Application of parametric discrete Fourier transform in nondestructive testing of composite materials with a free oscillation method

Abstract

The paper discusses the use of discrete parametric Fourier transform (DFT-P) in nondestructive testing (NDT) of composite materials using the free oscillation method. It is shown that the methods and algorithms of spectral and vector processing of information signals based on the DFT retain their leading role in NDT despite a number of negative effects inherent to them (aliasing, stockade, leakage and scalloping effects). Based on the systems analysis of the advantages and disadvantages of digital processing on the basis of the DFT of information signals in nondestructive testing, its generalization in the form of a parametric DFT (DFT-P) is proposed. The analytical properties of the basic system of the proposed discrete transform are investigated.