Flexural wave band gaps analysis of a bidirectional periodic stiffened steel bridge deck

This study investigates the flexural wave dispersion and bandgap mechanisms in bidirectional stiffened plates to quantify the influence of design parameters on bandgap properties and to support low-noise bridge design. A finite element model of the periodic unit cell is established, and a novel wavefield analysis based on a polarization ratio—defined as the proportion of out-of-plane displacement energy of the base plate—is proposed to identify flexural wave modes. Using this approach, dispersion characteristics and vibration transmission are computed, and bandgap formation mechanisms are clarified through eigenmode displacement fields. A parametric study assesses the effects of key design parameters on flexural wave bandgaps. Results show that the proposed method accurately identifies complex flexural wave modes. This research provides new insights and design references for source control of bridge structure-borne noise.