Engineering

DYNAMIC AND MATHEMATICAL MODELING OF VIBRATION PROCESSES IN GAS TRANSPORTATION EQUIPMENT

PROKOPENKO О. — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-01

The article considers aspects of an integrated approach to vibration inspections of gas transportation equipment. A critical analysis of scientific literature and regulatory documents covering existing approaches to solving issues related to determining the actual technical condition of equipment, assessing its service life, and making decisions on extending its service life has been carried out. The application of vibroacoustic research to solve control problems has been analyzed by studying the scientific literature. Dynamic and mathematical models of gas transportation equipment have been developed, particularly models of the general level and harmonics of the vibration velocity spectrum of bearing housings, models of oscillations of the centrifugal supercharger housing at the rotor blade frequencies, models of the force generated by the turbine or compressor blade stage of a gas turbine unit transmitted to the rotor, and models of gas pressure pulsation in the pipe. The modeling has been performed using the developed dynamic and mathematical models. The analysis of the modeling results, corresponding to the results of experimental studies, has been presented.

In cites: Prokopenko О., Antonenko N., Tiupa I., Ananieva Y., Khalimov D.,. Khalimov P. (2025). Dynamic
And Mathematical Modeling Of Vibration Processes In Gas Transportation Equipment. Engineering, (35), 6-16.
https://doi.org/10.26565/2079-1747-2025-35-01

ANALYSIS OF ENERGY EFFICIENCY AND OPERATIONAL RELIABILITY OF HEAT AND MASS EXCHANGE EQUOPMENT AT POWER PLANTS FOR IMPROVING THEIR PERFORMANCE QUALITY

Тетяна Фурсова — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-02

Energy efficiency and reliable operation are fundamental factors shaping the modern energy sector under the paradigm of sustainable development. Heat and mass exchange equipment constitutes a critical component in the functioning of thermal and nuclear power plants (TPP and NPP), enabling efficient thermal transfer and optimizing the use of available energy resources. This article presents a comprehensive analysis of the energy efficiency and operational reliability of heat and mass exchange devices used in turbine units, focusing on improving the performance and capacity of low-potential complex condensing power units. Through statistical analysis and expert evaluation methods, key reliability indicators of heat exchange equipment in turbine installations were examined. The study highlights the predominance of condensers as essential components in low-potential complexes and investigates common defects affecting their operation, including corrosion, erosion, mechanical wear, and sealing failures. The research applies finite element analysis and automated engineering design techniques to assess the stress-strain states of condenser structures, pinpointing critical zones prone to mechanical failure. Additionally, temperature distribution within the condenser under stationary operating conditions is modeled to optimize thermal performance. The findings underline the significant impact of material degradation and mechanical stresses on the durability and efficiency of heat exchange apparatuses. Consequently, the article offers targeted recommendations for the enhancement of heat and mass exchange equipment. These include the adoption of advanced corrosion-resistant and high-strength materials such as titanium alloys and composites, implementation of automated monitoring and diagnostic systems for real-time condition assessment, and refinement of condenser designs to improve thermal-hydraulic performance and minimize energy losses. The proposed measures aim to elevate the operational reliability, extend the service life, and increase the energy efficiency of power plant heat exchange systems, contributing to reduced operational costs and environmental impact. This work supports the advancement of energy technologies aligned with global trends toward sustainable and efficient power generation.

In cites: H.I. Kanuk, T.M. Fursova, А.U.Mezeria, D.O.Chyrochkin, O.M. Epik, D.O.Shvorak (2025). Analysis
of energy efficiency and operational reliability of heat and mass exchange equopment at power plants for
improving their performance quality. Engineering, (35), 17-25. https://doi.org/10.26565/2079-1747-2025-35-02

INCREASING THE SPEED OF THE CONTROL SYSTEM OF THE THYRISTOR COMPENSATOR OF REACTIVE POWER OF ELECTRIC ARC FURNACES

KHOMIAK E. — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-03

Electric arc furnaces (EDP) contain furnace transformers with a power factor of 0.3, which randomly consume reactive power in the form of jumps when non-sinusoidal currents are present. Thyristor reactive power compensators (TRPC) are used to compensate for the latter. When reactive power jumps occur, the known TCRP control system provides a regulation time of 0.02 s, since it determines the control angle of the thyristors for the last period of the mains voltage. At the same time, during the transient processes of TCRP regulation, the reactive power of the EAF is not compensated.

