Pavlo Maruschak

• Professor (Full) D.Sc. (Tech.)
• Vice-Rector for Scientific Research at Ternopil Ivan Pului National Technical University

The influence of irradiation in a transparent condensed medium on the impact toughness of heat-resistant steels is investigated. The irradiation of a specimen in front of a concentrator causes a substantial increase (up to a factor of two) in the impact toughness of 15Kh13_F steel. Using fractographic analysis, we established that the steel was fra...

An experimental study of the thermally induced surface multiple cracking, on the example of steam superheater collector was carried out. The structure’s perforated area has 3 rows of holes, to which the connection sleeves are welded. On the first stage, the cracks initiate on the inner surface of the perforated area of the collector. These cracks a...

It was shown by tests conducted at the National Aviation University (Kiev, Ukraine) that fatigue damage of metal structures may be estimated by sensors with the surface relief pattern to indicate the accumulated fatigue damage. The nature of the deformation relief has been investigated by the light, scan and transmission microscopy, as well as by a...

The presented paper is mainly aimed at estimating the residual lifetime of metal used for the offshore gas pipeline under a low amplitude cyclic load applying S- and J-methods for pipelaying. Taking into account the preliminary effect of deformation on the welded joint and the base material of the pipe, the tests on fatigue have been carried out an...

The influence of regular relief formation modes on the microhardness of the formed groove surface near the apex at the bottom of the groove has been studied. It has been established that the rate of plastic deformation, expressed as the feed rate of the deforming element, has a significant impact on the plastic deformation mechanism, and the micros...

The problem of classification of epoxy composites used for the manufacture of aircraft structures is solved by machine learning methods: neural network, reinforced trees and random forests. Classification metrics were obtained for each method used. Parameters such as precision, recall, F1 score and support were determined. The neural network classi...

A new scheme for forming partially regular microreliefs by rotational rolling is proposed. A new transcendental curve-shaped, partially regular microrelief (of a trochoid type) is discussed; the shape and geometric parameters of its grooves are substantiated. Grooves discussed below proved to be technologically advanced, providing for a high perfor...

This paper investigates the use of machine learning methods to predict the loading frequency of shape memory alloys (SMAs) based on experimental data. SMAs, in particular nickel-titanium (NiTi) alloys, have unique properties that restore the original shape after significant deformation. The frequency of loading significantly affects the functional...

New experimental results concerning the strength properties of stainless steels are analyzed. In particular, the strength properties of steels were improved at room temperature using the preliminary impact-oscillatory loading (IOL) in liquid nitrogen. Mechanical tests performed on stainless steel 12Kh18N10T have found the IOL conditions (eimp = 9.6...

A review of the main literature sources was conducted, which made it possible to systematise various techniques, methods and software for studying the fracture mechanisms of polycrystalline materials. The principles of describing the patterns of failure surfaces based on multi-scale analysis (at the macro-, meso‑ and microlevels) were considered. A...

The results of the influence of a range of process liquids on the formation of strengthened nanocrystalline structures in the surface layers of steel samples with different carbon content during thermo-deformation treatment are presented. The liquids were mineral oil; mineral oil with active additives containing polymers; water; and an aqueous solu...

Impact-oscillatory loading of variable intensity was applied to the VT23M high-strength sheet two-phase titanium alloy in liquid nitrogen. This was carried out to investigate the effect of this loading type on changes in the mechanical properties and structural condition of the alloy upon subsequent static tensioning at normal temperature. Dynamic...

Ambient temperature has a significant effect on the electrical and luminous parameters of light-emitting diodes (LEDs), which include forward and reverse current, forward voltage, and luminous flux. This paper gives insight into the influence of ambient temperature on the electrical and luminous parameters of LEDs powered by a rectangular pulsed vo...

The thermal conductivity coefficient of epoxy composites for aircraft, which are reinforced with glass fiber and filled with aerosil, γ-aminopropylaerosil, aluminum oxide, chromium oxide, respectively, was simulated. To this end, various machine learning methods were used, in particular, neural networks and boosted trees. The results obtained were...

In adhesive joints, the integrity of the adhesive and the joined parts results from intermolecular forces. The determinationof the total elastic energy at the interface of two different bodies is possible by introducing the contact problem in the numerical modelof the system. The paper presents the optimization of a single lap adhesive joint by est...

