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A new viscoelastic micro-vibration isolation and mitigation platform is proposed to reduce disturbances generated by flywheels on board spacecraft. Firstly, property tests on the high-damping viscoelastic material used in the micro-vibration isolation and mitigation element are conducted. Experimental results show that the developed viscoelastic material has better energy dissipation capability under micro-vibration conditions. A mathematic model is employed to describe the dynamic properties of the high-damping viscoelastic material and is used to model the isolation and mitigation element. Secondly, a viscoelastic micro-vibration isolation and mitigation platform, which consists of four elements, is proposed and the analytical model of the coupled system that consists of the platform with flywheel is established. Finally, the isolation and mitigation performances of this micro-vibration isolation and mitigation platform are analyzed and discussed. The results show that the isolation and mitigation platform can effectively reduce the micro-vibration disturbances induced by the flywheel.

Earthquake excitation is a kind of complicated multi-dimensional ground motion. Therefore, anti-earthquake measuresfor complex and important engineering structures, such as long-span structures and high rise buildings under multi-dimensional earthquake excitations, have become an extremely important research topic. In this paper, a new multi-dimensional earthquake isolation and mitigation device (MEIMD) is proposed for protecting long-span reticulated structures due to strong earthquake motions. It consists of a viscoelastic bearing and several viscoelastic dampers. Property tests on the MEIMD under different excitation frequencies, excitation amplitudes and vertical pressure forces are carried out. Then, a mathematical simulation is carried out for the equivalent stiffness and the equivalent damping of the device, and the numerical results agree reasonably well with the experimental data. Experimental and numerical results show that the MEIMD has a fine energy dissipation capacity, and can be used for anti-earthquake purposes for long-span reticulated structures.