The aim of the work is to increase the speed of the TPRC control system in order to reduce uncompensated reactive power in transient control processes. The goal is achieved by the fact that, unlike the known control system, the control angle is determined every half-period by solving the equation of minimizing the functional of the root mean square error of the equality of the reactor current and the transformer current with a capacitor at the moments of the amplitude value of the mains voltage. As a result, the speed of the control system increases to 0.01 s.

The scientific novelty of the work lies in the further development of the expression of the functional for determining the control angle of the TCRP at each half-period of voltage. Practical significance: doubling the speed of the TCRP control system reduces reactive power consumption in transient control processes by half and increases the resulting power factor to unity. The performance of the proposed TCRP control system has been verified on a mathematical model

In cites: Kovalov V., Khomiak E., Miroshnyk Ye., Tymofieiev О., Krutko V., Shevchenko V., (2025). Statistical methods for quality control of small-batch machining. Engineering, (35), 26-35.
https://doi.org/10.26565/2079-1747-2025-35-03 ( in Ukraine)

STATISTICAL METHODS FOR ASSESSING THE QUALITY OF TECHNOLOGICAL PROCESSES WITH LIMITED INFORMATION

LOMANOV K. — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-04

The article discusses the issue of improving the efficiency of quality management in the mechanical processing of machine-building products in small-batch production. The main focus is on the application of statistical control methods, in particular the cumulative sum method, as a tool for diagnosing the accuracy of the technological process on numerically controlled lathes. The feasibility of using cumulative sum control charts instead of traditional methods that do not take into account the dynamics of parameter changes over time is justified.

The study analysed the results of mechanical processing of a crankshaft flange made of 20X steel on a 16K20F3 machine. Twenty-five samples of five products each were taken to assess deviations from the nominal value and construct the corresponding cumulative curves. Based on the experimental data, graphs of cumulative sums were constructed, and a reference chart for use in production was proposed. A clear relationship was established between the slope of the cumulative sum curve and the quality level of the machining process: a horizontal curve corresponds to a satisfactory state, a downward curve corresponds to poor quality, and an upward curve corresponds to high quality.

A mathematical apparatus is proposed for calculating a comprehensive indicator of machining quality, taking into account the weight of individual quality indicators (accuracy, roughness, spatial deviations, etc.). It has been established that this comprehensive indicator correlates with the level of the technological process and can be an effective criterion for its assessment.

The results of the study can be used for operational control and quality improvement in the production of small batches of machine-building products, which is especially relevant for small-batch and multi-product production.

In cites: Lomanov K., Holovko M., (2025), Statistical methods for assessing the quality of technological processes with limited information. Engineering, (35), 36-45. https://doi.org/10.26565/2079-1747-2025-35-04 (in Ukraine)

DETERMINATION OF LOADS ARISING DURING MOVEMENT OF TRAVELING WHEELS OF BRIDGE CRANES

PEREVOZNYK I.A. — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-05

Different working conditions and design features of individual lifting machines and crane paths cause a wide variety of mechanisms for moving cranes and crane trolleys. The movement resistance of the crane or trolley is formed when the wheels roll on the rails and in the wheel bearings.

During the operation of the crane, the running wheels are under the influence of various loads - the weight of the cargo, the crane's own weight, air pressure, the force of inertia and loads that occur when the cranes are skewed on the under-crane paths, when there are defects in the under-crane paths and the crane's undercarriage.

