METHOD OF DETERMINING TYPE OF DEFECT IN METAL ARTICLES Russian patent published in 2014 - IPC G01N29/00 

FIELD: physics.

SUBSTANCE: method includes pulsed irradiation of the investigated area with ultrasonic radiation; detecting the initial reflected signal; computer processing thereof to determine information-bearing parameters from which the presence and type of defect is determined, wherein Hilbert transform is applied to the initial reflected signal from each detected defect to obtain an analytical signal; then calculating the modulus of the analytical signal to obtain an envelope of the initial signal; finding, on the envelope, moments in time t₀, t₁, and t₂, corresponding to the maximum of the envelope amplitude and half the maximum value thereof to the left and to the right of the maximum, by applying continuous wavelet transform to the analytical signal; using a defined formula to find the relationship between instantaneous frequency and time, on which frequencies ƒ₀, ƒ₁ and ƒ₂, which correspond to time t₀, t₁ and t₂, are selected for further analysis; then using the frequencies ƒ₀, ƒ₁ and ƒ₂ to generate new dimensionless parameters - standard deviation of frequencies ƒ_r1 and ƒ_r2; displaying values of ƒ_r1 and ƒ_r2 in form of points on a two-dimensional diagram, from the arrangement in a defined region of the diagram of which the type of defect is determined.

EFFECT: broader capabilities of determining the type of hidden defects during non-destructive ultrasonic inspection.

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