Enhanced dynamical stability of rotating composite pipes conveying fluid by a smart piezoelectric design

This paper aims to improve the flexural stability of rotating pipes conveying fluid by introducing a smart piezoelectric feedback structure. The pipe is laminated along the radial direction, and a steady fluid flows inside the pipe. In the meantime, the pipe rotates around a vertical axis at one end. A pair of piezoelectric sensor and actuator connected with a feedback gain circuit are designed to place on the pipe in order to reduce the transverse vibration by providing dynamic stiffness. Theoretical modeling finds it a fully coupled system among the axial, in-plane and outof-plane transverse direction due to the presence of the piezoelectric feedback structure. However, such smart structure is demonstrated to have excellent capability of enhancing the natural frequency and static and dynamic critical flow velocities of the pipe. Vibration response analysis also reveals an interesting phenomenon that under the gyroscopic effect of flowing fluid, the introduced piezoelectric design is able to attenuate the vibration of the system periodically, similar to a beat vibration. This study is expected to provide a technical way for enhancing the stability of engineering motional pipes.