Low-frequency band gap characteristics of a novel spinning metamaterial pipe with Timoshenko model

As a representative artificial periodic composite, metamaterials have presented broad application prospects in vibration attenuation and noise reduction of engineering devices owing to their extraordinary band gap (BG) properties. In this paper, a novel type of dynamic metamaterial structure is proposed on the basis of a spinning locally resonant (LR) pipe conveying fluid, and the coupled BG characteristics of such meta-structure are investigated. By applying the Timoshenko beam model, the differential equations governing the orthogonally transverse vibrations of spinning pipes conveying fluid are deduced by the Hamilton principle. Based upon the two resulting transverse waves, a dynamic two-dimensional LR pipe structure is developed by peri-odically encircling the pipe with dual-layer rings. An additional centrifugal force due to spin as well as the conventional inertial force is introduced into the local resonators. It is revealed that the present LR pipe makes a great contribution to the formation of low-frequency BGs below 500 Hz, which is conducive to the vibration suppression of large-size structures in engineering. Moreover, original BGs of non-spin structures will separate to different pseudo BGs towards the precession motions, while the true BGs are actually located in their coincident areas. Numerical results also demonstrate the significant effects of various physical, geometrical and motional parameters on the low-frequency BGs of the pipe.

Automated summary

This paper proposes a novel type of dynamic metamaterial structure based on a spinning locally resonant pipe and investigates its coupled band gap (BG) characteristics. The study reveals that this metamaterial structure plays a significant role in the formation of low-frequency BGs, which is beneficial for vibration suppression in large-size engineering structures. Additionally, the paper shows that original BGs of non-spin structures separate into different pseudo BGs during precession motions, while the true BGs are located in their coincident areas.