SU1138733A1 - Acoustic-emission device for article and material quality control - Google Patents

Abstract

AK STZHO-EMISSION STRONG CONTROL QUALITY OF PRODUCTS AND MATERIALS, containing series-connected transducer, amplifier and shaper shaper, series-connected electronic key and intensimeter, the first counter connected to the output of the electronic terminal, which was unlocked with a target, Equipped with series-connected extremum extrusion unit, shaper of normalized pulses, trigger, delay circuit, second counter, digital-to-analog converter m and the recorder, the first comparator connected between the envelope former and the second trigger input, the second comparator connected between the amplifier and the second input of the third meter, the trigger output is connected to the second input of the digital-analog converter, the output of the {normalized pulse body) is combined with the second input electronic key. with

Description

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SAE 09 The invention relates to non-destructive quality control by the method of acoustic emission (AE | and can be used for mechanical testing of materials and structures. A device for testing products that contains a serially connected converter, amplifier, threshold unit, pulse counter, digital-analogue is known. a converter and a recording unit, the delay line of which output is connected to the input of a pulse counter, and an amplitude detector, the input of which is connected to the output of the threshold unit, and the output to the inputs delay lines and digital-to-analog converter Cl). The disadvantage is that the reliability of the device is low due to the change in measurement error depending on the frequency of the input signal and the selected discrimination threshold. The closest in technical essence to the invention is an acoustic emission device for controlling the quality of products and materials, containing a series-connected transducer, amplifier and envelope former, a serially connected electronic key and an intensity meter, the first counter connected to the output of the electronic key 2. A disadvantage of the known device is low reliability, since the amplitude of the signal AE is estimated approximately from the total number of oscillations. The aim of the invention is to increase reliability. This goal is achieved by the fact that the acoustic emission device for controlling the quality of products and materials, containing a series-connected converter, amplifier and shaper envelope, a series-connected electronic key and intensity meter, the first counter connected to the output of the electronic key, is equipped with a series-connected extremum extraction unit shaper normalized pulses, trigger, delay circuit, second counter, digital-to-analog converter and recorder, the first comp Attorney connected between the envelope former and the second trigger input, the second comparator connected between the amplifier and the second input of the second counter, the trigger output is connected to the second input of the D / A converter, the output of the normalized pulse former is connected to the second input of the electronic key. The drawing shows acoustic-emission device quality control products and materials. The device contains a transducer 1 connected in series, an amplifier 2 and an envelope former 3, an electronic switch 4 connected in series and an intensity meter 5, a first counter 6 connected to the output of the electronic switch 4. , trigger 9, delay circuit 10, second counter 11, digital-to-analog converter 12 and recorder 13, first comparator 14 connected between the envelope 3 and in The first input of the trigger 9, the second camparator 15 connected between the amplifier 2 and the second input of the second counter 1I, the input of the trigger 9 is connected to the second input of the digital-to-analog converter 12, the output of the shaping device 8 of the normalized pulses products and materials works as follows. The AE signals transformed by converter 1 into an electrical signal are amplified and selected in frequency by amplifier 2 and fed to an envelope shaper 3, where AE pulses are extracted. Then the signal goes to the first comparator 14, which converts the sinusoidal signal into a pulse signal, and to the extremum block 7, Using the reference voltage, the noise cut-off is performed. Trigger 9 is running in counting mode. When the amplitude exceeds the input voltage of the reference voltage, a positive potential is produced at the output of the first comparator 14, which prepares the trigger 9 for operation. Block 7, extremum extraction together with the former 8 normalized pulses produces rectangular normalized pulses, which are fed to the electronic key 4 and the count 3n

the trigger input 9, its transfer to the unit state in the initial state of the electronic key 4 is open, and the first pulse passes to the intensity meter 5 and the first counter 6. The logical unit pulse produced by the trigger 9 and delayed by the delay circuit 10 closes the electronic key 4. The delay time is determined from the expression

, about

where Cj is the control delay time

pulse;

Sf is the pulse duration of the driver 7;

 - maximum pulse frequency A3. The second I1 pulse, produced by the shaper of 8 normalized pulses, has no useful information and does not pass to the input of the first: counter 6 and the intensity meter 5, since the electronic key 4 is closed. At the same time, the second pulse, acting on the counting input of the trigger 9, transfers it to the zero state. A logical zero pulse, delayed by time .Tj, opens the electric key 4, preparing it for the arrival of the third pulse, carrying useful information. Thus, the continuous pulses produced by the organizer are 8 normalized by 87334.

pulses and being false do not pass to the recording device. After the arrival of the last pulse, the level of the input signal becomes less than the reference voltage. At the output of the first comparator, 14 generates a potential which flushes trigger 9 to the zero state. This is how speed measurement is performed.

o AE accounts and total AE accounts. The signal from the output of the amplifier 2 is fed to the information input of the second counter 11, is converted into a tax form of a digital-to-analog conversion by v-gel 12 and is fed to the register-tor 13. A negative trigger difference 9 arrives at the control input of the digital-analog converter 1 2 and corresponds to the end one

0 pulse AE, is permissive for output information. This difference, delayed by the delay circuit 10, resets the second counter 11 to zero. Thus, the amplitude of the AE pulses is measured.

Thus, the proposed device makes it possible to increase the reliability of measuring the counting rate, total counting and a1L1liters of AE pulses by introducing new blocks and links between them, ensuring the selection of individual AE acts at a higher frequency of the latter,

Claims (1)

ACOUSTIC-EMISSION DEVICE FOR QUALITY CONTROL OF PRODUCTS AND MATERIALS, containing a serially connected transducer, amplifier and envelope former, serially connected electronic key and intensimeter, the first counter connected to the output of the electronic key, characterized in that, in order to increase the reliability, it is equipped with connected in series by an extremum extraction unit, a shaper. normalized pulses, a trigger, a delay circuit, a second counter, a digital-to-analog converter and a registrar, a first comparator connected between the envelope former and the second trigger input, a second comparator connected between the amplifier and the second input of the second counter, the trigger output is connected to the second input of the digital-to-analog converter, the output of the generator of normalized pulses is connected to the second input of the electronic key. from: 00 m oo 1 1138733 2