No 12 (2024)

This paper presents a methodology for enhancing the efficiency of acoustic emission (AE) source detection during planar localization using the Inglada’s algorithm. The study analyzes the main factors affecting the accuracy of AE source localization when using a standard planar localization approach. These factors include the threshold-based method of determining the signal registration time by AE sensors, which is based on detecting the moment when the rising wavefront voltage exceeds the discrimination threshold (u_th), the signal sampling frequency (f_d), and the influence of the medium’s dispersion properties on the attenuation of signal amplitude and wave propagation speed. To reduce the impact of these factors on the localization accuracy of AE sources, a novel methodology is proposed based on the use of correlation dependencies of AE pulse propagation speed on the amplitude of the recorded signals, as well as on accounting for the delay in the registration time of AE pulses during threshold detection. A series of preliminary experiments was conducted to implement the proposed methodology, where AE pulses were generated using an electronic simulator with a maximum amplitude level of u_m = 45—90 dB. The position of the AE pulse source varied in the range of 150 to 700 mm relative to the receiving sensors of the antenna array. As a result of applying the developed methodology, the probability of AE source detection increased to p = 0,71, compared to p = 0,36 when using the standard approach.

This paper presents the results of a gas-discharge electro acoustic transducer of two configurations, operating on the basis of a pulsed discharge in air at atmospheric pressure. The influence of the electrode configuration on the acoustic characteristics of the transducer is considered. It is shown that a change in the volume of the discharge chamber and the inter electrode gap have a significant effect on the radiation intensity of the transducer. The features that arise when using open and closed type electro acoustic transducers in flaw detection problems are revealed. It is shown that an open type gas-discharge electroacoustic transducer is a sufficiently powerful broadband source of the excitation signal and has prospects for use in non-destructive testing. A closed type gas-discharge electroacoustic transducer has advantages when testing materials with special requirements for surface cleanliness or the magnitude of the applied external electric field.

This article is devoted to improving the efficiency of flaw image identification during computer decoding of digital radiographic images. The paper studies the problem of segmentation of flaw images. Models of segmentation of flaw images on a radiographic image are studied for both manual and computer decoding. The difference between algorithms for searching and identifying groups, clusters, chains of pores, slag and metal inclusions from manual decoding of images is shown.

Algorithms for the search and identification of flaws for use in digital radiography complexes have been developed and experimentally tested at HSC KARS. The convergence of the results of computer and manual decryption was 0,85.

A series of measurements on two pipeline sections made of 17G1S (17Г1С) steel using two measuring devices: magnetic multitester MMT-3 and magnetic analyser of structure KRM-C-K2M (КРМ-Ц-К2М) has been carried out. Maps of coercive force, residual magnetic induction and maximum magnetic induction on the pipes were obtained. The coefficient of loading for different cross-sections of the pipeline was calculated. Dependence of magnetic characteristics averaged over the cross-section on the coefficient of loading is plotted. It is revealed that the most dangerous for destruction cross-sections, in which the coefficient of loading exceeded the critical value of 1,2, correspond to the reduced values of coercive force and residual magnetic induction, obtained in the direction of measurement along the pipeline axis. It is shown that measurement along the axis at the top of the pipeline shows a similar relationship as for the cross-sectional averaged values, which means that in pipeline aerial crossings, measurement only at the top of the pipeline may be sufficient.