rather different with regard to varied dynamic indices.