Science and Transport Progress

Determination of the Constituent Elements of a Three-Component Hybrid Energy Storage Device for a Plug-In Power Plant for Rolling Stock

B. G. Liubarskyi — 2025-09-26

Purpose. The study is aimed at determining the quantitative components of a hybrid three-component energy storage device for a plug-in power plant of rolling stock. Methodology. It was determined that according to the criteria of mass, volume, cost and cost of one kilowatt-hour, none of the options for a single-element storage device simultaneously provides the minimum indicators for all criteria. Thus, it is rational to use a combined three-component energy storage device. An algorithm for setting the problem of conditional minimization of the cost of elements of a three-component combined storage device is considered, which includes the following: 1) setting the objective function in the form of the total cost of the elements; 2) determining the parameters – the number of branches of each type of storage device; 3) setting restrictions on the given energy capacity, power, mass and dimensions and restrictions on the parameters; 4) determining the method for solving the problem, which is the Weyl method. Findings. The authors proved: 1) Analysis of the obtained general results proves the following. With an increase in the specified power, the number of branches of supercapacitors increases and the number of branches of LTO cells decreases. This is due to the fact that supercapacitor cells have the best charge/discharge power indicators, and LTO cells have the best energy-intensive indicators. As for LFP cells, the number of branches ranges from 5 to 24, which provides additional capacity of the storage elements, especially at medium power values; 2) The total capacity component of LTO cells increases with a decrease in the storage power and is 11.5% of the total capacity to 66.4% when the power is reduced from 4,740 kW to 920 kW. The component capacity of supercapacitors, on the contrary, decreases with a decrease in the storage capacity and is 70.6% of the total capacity to 2.4% when the capacity decreases from 4,949 kW to 920 kW, which is due to the expediency of using supercapacitors at high capacities. Originality. The authors of this work have for the first time developed a method for determining the optimal parameters of a combined three-component energy storage based on solving the problem of conditional minimization taking into account mass and dimensional constraints. Practical value. Based on the results obtained, it is possible to determine the parameters of combined storage for rolling stock using the example of plug-in hybrid power plants of rail rolling stock of a quarry locomotive.

Prediction of the Technical Condition of the Brake System of a Diesel Locomotive using the Markov Analysis Method

O. V. Nevedrov — 2025-09-26

Purpose. The article considers the issue of predicting the technical condition of the brake system of a diesel locomotive using the Markov analysis method. The purpose of the study is to build a mathematical model that allows for high-precision assessment of the current and future technical condition of the system based on statistical data. The proposed model allows for formalizing transitions between the technical states of serviceable, partially faulty, critical, and restored, which allows for effective maintenance planning. Methodology. To solve the problem, we will build
a mathematical model for predicting the technical condition of the brake system of a diesel locomotive based on
a discrete Markov process with four states: «serviceable», «partially faulty», «critical», «restored». This model allows for formalizing the probabilities of transitions between states at discrete points in time and assessing the dynamics of system degradation. The set of system states is represented as «serviceable» (normal functioning, no maintenance required), «partially faulty» (additional diagnostics or maintenance required), «critical state» (failure state requiring repair or replacement of a node – absorbing state), «restored» (after repair, the state is close to the initial state).
The structure of the transition matrix is constructed and the probability of transition from state to state is denoted. Finding. Based on the above data, the vector of the average time to absorption is constructed. Originality. The novelty of the work lies in obtaining the matrix N, which contains information about the expected number of times when the system, starting from a certain initial state, can transition or remain in an acceptable state until it enters an absorbing critical state. This makes it possible to identify weaknesses, namely frequent returns to a partially faulty state. It is also possible to determine the dynamics of the degradation of the brake system and, depending on it, optimize maintenance. Practical value. As part of the research, a formalized mathematical model of the locomotive brake system was constructed in the form of a discrete Markov process with four defined technical states.

