Parametrically excited non-linear systems: a comparison of two methods

Subharmonic resonance of two-degree-of-freedom systems with cubic non-linearities to multifrequency parametric excitations in the presence of three-to-one internal resonance is investigated. Two approximate methods (the multiple scales and the generalized synchronization) are used to construct first-order non-linear ordinary differential equations governing the modulation of the amplitudes and phases. Steady-state solutions and their stability are computed for selected values of the system parameters. The results obtained by the two methods are in excellent agreement. Numerical solutions are carried out and graphical representations of the results are presented and discussed. (C) 2002 Elsevier Science Inc. All rights reserved.