SU1024827A1 - Device for localizing flaws in articles in acoustic emission testing - Google Patents

Abstract

DEVICE FOR LOCALIZATION OF DEFECTS IN PRODUCTS WITH ACOUSTIC EMISSION CONTROL, containing at least three channels, each of co-; They are made of a series of connected electroacoustic transducers and an amplifying path, and the electroacoustic transducers form a triangular group, logic and localization blocks whose inputs are connected to the channel outputs, the first output of the logic block is connected to the control input of the localization unit, the decoder with I outputs, the inputs of which connected to the outputs of the localization unit, and N counters, which is so that, in order to increase the reliability of the control, it is equipped with interconnected M Keys connected between the inputs of the respective counters and the decoder outputs, after | Delayed on by the delay unit, the first trigger and the additional key, the input of the zz support unit connected to the second output of the logic block §, connected in series by the interference release unit and (O C second trigger, moreover, the input of the noise elimination unit is connected to the output of the channel with a converter located in the center of the triangulation group, the output of the second trigger is connected to the control input of the additional key, and you od the latter is connected to the control inputs of N whose klie. eee | Nd h

Description

The invention relates to non-destructive testing of products by the method of acoustic emission and can be used to control large-sized products from materials with high ultrasound attenuation.

A device is known for detecting defects in products made from sheet materials, which contains a group of channels, each of which consists of an electroacoustic converter of the amplifier path, as well as a coordinate determination unit (locale block, appli cation), inputs connected to the outputs of channels 1,

A disadvantage of this device is the low reliability of the localization of defects.

The closest to the invention is a device for localizing defects in products during acoustic emission monitoring, which contains at least three channels, each of which consists of a series-connected electro-acoustic transducer and an amplifying path, and the electro-acoustic transducers form a triangulation group of logic and localization blocks whose inputs connected to the channel outputs, the first output of the logic unit is connected to the control input of the localization unit, the decoder with the S outputs, the inputs of which are th connected to the outputs of the localization unit, and W counters 2,

A disadvantage of the known devices is the low reliability of the location of defects, since in addition to signals from defects, sources of acoustic interference from friction (for example, in threaded connections) are also recorded.

The aim of the invention is to increase the reliability of the control

This goal is achieved by the fact that a device for localizing defet in products with acoustic emission monitoring contains at least three channels, each of which consists of series-connected electro-acoustic transducers and an amplifying path, and electro-acoustic transducers form a triangulation group, logic and localization blocks , the inputs of which are connected to the outputs of the channels, the first output of the logic unit is connected to the control input of the localization unit, the decoder with V outputs, the inputs of which are connected to the outputs of the localization unit, and VI counters, equipped with keys connected between an H key, connected between the inputs of the respective counters and the decoder outputs, a delay block connected in series, a first trigger and an additional switch, the delay block input connected to the second output block logic, sequentially connected blocks of interference and a second trigger, with the input of the block of interference noises connected to the output of the channel with a converter located in the center of the triangulation group, the output the second trigger is connected to the control input of the additional key, and the output of the latter is connected to the control inputs of the Ki keys.

The drawing shows the block diagram of the device for the localization of defects

5 in item x.

The device for localization of def, ect in products with acoustic emission monitoring contains electroacoustic transducers 1-5, amplification paths 6-10, logic block 11, block 12 localization, decoder 13, first counter 14, Nth counter 15, first key 16, M th key 17, delay block 18., first trigger 19, additional switch 20, block 21 of noise cancellation, second trigger 22, block 21 of noise cancellation consists of an envelope detector 23, a driver 24, a converter 25, duration the amplitude of the threshold element 26, the output of which is the output of block 21 interference and signaling circuit 27.

