Choi-Wiliams time frequency analysis of a three degree freedom non-linear system

Abstract

The response of a non-linear mechanical oscillator, depending on the type of non-linearity, to an excitation of particular harmonic might contain sub- and super-harmonics, transients and chaotic components. The conventional frequency response function, used to completely characterise the input-output behaviour of a linear mechanical oscillator, not only does not capture the above characteristics but also, in case of broadband excitation, fails to attribute them to individual frequencies. In this paper we apply the Choi-Williams time frequency distribution to simulated data of a single and three degree of freedom Duffing oscillator in order to assess its input-output relationship. © (2006) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved.