Chaotic characteristic analysis of the vibration responses of pumping station pipelines under overflow conditions

In order to verify the chaotic characteristics of pumping station pipeline structures and to clarify the chaotic excitation source, the chaotic characteristics of pipeline vibration responses were analyzed and validated by using the saturation correlation dimension and the largest Lyapunov exponent. The multi-time-scale chaotic analysis of pipeline vibration responses was carried out by using the improved variational mode decomposition (IVMD). It is shown the chaotic characteristics of the vibration at the fork part of pipeline are enhanced due to the sudden expansion of pipe diameter at the fork part and the impact of water heads at different flow velocities. The analysis results show that the vibration responses at each measuring point of the pumping station pipeline under different working conditions have chaotic characteristics, and the chaotic characteristics at axial points and fork pipe points are relatively strong. After the IVMD of pipeline vibration responses, the intrinsic mode function component representing the water pulsation excitation presents a lower-dimensional chaotic attractor, while the others representing the vibration excitation of the unit operation have no chaotic characteristics, which indicates that the water pulsation excitation makes the vibration of the pump station pipeline chaotic, and the unit operation covers up the chaotic characteristics of the pipeline vibration and increases its uncertainty. The results provide a theoretical basis for exploring the chaotic characteristics and excitation source characteristics of pumping station pipelines. © 2022, Editorial Office of Journal of Vibration and Shock. All right reserved.