SU1559279A1 - Method of checking quality of acoustic contact in ultrasonic examination of articles - Google Patents

Abstract

The invention relates to non-destructive testing and can be used for ultrasonic testing of metal structures of materials. The aim of the invention is to improve the accuracy by assessing the position of the transducer relative to the surface to be monitored. Measuring the average value of the capacitance between the cells of the cells of the matrix piezoelectric transducer and the surface of the tested product and the dispersion of normalized capacitances normalized to the reference surface and allows us to estimate the uniformity of the transducer's surface against the surface of the product under investigation and unambiguously assess the geometric location of the transducer relative to the surface of the material under study.

Description

The invention relates to the field of non-destructive testing and can be used for ultrasonic testing of metal structural materials.

The purpose of the invention is to improve the manufacturability by assessing the position of the converter relative to the surface being monitored.

The method is carried out as follows.

Using a matrix-type piezoelectric transducer, when studying its acoustic contact with the surface of the material under investigation, an electric field is created between the electrodes of the cells of the piezoelectric transducer matrix and the surface of the material under investigation, the capacitances between the electrodes of the piezoelectric transducer matrix cell and the surface of the material are measured, and compared with the capacitances between the electrodes of the matrix cells piezoelectric transducer and reference surface mat serial The following parameters are obtained.

j N

  th 2LciMop / w;

ate

SP

WITH

u 1

about

: normal unopiw

where .Snord, the average value of the normalized relatively

reference surface capacity C;

with;

 the norm

C; / C;

 ceruR

t

de C1 - capacity of the i-th cell of the matrix

relative to the surface of the material under study; C; et is the capacity of the i-th matrix cell

one

D,

enorm

relative to the reference surface;

-the number of matrix cells;

- informative parameter; -dispersed

N containers

ten

one

D-PM ICG; YorlG with "" p "

“Yorh”

According to the value of .SI0. / And the thickness of the contact layer is judged. When the thickness of the contact layer is changed, the parameter Ј does not change if there is no tilt of the transducer relative to the surface to be tested. Overlapping the transducer or changing the waviness of the surface of the tested product leads to a significant change in the value of 8.

To ensure a given value of the measurement error of the acoustic parameter, for example, the attenuation of ultrasonic waves, which introduces the surface of the material under study, the maximum permissible values of the Snorm and & DETECTION of acoustic contact by С „„., M and Ј parameters provides

assessment of the uniformity of the fit of the entire surface of the transducer to the surface of the material under study. Thus, the method makes it possible to unambiguously evaluate the geometrical arrangement of the transducer relative to the surface of the material under study.

Claims (1)

Invention Formula The method of controlling the quality of acoustic contact with ultrasonic testing of products, which consists in creating a physical field between the transducer and the object and determining its parameters, according to which the quality of the contact is judged, characterized in that, in order to improve accuracy, a matrix transducer is used. electrically isolated electrodes, an electric field is created as a physical field, and the parameters are the average value of the normalized relative to the reference surface between the electrodes of the cells of the matrix and the surface of the material under study and the ratio of the dispersions of the normalized containers to their average value.