Normal Form Solution of Reduced Order Oscillating Systems

This paper describes a preliminary investigation into the use of normal formtheory for modelling large non-linear dynamic systems. limit cycle oscillationsare determined for simple two-degree-of-freedom double pendulum systems.such a system is reduced into its centre manifold before computation of normalforms, which are obtained using a period averaging method applicable to 71071autonomoussystems and more advantageous than the classical methods. agood agreement was observed between the predicted results from the normalform theory and the numerical simulations of the original system.