Experiments on vibration absorption using energy sinks

Abstract

This presentation describes experiments that demonstrate the concept of energy sinks where a set of multiple undamped linear oscillators attached to a vibrating structure can absorb most of its energy. In principle, energy sinks do not require presence of damping in the classical sense. A set of undamped oscillators that make up an energy sink collectively absorb the vibratory energy and retain it in their phase space. Earlier optimization studies by the authors have shown the feasibility of vibration absorption and retention by energy sinks if the set of oscillators have a particular frequency distribution. Experimental results support the concept of energy sinks. Different physical realizations of energy sinks demonstrate the significance of frequency distributions and the ability of energy sinks to reduce vibration amplitude of a primary structure to which they are attached.

Trapping of vibration energy into a set of resonators: Theory and application to aerospace structures

“…In this sense, the cluster performs as a vibration or shock absorber, as demonstrated with simpler systems in [20].…”

“…The resulting solutions belong to families of exponentials. Among them, a rather simple and effective distribution proposed in [20] is…”

“…The concept of linear energy sink was demonstrated through simple experiments that demonstrated how attached oscillators with the optimum frequency distributions can collectively absorb and retain the vibratory energy from an impulsively excited structure [20]. Analyses inspired by probably density distributions showed the existence of a family of frequency distributions for attached oscillators that lead to near-irreversibility of vibratory energy transfer [18][19][20][21]. These studies demonstrated the key characteristic of the frequency distributions as having condensation points, which lead to decaying impulse response function even in lossless systems, a phenomenon that can be observed in preloaded plates on elastic foundations and shells [22].…”

“…Based on these findings, the concept of linear energy sink was developed by optimizing the natural frequency distribution of the attached oscillators to minimize the energy retained by the structure to which they are attached [19]. The concept of linear energy sink was demonstrated through simple experiments that demonstrated how attached oscillators with the optimum frequency distributions can collectively absorb and retain the vibratory energy from an impulsively excited structure [20]. Analyses inspired by probably density distributions showed the existence of a family of frequency distributions for attached oscillators that lead to near-irreversibility of vibratory energy transfer [18][19][20][21].…”

Vibration absorption using non-dissipative complex attachments with impacts and parametric stiffness

“…Several studies examined the conditions that, even in the absence of energy dissipation, prevent energy transport back to the master, which lead to the so called near-irreversibility condition [8][9][10] also confirmed by experimental tests. 11 Finally, the problem of an efficient design of a multi-degrees of freedom tuned-mass-damper has been also considered in the context of control theory. 12 In all these studies, energy redistribution process is considered in the framework of ͑i͒ linear interaction between the master and the attached resonators and ͑ii͒ in the absence of any direct interaction among the resonators, except through their reactions on the primary.…”