The dimensions of the rails must correspond to the loads and dimensions of the running wheels and are ensured by calculating them for bending and for local compression under the wheel. During the operation of the crane, the load on the running wheels sometimes varies widely. Its durability, reliability, ease of manufacture and maintenance largely depends on the structural form of the beam. The design of the closed profile gives the maximum increase in torsional stiffness. Tilting of a moving crane is the result of such reasons as slipping or slipping of the crane's drive wheels on the rails, differences in the diameters of the drive wheels, incorrect installation of the wheels, and defects in the crane paths. Impact loads that occur during the movement of the running wheels occur in two cases: when the cranes hit the end stops and when passing the joints of the rail path and local irregularities. In order to reduce shock loads, modern cranes and cargo trolleys have buffers when they approach the end stops, which allow to extend the working stroke of the crane Impact loads that occur during the movement of the running wheels occur in two cases: when the cranes hit the end stops and when passing the joints of the rail path and local irregularities. In order to reduce shock loads, modern cranes and cargo trolleys have buffers when they approach the end stops, which allow to extend the working stroke of the crane and increase the reliability and safety of crane operation. The choice of the type of running rail is related to the amount of load on the running wheels and the design features of the movement mechanism - conical running wheels can move only on a convex rail, cylindrical wheels - on both convex and flat rails. The wear and tear of the elements of the under-crane path leads to the failure of the metal structures of the under-crane beams, which causes significant economic losses. The transition in crane structures from riveted under-crane beams, which had discrete belt connections with defined mobility to welded beams with a rigid system of belt connections without structural compensation of mobility, led to a significant decrease in the durability of welded beams.

The local stress state of the wall in the welded crane girders, which determines the fatigue strength in this zone, can only be adjusted using the crane rail. But the operation of the under-crane path has not been properly investigated until now. Possible deformations of both the running wheels themselves and the rail tracks depend to a large extent on the height and nature of the rail joint, the shape of the rail and the speed of the running wheels. In the article, a more precise definition of the loads that occur in the under-rail beams was carried out, some assumptions were rejected and new calculation formulas were obtained. In addition, an analysis of the influence of the method of installing rails on the value of force factors was carried out.

In cites: I.A. Perevoznyk (2025). Determination of loads arising during movement of traveling wheels of bridge cranes. Engineering, (35), 46-53. https://doi.org/10.26565/2079-1747-2025-35-05 (in Ukraine)

Dependence of ground pressure on internal pressure in winter tires Triangle Snowlink size 225/55 R18

Oleksandr Pysartsov — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-06

In the course of studying the influence of internal tire pressure in M1 category vehicles on their interaction with the supporting surface, it was established that no in-depth research has yet been conducted for modern tire sizes. Considering the relevance of this issue for improving the off-road performance of general-purpose vehicles when driving on rough terrain, a corresponding experimental study was initiated.

This study investigates the relationship between the internal pressure of Triangle Snowlink winter tires in size 225/55 R18 and the pressure exerted on the supporting surface by the vehicle. Optimizing tire pressure is crucial for increasing vehicle mobility, reducing the load on the road infrastructure, and improving handling, especially when driving on soft or uneven surfaces (such as sand, snow, or mud).

The research also considers methods for influencing the pressure exerted by the vehicle on the supporting surface and proposes practical measures aimed at improving off-road performance. The main goal of the study was to determine the nature of the dependence between changes in internal tire pressure and the corresponding changes on the supporting surface pressure.

The field experiments were conducted according to a defined methodology using an M1 category vehicle with improved off-road capabilities — the Opel Grandland 1.5 BHDi. The tests were performed on a flat concrete surface using winter tires Triangle Snowlink size 225/55 R18.

The experimental results demonstrated that reducing tire pressure from 2.2 atm to 1.5 atm leads to a decrease in ground pressure from 1.39 to 1.07 kg/cm². This indicates a potential improvement in the vehicle’s off-road capability. The study analyzed the mechanism by which vehicle mass and tire contact area influence on the supporting surface. An almost inverse proportional relationship was observed between internal tire pressure and the supporting surface.

The paper presents graphical and analytical dependencies that justify the feasibility of reducing tire pressure when operating vehicles under difficult road conditions. The findings may be useful in the design of wheeled vehicles and in their practical use in off-road environments.