Mathematical Formulation of the Objective Function for Improving the Protection Efficiency of Load-Bearing Elements of Freight Cars Using Anti-Vibration Coatings

O. V. Fomin — 2025-09-26

Purpose. To develop a mathematical model of an objective function that enhances the efficiency of protecting load-bearing elements of freight cars by optimally selecting anti-vibration coatings, taking into account operational conditions, cargo type, structural materials, and the intensity of dynamic loads. Methodology. The study employs methods of mathematical modeling, functional optimization, and numerical analysis. The efficiency criterion is defined as an integral function minimizing the transmission of vibrations from the bogie to the load-bearing structures of the car body. A model was constructed that accounts for the mechanical properties of coatings, their thickness, adhesion to the surface, and application cost. The influence of environmental parameters and cyclic loading was also analyzed. Findings. A generalized mathematical equation of the efficiency objective function was developed, which can be adapted to various types of railcars and operating conditions. Model validation was carried out using the center sill of an open-top freight car with different types of polymer coatings. Optimal coating layer configurations were obtained, providing up to a 35% reduction in vibrational deformations compared to traditional protection schemes. Originality. For the first time, an objective function based on multiparametric optimization has been proposed, considering both mechanical and operational-economic impact factors. The model allows flexible adjustment to specific technical requirements. Practical value. The developed mathematical model of the objective function enables engineers and designers to make informed decisions when selecting anti-vibration coatings for the load-bearing elements of freight railcars. By accounting for a comprehensive set of factors – including cargo type, operating conditions, structural materials, and the intensity of dynamic loads – the model ensures a customized approach to each specific design task. The proposed approach can be implemented in the design and modernization processes of freight cars, contributing to increased service life, reduced maintenance costs, and improved cargo transportation safety. The model enables automation of the coating selection process within computer-aided engineering decision support systems.

Research of the Dynamic Indicators of the Track Coil of a Full-Scale Model of High-Speed Magnetic Levitation Transport

Y. M. Chupryna — 2025-09-26

Purpose. The main idea of the work is to experimentally study the dynamic performance of the track coils of a physical model of high-speed magnetolevitation transport with further comparison of their characteristics for a reasonable choice of a rational coil according to such criteria as current rise time and thrust force. Methodology. The research was carried out experimentally. A test bench for determining the dynamic characteristics of track coils was developed specifically for these purposes. The main dynamic indicators include: the time of current rise in the coil, and the auxiliary indicators include: traction force and temperature conditions. Measurements of the time characteristics, in particular, the current rise, were carried out using an oscilloscope, and the traction force was determined by gradually loading a platform mounted on a levitating magnet with a non-magnetic load. Temperature conditions were recorded using a thermal imager. During the work, four types of coils were studied, which differ from each other in such indicators as wire diameter, number of turns, electrical resistance, and inductance. For each of the coils, a series of measurements were made taking into account changes in the duty cycle of the electrical signal. This approach made it possible to assess the effect of the electrical signal duty cycle on the operating modes and dynamic performance of the coils under study. Findings. As a result of the experimental study, the time characteristics of four samples of track coils for a physical model of high-speed magnetolevitation transport were obtained, in particular, the time of current rise, the magnitude of the traction force, and the temperature conditions under load. It has been established that the coil labeled «A» is characterized by relatively high dynamic indicators, namely: the shortest time to reach its operating mode, which is 0.4 s, and the highest thrust, which is 139 g of cargo. In general, these indicators make it possible to determine the coil with the «A» marking as the most rational option for use in a full-scale model.Originality. The prerequisites for further characterization of the physical model of a two-mode magneto-levitation module are created. For the first time, the dynamic parameters of the track coil for a physical model of high-speed magneto-levitation transport were obtained during a laboratory study of its experimental samples. Practical value. Based on the results of the research, a methodology has been developed that establishes a link between the coil's structural parameters and its dynamic performance, which makes it possible to establish rational parameters of the track coil. The parameters of the electrodynamic process, in particular, the time of current rise, the magnitude of the traction force, and the temperature conditions of the coil operation under experimental load were determined.

