A modal identification method based on fast ICA

It's important to identify structural modal parameters,especially,accurate modal shapes in time domain for accurate damage identification and health monitoring of structures.Normally,lots of time domain modal identification methods are generally realized through curve-fitting or calculating eigenvalues.Modal shape matrix is obtained by calculat-ing various modal residues.These methods depend on identifying modal frequencies and modal damping ratios.Here,a novel method based on Fast ICA for modal shapes identification was proposed.This method used the independence be-tween modal responses to create an objective function,and obtained the optimal solutions of the modal shape matrix by op-timizing the objective function.It extracted the modal shapes directly from free responses or impulse responses of struc-tures.A numerical example of a three DOF system was performed and showed the efficiency of this method,which gave a high identification accuracy and a good rebustness to measuring noises.