Identifying dominant components of vibrational energy flow in U-rib plates of bridge based on structural intensity

Abstract

Stiffened U-rib plates are the elementary components of steel box girders in bridges that directly bear the input external energy before transferring it to other components. Research on the dynamic characteristics of stiffened U-rib plates is the basis for examining vibration and noise in steel box girders. Most relevant studies have focused on the vibrational modes and single-frequency responses in this context, and few researchers have sought to optimize the design of stiffened U-rib plates to reduce responses due to vibrations and noise. This study identifies the global and local laws of vibrational transmission in stiffened U-rib plates subjected to harmonic loads through structural intensity (SI) analysis that is carried out by jointly using standard finite element software and a post-processing code created by the authors. The contributions of each component of vibrational waves are represented to reflect the dominant roles of the bending wave in the baseplate and the in-plane wave in the U-ribs, respectively. The effects of parameters of the U-rib plates on SI are also quantitatively investigated. SI analysis can be used as a new criterion for designing and optimizing bridges as well as formulating measures for vibration reduction.