Performance of a Type of Nonlinear Fluid Microvibration Isolators

Vibration isolation is an important method of spacecraft vibration control, and the study of vibration isolation performance is the theoretical basis to design isolators and analyze transmissibility characteristics. This paper mainly studies a type of fluid microvibration isolators and a new nonlinear three-parameter model is first constructed in which a pth power damping and a qth power stiffness are placed in series. With the application of the harmonic balance method (HBM), the force and absolute displacement transmissibility curves under different parameters are obtained. Then based on self-defined evaluation indexes of vibration isolation performance, the corresponding transmissibility characteristics are estimated and the effects of key factors, e.g., excitation amplitude and ratio of stiffness, are also analyzed. Moreover, the analytical results are numerically validated by the Runge-Kutta method, and a stability analysis is further carried out to show the practicability of these solutions. Finally, an optimization method called the generalized pattern search (GPS) algorithm is proposed and applied to identify the nonlinear model parameters. The presented theory and method can be used to analyze the multiparameter nonlinear models, and they can also provide a reference and a theoretical basis for the design and engineering application of this type of fluid microvibration isolators.