Design of annular metastructures vibration suppression in rotating machinery

This paper introduces an innovative annular metastructure (AM) designed to transfer the vibration transmission pass from the radial direction to the circumferential direction, which can effectively elongate the vibration transmission pass to include more local resonance vibration mitigation cell structures and overcome the band gap prediction problem due to the non-translation periodicity of the traditional radial metastructure. The study includes the development and fabrication of the AM, as well as the analytical analysis, numerical simulations, and experimental validations. An analytical model of a five-cell structure is developed to predict its vibration transmission characteristics. A finite element model of the rotor system, integrated with the AM, is established, and a rotor vibration test rig is constructed to validate the numerical analysis results. Both the analytical model and numerical results indicate that the negative effective mass characteristic of the local resonator is the intrinsic mechanism for the vibration mitigation of the AM. Additionally, the AM significantly reduces the rotor′s unbalanced response within the vibration band gap. This study shows the designed AM offers several advantages, such as low-frequency vibration suppression capability, structure compact, and comparative load capacity. This study provides valuable insights for the potential practical applications of the AM in rotor dynamics systems.