Vibration Reduction for Shell Structures Based on Elastic Wave Band Gaps in Periodic Structures

Abstract

Lightweight structure is required due to ecological considerations. However, the lightweight requirements conflict with noise and vibration (NV) performance. To satisfy both of lightweight solution and NV performance, vibration reduction based on periodic structures is of interest because the periodic structures have wave filtering characteristics which inhibit elastic wave propagation at the frequency ranges referred as band gaps. This paper presents a vibration reduction method using the band gaps of periodic shell structures. The frequency of band gaps can be calculated by using reduced FEA model which is applied the Bloch's theory. We can design shapes of unit cells using the calculated band gaps which relate to frequency range with vibration reduction. Frequency response of a finite periodic shell is carried out to demonstrate vibration reduction based on the band gaps. The results of analysis suggested that the band gaps of periodic shell restrain formation of natural vibration.