Summary
Vibro-impact absorbers are small devices that consist of a small mass which is freely placed inside a cavity of a vibrating host-structure. During operation it undergoes recurrent impacts with the cavity walls that lead to a strong and nearly irreversible scattering of the mechanical energy within the primary structure’s modal space. As higher modes accumulate more vibration cycles within a given time during their free response than the substantially excited lower modes, they are able to dissipate the mechanical energy on a faster timescale. This results in an overall reduction of the amplitude and does theoretically not rely on local dissipation due to e. g. dissipative materials in the contact area. Experimental investigations of this working principle so far lacked a way of quantifying the instantaneous energy transfer to higher modes, which is crucial to develop better predictable models of the absorber. To this end, we measure the response of a harmonically excited beam structure with vibro-impact absorber at multiple points across its span and project it onto its prior experimentally determined linear modes to reconstruct the instantaneous modal energy distribution.
