SU1525563A1 - Method of determining index of heterogeneity of acoustic field of transducers - Google Patents

Abstract

This invention relates to non-destructive testing. The aim of the invention is to increase productivity by simplifying the measurement operation. A uniform acoustic contact is formed between the transducer and the sound guide. At a given distance within the near radiation zone on the side of the duct, which is opposite to the transducer, a flat reflecting surface is formed of at least two types of areas with differing reflection coefficients of ultrasonic waves. The ultrasound waves are emitted by the transducer in the direction of the reflecting surface. The ultrasonic waves reflected from it are received, the reflection coefficient is measured, it is compared with the reference value of the reflection coefficient, and as a result, the heterogeneity index of the acoustic field is determined from the direct measurement of the reflection coefficient. 1 hp f-ly.

Description

The invention relates to non-destructive testing and can be used for ultrasonic measurements of the parameters of the acoustic field of transducers in the near radiation zone.

The purpose of the invention is to increase productivity by simplifying measurement operations.

The method for determining the inhomogeneity index of the acoustic field of the transducers is carried out as follows.

A uniform stable acoustic contact is formed between the transducer and the sound conductor. At a given distance within the near radiation zone, on the opposite side of the transducer and on the side of the sound duct, a reflecting surface is formed

from areas of at least two types differing in the value of the reflection coefficient of ultrasonic waves. The ultrasound waves are emitted by the transducer in the direction of the formed reflecting surface. The ultrasonic waves reflected from this surface are taken by the transducer and the reflection coefficient R is measured. Then calculate the indicator / heterogeneity of the acoustic floor of the transducer according to the formula

SP

Yu

JV JV

ABOUT)

P.5

..

(one)

where R (, the control value of the reflection coefficient of a plane wave from the formed surface, determined by its acoustic and geometrical parameters. The value of R is determined by the ratio, which for the case of the formation of a reflective surface from the two types of sections has the form

RC de R and R and - Rich

t-o R

(2)

reflection coefficients of ultrasonic waves from the first and second type areas, respectively;

specific areas of these areas with respect to the total area of the reflecting surface.

o / h with

R value

13)

for an arbitrary number of sections of the reflecting surface can be obtained similarly to (2) and (3) by adding the corresponding terms.

By the expression (2), the reflection coefficient of a plane wave from the formed surface is determined. In the case of uneven distribution of the amplitude of the ultrasonic wave over the cross section of the transducer, the reflection coefficient differs from the calculated value (2). The higher the heterogeneity of the acoustic field, the greater the difference between the values of R and R. In addition, the exponent c / is a relative value, therefore normalization is introduced in formula (1).

In the case of the formation of a reflecting surface from areas of an ultrasonic beam equally distributed over the cross section with equal in magnitude but opposite in sign amplitude reflection coefficients of ultrasonic waves, calculation formula (I) is simplified, since oi o and R - -R. Therefore R Oh and

As follows from (1), in order to increase the sensitivity of measurements, compiler B. Editor M.Petrova Tehred L. Serdu is needed.

o

five

0

five

0

five

MO choose materials of the sound duct and the areas of the reflecting surface so as to obtain the maximum value of Rp.

Thus, the proposed method allows determining the degree of heterogeneity of the acoustic field of the transducers by directly measuring the reflection coefficient of ultrasonic waves from the formed surface, which improves the performance of the control.

Claims (2)

1. A method for determining the inhomogeneity index of an acoustic field of transducers, including transducer radiation in the direction of a flat reflective surface of ultrasonic waves, receiving reflected ultrasonic waves, and determining the heterogeneity index of an acoustic field over an ultrasonic beam section, characterized in that they receive reflected ultrasonic waves from surface areas of at least two types with different values of the reflection coefficient of ultrasound s waves measured ratio R, the reflection of the ultrasonic waves from the surface portions, and display nonuniformity acoustic field transducer is determined from the relationship if a - -tS 1 - 7R, 7 where RO is the reflection coefficient of a flat ultrasonic wave from surface areas. 2. The method of pop. 1, which differs from the fact that they receive reflected ultrasonic waves from surface areas with equal in magnitude but opposite in sign amplitude coefficients of reflection of ultrasonic waves. Proofreader L. Obruchar