Development and robustness investigation of track-based asymmetric nonlinear energy sink for impulsive response mitigation

Abstract

Nonlinear energy sinks (NESs) are known for their capacity of resonating with a wide range of frequencies. However, the occurrence of resonance in NESs strongly depends on the input energy level. To further enhance energy as well as frequency-related robustness and tailor the robust performance to the need of engineering structures, track asymmetric nonlinear energy sinks (TANESs) are proposed in this study. Integrating the merits of two existing mass dampers, TANESs are able to broaden the energy range for effective response mitigation toward both the upper and lower limits. First, the theoretical model of TANESs is developed and validated through experiments on a two-story frame structure. The validated model is then applied to analytically derive the fundamental dynamics of the standalone TANES under impulsive and harmonic excitation. Subsequently, the robust performance of the TANES predicted by the analytical results is numerically investigated when the structure, considering natural frequency variations, is subjected to impulsive excitation of different amplitudes. Finally, the control characteristics and applicable situations of the TANES and other comparable mass dampers are discussed. The results show that the TANES can act as a well-tuned linear mass damper when the input energy is below a certain level and perform more effectively on frequency-decreased structure as the energy level further increases. As decrease in structural frequency is often caused by damages under stronger excitation, TANESs are considered to be a suitable control strategy for engineering structures in practice.