ABSTRACT
Liquid-filled pipelines are widely used in energy, chemical and other industrial fields as well as aircraft, ships, submarines, vehicles and other equipment. Vibration related issues can be a challenging part of pipeline integrity management. There are two form of excitations that cause pipeline vibration. One is the external random excitation, the other is the internal flow-induced vibration. These two types of excitations form complex fluid-structure interaction vibration, which leads to fatigue failures of liquid-filled pipelines. The aim of this paper is to analyze the vibration fatigue life of liquid-filled pipelines subjected to simultaneous external random excitation and internal flow-induced vibration by means of finite element simulation and actual experiments. Firstly, the influences of frequency band of power spectral density, kurtosis value of the external random excitation, and the damping ratio and wall thickness of the pipelines on the vibration fatigue life of the pipelines were comprehensively analyzed by ANSYS software. Secondly, a vibration fatigue test system of liquid-filled pipelines was developed by combining vibration table, vibration controller, hydraulic pulse testing machine, protective box, accelerometers and U-shaped pipeline. A series of vibration fatigue tests of liquid-filled pipelines considering fluid-structure interaction were carried out by the above test system, and the fatigue life of the liquid-filled pipelines with different working conditions and different pipeline parameters was analyzed and compared. The results can be used as guidelines for vibration fatigue life assessment and anti-fatigue design of liquid-filled pipelines.
