Stability and transient analyses of asymmetric rotors on anisotropic supports

This paper makes use of high-order finite beam elements to perform stability evaluations and transient analyses of asymmetric rotors on anisotropic supports. Periodically time-varying motion equations are derived in the co-rotating reference frame, and they include all effects due to the rotational speed and angular acceleration. The periodic system stability is evaluated through the analysis of the monodromy matrix obtained by integrating the motion equations with Newmark's scheme. Computational efficiency is improved by exploiting the modal coordinate transformation method for reducing the number of equations to be integrated. The methodology is validated by using three-dimensional finite element solutions related to simple bearing-rotor configurations. Moreover, the angular acceleration effect on the response of a realistic gas turbine supported by anisotropic bearings with speed-dependent properties is investigated. (C) 2021 Elsevier Ltd. All rights reserved.