METHOD TO MONITOR DYNAMICS OF VARIATION OF CONTROLLED OBJECT WALL THICKNESS Russian patent published in 2015 - IPC G01B17/02 

FIELD: measurement equipment.

SUBSTANCE: solution includes the method of monitoring of controlled object wall thickness variation dynamics, including placement of at least one acoustic converter on its surface at the available distance from each other for emission of Lamb waves, and at least one converter for their reception, emission of a pulse signal at the specified moment of time, calculation of dependence of spectral density of received signal capacity on time, selection of the Lamb wave and frequency, determination of difference between time of reception of the selected frequency component of the selected Lamb wave and time of signal emission, determination of the value of group speed of the selected frequency component of the selected Lamb wave by available value of the distance between converters and value of the difference between time of reception of the selected frequency component of the selected Lamb wave and the time of signal emission, determination of the value of wall thickness by the produced value of the group speed selected by the value of frequency and reference dependence of the group speed of the selected Lamb wave on the product of wall thickness and frequency. The minimum value of wall thickness is established by produced arithmetic mean value of wall thickness and dispersion of object wall thickness values, besides, the arithmetic mean value of the wall is determined with selection of the symmetrical Lamb wave of zero order and at least one frequency, at which the reference dependence of the inverse value of the group speed of the symmetrical Lamb wave of zero order on the product of wall thickness and frequency is close to linear, and dispersion of wall thickness values is determined with selection of the antisymmetric Lamb wave of zero order and frequency, at which the reference dependence of the inverse value of the group speed of the antisymmetric Lamb wave of zero order on the product of wall thickness and frequency is substantially non-linear.

EFFECT: reduced labour intensiveness, simplification and acceleration of wall thickness monitoring in objects of large area, elimination of necessity to obtain physical access to the entire surface of the object, subject to thickness monitoring, provision of the possibility to monitor thickness with available variations of thickness values, provision of the possibility to determine arithmetic mean and minimum values of thickness in a section between two acoustic converters installed on the object in random points, without prior measurement of thickness in the same points.

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