Modern neural networks have made great strides in recognising objects in images and are widely used in defect detection. However, the output of a neural network strongly depends on both the training dataset and the conditions under which the image was acquired for analysis. We have developed a software–hardware method for evaluating the effect of v...

The article provides a detailed analysis of causes leading to defects formed on the working surfaces of conical discs of variable automatic transmissions. The defect morphology was analyzed at the macro- and microlevels. Technologies for preventing defects are proposed. In particular, they include new type partially regular microreliefs applied to...

This paper presents the results of research focused on increasing the lifespan of HPDC moulds for casting aluminium alloys by applying duplex PVD coatings in combination with laser texturing the base material before the coatings’ deposition. This article describes the HPDC process and the degradation mechanisms of the moulds that arose during this...

While investigating the variator transmission of vehicles, the relationship between the technological and service parameters of the working surfaces of conical disks treated by technological methods was established. The service properties are proposed to be enhanced by Regular MicroReliefs (RMRs) created on such surfaces. The optimal technological...

In this paper, the mechanical properties of various zones of the welded joints of a heat-resistant steel 15Kh1M1F in different states (in the initial state, after an operation on the main steam piping of a thermal power plant (TPP) for 23 years) were determined, and the fracture surfaces were analyzed using scanning electron microscopy (SEM) images...

During the TDT of 41Cr4 steel specimens, a uniformly reinforced white layer with a nano-crystalline structure is formed in the surface layers. The wear resistance of sliding friction without the lubrication of a pair of steel 41Cr4—grey cast iron EN-GJL-200 (EN) under the face-to-face (“ring-ring”) scheme has been studied. It is revealed that when...

The electrical and light characteristics of light-emitting diodes (LEDs), upon which modern lighting devices are constructed, are significantly influenced by ambient temperature. As the temperature rises, the luminous flux of LEDs diminishes, and the lifespan of LED devices also decreases. The control devices (drivers) used in LED lighting systems,...

In the present work, functional properties of three different types of regular microreliefs, formed by ball burnishing process on flat surfaces are evaluated. For their estimation, heights and material ratio curve's criteria were used, according to the international standard ISO 21920-2:2021. The influence of the regular relief's type and ball burn...

Thermo-deformation treatment refers to methods of strengthening during which strengthened layers with a nanocrystalline structure are formed in the surface layers by modifying the metal surface layer, which changes its phase and structural and chemical compositions, reduces grain size, and improves performance. Grinding of the metal structure was a...

Ambient temperature significantly affects the electrical and light parameters of LEDs, such as forward and reverse current, voltage drop LEDs and luminous flux. With an increase in temperature, the decrease in the intensity of LED radiation is explained by physical processes, including the phenomena of non-radiative recombination due to impurity le...

This book reports on innovative research and developments in the broad field of transportation. It covers solutions relating to intelligent vehicles and infrastructure, energy and combustion management, vehicle dynamics and engineering, as well as research on railway transport, aerospace technologies, logistics and security. Contributions are based...

The impact of the initial phase composition of alloys was evaluated, in particular, the content of Cu, Mn, and Mg in aluminum alloys D16ChATW, 2024-T351 and aluminum alloy T, which in its physical and mechanical characteristics is close to alloy 6013. The impact was evaluated on the effects manifested by yield sites that occur on aluminum alloys th...

Improving the reliability of transport vehicles requires ensuring their durability while reducing metal consumption [...]

The effect of heat treatment in oxygen-containing medium on fatigue properties of zirconium alloy samples was shown. This gas treatment improved fatigue life in pure bending and cyclic tensile testing. An increase in fatigue life was explained by the formation of a hardened near-surface layer. According to the data of fractographic studies of destr...

The authors have previously proposed and tested a method for increasing the wear resistance of heavy-loaded friction pairs by saturating industrial lubricants with the metallic nanopowder of the friction pair’s component that has a lower hardness. To confirm the effectiveness of this concept, this paper presents the results of experimental investig...

Based on the literature review, the article presents the analysis of approaches to classifying Gripping Devices (GDs) of Industrial Robots (IRs) and substantiates the need for systematising Pneumatic GDs (PGDs). The authors propose a classification of well-known PGDs, in which the holding force of the Manipulated Object (MO) is formed under the act...

The main regularities in the impact of varying intensity impact-oscillatory loading on the variation of the mechanical and structural properties of the VT23 high-strength two-phase transverse-rolled sheet titanium alloy have been found. The intensity of the impulse introduction of energy into the alloy under the dynamic non-equilibrium process (DNP...

