Effects of modal energy scattering and friction on the resonance mitigation with an impact absorber

TL;DR

This paper investigates how modal energy scattering and friction influence the effectiveness of impact absorbers in mitigating resonance, comparing their performance to linear and friction dampers across multiple resonances.

Contribution

It provides a detailed analysis of impact absorbers' nonlinear dynamics and their ability to suppress multiple resonances, considering energy scattering and friction effects.

Findings

Impact absorbers effectively suppress multiple resonances.

Friction and impact dissipation enhance vibration mitigation.

Impact absorbers outperform linear tuned absorbers in certain conditions.

Abstract

A linear vibration absorber can be tuned to effectively suppress the resonance of a particular vibration mode. It relies on the targeted energy transfer into the absorber within a narrow and fixed frequency band. Nonlinear energy sinks (NES) have a similar working principle. They are effective in a much wider frequency band but generally only in a limited range of excitation levels. To design NES, their working principle must be thoroughly understood. We consider a particular type of NES, a small mass undergoing impacts and dry friction within a cavity of a base structure (vibro-impact NES or impact absorber). The nonlinear dynamic regimes under near-resonant forcing and resulting operating ranges are first revisited. We then investigate how off-resonant vibration modes and dissipation via impacts and dry friction contribute to the vibration suppression. Moreover, we assess the effectiveness of the impact absorber for suppressing multiple resonances in comparison to a linear tuned vibration absorber (LTVA) and a pure friction damper with the same mass.