In cites: Pysartsov O. (2025). Dependence of ground pressure on internal pressure in winter tires Triangle Snowlink size 225/55 R18. Engineering, (35), 54-64. https://doi.org/10.26565/2079-1747-2025-35-06
(in Ukraine)

EXPERIMENTAL STUDIES OF METAL STRUCTURE LOADS WHEN USING ROLLING WHEELS OF THE NEW DESIGN

FIDROVSKA N. — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-07

The article considered the problems of experimental determination of the advantages of running wheels of a new design with elastic inserts. The study was carried out on an operating electric, support, two-girder bridge crane with a load capacity of 10 tons and a span of 22.5 m. With the help of strain gauges assembled in a half-bridge circuit and connected to the Zetlab210 analog-digital converter, the deformations of the main beam at the moment of lifting and moving a load of different weights were determined. The lifting and moving of the cargo was carried out under the same conditions on standard wheels of the cargo cart and on wheels with an elastic rubber insert.
Graphs of the deformation of the main beam were obtained. In the further calculation, the dependences of the stress state at each moment of the movement of the load were obtained when using both standard wheels and wheels with an elastic rubber insert. The dependences and duration of oscillations that occur during the cycle of lifting and moving the load were also revealed. The cycle of the experimental study consisted of lifting the load in the extreme left position with the cargo cart, moving the cargo to the extreme right position, and returning the cargo cart with the cargo to the initial position.

The scientific novelty of the work consists in the application of a new, modernized design of the running wheels of a cargo cart with an elastic rubber insert, which effectively dampen fluctuations in the metal structure of the bridge crane.

Experimental studies of loads that occur in the metal structure of the bridge of the overhead crane were carried out using double-sided cylindrical wheels on the truck of the operating overhead crane. During the registration of the resulting loads, the standard wheels were first installed on the trolley of the overhead crane, then the standard wheels were replaced with modernized wheels (with an elastic, rubber insert).

According to the results of experimental studies, it was found that the stress in the main beam of the bridge crane was reduced by 18% and reducing peak vibrations by 20 seconds at the same load lifting and moving cycles. Also, when using wheels with an elastic rubber insert, the damping period of oscillations at the end of the load movement cycle is reduced by at least 30%.

In cites: Fidrovska N., Slepuzhnshkov E.D., Kyrychenko, I., Ragulin V. (2025). Experimental studies of metal structure loads when using rollingwheels of the new design. Engineering, (35), 65-73. https://doi.org/10.26565/2079-1747-2025-35-07 (in Ukraine)

ADHESIVE-ELASTIC MODEL OF DETERMINING THE FRICTION COEFFICIENT OF ENGINEERING MATERIALS IN CONNECTION WITH SURFACE ROUGHNESS INDICATORS

Микола Рябчиков — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-08

The article addresses the relevant issue of reducing the coefficient of friction under dry contact conditions between surfaces of mechanical components by optimizing surface roughness parameters. Based on an analysis of current research in the field of tribology, it is established that traditional approaches focused on lubrication are not effective or feasible in several high-tech processes such as vacuum metallization, application of functional coatings, and others. Therefore, the search for methods to reduce friction under dry contact conditions is particularly important for improving the durability and energy efficiency of technical systems. The study focuses on the development of a mathematical model that considers both the elastic deformation of surface microasperities and the adhesive interactions arising in the contact zone. To describe the bending of microasperities, a plate bending equation is used, while the Hertzian contact model is applied to describe the contact interaction. As a result of numerical modelling, it is shown that the coefficient of friction significantly depends on the surface roughness height (Ra) and average spacing (Sm), as well as on the material properties that determine their elasticity and adhesive behaviour. It is found that with changes in the geometric parameters of microasperities and the properties of the materials, the coefficient of friction can exhibit both increasing and decreasing trends. Of greatest engineering interest is the identification of a clearly defined minimum of the friction coefficient for a specific combination of surface roughness parameters and material characteristics. This creates opportunities for the intentional design of surface finishing technologies aimed at achieving optimal frictional performance without the use of lubricants. The article provides graphical dependencies illustrating the behavior of the friction coefficient as a function of surface parameters and adhesion level. The theoretical conclusions presented can be used to determine optimal roughness values when designing and manufacturing machine parts that operate in vacuum, biomedical devices, or environments with limited lubricant access. The authors also emphasize the need for further research aimed at determining the coefficients of adhesive interaction (k₁ and k₂), as well as refining the role of the actual contact area, which may significantly affect the frictional force.