The mechanical properties (hardness, cohesion, and residual stresses) of arc coatings designed for operation under conditions of boundary friction and corrosive-abrasive wear are analyzed. The coatings were formed by arc spraying cored wires (CW) with different charge compositions (the content of carbon, aluminum, and boron in CW charge varied). It...

A method of mathematical modeling of the ordered surface relief of titanium alloy Ti6Al4V after femtosecond laser treatment is proposed, which allowed obtaining the informative signs of the self-organized surface irregularities, taking into account the stochastic and cyclic nature of this process. An algorithm has been developed, and a package of c...

The quality, wear and safety of metal structures can be controlled effectively, provided that surface defects, which occur on metal structures, are detected at the right time. Over the past 10 years, researchers have proposed a number of neural network architectures that have shown high efficiency in various areas, including image classification, s...

This paper provides experimental data on the effective use of a new lubricating composition, which includes industrial oil of any brand with the addition of a nanometal of the component of a friction pair, which has a lower hardness. It is shown that this composition significantly reduces the wear resistance of the rails and wheels of rolling stock...

An analysis of modern literature sources to search for mathematical models describing the dynamics of the process of forming a regular microrelief on the inner cylindrical surface of parts, gas transmission equipment operating in severe operating conditions, in order to increase their life. It is established that there are no mathematical models de...

The impact of the illumination level on the quantitative indicators of mechanical damage of the rolled strip is investigated. To do so, a physical model experiment was conducted in the laboratory. The obtained images of defects at light levels in the range of 2–800 lx were recognized by a neural network model based on the U-net architecture with a...

The problem of ensuring technological reliability and environmental friendliness of the natural gas transportation process is considered along with the main approaches to risk assessment and management at industrial facilities. To increase the trouble-free operation of the gas transmission system, a comprehensive risk management system has been pro...

The conditions of ecologically dangerous emergencies in the oil and gas industry have been investigated in the work. The high degree of environmental risk that is present in case of emergency requires measures to prevent their occurrence. To improve the environmental risk management system in the oil and gas industry, a comprehensive study of both...

The correlation between the service characteristics of the working surfaces of car parts belonging to the rotary body class, and quality parameters—in particular, the height-related roughness parameter Ra—was estimated. Low values of Ra were found to be unable to guarantee an optimal microrelief geometry and, accordingly, high-performance character...

The basic regularities in the influence of processing parameters on the geometrical characteristics of the partially regular microreliefs, formed on the rotary body face surface, are established. Combinations of partially regular microreliefs are formed by using a contemporary CNC milling machine, and an advanced programing method, based on previou...

Features of the defect class “scratches, attritions, lines”, their geometric structure, and their causes are analyzed. An approach is developed that defines subclasses within this class of technological defects based on additional analysis of morphological features. The analysis of the reasons for these subclasses allows additional information to b...

We develop and study an automated method for the detection and classification of three types of technological defects in rolled metal products. The method is based on the ResNet50 neural network classifier, which makes it possible to recognize three classes of defects in the images of flat surfaces with a total accuracy of 95.8% on the basis of the...

The micro- and macroscopic fatigue crack growth (FCG) rates of a wide class of structural materials were analyzed and it was concluded that both rates coincide either during high-temperature tests or at high stress intensity factor (SIF) values. Their coincidence requires a high level of cyclic deformation of the metal along the entire crack front...

Physical-mechanical models for predicting the fatigue life of aluminum alloys D16ChATW and 2024-T351 are proposed and tested. Damage accumulation patterns are established for these alloys in the initial state and after dynamic non-equilibrium processes (DNP) of different intensity that occur at maximum cycle stresses σmax from 340 to 440 MPa, cycle...

We develop new methods of the laboratory defectometry of biocorroded microareas in structural steels based on the quantitative analysis of variations of their roughness. We establish the influence of sulfatereducing bacteria on the microgeometry of surface topography of specimens of 17G1S-U and 20 steels. It was discovered that bacteria are accumul...

The scheme of arrangement of grooves of partially regular microrelief of type II shifted by 0.5 angular pitch is considered. Such grooves are formed by vibration on end faces of rotary bodies. An analytical dependence was obtained to determine the relative area of a partially regular microrelief depending on the geometric parameters of V-shaped gro...

