SU1758541A1 - Method of ultrasonic testing of articles - Google Patents

Abstract

The invention relates to the field of acoustic methods of non-destructive testing and can be used in the inspection of multilayer structures, in particular three-layer structures with network filling. The aim of the invention is to increase the information content of the control of three-layer products. The essence of the invention is that due to the combination of the shadow and reverberation control methods, along with the presence of a defect, its location is determined. In this case, the transducers are arranged coaxially on the opposed skins of the product with the network filler. Ultrasonic vibrations in the product are excited and each transducer receives reflected and ultrasonic vibrations transmitted through the product. The amplitude of the vibrations passing through the product and the parameters of the reverberation signals are measured. The amplitude of the ultrasonic vibrations transmitted through the product determines the presence of a defect, and the parameters of the reverberation signals determine whether the detected defect is a discontinuity in the network filler or a violation of the skin connection with the filler and under which skin it is located. 5 il. Yo

Description

The invention relates to acoustic methods of non-destructive testing and can be used in the defectoscopy of multilayer structures, in particular, three-layer structures with a honeycomb core.

The known method of ultrasonic (US) control of multilayer products, which consists in placing an ultrasonic transducer on the product's surface, using a transducer to emit pulses of vibration patterns, receive oscillations reflected by the product, measure the parameters of received vibrations in the time interval corresponding to the reverberation finding in contact with the transducer layer of the product, and the measured parameters determine the defectiveness of the connection between the layers of the product.

The disadvantage of this method is that the control of three-layer structures is not sufficiently high, since there are no defects in the middle layer, for example, the type of cell breakage.

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The closest to the present invention is an ultrasound control method, which consists in installing transducers coaxially on opposite surfaces of an ultrasonic product, radiating ultrasonic vibrations into the product, receiving ultrasonic vibrations passing through the product with the second converter, measuring the parameters of received vibrations, in particular, the amplitude, and the measured parameters determine the defectiveness of the product.

However, the method is characterized by insufficiently informative control of three-layer products due to the lack of information about the location of the defect in the cross section of the product.

The purpose of the invention is to increase the information content of monitoring three-layer products by detecting, along with the presence of a defect, its location over the cross section of the product.

The goal is achieved by an additional reception of the first transducer of the reflected ultrasonic vibrations. radiation by the second transducer and its reception of the reflected ultrasonic vibrations, as well as the fact that the product is judged on the flaw detection by the ratio of the parameters of the three received ultrasonic vibrations, resulting in a combination of the shadow and two-way reverberation control.

Figure 1 presents the scheme of implementation of the method of ultrasonic control products; figure 2 - timing diagrams of signals from the outputs of the first (a) and second (b) transducers when monitoring a three-layer product with a defect located between the middle layer and the lining on the installation side of the first transducer; FIG. 3 shows timing diagrams of signals from the outputs of the first (a) and second (b) transducers when monitoring a three-layer product with a defect located between the middle layer and the lining on the installation side of the second transducer; figure 4 - timing diagrams of signals from the outputs of the first (a) and second (b) transducers when monitoring a three-layer product with a defect located in the middle layer; 5 shows time diagrams of signals from the outputs of the first (a) and second (b) transducers while monitoring a defect-free three-layer product.

The method of ultrasonic testing of products can, for example, be implemented using a device containing the first and second ultrasonic transducers 1 and 2, respectively, two synchronized oscillators 3 and a two-channel amplifier 4 connected to transducers 1 and 2, and a dual-beam oscillator. A graphic indicator 5 connected to the outputs of the amplifier 4. The controlled product with the casings 6 and the honeycomb filler 7 may have a defect 8 connecting the skin 6 and the filler 7 and defect 9 in the form of a rupture of the honeycomb 7. In figure 2-5 the position 10 is labeled probing th signal, position 11 - reverb

0 signals, position 12 - signal of the oscillations passing through the product, position 13 - the first time interval in which the parameters of the oscillations passing through the product are measured, position 14 5 the second time interval in which the parameters of reverberation signals are measured.

