Vibration mitigation and dynamics of pipeline system with nonlinear soft clamp by a nonlinear energy sink

This article delves into the vibration suppression and dynamics of a pipeline-soft clamp system, incorporating nonlinearity, through the utilization of a non-smooth nonlinear energy sink (NSNES) featuring piecewise linear stiffness, specifically targeting bending vibrations. Building upon the fact that the clamp, as a vital supporting component, introduces constrained nonlinearity and complex dynamics into the pipeline system, this paper primarily focuses on elucidating and investigating the impact of the nonlinearity inherent in soft clamps on the vibration mitigation performance of the NSNES. In this study, the finite element method is utilized to develop a dynamic model of a pipeline-soft clamp system, showcasing nonlinear stiffness and damping forces in the clamps. Following the introduction of the NSNES model, the dynamic model of the pipeline-soft clamp-NSNES system is elucidated. The vibration attenuation potential of the NSNES within the pipeline-soft clamp system is assessed through base steady-state excitation, with the optimization achieved via a genetic algorithm (GA). Subsequently, the key impact of the nonlinear properties of the soft clamp on the vibration suppression effect of NSNES is emphasized. The findings show that the soft clamp, when employed standalone, exhibits a certain degree of vibration reduction capacity to mitigate the vibration response of the pipeline. Remarkably, the inherent soft nonlinearity within the pipeline-soft clamp system does not detract from the exceptional vibration suppression performance of the NSNES. In fact, the NSNES maintains its superior vibration attenuation capabilities even within this nonlinear environment, demonstrating its robustness and adaptability in enhancing the overall stability and performance of the pipeline-soft clamp system. Under steady-state vibrations, the NSNES demonstrates a peak vibration elimination of 82.7% in simulations without clamp nonlinearity, whereas this figure drops to 72.2% when nonlinearity is introduced, owing to the decreased response of the pipeline-soft clamp system. In experimental tests, the NSNES effectively suppressed vibrations by 71.7% for the pipeline-soft clamp system.