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.

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The absorbing effect of traditional dynamic vibration absorber (TDVA) is satisfactory only when the natural frequency is close to the excitation frequency. For this defect, a semi-active vibration absorber is designed with magnetorheological elastomer (MRE) as a stiffness element, that its stiffness can be controlled by magnetic field, to widen the frequency band of the absorber. Theory and experiments show that reducing the damp of the absorber can improve the performance of the absorber at the anti-resonance point, but it will cause the vibration of the controlled system at the new resonance point, which caused by the addition of a DVA, to be more intense. For this problem, the compatibilizer: silane coupling agent KH570, is added to the preparation of MRE to reduce material damping, at the same time, the stiffness control strategy is used to eliminate the resonance of the controlled system caused by the addition of DVA. The final experimental results show that the frequency band of vibration reduction has been broadened effectively and the vibration reduction performance has been improved considerably. Moreover, the resonance has been eliminated very well.