The essence of the invention is that acoustically coaxially with ultrasonic transducers are located on opposite sides of the product. Each transducer radiates and receives ultrasonic vibration pulses. The parameters of the reflected oscillations received by the first transducer, the parameters of the reflected oscillations received by the second transducer and the parameters of the vibrations transmitted through the product by the second transducer are measured. About the defectiveness of the product and

0 the location of the defect is judged by the ratio of the parameters of the three received signals of ultrasonic vibrations.

The method of ultrasonic control products is implemented as follows

5 Transducers 1 and 2 are placed on different skins 6 in such a way that the acoustic axes coincide. The generators 3 excite the transducers 1 and 2. The oscillations excited by the transducer 1

0 reverberate the casing 6, which is in contact with the converter 1, pass through the filler 7 and through the other casing 6 enter the converter 2. The oscillations excited by the converter 2

5 is reverberated in the casing 6, which is in contact with the converter 2, passes through the filler 7 and through the other casing 6 is fed to the converter 1. Passed on the converters 1 and 2

0 reverberation signals and oscillations passing through the product are fed to a two-channel amplifier 4 and from its output to a dual-beam oscillographic indicator 5. Using indicator 5, the received oscillations in two intervals 13 and 14 are fixed, and the interval 13 corresponds to the oscillations passed through the product, and the interval 14 corresponds to the reverberation signals and is set, for example, so that the defect-free participation

Signals 11 are not recorded in it, and in the area with defect 8 are fixed. The presence of a defect 8 or 9 in the product is determined by the absence of a signal 12 of oscillations passing through the product (Figures 2, 3 and 4). If the reason for the absence of a signal 12 to reduce its amplitude below the rejection level is the defect 8 of the connection of the skin 6 with the filler 7, then reverberation signals 11 are fixed in the time interval 14 of one of the transducers 1 or 2, and the defect 8 is on the side from which the transducer is located

1 or 2, recorded the reverb signals 11 (Fig.2, 3). If the reason for the absence of signal 12 or a decrease in its amplitude below the rejection level is defect 9, i.e. rupture of the cell filler 7, then in the time interval 14 neither for converter 1 nor for converter

2, the reverb signals 11 are not fixed (Fig. 4). In the case of sounding a defect-free product in the interval 13, the signal 12 is fixed, and in the interval neither for the converter 1 nor for the converter 2 reverberation signals 11 are not fixed. Thus, fixing signals in time intervals 13 and 14 allows not only to reveal the presence of a defect in the product, but also to determine the direction of its occurrence.

The method of ultrasonic control products can be implemented using a device containing two transducers, a generator of probe pulses, an amplifier and a single-beam indicator. In this case, the generator excites the probe pulses in pairs so that the distance between the probe pulses in each cycle exceeds the duration of the reverberation signal on the defective part of the product, but

there was less time difference between the passage of oscillations through the product and the duration of the reverberation signal. When starting the indicator sweep from each 5 first probe pulse of the cycle, the reverberation signals and the signals of the oscillations passed through the product, received by each of the transducers, are simultaneously observed on the indicator screen. This method can also be implemented by alternately operating the converters in the shadow mode, the first converter in the combined mode and the second converter 5 in the combined mode. The duration of the measured parameters of the reverberation signals can be used.

Claims (1)

Invention Formula 0 The method of ultrasonic testing of products, which consists in installing the ultrasonic transducers coaxially on opposite surfaces of the product, radiates into the product first 5 transducer ultrasonic vibrations, take the second transducer ultrasonic vibrations that have passed through the product, measure the parameters of the received vibrations, taking into account 0 determines the defectiveness of the product, that is, so that, in order to increase the informativeness of the control of three-layer products by determining the location of the defect over the cross section of the product, it is additionally acceptable first transducer of the reflected ultrasonic vibrations, emit the second transducer and receive them the reflected ultrasonic vibrations, and about defectiveness 0 products are judged by the ratio of the parameters of the three received ultrasonic vibrations. L g / X ten D eleven Ng 5 Th./ / 4 10 14 FIG, g13 eleven YU ; L / 6 FIG. 3 zf Fiyo. one / J 13 /I Yu 13 / J