Dynamic characteristics of a periodic rib-skin structure

Abstract

Periodic rib-skin structure is composed of an array of identical elements connected in parallel and each element is a stiffened structure consisting of skins and ribs which are modeled as elastic beams and rigid bodies respectively. The periodic structure is designed to gain excellent longitudinal and flexural vibration band gaps in which corresponding waves cannot propagate in the structure freely. Firstly, longitudinal and flexural vibration mobility matrices of the skins and ribs are derived to obtain mobility equations of single-floor and multi-floor periodic elements. Then, propagation constants of the infinite rib-skin structure are calculated and an in-depth numerical study is performed to examine the relationships between the wave propagation constants and dynamic response of semi-infinite and finite periodic structures. Furthermore, flexural vibration reduction performances of the periodic rib-skin structure below 3000 Hz are discussed in detail. Finally, an experimental setup for measuring the acceleration frequency response of a two-floor periodic rib-skin structure is carried out to verify the numerical solution. Both predicted and measured results have demonstrated that longitudinal and flexural band gaps exist in the periodic rib-skin structure. The flexural vibration transmitted through the structure is substantially suppressed in a wide frequency range below 3000 Hz.