Extremely large-amplitude oscillation of soft pipes conveying fluid under gravity

Abstract

In this work, the nonlinear behaviors of soft cantilevered pipes containing internal fluid flow are studied based on a geometrically exact model, with particular focus on the mechanism of large-amplitude oscillations of the pipe under gravity. Four key parameters, including the flow velocity, the mass ratio, the gravity parameter, and the inclination angle between the pipe length and the gravity direction, are considered to affect the static and dynamic behaviors of the soft pipe. The stability analyses show that, provided that the inclination angle is not equal to π, the soft pipe is stable at a low flow velocity and becomes unstable via flutter once the flow velocity is beyond a critical value. As the inclination angle is equal to π, the pipe experiences, in turn, buckling instability, regaining stability, and flutter instability with the increase in the flow velocity. Interestingly, the stability of the pipe can be either enhanced or weakened by varying the gravity parameter, mainly dependent on the value of the inclination angle. In the nonlinear dynamic analysis, it is demonstrated that the post-flutter amplitude of the soft pipe can be extremely large in the form of limit-cycle oscillations. Besides, the oscillating shapes for various inclination angles are provided to display interesting dynamical behaviors of the inclined soft pipe conveying fluid.

Nonlinear geometrically exact dynamics of fluid-conveying cantilevered hard magnetic soft pipe with uniform and nonuniform magnetizations

“…For the first time, Chen et al [28] developed the governing equation and corresponding boundary conditions of this model and studied the post-flutter self-excited oscillations of cantilevered flexible pipes conveying fluid. In another study [30], they employed the geometrically exact rotation-based model to investigate the role of gravity in the nonlinear dynamics of highly flexible cantilevered pipe conveying fluid. Farokhi et al [31] employed this model to study the extremely large oscillations of cantilevered pipe conveying fluid with added end-mass.…”

Resonance response of fluid-conveying pipe with asymmetric elastic supports coupled to lever-type nonlinear energy sink

“…Meanwhile, various computation approaches and techniques have been developed and used to obtain geometrically exact governing equations [21][22][23] , to investigate the nonlinear dynamics and stability of the system [24][25][26][27][28] , and to calculate the resonance response [29] . Other researchers explore the material effects on resonance attenuation [30][31] , especially soft materials [32] . Also, some researchers used the energy harvesting method to suppress vibration [33] .…”

Nonlinear Analysis of L-shaped Pipe Conveying Fluid with the Aid of Absolute Nodal Coordinate Formulation

“…Unfortunately, this pipe model could only deal with the situation when the deformation of the pipe was considered to be small. To solve this problem, several large-deformation-based theoretical models were developed based on the absolute nodal coordinate formulation (ANCF) [14,15] or the geometrically accurate beam model [16,17]. As another kind of pipe commonly used in engineering, the curved fluid-conveying pipe, has also been received extensive attention from scholars [18][19][20][21][22][23][24][25][26][27].…”