SU1385066A1 - Device for acoustoemission checking of an article - Google Patents

Abstract

The invention relates to non-destructive testing by an acoustoemission method and can be used in determining the degree of danger of developing defects in products. The purpose of the invention is to increase the reliability of control by taking into account the increase and decrease in the envelope of an acoustoemission emission act. The acoustic emission signal is received by a piezo transducer 1, amplified, detected and integrated. When the signal reaches the reference threshold of the first comparator 8 in the information processing unit 7, the digital amplitude of the signal is entered, and the counter 10 starts counting the current time. When the input signal envelope amplitude reaches the thresholds of the comparators 11 and 12, the information processing unit 7 records the values of the time points corresponding to these events. When the input signal envelope falls, the time points corresponding to the values of the Q and the thresholds of the comparators 11 and 12 are also recorded. coefficients of increase and decline of the signal envelope are judged on the development of defects in the product. 2 Il. (L

Description

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 9 SP

O 05 O5

The invention relates to non-destructive testing by acoustic emission method and can be used to determine the presence and degree of danger of developing defects in various products.

The purpose of the invention is to increase the reliability of the control by taking into account the increase and decrease of the envelope of the acousto-emission act.

FIG. 1 shows a structural electrical circuit of the device; in fig. 2 - timing diagrams for the operation of the device.

Device for acoustic emission-. The control of products (Fig. 1) contains acoustic oscillations connected to piezoelectric transducer 1 in series into electric, preamplifier 2, amplifier 3, amplitude detector 4, integrator 5, analog-to-digital converter 6 and information processing unit 7.

In addition, the device contains the first comparator 8, the signal input of which is connected to the output of the integrator 5, and the reference input to the first output of the source 9 of the reference voltage, the pulse counter 10, whose output is connected to the second input of the information processing unit 7, the second and the third comparators 11, 12, the signal inputs of which are connected to the output of the integrator 5, the reference inputs to the second and third outputs of the source U of the reference voltage, and the outputs to the third and fourth inputs of the information processing unit 7.

The input of the pulse former 13 is connected to the output of the comparator 8, and the transducer is connected to the installation input of the counter 10 pulses. The counting input of the counter 10 pulses is connected to the generator 14 pulses. .

The device works as follows.

Acoustic emission signals (AE), excited in piezoelectric transducer 1, are amplified in preamplifier 2 and amplifier 3 and converted by amplitude detector 4 and integrator 5 to video signal fed to analog-to-digital converter 6 and signal inputs of comparator 8, 11 and 12. When the video signal exceeds the threshold, a short pulse is generated at the output of the imaging unit 13, which

arrives at the 10J installation input, dumping it to -nol. The counter 10 counts the number of pulses arriving at the counting input from the generator 14. When the video signal threshold Upop, from the output of the comparator 11 to the third input of the information processing unit 7, a logical 1 signal is received, which the information processing unit 7 reads from the analog-digital converter 6 the exact the value of A, the signal at the code of the integrator 5, and from the output of the counter 10 pulses - the value of the code proportional to the time t ,. When the video signal threshold from the output of the comparator 12 to the fourth input of the information processing unit 7 receives a logical signal 1, the information processing unit reads from the analog-digital converter 6 the exact value A of the signal at the output of the integrator 5, and the output of the pulse counter 10 reads the code value proportional to time t ,. When the video signal drops below the threshold and then from the output of the comparator 12 to the even input of the information processing unit 7, a logical signal O is received, through which the information processing unit 7 reads the exact value of A, the output signal of the integrator 5 from the analog-digital converter 6, and counter 10 pulses - code value proportional to time t.

When the video signal drops below the Unopi threshold from the output of the comparator 11, the third input of the information processing unit 7 receives a logical signal O, which the Information processing unit 7 reads from the analog-digital converter 6 the exact value of the signal Ad at the output of the integrator 5, and the output of the counter of 10 pulses - code value proportional to time t.

As a result of the pulse processing, the AEs are measured 8 parameters: A, A, j, Aj, A, t ,, t 2, tj, t4, related by the relations:

A, A ()

BUT ( )

The second system of equations can be converted to the equation

A5 -o / 3 (tj-t4)

Gf BUT-

The information processing unit 7, solving the first system of equations and the second equation, finds the values A, o (q and i / e, which are the directly objective characteristics of the initial processes associated with the AE signals.

Claims (1)

Invention Formula Device for acoustic emission monitoring of products containing serially connected piezoelectric transducer, preamplifier, amplifier, amplitude tsetektor, integrator, analog-to-digital converter and information processing unit, connected in series the first comparator, whose input is associated with the integrator output, driver and counter , the output of which is connected to the second input of the information processing unit, and the source of the reference voltage, the output of which is connected to the reference input of the first comparator from In order to increase the reliability, it is equipped with second and third comparators, connected respectively between the integrator's output and the third and fourth inputs of the information processing unit, and a pulse generator connected to the second input of the counter, the voltages are associated respectively with the reference inputs of the second and third comparators. % 0111ПМ