SU926598A1

SU926598A1 - Device for checking articles by acoustic emission signals

Info

Publication number: SU926598A1
Application number: SU802982508A
Authority: SU
Inventors: Владимир Константинович Анисимов
Priority date: 1980-09-12
Filing date: 1980-09-12
Publication date: 1982-05-07

Description

(5) УСТРОЙСТВО ДЛЯ КОНТРОЛЯ ИЗДЕЛИЙ ПО СИГНАЛАМ АКУСТИЧЕСКОЙ ЭМИССИИ(5) DEVICE FOR MONITORING PRODUCTS BY ACOUSTIC EMISSION SIGNALS

II

Изобретение относитс к неразрушающему контролю качества изделий и может быть использовано дл измерени качества сигналов акустической эмиссии и определени моментов их по влени .The invention relates to non-destructive quality control of products and can be used to measure the quality of acoustic emission signals and determine the moments of their occurrence.

Известно устройство дл контрол изделий по сигналам акустической эмиссии, которое содержит соединенные последовательно электроакустический преобразователь, усилитель, блок измерени параметров сигнала и другие блоки 11..A device for monitoring products by acoustic emission signals is known, which contains electroacoustic transducers connected in series, an amplifier, a unit for measuring signal parameters, and other units 11.

Недостатком этого устройства вл етс низка разрешающа способность сигналов, следующих друг за другом с интервалом, меньшим, чем 5-7 периодов колебаний сигнала.A disadvantage of this device is the low resolution of signals following each other at intervals less than 5-7 periods of signal oscillations.

Наиболее близкое к предлагаемому по технической сущности устройство дл контрол изделий по сигналам акустической эмиссии содержит соединенные последовательно электроакустический преобразователь, усилитель.Closest to the proposed by the technical nature of the device for the control of products by acoustic emission signals contains connected in series electroacoustic transducer, amplifier.

сумматор и блок измерени параметров сигнала, а также первый дифференциатор 2.an adder and a unit for measuring signal parameters, as well as a first differentiator 2.

Недостатком этого устройства вл етс низка разрешающа способность, обусловленна тем, что сигналы акустической эмиссии, по вившиес в точке приема через интервал времени, меньший чем некотора величина tj, сливаютс вместе и регистрируютс A disadvantage of this device is the low resolution, due to the fact that acoustic emission signals, which have increased at the reception point over a time interval smaller than a certain value of tj, are merged together and are recorded

10 как один.10 as one.

Цель изобретени - повышение разрешающей способности.The purpose of the invention is to increase the resolution.

Указанна цель достигаетс тем, This goal is achieved by

Claims

IS that the device is equipped with two matching blocks, a second differentiator, the output of which is connected to the second input of the adder, and the input is connected to the output of the first differentiator through the second matching block, the input of the first differentiator is connected to the output of the amplifier through the first matching block. Figure 1 shows the block diagram of the proposed device; in Fig. 2, voltage pins at the outputs of blocks a are at the output of amplifier 2; b - at the output of the first differentiator; in the output of the second differentiator; Mr. output of the adder). The device consists of serially connected converter 1, amplifier 2, first matching unit 3, first differentiator 4, second matching unit 5, second differentiator 6, adder 7 and parameter measuring unit 8, the output of amplifier 2 being connected to the first input of adder 7. The device works as follows. The acoustical transducer 1 converts the acoustic emission signals into bursts of resonant oscillations that can be superimposed and, after amplification, have the form shown in the plot After the first matching unit 3 and the first differentiator k, the signal takes the form shown in the plot of FIG. A similar procedure passes the signal in the matching unit 5 and in the second differentiator 6. The signal at the output of the second differentiator 6 is shown in the diagram of Figure 2b. This signal and the signal from the amplifier 2 are fed to the adder 7. The signal at the output of the adder is shown in the plot of figure 2d. When summing, the first half-waves of each of the signals are added in phase, and the subsequent half-waves are in antiphase and, accordingly, compensate each other. In order to more fully compensate for the oscillations, experimental adjustment of the transmission coefficient is required at each differentiation, which is carried out in blocks 3 and 5 of the matching. Useful signals from the output of adder 7 are already easy to distinguish by discrimination. In block 8, the measurement parameters of the processed signals. The proposed device allows to increase the resolution of acoustic emission devices by introducing a second differentiator. Claims An apparatus for monitoring products based on acoustic emission signals comprising an electroacoustic transducer connected in series, an amplifier, an adder and a unit for measuring signal parameters, as well as a first differentiator, which, in order to increase the resolution, it is equipped with two matching units, a second differentiator, the output of which is connected to the second input of the adder, and the input is connected to the output of the first differentiator through the second matching unit, the input of the first differential ora connected to the output amplifier via a first matching block. Sources of information taken into account in the examination 1. USSR author's certificate number, cl. G 01 N 29/04, 1975, 2, Greshnikov V.A., Drobot Yu.B. Acoustic emission. M., Publishing house of standards, 1976, pp.82-83.