Simulation of aerodynamic impact of a high-speed train on a shell-type protective tunnel

Abstract

   The article presents the research of the loading regime of a membrane shell of an above-ground tunnel under the aerodynamic impact of a high-speed train. The authors solve the coupled problem of aerodynamics and deformable solid mechanics numerically by the Reynolds-averaged Navier-Stokes equations and the finite element method. Moreover, it is established that the governing loading parameters are the tunnel length and the relativeair gap, which controls the intensity of the piston effect. The maximum impact is produced by an alternatingsign pressure pulse in the region of the head nose cone; the tail zone is characterised by the developed turbulence and jet-separation flows. By the comparative analysis of smooth and corrugated shells, as well as a reinforced frame, the authors identify a structural solution combining aerodynamic efficiency and resistance to lateral loads. The service life under cyclic loading is assessed using the Palmgren-Miner damage accumulation rule and fatigue curves.    The scientific novelty consists in a unified computational methodology integrating aerodynamic modeling, stress-strain analysis and fatigue assessment as applied to above-ground shell-type tunnels.    The results are intended for optimizing geometric parameters and improving the durability of protective structures.