Development of curved beam periodic structure in broadband resonance suppression for cylindrical shell structure

Abstract

A dynamic model is developed to incorporate a curved beam periodic structure in the transfer path of an internal isolation system to reduce the resultant vibro-acoustic of the receiving cylindrical shell structure in a passive broadband way. The vibration transmission from the multi-connected internal isolation system with/without the curved beam periodic structure is built by the matrix method. The analytical representation of the curved beam is employed to establish the transfer matrix dynamic model of the proposed multi-layer curved beam periodic structure. Both numerical simulations and experimental investigations are carried out. The numerical simulations demonstrate that the resonances of the internal isolation system will magnify the vibro-acoustic responses notably and the designed curved beam periodic structure is an effective band-stop mechanical filter to minimize the vibration transmission and acoustic radiation responses at resonances in the band gap. The experimental results confirm that the normal acceleration responses on both the bases and the surface of the cylindrical shell are reduced in the band gap of the curved beam periodic structure. An average reduction amount of 9∼12 dB on the bases and 2∼3 dB on the shell is obtained. The vibration transmission in the curved beam periodic structure is tested and found to be influenced by the boundary conditions at the input and output ends, which is different from that under the free boundary conditions.