Dynamic modeling and analysis of fluid-delivering cracked pipeline considering breathing effect

Abstract

Crack is the most common failure mode of the pipeline system, which may lead to high-speed and high-pressure hydraulic oil leakage. In this paper, the dynamic modeling and model order reduction methods for the fluid-delivering cracked pipeline (FDCP) considering the breathing effect are proposed, and the structural intensity method (SIM) is introduced to visualize the vibration transmission and breathing effect of FDCP. The fluid, solid, and coupling elements are constructed to establish the dynamic model of FDCP, the spring element is used to simulate the breathing effect, the dynamic substructure method is extended to perform the model order reduction of FDCP, and the rationality of the modeling method is verified by experiments. SIM and energy principles are used to visualize and analyze the vibration transmission of FDCP. The analysis results show that the natural frequencies are sensitive to the cracks in the maximum modal displacement and stress regions, and the fluid velocity and pressure (FVAP) will enhance the breathing effect of FDCP. In addition, the vibration transmission analysis can accurately detect the crack with different damage degrees, and FVAP do not influence the vibration transmission laws. The modeling and analysis method in this paper can provide a theoretical reference for fault diagnosis of FDCP.