Determination of limit cycles for a modified van der Pol oscillator

The determination of amplitude and period of limit cycles is a crucial question in non-linear mechanics. In this paper, a van der Pol oscillator containing a periodic potential is considered. Amplitude and period of limit cycles are calculated by He's variational method and Krylov-Bogoliubov-Mitropol sky (KBM) method. (c) 2005 Elsevier Ltd. All rights reserved.