Regulation strategies and vibration reduction effects of a novel pipeline vibration absorber under complex excitations

Marine pipelines under complex excitations generate broadband vibrations superimposed with line-spectrum components. A novel dynamic vibration absorber (NDVA) for pipelines, leveraging the vibration localization energy dissipation mechanism, can achieve low-frequency broadband vibration reduction capability. However, its regulation strategy and vibration reduction effect under complex excitations have not been systematically investigated. In this paper, band-limited white noise superimposed with harmonic excitation is adopted to simulate the complex excitation condition of pipelines. The response power spectral density and mean square response of the pipeline are derived to characterize the magnitudes of line-spectrum and broadband vibrations, respectively. On this basis, following the regulation strategy of “line-spectrum reduction first, broadband reduction second,” the additional masses of the resonant units of the NDVA are regulated to simultaneously achieve both broadband and line-spectrum vibration reduction effects. Finally, vibration control experiments on pipelines under broadband superimposed line-spectrum excitation are conducted. The results demonstrate that under 70–120 Hz band-limited white noise superimposed with 90 Hz line-spectrum excitation, the regulated NDVA reduces the pipeline broadband vibration level by 21.6 dB and the vibration amplitude at the line-spectrum excitation frequency by 22.0 dB, thereby validating the effectiveness of the proposed regulation strategy under complex excitations.