The Effect of Stress Pulses on the Limited Endurance Under Cyclic Loading of Thermal-Hardened Carbon Steel

I. O. Vakulenko — 2025-09-25

Purpose. The assess effect of stress pulses on the cyclic endurance of thermal-hardened carbon steel. Methodology. A sheet with a thickness of 1 mm was selected for the study, made of steel with 0.42% С after thermal hardening. The treatment consisted of quenching and tempering at 300 °С. The samples were subjected to cyclic loading on the Saturn-10 machine, under a symmetrical cycle of alternating bending, with a frequency of 100 min^-1. Treatment with pulses of stress was carried out under conditions of «Iskra–23». To determine the effect pulses of stress on the cyclic endurance, samples after 50–60% by limit of endurance were subjected to doing pulses of stress. After completion treatment pulse of stress, the samples continued to be cyclically loaded until the moment of failure. The density of dislocations was measured by method of X-ray structural analysis on a DRON-3 diffractometer, by interferences (110), (211), (321). The complex of properties after thermal strengthening was determined under static tension, at a strain rate of 10^-3 s^-1. Findings. After processing with pulses of stress studied, thermally hardened steel with a hardness of 46–47 HRC, an increase in hardness by 11 % was obtained. According to the analysis of the cyclic loading curves of thermally hardened carbon steel, it was determined that due to the action pulses of stress, an increase in limit of endurance occurs in a wide range of cyclic overload. Structural studies have determined that, in proportion to decrease at magnitude of cyclic overload, an increase limit of endurance corresponds to higher number accumulated dislocations by different slip systems. Originality. The increase at density of dislocations from the action pulses of stress is due to the development processes of partial unlocking of dislocations after thermal strengthening and activation systems of sliding, which are not characteristic of these loading conditions of the steels. As a result of the action pulses of stress, the propagation deformation per cycle occurs at lower amplitudes of load, due to formation of an additional number of dislocations. According to analysis lines of French, it was determined that participation of an increased number of dislocations at propagation of deformation per cycle shifts a moment transformation of reversible damages into irreversible ones, towards an increase at number of cycles. Practical value. The obtained research results can be useful for assessing by influence of an external source of stress on the behavior of a carbon steel product under cyclic loading.

Mathematical Modeling of the Process of Non-Stationary Heat Conduction Throughout the Wall

M. M. Biliaiev — 2025-09-26

Purpose. Extreme situations at industrial facilities often lead to fires, in particular, fires occur in the event of drone attacks on oil storage facilities. In such cases, a significant amount of chemically hazardous substances (fuel combustion products) are released into the air, posing a risk of thermal injury to workers. Various means and structures are used to reduce the risk of thermal injury. When designing protective structures, it is necessary to determine in advance their effectiveness and the time of possible destruction. This requires the development and use of specialized mathematical models. This work is devoted to the development of numerical models that allow predicting thermal fields at an industrial site in case of fire and assessing the risk of destruction of a protective wall (barrier). Methodology. To numerically solve aerodynamic problems (determining the wind speed field), calculate areas of thermal pollution of the air at an industrial site, and determine the dynamics of temperature changes inside a protective barrier (wall), we use fundamental models of continuum mechanics. Finite difference schemes are used for the numerical solution of simulation equations. Findings. A computer program has been developed that makes it possible to solve a «coupled» problem of determining the zone of thermal pollution of air at an industrial site and the dynamics of heating of a protective barrier (wall). Using the proposed numerical model and computer program, it is possible to solve the problem of thermal conductivity and heat transfer in real time. Originality. A fast-calculation numerical model is presented for estimating the time of destruction of a protective barrier at an industrial site where a fire occurs. The analysis of thermal fields at an industrial site and inside the protective barrier was carried out by numerical integration of a multivariable heat transfer and heat conduction equation. The aerodynamics problem was solved based on a potential motion model. These numerical models require little computer time for practical implementation. Practical value. The proposed numerical models can be used for a preliminary assessment of the temperature field inside the protective barrier to determine its effectiveness in terms of protecting areas from thermal pollution at an industrial site. This info can be useful at the preliminary design stage of protective structures.

