Design and vibration characteristics analysis of periodic truss structures

To address the low-frequency vibration and noise problem in a ship power system, a truss-type floating-raft structure incorporating periodic oscillators is designed according to the local resonance theory of phononic crystals. The finite element method and Bloch theory are used to analyze the formation mechanisms of the band gap in the periodic oscillator truss. The paper discusses the effects of oscillator mass, installation form, and truss structure parameters on the characteristics of the band gap. Additionally, a vibration characteristic test for the truss equipped with periodic oscillators is designed, and the vibration transmission loss of the truss structure is studied. The results show that the larger the oscillator mass, the wider the band gap, and the larger the cell size, the smaller the band gap bandwidth. The arrangement of oscillators has less effect on the band gap characteristics, and increasing the number of oscillators may result in significant broadband characteristics. Compared with the complete mounting method, the spaced oscillator mounting method may result in less variation in band gap characteristics, allowing for an effective reduction in the number of oscillators. © 2024 Editorial Board of Journal of Harbin Engineering. All rights reserved.