# The Tuned Bistable Nonlinear Energy Sink

## TL;DR

This paper introduces a tuned bistable nonlinear energy sink (TBNES) designed to effectively mitigate vibrations in coupled oscillator systems across a broad range of impulsive loads, outperforming traditional dampers.

## Contribution

The paper develops an analytical model for a bistable nonlinear energy sink, tuning it for broad-range vibration mitigation and validating its superior performance through numerical simulations.

## Key findings

- TBNES outperforms traditional TMD and cubic NES in vibration absorption.
- Analytical models accurately predict TBNES performance.
- TBNES effectively mitigates both low- and high-amplitude oscillations.

## Abstract

A bistable nonlinear energy sink conceived to mitigate the vibrations of host structural systems is considered in this paper. The hosting structure consists of two coupled symmetric linear oscillators (LOs) and the nonlinear energy sink (NES) is connected to one of them. The peculiar nonlinear dynamics of the resulting three-degree-of-freedom system is analytically described by means of its slow invariant manifold derived from a suitable rescaling, coupled with a harmonic balance procedure, applied to the governing equations transformed in modal coordinates. On the basis of the first-order reduced model, the absorber is tuned and optimized to mitigate both modes for a broad range of impulsive load magnitudes applied to the LOs. On the one hand, for low-amplitude, in-well, oscillations, the parameters governing the bistable NES are tuned in order to make it functioning as a linear tuned mass damper (TMD); on the other, for high-amplitude, cross-well, oscillations, the absorber is optimized on the basis of the invariant manifolds features. The analytically predicted performance of the resulting tuned bistable nonlinear energy sink (TBNES) are numerically validated in terms of dissipation time; the absorption capabilities are eventually compared with either a TMD and a purely cubic NES. It is shown that, for a wide range of impulse amplitudes, the TBNES allows the most efficient absorption even for the detuned mode, where a single TMD cannot be effective.