Reduced-order modeling and vibration transfer analysis of a fluid-delivering branch pipeline that consider fluid–solid interactions

The efficient dynamic modeling and vibration transfer analysis of a fluid-delivering branch pipeline (FDBP) are essential for analyzing vibration coupling effects and implementing vibration reduction optimization. Therefore, this study proposes a reduced-order dynamic modeling method suitable for FDBPs and then analyzes the vibration transfer characteristics. For the modeling method, the finite element method and absorbing transfer matrix method (ATMM) are integrated, considering the fluid–structure coupling effect and fluid disturbances. The dual-domain dynamic substructure method is developed to perform the reduced-order modeling of FDBP, and ATMM is adopted to reduce the matrix order when solving fluid disturbances. Furthermore, the modeling method is validated by experiments on an H-shaped branch pipeline. Finally, transient and steady-state vibration transfer analyses of FDBP are performed, and the effects of branch locations on natural characteristics and vibration transfer behavior are analyzed. Results show that transient vibration transfer represents the transfer and conversion of the kinematic, strain, and damping energies, while steady-state vibration transfer characteristics are related to the vibration mode. In addition, multiple-order mode exchanges are triggered when branch locations vary in frequency-shift regions, and the mode-exchange regions are also the transformation ones for vibration transfer patterns.