The electroacoustic transducers 1-5 form one triangulation group in the form of a square in which the third (3) electroacoustic transducer is located in the center. They are respectively connected with amplifying paths 6-10. Together with

With electroacoustic converters, they form five identical channels, the third of which corresponds to the central electroacoustic converter. Block 11 logic

5 and block 12 localization inputs connected to the outputs of these channels. The decoder 13 is connected to the outputs of the block .12 localization. Counters 14 ... 15 are connected to the corresponding output Q of the decoder 13 via keys 16 ... 17. The first output of the logic block C is connected to the control input | of the localization unit 12, and the second output is connected to the delay block 18,

C-OUTPUT of an additional key 20 is connected to the control inputs of the keys 16. ..17 connected together. The interference suppression unit 21 is connected to the output of the amplifier path 8. A second trigger 22 is connected to the output

0 of the block 21, the allocation of interference, and the output to the control input of the additional key 20.

The device works as follows. Acoustic emission signals penetrating from defects in the product, as well as signals of interference from friction, acquire electroacoustic converters 1–5 at different points in time. The signals arising at their outputs amplify the amplification paths in a certain frequency band to the required size. The signals from the outputs of these channels go to logic block 11, which determines whether a group of signals belonging to the same source can be received or not. If it cannot, then from its first output to the control input of the localization unit 12. the Reset command arrives. If it can, then the signal appears at the second output. The localization unit 12, which also receives signals from the channel outputs, determines the location of their source, and in the absence of the Reset command from the logic unit 11, transmits the results to the decoder 13 The latter determines the number of the counter from 14 ... 15, which corresponds to This position of the source, and at the corresponding output of the decoder 13, a special signal appears that does not pass through the normally closed key (one of the keys. 16 ... 17). Simultaneously from the second output of the logic block 11, a signal arrives. It is possible that the delay block 18 passes, and after a delay time exceeding sufficient for analyzing the signal in the interference block 21, the first flip-flop 19 tilts, and a signal is received at the input of the additional key 20. Somewhat earlier (according to the reception of the center signal by the central channel), a signal arrives at the input of the interference suppression unit 21. If this signal is an interference signal from friction, then at the output of the interference block 21, a signal appears that overturns the second trigger 22. The signal of this trigger is an additional key 20 and the signal from the first trigger 19 that arrives somewhat later the control inputs of the keys 16 ... 17, respectively, the signal from the decoder 13 does not fall into the counters 14 ... 15 and the interference is not registered -. If the received signal is not an interference signal, then there is no signal at the output of the allocation unit 21, the additional key 20 is open, and the signal of the first trigger 19 arrives at the control inputs of the keys 16 ... 17 and opens them. The signal from the output of the decoder 13 enters the corresponding counter (from 14 ... 15). Thus, acoustic emission signals are recorded, but no interference signals. The frictional interference allocation unit 21 operates as follows. The envelope signal from the output of the envelope detector 23 is fed to the input of the imaging unit 24, which forms: from it, a rectangular pulse of the corresponding duration. Transducer 25 duration - amplitude converts this pulse into a voltage that, for interference signals that have a much longer jHOcTb signal than signals from defects developed in materials with a large ultrasound attenuation, exceeds the trigger level of the threshold element 26. The latter produces a trigger signal 22 and signaling circuits 27. The use of the device will make it possible to increase the reliability of localization of defects in large-sized products made of materials with a large attenuation of ultrasound.

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Claims (1)

LOCALIZATION DEVICE FOR DEFECTS IN ARTICLES WITH CONTROL AKUSTIKOEMISSIONNOM comprising at least three channels each of _Ko: toryh consists of series-connected electro-acoustic transducer and amplifying path, wherein electroacoustic transducers are formed triangulation onnuyu group logic blocks and localization, inputs of which are connected to ι channel outputs, the first output of the logic block is connected to the control input of the localization block, a decoder with H outputs, the inputs of which are connected to the outputs of the locale block nation, and N account. In order to increase the reliability of control, it is equipped with interconnected M keys connected between the inputs of the respective counters and the outputs of the decoder, sequentially connected by a delay unit, the First trigger and an additional key, moreover the input of the delay unit is connected to the second output of the logic unit, sequentially connected to the interference isolation unit and the second trigger, and the input of the interference isolation unit is connected to the output of the channel with a converter located in the center of the triang group, the output of the second trigger is ⁴ · £ ·. dinan with the control input of the additional key, and the output of the latter is connected to the control inputs of N keys. (L a