SU1270674A1 - Device for determining coordinates of flaws in flat electroconductive objects - Google Patents

Abstract

The invention relates to non-destructive testing of products using acoustic emission and can be used to determine the coordinates of their defects. The aim of the invention is to improve the accuracy. A short, powerful current pulse from the pulse generator is passed through the object. This triggers the occurrence of acoustic emission signals from the defect, which are perceived by two transducers mounted on the monitored object. The signals are amplified and fed respectively to the first inputs of time-measuring units, the second inputs of which are connected to another output of the pulse generator, through which the start signal is received, synchronous with a powerful current pulse. According to the obtained time intervals in the AS of the calculating unit, the coordinates of the defect in the object are calculated and registered. I il.

Description

The invention relates to non-ugly control of products by acoustic emission signals and can be used to determine the coordinates of their defects. 5

The purpose of the invention is to increase the accuracy of determining coordinates.

The drawing shows the proposed device.

The device consists of successively connected receiving transducer 1, pre-amplifier 2, amplifier 3 and time interval measuring unit 4, series-connected converter 15, pre-amplifier 6 _{} of} amplifier 7 and time interval measuring unit 8. The outputs of blocks 8 and 4 of measuring time intervals with the outputs connected through the calculation unit 9 to the registrar 1Q, and the second inputs to the first output of the pulse generator 11, the second output of which is intended for electrical communication with the object being monitored

12.

The device operates as follows.

A short powerful current pulse from the second output of the pulse generator 11 is passed through object 12. This initiates the occurrence of acoustic emission signals from the defect, which are perceived by the transducers 1 and 5 installed on the controlled object. The signals are amplified and fed to the first inputs of blocks 4 and 8 measuring time intervals. Synchronously with a powerful current pulse, the pulse generator from the first output generates a pulse that sets the reference time interval for the acoustic emission signal from the defect to transducers 1 and 5. The calculation unit 9 determines the defect coordinates from the following equations based on data on these time intervals

At - C = l | (x-x ₁ ) ^r + (y-y4 Y at ^ C = + Gx-x2 Y + (y-y4) ⁷ , where at, Hzjt2 are the time intervals of the arrival of signals to the converters;

With ¹ - the speed of sound in the material of the object;

^χ · ^χ 1 ^ 'y - coordinates of the transducers;

x and y are the coordinates of the defect.

'The coordinate signal is then recorded by recorder 10.

The proposed device allows to increase the accuracy of determining coordinates by increasing the noise immunity of the device. In addition, the control does not require mechanical loading and a third conversion circuit, which simplifies the device.

Claims (1)

1 The invention relates to non-destructive testing of products by acoustic emission signals and can be used to determine the coordinates of their defects. The purpose of the invention is to improve the accuracy of the coordinate system. The drawing shows the proposed device. The device consists of a series-connected receiving transducer 1, a preamplifier 2, an amplifier 3 and a time interval measurement unit 4, a series-connected transducer 5, a preamplifier amplifier 7 and a time interval measurement unit 8. The outputs of blocks 8 and 4 of the time interval measurement are connected via the calculation block 9 to the 1Q recorder, and the second inputs to the first output of the pulse generator 11, the second output of which is intended for electrical communication with the controlled object 12. The device works in the same way. Through object 12 pass a short powerful current pulse from the second output of the generator 11 pulses. This triggers the occurrence of acoustic emission signals from the defect, which are perceived by transducers 1 and 5 installed on the monitored object. The signals are amplified and fed to the first inputs of time interval measurement units 4 and 8. Synchronously with a powerful current pulse, the pulse generator from the first output produces a pulse, which sets the origin of the acoustic emission signal from the defect to the transducers 1 and 5. Calculation unit 9 Based on these time intervals, the coordinates of the defect are determined from the following equations At – C l | (xx) (yyy Y4 (xxx)) + (yyy7), where ls idc are temporary intervals of arrival of signals to converters; C - soon sound in the material of the object; x, x, y are the coordinates of the transducers; X and y are the coordinates of the defect. The coordinate signal is then recorded by the recorder 10. The proposed device improves the accuracy of determining the coordinates by increasing the noise immunity of the device. loading and a third conversion circuit, which simplifies the device. Formula of the invention A device for determining the coordinates of defects in flat electrically conducting objects, containing two circuits the receiving transducer, the preamplifier, the amplifier, and the time interval measuring unit, and the sequentially connected calculation cells, the input of which is connected to the outputs of the time interval measurement units, and the recorder, which differs in that it is equipped with a generator pulses, the first output of which is connected to the second inputs of the time interval measurement units, and the second is intended for electrical communication with the object being monitored. //