Dynamic stability of a Hyperloop System Employing a Tubular Shell Theory on Continuous and Periodic Supports

The Hyperloop represents an emerging mode of high-speed transportation distinguished by two key characteristics: (i) a tubular infrastructure enabling a low-pressure environment to minimise aerodynamic drag, and (ii) an electromagnetic suspension system with active control to reduce frictional resistance. The combination of these features allows operational speeds far exceeding those of conventional high-speed and Maglev trains. In systems employing purely attractive magnetic suspension, active control is required to regulate the electromagnetic forces and maintain a consistent air gap. This dependence on feedback control makes Hyperloop systems, and other magnetically levitated vehicles, susceptible to unique instability mechanisms. In this study, we focus on the interplay between two principal forms of instability: (i) wave-induced instability, arising from vehicle–structure interaction at very high velocities, and (ii) electromagnetic instability, inherent to the suspension design. Emphasis is placed on the role of periodic structural features in the form of stiffeners and supports, which can promote the manifestation of these instability mechanisms as parametric instabilities. The novelty of this work lies in the adoption of a refined structural formulation of the tubular infrastructure based on thin shell theory—more specifically, Flügge’s thin shell theory for tubular shells—offering a more realistic representation of the tube dynamics compared to conventional beam models. Based on this model, the instability of the vehicle–structure interaction can be assessed as a function of velocity.