METHOD AND SYSTEM OF THERMOGRAPHIC NON-DESTRUCTIVE INSPECTION FOR DETECTING AND MEASURING VOLUMETRIC DEFECTS IN COMPOSITE MATERIAL STRUCTURES

摘要

A thermographic non-destructive inspection method of a structure, comprising the steps of: generating a modulated thermal wave in the direction of the structure; generating a temperature signal identifying a phase shift between the modulated thermal wave and a return thermal wave emitted from the structure; processing the temperature signal to obtain a first sub-signal related to the phase of the first harmonic of the temperature signal; identifying a first dimension of said defect as a function of the phase of the first harmonic of the temperature signal; calculating a first and a second intermediate parameter, ΔΦ₁ for the first harmonic and ΔΦ₂ for the third harmonic of the temperature signal, by calculating the difference, in degrees, between the phase value inside the zone with a defect and the phase value, absolute or mean of a plurality of points, of the undamaged zone close to the defect; and identifying a second dimension of the defect as a function of the first dimension and of the intermediate parameters ΔΦ₁ and ΔΦ₂.