%0 Journal Article %T NORMAL FORM SOLUTION OF REDUCED ORDER OSCILLATING SYSTEMS %J Journal of Aerospace Science and Technology %I Iranian Aerospace Society %Z 1735-2134 %A Dr. Sedaghat, Ahmad %D 2006 %\ 09/01/2006 %V 3 %N 3 %P 153-158 %! NORMAL FORM SOLUTION OF REDUCED ORDER OSCILLATING SYSTEMS %R %X This paper describes a preliminary investigation into the use of normal form theory for modelling large non-linear dynamical systems. Limit cycle oscillations are determined for simple two-degree-of-freedom double pendulum systems. The double pendulum system is reduced into its centre manifold before computing normal forms. Normal forms are obtained using a period averaging method which is applicable to non-autonomous systems, more advantageous than the classical methods. Good agreement is observed between the predicted results from the normal form theory and numerical simulations of the original system. %U https://jast.ias.ir/article_51521_58aab625c875846934d932b76b58fd3d.pdf