Dynamic non-equilibrium processes (DNP) caused by impact-oscillatory loading affect the mechanical/structural changes and fatigue life of aluminium alloy 2024-T351 under static tension at a load frequency of 110 Hz. The main patterns of this effect are considered. Dynamic deformation εimp was chosen as the control parameter of DNP. In other words,...

This study focused on improving plasma-electrolytic oxidation (PEO) technology of aluminum alloys with the aim to increase their abrasive wear resistance. Using thermodynamic calculations of the reactions between hydrogen and aluminum oxides in solid, liquid and gaseous states, it is established that hydrogen (while in the channels of microplasma d...

This paper deals with the determination of the basic corrosion characteristics of metallic materials used as components in car construction to achieve a lighter vehicle with higher rigidity, a more complex “hybrid” of diverse materials is needed for the car body structure. Due to the different types of material used in the manufacture of components...

Causes of the in-service damage to hydrocylinder liners were investigated, and the requirements to their working surfaces were systematized. Roughness parameter Ra was found not to provide a precise estimate of the surface quality because its reduction did not affect surface microgeometry. Additionally, the surface quality was assessed by the Abbot...

Steel defect diagnostics is important for industry task as it is tied to the product quality and production efficiency. The aim of this paper is evaluating the application of residual neural networks for recognition of industrial steel defects of three classes. Developed and investigated models based on deep residual neural networks for the recogni...

Regularities in the structure self-organization of aluminum alloy D16ChATW due to impact-oscillatory loading and its influence on changes in the mechanical characteristics during subsequent static tension and cyclic loading at a frequency of 110 Hz are revealed. Dynamic deformation of the alloy under dynamic non-balanced processes (DNP) due to impa...

We construct diagrams of fatigue crack growth for St3ps steel placed in demineralized water and in saturated solutions of the Nurelle D insecticide and UN-32 complex liquid fertilizer and evaluate the corresponding values of threshold and critical stress intensity factors. It is established that, in a Nurelle D solutions, the fatigue crack-growth r...

The process of laser welding of sheets of HSLA (high-strength low-alloy steel), DP600 (dual-phase steel) and TRIP steels was investigated. A weld was successfully made in a double-sided hot-dip galvanized sheet with a thickness of 0.78–0.81 mm using a laser power of 2 kW per pass without any pretreatment of the weld zone. Microstructure studies rev...

Invention proposes an adaptive gripping device of an industrial robot, which combines functions of capturing different-shape manipulation objects with control of deviations from the shape of these objects. The device is a T-shaped frame with three Bernoulli grips pivotally mounted thereon and a pneumatic sensor. Analytical dependencies are presente...

Classification of steel surface defects in steel industry is essential for their detection and also fundamental for the analysis of causes that lead to damages. Timely detection of defects allows to reduce the frequency of their appearance in the final product. This paper considers the classifiers for the recognition of scratches, scrapes and abras...

Purpose: of this paper is to analyse the mechanism of near-neutral pH corrosion of main gas pipelines. The stages of main gas pipelines in model environments that meet the soil conditions of Ukraine have been studied. Design/methodology/approach: The corrosion rate of steel specimens from steels 17G1S-U and 20 and the influence of borate buffers on...

The aim of the paper was to investigate the helical rolling parameters (a number of passes) for the microstructural modification and the low-temperature impact toughness improvement of the 09Mn2Si High Strength Low-Alloyed (HSLA) steel. In order to achieve this purpose, work spent to crack initiation and propagation was analyzed and compared with p...

New experimental results on extending the fatigue life of aluminum alloys D16ChATW and 2024-T351 due to impact-oscillatory loading of different intensities and the use of nanosolutions of different materials are generalized. Dynamic deformation of alloys subjected to dynamic non-balanced processes (DNP) under impact-oscillatory loading εimp was cho...

The analytical dependences for determining the overlap area of V-shaped grooves of partially regular microrelief shifted by an angular pitch of 0.5° are established. The V-shaped grooves are formed on the end surface of the rotary body by vibration. In addition, the intersection between groove elements can be of different types. The relationship be...

The methods for ensuring long-term and safe operation of marine equipment due to comprehensive repair technologies that use epoxy oligomers and new compositions based on them are developed. The influence of temperature and UltraSonic Treatment (UST) on the rheological properties of the pure epoxy matrix and compositions based on it is explored. The...

