Analysis of vibration suppression performance of parallel nonlinear energy sink

With the increase of excitation, the nonlinear energy sink (NES) will cause the controlled system to produce high branch response and lead to sudden failure. Increasing the mass of the NES can prevent the generation of high branch within a certain range, but high-precision instruments such as aerospace have strict requirements for additional mass. A parallel NES (PNES) is proposed to improve the robustness without increasing the mass. The slow flow equations of the system are derived by using complexification-averaging (CX-A) method, and the vibration suppression performance of the PNES is analyzed from the frequency domain. Compared with purely cubic stiffness NES (CNES), it is found that PNES has better performance near the main resonance. And it is not easy to produce high branch response under the same excitation intensity. Finally, the performance of PNES and CNES is compared by numerical method from time domain and energy spectrum. The results show that when PNES is attached, the attenuation time of the controlled system is shorter under impact excitation, much more, the controlled system has a smaller energy amplitude near the main resonance under harmonic excitation.