Design and Vibration Characteristics Analysis of Marine Hydraulic Pipelines Under Multi-Source Excitation

To address the difficulty in eliminating low-frequency vibrations in the hydraulic pipelines of large marine vessels, this study first investigates the vibration characteristics of hydraulic pipelines. The research is conducted based on the stress states of pipelines under external excitations—specifically axial (X-direction), radial (Y-direction), and combined radial–axial (X + Y) excitations and integrates theoretical derivation, simulation, and experimental validation. Firstly, a multidimensional directional vibration equation for the pipeline was derived based on its stress distribution, yielding a more accurate vibration model for marine pipelines. Subsequently, simulations were performed to analyze the effects of fluid velocity, pipeline layout, and support distribution on the pipeline’s vibration characteristics. Finally, experiments were designed to verify the simulation results and examine the impact of external interference on pipeline vibration. The experimental results indicate the following: the influence of flow velocity variations on pipeline modes is generally negligible; increasing the number of pipeline circuits effectively reduces its natural frequencies; increasing the number of supports not only lowers the overall vibration intensity of the pipeline but also achieves peak shaving, thereby effectively reducing the maximum vibration amplitude; and the impact of external environmental interference on the pipeline’s vibration characteristics is complex, as it not only enhances vibration intensity but also weakens vibrations in specific directions. This study lays a theoretical foundation for subsequent vibration reduction efforts for marine hydraulic pipelines.