Instantaneous structural intensity by the harmonic wavelet transform

The wavelet transform is an analysis method to measure the transient signals instead of the conventional Fourier analysis, which is difficult to obtain high-definition time–frequency maps for rapidly changing signals. In this paper, we present a new method for the calculation of instantaneous structural intensity on the beam by using the wavelet transform and the details of the computational algorithm to obtain structural intensity by the harmonic wavelet transform is described. By applying this method for the data measured by hammering the beam structure, we confirmed that instantaneous intensity obtained by using the harmonic wavelet transform is a useful tool for analyzing the propagation of flexural waves on the beam structure.