The new frequency response functions for structural health monitoring

New monitoring techniques, with the frequency response functions based on the higher order spectra, are proposed and developed for the monitoring of structure non-linearity and signal non-Gaussianity due to damage and estimating the harmonic phase coupling of signals from structures for cases of the phase coupled interferences of a structure excitation.The proposed techniques are generalisations of the classical frequency response functions for the higher order spectral analysis for real valued transforms. It is shown that the proposed techniques provide an essential effectiveness gain for the detection of non-linearity due to fatigue damage in comparison with the classical HOS for the case of the phase coupled interferences of a structure excitation.