A direct method for analyzing the nonlinear vehicle-structure interaction in high-speed railway lines

This article presents an accurate, efficient and stable algorithm to analyse the
nonlinear vertical vehicle-structure interaction. The governing equilibrium equations
of the vehicle and structure are complemented with additional constraint equations
that relate the displacements of the vehicle with the corresponding displacements of
the structure. These equations form a single system, with displacements and contact
forces as unknowns, that is solved using an optimized block factorization algorithm.
Due to the nonlinear nature of contact, an incremental formulation based on the
Newton method is adopted. The track and structure are modelled using finite
elements to take into account all the significant deformations. In the numerical
example presented, the passage of the KHST over a railway viaduct is analysed,
being the accuracy and computational efficiency of the proposed method clearly
demonstrated.