Modelling of filtration and heat and mass transfer processes in groundwater: applied aspects

O. A. Bubnova — 2025-09-26

Purpose. Liquid waste disposal is an urgent problem in many countries around the world. The most widely used method of liquid waste disposal is the creation of sedimentation ponds. However, this approach takes a significant amount of land out of use and, in combination with intensive pollution of the aeration zone and groundwater, is widely used for water supply in rural areas. Therefore, alternative methods of liquid waste disposal are constantly being sought for each specific region. One of the ways to dispose of liquid waste that is often used, in particular abroad, is underground disposal. This approach can be very effective and environmentally friendly if there are suitable hydrological conditions in the region, namely deep underground horizons containing substandard groundwater. This approach requires the use of specialised mathematical models. The aim of this study is to develop fast-calculating mathematical models for assessing the impact of underground disposal of liquid wastewater on groundwater pollution. Methodology. The mass transfer equation is used to solve the problems of mass transfer of impurities in the underground aquifer. A planned filtration model is used to model groundwater dynamics. A two-dimensional mass transfer equation is used to describe the geomigration process. The process of thermal contamination of groundwater is modeled on the basis of the energy equation. An explicit difference scheme is used to numerically integrate the filtration equation. Numerical integration of the modeling equation of mass transfer and energy is carried out on the basis of a variable-triangular splitting scheme. Findings. The development of mathematical models of heat and mass transfer, which allow to estimate the dynamics of changes in the groundwater regime and heat and mass transfer processes during underground disposal of liquid waste, is considered. Originality. The article considers the development of numerical models for analyzing the impact of underground disposal of liquid waste on groundwater. Numerical models take into account the convective-diffusion process of impurity propagation and changes in the thermal regime in groundwater. Practical value. The considered mathematical models can be used in the design of underground liquid waste disposal systems.

Modeling of filtration and geomigration under anthropogenic impact on groundwater

O. O. Medvedieva — 2025-09-26

Purpose. One of the most widespread methods of liquid waste disposal is the use of settling ponds. Wastewater in such lagoons eventually infiltrates into the aeration zone and reaches groundwater. Thus, a chemical contamination area is formed both in the aeration zone and in groundwater. When reengineering sedimentation ponds (for example, when increasing the height of the dam), there is an increase in the pressure in the structure, which will affect the intensity of infiltration of wastewater from the pond into the aeration zone), it is necessary to determine the change in the intensity of environmental pollution in advance. To solve such a forecasting problem, it is necessary to use specialized mathematical models. The aim of the study is to develop numerical models for assessing the dynamics of aeration zone pollution during the infiltration of liquid waste from a sedimentation pond. Methodology. The Laplace equation for the head is used to solve the filtration problem. The process of mass transfer of impurities in the aeration zone is modeled using the mass transfer equation, which takes into account the convective-dispersive transfer of impurities. The numerical integration of the modeling equations is carried out using finite-difference schemes. Findings. Numerical models of filtration and mass transfer are considered, which allow to estimate the dynamics of changes in the contamination area in the aeration zone during the infiltration of liquid wastewater from a sedimentation pond. Originality. The construction of mathematical models for analyzing the infiltration of liquid wastewater from a sedimentation pond is considered. Numerical models take into account the convective-dispersion process of impurity propagation in the aeration area. Practical value. The considered numerical models can be used to assess the environmental impact of sedimentation ponds used for the accumulation of liquid waste.

