Finite element analysis of misaligned rotors on oil-film bearings

The present work deals with a two-step nonlinear finite element analysis for misaligned multi-disk rotors on short oil-film bearings of various types (cylindrical, pocket, symmetrical three-lobed, unsymmetrical three-lobed). As a first step, the conventional parallel, angular and combined parallel and angular misalignments are modelled using Lagrange multipliers. The static equilibrium position of the journal within the bearing is determined using an iterative nonlinear static finite element analysis. The present work proposes a method for computing the displacement-dependent stiffness terms from the experimental static load-displacement data. Finally, the orbit of the rotor around the static equilibrium is determined using a time-integration scheme.