Dynamic characteristics of quasi-zero stiffness vibration isolation system for coupled dynamic vibration absorber

Based on the principle of dynamic vibration absorption, a quasi-zero stiffness (QZS) vibration isolation system for coupled a linear dynamic vibration absorber was designed. The dynamic model of the coupled system is established, and the frequency domain analytical solutions and the expression of force transmissibility are deduced by the averaging method. The effects of mass, stiffness and damping of the vibration absorber on the dynamic response and force transmissibility characteristics of the coupled system are analyzed numerically, and compared with an equivalent QZS vibration isolation system. The results reveal that the amplitude curve of the primary system shifts to the low-frequency range with the increase ofmass ratio, the valley value appears and lower to 2 x 10(-4) when the excitation frequency equals to the natural frequency of the absorber. Increase stiffness ratio can reduce the valley amplitude and the second peak amplitude of the primary system. The large the damping of the absorber, the lower the valley amplitude of the primary system can be acquired. As the mass ratio increases from 0.2 to 1, the initial isolation frequency of the coupled system decreases by 23.2%, which enlarges the bandwidth of the effective isolation frequency range. Large stiffness ratio or larger damping ratio of the absorber can improve the isolation performance in the frequency range near the second peak amplitude. Compared with the equivalent QZS isolation system, the coupled system possesses more excellent performance in the frequency domain near the valley amplitude and wider vibration isolation frequency bandwidth.