Parametric excitation suppression in a floating cylinder via dynamic vibration absorbers: a comparative analysis

Abstract

Parametric excitation in the pitch/roll degrees of freedom (DoFs) can induce dynamic instability in floating cylinder-type structures such as spar buoys, floating offshore wind or wave energy converters. At certain frequency and amplitude ranges of the input waves, parametric coupling between the heave and pitch/roll DoFs results in undesirable large amplitude rotational motion. One possible remedy to mitigate the existence of parametric resonance is the use of dynamic vibration absorbers. Two prominent types of dynamic vibration absorbers are tuned mass dampers (TMDs) and nonlinear energy sinks (NESs), which have contrasting properties with regard to their amplitude and frequency dependencies when absorbing kinetic energy from oscillating bodies. This paper investigates the suppression of parametric resonance in floating bodies utilizing dynamic vibration absorbers, comparing the performance of TMDs against NESs for a test case considering a floating vertical cylinder. In addition to the type of dynamic vibration absorber utilized, the paper also examines the DoF which it acts on, comparing the benefits between attaching the vibration absorber to the primary (heave) DoF or the secondary (pitch) DoF. The results show that the TMD outperforms the NES and that it is more effective to attach the vibration absorber to the heave DoF when eliminating parametric resonance in the pitch DoF.

A Computationally Efficient Analytical Modelling Approach for Parametric Oscillations in Floating Bodies

“…In contrast, analytical models are typically more computationally efficient, but may not achieve the same accuracy for as broad range of conditions as the numerical models. In other fields and applications, parametric resonance is well understood, and a wealth of analysis tools and techniques have been developed by the nonlinear dynamics community [22][23][24][25][26][27][28][29][30][31]. These tools enable the conditions for the existence of parametric resonance to be efficiently examined across large parameter spaces; however, they require an analytical model of the system under study.…”

Application of nonlinear energy sink in suppressing wheel shimmy for advanced vehicle chassis design under independent wheel subsystems

“…The NES was implemented to mitigate impulsive [11,6], forced [12], self-excited [20,15], or parametric vibrations [5] in various applications, including aeroelastic instabilities [20], machine tool vibrations vibrations [15], seismic vibrations [27], to name a few. These studies exhibited promising results but also some limitations.…”

Energy transfer mechanisms in binary tree-structured oscillator with nonlinear energy sinks

“…Hence, there is a growing interest toward the study of energy cascades and targeted energy transfer (TET). Many studies demonstrate the superior dissipative property of nonlinear energy sinks (NES), that are essentially nonlinear dissipative attachments, over linear tuned mass dampers [1][2][3][4] (although there are exceptions, see, for example, [5]). Vakakis et al [6] discuss energy transfer through the example of simple mechanical oscillators.…”