No 1 (2024)

The paper considers several methods of measuring the arrival time of ultrasonic pulses. A method for determining the pulse arrival time based on the construction of a signal model with an adaptive dictionary and the search for the minimum of the target function by the quantum swarm intelligence method is proposed. The results of numerical and modeling experiments on measuring the propagation velocity of ultrasonic waves in various samples are presented. It is shown that the proposed method of determining the time of pulse arrival is more resistant to distortion of the echo waveform arising due to frequency-dependent attenuation in the material of the control object.

The article presents the results of studies of additively manufactured metal samples using neutron imaging at the IR-8 research reactor of the National Research Center “Kurchatov Institute” (NRC KI). The advantages and disadvantages of neutron imaging using monochromatic (DRAGON station) and polychromatic (PONI tomograph) neutrons when studying internal structure of the samples are demonstrated.

The method of laser point scanning thermography is highly sensitive and allows for reliable detection of surface and subsurface defects in products made of polymer composite materials. When implementing this method, the use of robotic manipulators as a scanning device makes it possible to inspect small objects with a curved surface or to further examine questionable areas identified by other methods. The article provides information about the layout of a robotic complex for laser scanning thermography based on a five-axis robotic manipulator, laser power up to 3 W and wavelength 405 nm, as well as a COX CG640 thermal imager. A technique for processing experimental data has been proposed and regression models have been developed to make it possible to measure the size of defects along the trajectory and determine their location. To test the protocol, a control sample was made from fiberglass laminate, including artificial defects of the “delamination” type, in the form of squares of various sizes. The coefficient of determination R² of regression models turned out to be no worse than 0.94, the root mean square error of the defect model and the transverse size were no worse than ±0.2 and ±1.5 mm², respectively.

The article investigates the possibility of detecting defects in the form of transverse cracks in the rail foot at continuous inspection of rails during their operation. Magnetic method is chosen as an alternative to ultrasonic inspection. Computer modeling was carried out, based on the results of which a working model of the magnetization system and registration of control signals was developed and manufactured. Experimental studies of detection of crack models in the rail foot were carried out in laboratory conditions. The studies confirmed the results of computer modeling and proved the possibility of detecting such crack models. The minimum sizes of detectable crack models in rail foot in the zone of rail fasteners and between them have been estimated.

The behavior of the construction under the influence of external factors is determined by three key groups of parameters of the metal composition (chemical, structural and deformation). Obtaining information about these parameters directly on the construction will effectively solve the problem of assessing its actual technical condition. The problem of non-destructive evaluation of the chemical composition of a metal is solved using portable spectrometers. The MicroLab-Z2 diagnostic complex has been developed to evaluate the other two groups of parameters. It has two functional blocks. The surface preparation unit ensures that the surface of the construction site has a roughness, flatness and level of applied mechanical hardening corresponding to the laboratory preparation of metallographic grinds. The research unit is a platform on which a metallographic microscope and a portable microhardness tester are installed. It allows metallographic researches with magnification up to x1000, surface microindentation, measurement of microhardness values at load of 0—200 gs and optical study of the morphology of imprints in any spatial position. The reliability of the data obtained by the MicroLab-Z2 diagnostic complex has been confirmed during comparative tests with stationary equipment. With the help of the developed device, an assessment of the structure parameters, contamination of metal with non-metallic inclusions, assessment of the degree of hardening and embrittlement of metal, detection of aging processes can be performed. The use of the MicroLab-Z2 diagnostic complex for operational non-destructive evaluation of structural and deformation parameters of metal constructions will allow us to reach a qualitatively different level of efficiency in performing production and input control of manufactured products, assessing the maintainability of defects, planning repairs and other compensating measures, and industrial safety expertise.