A negative stiffness inertial nonlinear energy sink

Abstract In this paper, a novel negative stiffness inertial nonlinear energy sink (NSI-NES) is proposed. The main structure is simulated as a single-degree-of-freedom linear oscillator. Newton's second law is applied to derive the kinematic equations of the coupled system. Based on the Runge–Kutta numerical solution, the complex dynamical behaviors of the system coupled with the NSI-NES are explored. Moreover, the quasiperiodic solution exhibited a strongly modulated response (SMR). The steady-state response of the system is obtained using the Runge–Kutta and harmonic balance methods and is cross-corroborated. Compared with the inertial nonlinear energy sink (I-NES) and the positive stiffness inertial nonlinear energy sink (PSI-NES), the damping effects of the NSI-NES are highlighted based on various excitations. The results show that the NSI-NES has a damping effect of up to 90%. In addition, the effect of the NSI-NES parameters on the damping effect is discussed. In general, the negative stiffness element can significantly improve NES performance. Therefore, this study promotes the application of negative stiffness and inerter in engineering.