A NEW PROCEDURE FOR DETECTING NONLINEARITY FROM TRANSIENT DATA USING THE GABOR TRANSFORM

A new technique for the identification of nonlinearity in multi-degree of freedom systems is presented. The technique is based on the joint application of the Gabor and the Hilbert transforms to the transient r esponse of a system, The Gabor transform is used first to identify a t ime-variant matrix representing the spatial behaviour of the system. T his matrix is then used to decouple the transient response into a set of uncoupled quasi-harmonic components. Finally the Hilbert transform is applied to identify the dissipative and restoring forces associated with each component which is equivalent to a single degree of freedom system. Numerical examples are supplied to help clarify the main adva ntages and the possible limitations of the method in the presence of s trong nonlinearities and closely spaced frequencies.