Vibration suppressing and energy harvesting research of an elastic beam by utilizing an adjustable imperfect nonlinear energy sink

Beams in ocean engineering are routinely exposed to vibrational forces during operation. These vibrations typically compromise the safety and stability of the beams, consuming much of the energy produced. Consequently, the suppression and harvesting of vibrational energy from elastic beams are critical. However, traditional nonlinear energy sinks (NESs) often lack the capability for real-time adjustment of core parameters, potentially diminishing their effectiveness in vibration suppression and energy harvesting as the operational conditions of the main structures change. In practice, most NESs, although considered optimal, may incorporate linear stiffness components. This study introduces a novel adjustable imperfect NES and evaluates its non-linear stiffness properties. The research explores both theoretical and experimental aspects of the vibration suppression and energy harvesting capabilities of an elastic beam using this new NES. The design of the adjustable imperfect NES involves magnets, a lead screw, and a slider mechanism, allowing for real-time adjustments of the non-linear stiffness coefficients by altering the operational state. The adjustable imperfect NES exhibits broadband vibration control properties, enabling the suppression and harvesting of vibrational energy across a wide range of frequencies. Notably, there exists an optimal operational state for the adjustable imperfect NES. At this stage, the adjustable imperfect NES can efficiently harvest vibrational energy transmitted from the elastic beam while effectively reducing its vibration. Overall, this investigation of the new adjustable nonlinear vibration energy harvesting and suppression device provides a theoretical and experimental foundation for the future application of adjustable nonlinearities in engineering projects.