Analysis of the Influence of the Relative Position of Retarders and Bypass Tracks on the Length of the Neck of the Sorting Slide and Their Automated Design

M. I. Berezovyi — 2025-09-25

Purpose. The purpose of this study is to find ways to reduce the length of sorting yard humps by analyzing the relative positioning of the decelerators on the descent section and other elements of the track layout of the humps, such as turnouts, their isolated pre-switch sections, curved track sections and adjacent tracks, including bypass tracks. Methodology. One of the approaches to reducing energy consumption during the breaking up and formation of trains on classification humps is the improvement of their track layout design, in particular the development and implementation of measures to reduce the length of hump throats. To solve the problem, a comprehensive analysis of the technology of dissolving trains on sorting humps was used, methods of scientific analysis and synthesis of track development design based on analytical geometry were applied, as well as simulation modelling methods to determine the mutual position of the decelerators of the descent section and adjacent bypass tracks. Findings. Based on an analysis of the lower clearance limits for structures (profile «C») and the dimensional characteristics of beam-type pneumatic wagon retarders, technical solutions were developed to allow a track from the outer group of classification tracks to approach the retarder pit area bypassing the hump body. The calculation of the parameters for connecting a bypass track from the group of classification tracks showed that the straight section of track behind the braking position can be reduced on average by 5.65 meters, depending on the type of lower retarder installed at the given braking point. Originality. The work improves the methods for designing the descent section of sorting humps and bypass tracks; for the first time, it establishes the dependence of the reduction in the length of the switch throat of the end track bundle of the sorting yard on the types of retarders with which the braking position is equipped. Practical value. The practical value of the study lies in the potential application of the obtained solutions by design engineers during reconstruction works on existing classification humps and in the design of new hump classification facilities on mainline railways and industrial railway systems.

Application of Smart Contracts in the Formalization of Roles in Freight Transportation Systems

Y. A. Velehura — 2025-09-25

Purpose. The aim of the study is to develop a detailed role model for the implementation of smart contracts in the logistics processes of freight transportation, which will enable the automation of interaction between participants and increase the transparency of operations. Methodology. To achieve the stated goal, a systemic approach using context-role analysis was applied. The study involves a detailed decomposition of the stages of the logistics chain when applying smart contracts, identification of key participants, and definition of their functions, rights, and responsibilities. This approach makes it possible to clearly delineate areas of responsibility, reduce the risk of conflicts, and ensure the transparency of each participant’s actions. The developed UML diagram demonstrates the sequence of interactions between subjects, and the integration of smart contracts ensures the automation and immutability of operations. Findings. A comprehensive analysis of logistics processes using smart contracts was carried out, which made it possible to define the rights and responsibilities for seven basic roles of logistics operation participants. This approach provides a holistic view of the system and makes it possible to describe the logic of interactions between subjects. The developed model demonstrates the automation of contract conclusion and execution, which contributes to the reduction of document processing time, optimization of operations, and ensuring a high level of data security in the distributed ledger. Originality. An approach is proposed that enables the integration of formalized roles of freight transportation participants with smart contract technology. The detailed structuring of the functional responsibilities of each role makes it possible to implement the program logic of a decentralized system, which significantly expands the possibilities of automated logistics process management. The approach is universal and can be adapted to different types of logistics scenarios. Practical value. The developed role model creates favorable conditions for the implementation of blockchain solutions in the field of freight transportation, which makes it possible to digitalize logistics processes, increase trust between supply chain participants, and reduce operational costs. The obtained results have practical application for logistics operators, software developers, and consulting companies that seek to modernize existing transportation management systems. The model can also be useful for educational purposes in the fields of logistics, computer science, and management.

