On the dynamic response regimes of a viscoelastic isolation system integrated with a nonlinear energy sink

The present study aims to investigate the dynamic response regimes of a base-excited viscoelastic isolation system with attached a nonlinear energy sink. The nonlinear energy sink is composed of a mass, a damper and a spring with cubic stiffness. By means of the complexification-averaging method, differential algebraic equations which control the amplitude-frequency response of the base-excited viscoelastic isolation system are derived. Then, based on the criteria of vibration mitigation and broader stability range, the optimal parameters of primary system and nonlinear energy sink are tuned. In this regard, the existence of five-valued responses is found and numerical simulation is also performed to examine the effectiveness of analytical results. The bifurcation phenomena under derived optimal parameters are compared with the case under common system parameters, which verify the selected optimal case more robustness against the uncertainties. Finally, the transmissibility of coupled base-excited viscoelastic isolation system is also considered. (C) 2019 Elsevier B.V. All rights reserved.