Influence of Dry Friction on the Dynamics of Cantilevered Pipes Conveying Fluid

Zilong Guo,Kun Zhou,Xiangkai Meng,Qiao Ni,Lin Wang

doi:10.3390/app12020724

Zilong Guo, Kun Zhou + Show 3 more

Open Access

https://doi.org/10.3390/app12020724

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Abstract

A cantilevered pipe conveying fluid can lose stability via flutter when the flow velocity becomes sufficiently high. In this paper, a dry friction restraint is introduced for the first time, to evaluate the possibility of improving the stability of cantilevered pipes conveying fluid. First, a dynamical model of the cantilevered pipe system with dry friction is established based on the generalized Hamilton’s principle. Then the Galerkin method is utilized to discretize the model of the pipe and to obtain the nonlinear dynamic responses of the pipe. Finally, by changing the values of the friction force and the installation position of the dry friction restraint, the effect of dry friction parameters on the flutter instability of the pipe is evaluated. The results show that the critical flow velocity of the pipe increases with the increment of the friction force. Installing a dry friction restraint near the middle of the pipe can significantly improve the stability of the pipe system. The vibration of the pipe can also be suppressed to some extent by setting reasonable dry friction parameters.

Highlights

Pipes conveying fluid have played an important role in aerospace, marine engineering, and the nuclear industry
For heat-exchange bundle structures existing in the nuclear industry, beyond the onset of flutter instability, the pipe would be subjected to periodic motion and might contact the surrounding supporting plates or pipes [11–13]
The cantilevered pipe is placed vertically and connected to the ground by a dry friction restraint at s = sd. This dry friction restraint would generate transversal friction force at the connection when the pipe is deformed at sd

Summary

Introduction

Pipes conveying fluid have played an important role in aerospace, marine engineering, and the nuclear industry. For heat-exchange bundle structures existing in the nuclear industry, beyond the onset of flutter instability, the pipe would be subjected to periodic motion and might contact the surrounding supporting plates or pipes [11–13] In this case, the effect of contact and possible dry friction between the pipe and the surrounding structures may be pronounced. The stability and dynamic responses of a cantilevered pipe conveying fluid with a dry friction constraint somewhere along the length of the pipe is explored.

Theoretical Model

Numerical Solution

Effect of Friction Force fn