In cites: Riabchykov M., Puts V., Martyniuk V. (2025). Adhesive-elastic model of determining the friction coefficient of engineering materials in connection with surface roughness indicators. Engineering, (35), 74-84. https://doi.org/10.26565/2079-1747-2025-35-08 (in Ukraine)

MODELING THE TRIBOLOGICAL PROPERTIES OF POLYMER COATINGS BASED ON PHENYLONE WITH COPPER (II) COMPLEX MODIFIERS USING MATLAB

Oleksandr STOVPNYK — 2025-07-03

DOI: https://doi.org/10.26565/2079-1747-2025-35-09

Purpose. This study is dedicated to designing and evaluating antifriction polymer coatings based on phenylone C2, an aromatic polyamide with high thermal stability, modified with copper (II) complexes of the composition [Cu(HL)X₂]₂, where HL represents derivatives of benzimidazole-2-thiocarboxylic acid arylamides. The research aims to model the tribological behavior of these coatings, focusing on the effects of sliding speed, specific load, and modifier concentration, to improve the performance and durability of friction units in mechanical engineering applications under high-load conditions typical of industrial machinery.

Methods. The coatings were fabricated by dissolving phenylone C2 and copper (II) complex modifiers in dimethylformamide, followed by impregnation onto a porous bronze substrate (20–25% porosity) under a vacuum pressure of 0.00001 MPa for 30 minutes. The coated samples were cured at 420 K for 1.5 hours and then at 723 K for 2 hours to ensure complete hardening. Tribological testing was conducted using an SMT-2010 friction machine in a block-on-disk configuration, lubricated with I-40A industrial oil (GOST 20799-88). Tests spanned sliding speeds of 0.15 to 1.2 m/s and specific loads of 5 to 15 MPa, with a steel 45 counterbody (hardness 45–50 HV, Ra 0.4–0.63 μm). Friction coefficients were measured with an accuracy of ±0.001, and wear rates were determined gravimetrically with a precision of ±0.01 mg/m after 10-hour test cycles. Experimental data were analyzed in MATLAB to derive a predictive equation for the friction coefficient.

Results. Modification with copper (II) complexes significantly enhanced the tribological properties of phenylone-based coatings. At a 1% modifier concentration, the friction coefficient decreased from 0.080 to 0.045, and wear resistance improved by 60%, with coating No. 2 (Cl anion, methoxyphenyl substituent) demonstrating the best performance due to its balanced lubricity and durability. MATLAB processing yielded the equation f(V,P)=0.0335+0.0095⋅V+0.0005⋅P, accurately describing the friction coefficient’s dependence on sliding speed (V, m/s) and specific load (P, MPa) with a maximum deviation of less than 5%. Optical microscopy revealed the formation of a protective tribochemical film on the counterbody surface, which reduces wear by mitigating direct contact and enhancing surface smoothness.

Conclusions. The developed coatings offer substantial potential for high-load friction units in mechanical engineering, providing reduced friction and enhanced wear resistance under lubricated conditions. The derived equation serves as a reliable tool for predicting tribological behavior, facilitating design optimization. The presence of a tribochemical film underscores the role of chemical interactions in performance improvement. Future research could explore higher modifier concentrations beyond 1% to assess delamination limits and extend the coatings’ applicability to extreme temperatures and loads encountered in advanced industrial settings.

In cites: Stovpnyk O. V. & Sytar V. I. (2025). Modeling the tribological properties of polymer coatings based on phenylone with copper (II) complex modifiers using matlab. Engineering, (35), 85-94. https://doi.org/10.26565/2079-1747-2025-35-09