Inverse Modeling of Structural Contact Mechanics Using the Finite Element Method

T. A. Zaytseva — 2025-09-26

Surpose. The research aims to develop and solving an inverse contact problem for two elastic bodies with different stiffnesses, enabling the identification of interaction parameters including friction zones, adhesion, sliding, and separation. A variational mathematical model is formulated, A finite element model is constructed. The use of ANSYS, automated via APDL, allows for the implementation of inverse modeling, considering the complex behavior of the system under external loading. Methodology.The study is based on a step-by-step approach to constructing the inverse contact problem, considering transitions between interaction modes (adhesion, sliding, separation), mathematical formalization, and numerical modeling using finite element analysis in ANSYS. First, a direct problem is formulated; based on its analysis, an inverse problem is constructed to identify unknown interaction parameters. A finite element model is then created, followed by result analysis. Findings.An inverse contact problem for two deformed bodies with different stiffnesses is formulated, taking into account the modes of adhesion, sliding, and separation. A finite element model is created in the ANSYS. Originality. The study proposes an integrated analytical-programmatic approach to solving the inverse contact problem for bodies with varying mechanical characteristics, considering zones of adhesion, sliding, and separation. The novelty lies in the combination of a variational mathematical problem formulation with Tikhonov regularization and finite element analysis, automated through APDL scripts within the ANSYS environment. Practical value. The developed methodology for solving inverse contact problems based on the analytical approach and its implementation in the ANSYS environment proves to be an effective tool for analyzing complex mechanical systems. The algorithm allows for the identification of contact interaction parameters (friction, adhesion zones, sliding, separation) based on actual loading conditions.

Software Implementation of an Algorithm for Solving a Dynamic Problem of Optimal Set Partitioning Under Uncertainty

E. M. Kiseleva — 2025-09-26

Purpose. Among various formulations of the optimal set partitioning (OSP) problem, dynamic variants—where optimization conditions change over time—are of particular interest due to their relevance for real-world applications. Such systems often operate under uncertainty, which may arise from imprecise or incomplete input data, vague parameters, or unreliable mathematical representations of system behavior. This study develops a comprehensive mathematical and computational framework for solving dynamic OSP problems under uncertainty. The aim of the study is to develop software for solving a novel dynamic optimal set partitioning problem under uncertainty, specifically including the formulation of a numerical experiment, the applied interpretation of the obtained results, and a comparative analysis of the numerical experiment outcomes with the analytical results of the model investigation. Methodology. The methodological basis of the study consists of the principles of optimal set partitioning theory and fuzzy set theory. Modern numerical methods were used to solve systems of ordinary differential equations necessary for determining the parameters of the dynamic model. Findings. The formulation of dynamic optimal set partitioning problems under uncertainty allows including fuzzy model parameters and obtaining results even with incomplete information about the system. The work presents a clearly defined algorithm for solving the problem, determined by its mathematical formulation. Originality. The proposed models represent a significant contribution to the development of mathematical modeling, particularly in dynamic and fuzzy problem formulations. Methods and algorithms for solving the formalized problems are presented, and the results of comparative analysis allow assessing the analytical and numerical advantages of both models and the dynamic approach to solving such problems. Practical value. The practical value of the results obtained in this study lies in the formulation of a novel dynamic optimal set partitioning problem under uncertainty, the development of software for the numerical implementation of the experiment, and the visualization of the obtained results. The formalized mathematical model and the developed software can be applied to a wide range of practical problems, such as logistics, facility location, partitioning of communities into administrative service centers, and others.

Principles and Models for Calculating Foundation Settlements for Calculating Soil Base Deformations