The article considers the schemes of groove arrangement on a partially regular microrelief of type I with coaxial grooves formed on end faces of rotary bodies because of vibration. An analytical dependence was obtained to determine the relative area of a partially regular microrelief depending on the geometrical parameters of the V-shaped grooves....

In this article, we analyse five types of coatings, in terms of their microstructure, hardness, porosity, and wear resistance, in the as-sprayed state. The coatings are WC-based (WC-FeCrAl, WC-WB-Co, and WC-NiMoCrFeCo), alloy-based (Co-MoCrSi), or nanoWC coating-based (nanoWC-CoCr). Two tests were applied to assess the wear resistance of the coatin...

A method of computer modeling of a surface relief is proposed, and its efficiency and high accuracy are proven. The method is based on the mathematical model of surface microrelief, using titanium alloy Ti6Al4V subjected to processing with femtosecond pulses as an example. When modeling the examples of microrelief, changes in the shape of segments-...

The micromechanisms of biocorrosion damage to specimens of 17G1S-U pipe steel are studied on the basis of a combination of the profilometry approaches with fracture mechanics. We develop new methods for the numerical analysis of stress concentration factors regarded as parameters of localization of the microscopic concentrators of corrosion stresse...

This work is devoted to establishing the effect of High Velocity Oxygen-Fuel (HVOF) method for spraying coatings with vanadium carbide (VC) (as an alternative to galvanic chromium plating) on the wear resistance of obtained coatings in friction conditions with a rigidly fixed and non-fixed abrasive. The initial components for spraying coatings were...

The structure and mechanical properties of the 09Mn2Si high-strength low-alloyed steel after the five-stage helical rolling (HR) were studied. It was revealed that the fine-grained structure had been formed in the surface layer ≈ 1 mm deep as a result of severe plastic strains. In the lower layers, the “lamellar” structure had been formed, which co...

To study a full range of the mechanical properties on small-sized flat specimens from the pipe steel, including the characteristics of crack resistance after the realization of certain loading modes, the authors used the method of complete stress–strain diagrams. This method was previously substantiated both theoretically and experimentally by prof...

We establish basic regularities of influence of sulfate-reducing bacteria on the biocorrosion of 17G1S-U steel. The mechanisms of degradation of steel surfaces are generalized by the methods of topographic analysis, microindentation, and fractographic diagnostics. We also propose inhibitors of biocorrosion and substantiate the efficiency of their a...

A new adhesive material and a restoration technology for marine equipment units are proposed. The optimal content of hardeners of different nature is found, and the effect of temperature conditions used for crosslinking epoxy resin DER-331, on the adhesive properties of the polymeric material is determined. The polymerization of the epoxy oligomer...

The effect of sulfate-reducing bacteria (SRB) on the corrosion of steel 20 was investigated. Results demonstrated that the chemical composition of corrosion products, the corrosion rate, and corrosion type were altered due to the adherence of SRB and the subsequent formation of biofilm on the steel 20 surface. The micromechanisms of biocorrosion da...

An automated method for detecting and classifying three classes of surface defects in rolled metal has been developed, which allows for conducting defectoscopy with specified parameters of efficiency and speed. The possibility of using the residual neural networks for classifying defects has been investigated. The classifier based on the ResNet50 n...

The structure nonuniformity a VT23 titanium alloy after shock and vibration loading is established to lead to larger plasticity of the material and changes in fracture mechanisms. Localization of deformation processes influences the sizes and quantitative distribution of tear dimples on the fracture surface. The approach was advanced to detect tear...

The paper focuses on the possibility of HPDC molds restoration for aluminium casting by laser and MAG weld cladding with a welding wire of the same grade like the base material. A chemical analysis of the weld deposits showed a decrease in the content of some elements in the MAG deposit due to the higher thermal input to the weld bath. The lower he...

Based on thermodynamic calculations, the possible options for forming of oxide-ceramic layers (Al2O3) alloyed with copper and nickel inclusions have been considered. For this purpose, plasma-electrolyte oxidation (PEO) of the directly aluminum alloys surfaces or the gas-thermal coatings sprayed on top of them was used. A sequence of reactions occur...

To the article “Effect of Shock and Vibration Preloading on the Parameters of Tear Dimples and Their Conglomerates,” by P. O. Marushchak, I. V. Konovalenko, and M. G. Chausov, Vol. 51, No. 6, pp. 868–878, November, 2019.