A Study on the Vibration Analysis of Thick-Walled, Fluid-Conveying Pipelines with Internal Hydrostatic Pressure

Abstract

Pipelines are designed to carry seawater with hydrostatic pressure below sea level in the ship industry. Previously conducted studies have established the FSI (Fluid–Structure Interaction) equations for thin-walled, fluid-filled pipelines based on the Timoshenko beam model; these equations now need to be modified for analyzing the vibration characteristics of thick-walled pipelines with hydrostatic pressure. The vibration of thick-walled pressurized pipes is studied in this paper. Effective and accurate numerical methods for solving vibration responses to either harmonic excitation or a random load have been developed using the spectral element method and pseudo-excitation method. It is found that the thick-walled theory and the thin-walled theory differ in axial wave transmissions. The internal pressure mainly affects the transverse vibration, which results in an increase in the natural frequencies in the lower frequency domain, an increase in the vibration transmission in the assembled pipeline, and an increase in the displacements when subjected to random loads. Using relatively thicker pipelines and introducing flexible pipes may reduce the vibration transmission when subjected to internal pressure.