Nonlinear dynamic analysis of an electrical machine rotor–bearing system by the optimal homotopy perturbation method

In this paper an analytical technique, called the optimal homotopy perturbation method (OHPM), is employed to study the nonlinear behaviour of an electrical machine modelled as a rotor supported by two journal bearings with nonlinear suspension. The dynamics of the rotor centre and bearing centre are studied and the spatial displacements in the horizontal and vertical directions are obtained. It is shown that the main strength of the OHPM is its fast convergence, since after only one iteration we obtain very accurate results for a complicated nonlinear problem, which proves that this method is very efficient in practice.