Study on Damage Identification Method of Stepped Beams Based on Localized Resonant Acoustic Metamaterials

In order to solve the problem of large data requirement for damage identification in the field of vibration signal-based damage identification, a damage identification method for step-beam based on transmission loss of local resonance acoustic metamaterials is proposed. As the elastic waves propagate in the acoustic meta-material medium, transmission spectrum valley is formed due to the local resonance effect in some frequency domain. But when the fissure appears, the amplitude value of the valley is promoted. Firstly, the energy band structure and transmission spectrum of the metamaterial are calculated by the finite element method. Secondly, the band gap formation mechanism is analyzed by the vibration modes of the points on the energy band structure. Finally, the influence of the structural parameters on the band gap is explored, and the damage characteristics of the stepped beam within the band gap are analyzed. The research results show that the proposed damage identification method combined with the frequency response curve can improve the efficiency and simplify the data processing. The research results provide a new idea and method for the field of online fault diagnosis based on vibration signals.