On the thermoelastic instability of foil bearings

Published experimental evidence reveals that foil bearings are prone to damage due to thermal runaway under certain operating conditions where thermoelastic instability sets in. This paper describes a methodology and a closed-form solution for prediction of the critical speed at which a foil bearing can become thermoelastically unstable. The theoretical predictions have been verified with several published experimental results. While the model pertains to a journal bearing-type configuration, it can be readily extended to other bearing configurations.