Design of hybrid resonant metamaterial fluid-filled pipe for broadband vibration reduction

A novel hybrid resonant metamaterial (HRM) pipe is proposed to achieve broadband vibration reduction of fluid-filled pipes. Rubber-copper ring resonators and piezoelectric patches with RLC circuits are periodically distributed on the fluid-filled pipe to form the HRM pipe. The dispersion relation and vibration transmission property of the HRM pipe are calculated by the proposed analytical method, and the accuracy is verified by using the finite element method (FEM). The results demonstrate that the mechanical and electromechanical locally resonant (LR) bandgaps can be obtained for low-frequency vibration reduction of fluid-filled pipe systems. By adjusting the RLC circuit parameters, the two types of LR bandgaps can be merged into a broader hybrid bandgap or separated according to application requirements. Moreover, the extra broad hybrid bandgap can be achieved through designing the multi-frequency mechanical and electromechanical resonators. By designing more resonant frequencies in multi-frequency resonators, the extremely broad hybrid bandgap can be recursively obtained in the low-frequency range. The present research incorporates the idea of HRM into fluid-filled pipe system, which may contribute to the design and application of broadband vibration reduction in engineering pipe systems.