A u-Vibration isolator using viscoelastic materials

Abstract

Over the years, performance degradation of the optical payloads due to onboard vibrations of very small amplitude, of a satellite has always been a major point of concern. Though there are many sources of this vibration, it predominantly comes from the reaction wheel assembly (RWA). These small vibrations cause considerable degradation in the quality of the images that are being obtained and hence are a serious concern to be addressed. The current study addresses the problem of attenuating very small amplitude vibrations, originating from reaction wheel assembly and reaching the sensitive optical payloads. An elastomer/viscoelastic material (VEM) based passive vibration isolator has been developed and tested for the significant reduction of the effect of small vibrations on the payload. The device comprises of four isolating modules of which two are rigid pieces, one is a central viscoelastic material and the other is a set of four viscoelastic materials located at the periphery of the central viscoelastic material. The two rigid pieces are connected with a set of elastomers which attenuate the transmission of low-amplitude vibrations in the frequency bandwidth of 20-200 Hz. In the current design, constrained layer damping is achieved by partly sandwiching the central viscoelastic material between the two rigid pieces. Frictional damping is achieved by the relative motion between the central viscoelastic material and the set of four viscoelastic materials. The viscoelastic materials for the current isolator have been chosen by trade-off between the stiffness and loss factor for the various viscoelastic materials that have been tested by standard test procedures. Of the various parameters studied, the area of contact of the central viscoelastic material and the set of four viscoelastic materials turns out to be the most influencing parameter on the performance of the current isolator. In this study, the performance results of the isolator obtained from both th...