Numerical investigation on dynamic interactions of non-contact maglev vehicle and two-span steel continuous bridge induced by high-frequency vibration modes

Abstract

As a novel type of non-mechanical contact rail transit, the maglev vehicle is stabilized by actively controlled levitation forces without contact. The steel bridge exhibits complex self-vibration characteristics with dense high-frequency vibration modes. The levitation gap and force are disturbed by the complex vehicle-induced deformation of the steel bridge, and significant moving maglev vehicle–steel bridge coupled vibration phenomena occur. To solve this problem, the vibration mechanism of a maglev vehicle moving on a steel bridge should be understood. This paper establishes detailed models of the theoretical dynamic interactions between a moving maglev vehicle and double-span steel and steel–concrete composite continuous bridges with active levitation control. The vehicle-induced vibration characteristics of the two bridges and the vehicle dynamic responses were compared, and the influence mechanism of the steel bridge on the maglev vehicle’s operation stability was examined. The influences of different high-order modes and modal stiffnesses on the coupled system’s dynamic performance were analyzed. The results demonstrated that the numerous high-order local vibration modes present in the steel top slab were responsible for the maglev vehicle’s smooth operation. High-order local vibration modes and short wavelengths were prone to the large fluctuations in the levitation gap and force. The greater the modal stiffness for a given local vibration mode was, the lower the vehicle-induced deformation became. Minimizing local high-frequency vibration modes of the steel top slab and increasing the local vibration mode stiffness could effectively reduce the excitations to the levitation control system.