Parametric Excitation of a Nonlinear System

A study has been made on the parametric excitation of a nonlinear system with hardening springs. In the parametric excitation of linear systems, the only subharmonic predicted is a subharmonic of order 1/2. However, in the parametric excitation of non-linear systems, it is shown that higher order subharmonics can exist, depending both on the amplitude and frequency of the parametric excitation.