流体微振动隔振器的热振耦合特性研究

Vibration isolation is an important method of spacecraft vibration control, and the theoretical study of the dynamic characteristics of vibration isolator is an important foundation of its design. In this paper, a new type of micro-vibration isolator which contains viscous fluid was studied. Based on the Non-Newtonian fluid property, macroscopic heat transfer characteristics of the isolator and the axial vibration behavior of a typical launch vehicle-satellite system, the nonlinear thermo-vibration coupling models of the isolator and the launch vehicle-satellite-isolator system during the launch stage were firstly proposed. Then the damping coefficients and volumetric stiffness coefficients under different temperature environments were measured with the self-designed base excitation test-setup, and these parameters were input into the above models to conduct a simulation. The results show that the behavior of the vibration isolation system is nonlinear and time-variant, and the fluid viscous heating can lead to the shift of resonant frequency and the fluctuation of resonant amplitude. Moreover, the performance of the isolator is also closely related to the excitation amplitude and excitation frequency.Two new conceptions, i.e., resonant band and isolated band, should be adopted to design the isolator. Thus the presented theory and method can provide reference and theoretical basis for the thermo-vibration coupling characteristics evaluation, optimal design and engineering application of this type of fluid micro-vibration isolators.