Adjacent mode resonance of a hydraulic pipe system consisting of parallel pipes coupled at middle points

Although most pipes are restrained by retaining clips in aircrafts, the influence of the clip parameters on the vibration of the fluid-conveying pipe has not been revealed. By considering the clip width, a new dynamic model of a fluid-conveying pipe restrained by an intermediate clip is established in this paper. To demonstrate the necessity of the proposed model, a half pipe model is established by modeling the clip as one end. By comparing the two models, it is found that the half pipe model overestimates the critical velocity and may estimate the dynamical behavior of the pipe incorrectly. In addition, with the increase in the clip stiffness, the conversion processes of the first two modes of the pipe are shown. Furthermore, by ignoring the width of the clip, the effect of the flow velocity on the accuracy of a concentrated restraint clip model is presented. When the flow velocity is close to the critical velocity, the accuracy of the concentrated restraint clip model significantly reduces, especially when the width of the clip is large. In general, the contribution of this paper is to establish a dynamic model of the fluid-conveying pipe which can describe the influence of the clip parameters, and to demonstrate the necessity of this model.

Dynamic modeling of fluid-conveying pipes restrained by a retaining clip

Dou¹,

Ding²,

Mao³

et al. 2023

Vibration control of fluid-conveying pipes: a state-of-the-art review

Ding,

2023

Fluid-conveying pipes are widely used to transfer bulk fluids from one point to another in many engineering applications. They are subject to various excitations from the conveying fluids, the supporting structures, and the working environment, and thus are prone to vibrations such as flow-induced vibrations and acoustic-induced vibrations. Vibrations can generate variable dynamic stress and large deformation on fluid-conveying pipes, leading to vibration-induced fatigue and damage on the pipes, or even leading to failure of the entire piping system and catastrophic accidents. Therefore, the vibration control of fluid-conveying pipes is essential to ensure the integrity and safety of pipeline systems, and has attracted considerable attention from both researchers and engineers. The present paper aims to provide an extensive review of the state-of-the-art research on the vibration control of fluid-conveying pipes. The vibration analysis of fluid-conveying pipes is briefly discussed to show some key issues involved in the vibration analysis. Then, the research progress on the vibration control of fluid-conveying pipes is reviewed from four aspects in terms of passive control, active vibration control, semi-active vibration control, and structural optimization design for vibration reduction. Furthermore, the main results of existing research on the vibration control of fluid-conveying pipes are summarized, and future promising research directions are recommended to address the current research gaps. This paper contributes to the understanding of vibration control of fluid-conveying pipes, and will help the research work on the vibration control of fluid-conveying pipes attract more attention.

Nonlinear dynamics of a circular curved cantilevered pipe conveying pulsating fluid based on the geometrically exact model

Cao,

Guo,

Chen

et al. 2024

Due to the novel applications of flexible pipes conveying fluid in the field of soft robotics and biomedicine, the investigations on the mechanical responses of the pipes have attracted considerable attention. The fluid-structure interaction (FSI) between the pipe with a curved shape and the time-varying internal fluid flow brings a great challenge to the revelation of the dynamical behaviors of flexible pipes, especially when the pipe is highly flexible and usually undergoes large deformations. In this work, the geometrically exact model (GEM) for a curved cantilevered pipe conveying pulsating fluid is developed based on the extended Hamilton’s principle. The stability of the curved pipe with three different subtended angles is examined with the consideration of steady fluid flow. Specific attention is concentrated on the large-deformation resonance of circular pipes conveying pulsating fluid, which is often encountered in practical engineering. By constructing bifurcation diagrams, oscillating shapes, phase portraits, time traces, and Poincare maps, the dynamic responses of the curved pipe under various system parameters are revealed. The mean flow velocity of the pulsating fluid is chosen to be either subcritical or supercritical. The numerical results show that the curved pipe conveying pulsating fluid can exhibit rich dynamical behaviors, including periodic and quasi-periodic motions. It is also found that the preferred instability type of a cantilevered curved pipe conveying steady fluid is mainly in the flutter of the second mode. For a moderate value of the mass ratio, however, a third-mode flutter may occur, which is quite different from that of a straight pipe system.