On the Use of Structural Noise Parameters in Testing 20GL Steel with Rayleigh Surface Waves under Elastoplastic Deformation

The possibility of approaching the problems of testing the regularities of elastoplastic deformation of 20GL steel by the method of analyzing the structural noise using Rayleigh surface acoustic waves is considered. Algorithms for mathematical processing of pattern noise used by various authors are analyzed. Refined computational algorithms for determining the spectral–energy parameters of pattern noise based on state-of-the-art radio engineering signal processing methods are proposed. The results of experimental verification of the proposed algorithms on samples of 20GL steel, which is widely used in railway transport, are presented. A sufficiently high sensitivity of the proposed informative parameters of structure-borne noise to the degree of plastic deformation is demonstrated as well as the simplicity of implementation of the measurement technique. The results obtained can serve as a basis for the development of an engineering technique for assessing stresses or the degree of plastic deformation in a structural material regardless of whether it is in an elastic or elastoplastic state; this considerably expands the capabilities of the acoustic method for monitoring the stress-strain state of structural materials in comparison with its velocimetric option.