Frequency Variation and Dynamic Behavior in a Moving Mass-Plate System

Abstract

As the frequency variation in a moving mass-plate system is seldom discussed in the previous work, this study first formulates the semi-analytical solutions of a system consisting of a moving mass on a square plate. Based on the moving mass-plate system, several finite element models with designed plate-type bridges are established to further investigate the effect of moving mass on a plate, the influence of bridge local modes, and the influence of moving loads on a bridge. The numerical results have shown that the frequency variation of a plate-type bridge can reach 30% for the first three modes. The unique phenomenon of wave propagation is exhibited in the acceleration responses of the plate-type bridge, while it is uncommon for a beam-type bridge. For design purpose, the following are remarked: (1) The use of Rayleigh damping on the stiffened bridge can effectively suppress the influence of local modes on the bridge deck. (2) The high stiffness in the moving load can be served as the damper to reduce the dynamic responses of a vehicle. (3) In the design stage of a plate-type bridge subjected to moving loads, the moving force is the most conservative one among the three moving loads.