A modal model for the experimental prediction of the stability threshold speed

The stability threshold speed caused by rotating damping in rotating machinery is a limitation on the operating speed. The presence of the gyroscopic effect and rotating damping not only cause this unstable effect, both also result in difficulties to and to analyze the system. Although studied extensively in the past, the phenomenon is still difficult to model and validate experimentally. In this paper, a theoretical framework for the experimental validation is created by using the concept of a modal model combined with perturbation analysis. The concepts are validated by simulation and experiments which predict the stability threshold speed in three different situations of rotating damping. The simulation shows that the decay rate can be approximated by the modal model after simplification. Experiments show that the stability threshold speed can be predicted and that instability occurs close to this predicted speed.