V. S. Andrieiev — 2025-09-24

Purpose. In engineering practice, the problem of calculating the settlement of foundations on a layered base often arises. The authors set the goal of conducting a comparative analysis of the issues of principles and models for calculating foundation settlements when calculating deformations of soil foundations. Methodology. Data available in scientific and technical literature indicate that the calculation methods currently in use do not allow the necessary accuracy to be achieved in a number of cases, since the influence of the rheological properties of the layered soil base and time indicators are not taken into account when determining the inclination of foundations. It is also known that one of the reasons for the discrepancy between calculations and operational parameters is the insufficiently complete account of the textural features of the soil layer, namely its layering. Current methods for calculating the settlement of foundations or structures on soil bases are usually based on solutions obtained within the framework of a linear-elastic isotropic medium model. However, this does not take into account the fact that in foundations with a layered texture, the distribution of stresses can differ significantly from their distribution in a homogeneous foundation. This has a negative impact on the methods currently used to calculate settlement. The article compares several models for calculating foundation settlements when calculating deformations of soil foundations and analyzes their principles. Finding. To solve this problem, it is necessary to substantiate analytical methods for calculating foundation settlements. Existing methods allow us to evaluate only some of their indicators, taking into account the conventionality of the calculation models used. Obtaining reliable results is possible only with a comprehensive approach to evaluating observations of foundation deformations. Originality. Lies in the selection and justification of solutions for calculating foundation settlements when calculating deformations of soil foundations. Practical value. Develop practical recommendations for calculating the settlement of rigid foundations, taking into account the layering of the base and temporary indicators.

The Latest Technologies in the Development and Practical Application of Helical Blade Screw Piles in Construction

O. I. Dubinchyk — 2025-09-24

Purpose. The purpose of the scientific article is to study the practical application of a screw pile with a spiral blade (geoscrew) in the construction of pile foundations, as well as the practical application of the principle methodology for calculating the bearing capacity of piles of this type. Analysis and assessment of the discrepancy between the actually obtained bearing capacity of piles based on the results of tests with static vertical loads in comparison with the calculated data. Experiment and creation of certain conclusions regarding the resistance of the soil in the process of immersion of piles in the form of friction on the lateral surface, the formation of certain conclusions regarding the level of such friction. Assessment of the level of labor intensity of construction work when using piles with a spiral blade in construction. Methodology. The materials presented for studying the features of structures are created on the basis of an implemented construction project for the construction of foundations for overhead power line supports using screw piles with a spiral blade. To create such a construction object with further scientific study of the features, research program and regulatory documentation for the design of building structures were used. As a result, an alternative design was developed and analyzed in relation to standard solutions for the construction of such foundations, namely screw piles with a spiral blade, combined with a reinforced concrete monolithic grillage. Findings. Results. The relevant data on the bearing capacity of piles were obtained, data on the level of soil resistance on the lateral surface of piles during their immersion, the methodology for theoretical calculation of piles was verified by full-scale tests for compressive and pulling loads. Information was obtained on the main design and calculation difficulties in the practical immersion of piles of this type. The experience of combining piles and grillage into one structure capable of taking on large loads and providing a reliable foundation for above-ground structures was studied. Originality. First, the correspondence of the results of field tests and the results of experimental theoretical calculations of the bearing capacity of piles with a spiral blade against the soil was confirmed. Practical value. It consists in the fact that on the basis of the study of this experience, answers to previously unknown questions on the calculation of geoscrews were obtained, which in turn makes it possible to design foundations using screw piles with a spiral blade.

Metal Structural Materials for the Production and Repair of Automobile Parts: Practice and Prospects

V. E. Olishevska — 2025-09-26

Purpose. The main purpose of the work is to review and systematize metal structural for the production and repair of automobile parts, as well as analyze modern trends in their further development. Methodology. The main problems associated with metal structural materials today include the following: high density of materials, which increases the mass of the car, the consumption of fuel and lubricants and the amount of harmful emissions into the atmosphere; the need to ensure the strength and reliability of automobile structures; the need to ensure passive and active safety; the susceptibility of materials to corrosion, the scale of which can be judged by the fact that approximately 20 % of the steel produced in the world is used to cover losses from corrosion; the task of reducing the environmental load on the environment; the development of new materials that meet modern requirements; the selection and justification of structural materials for car parts; preparation for post-war reconstruction, the need to save resources. The following research methods were used in the work: theoretical research (classification, systematization), analysis and generalization of known scientific results, empirical methods (comparison, observation), experimental research (metallographic analysis, impact toughness testing). Findings. The current state and problems associated with metal structural materials are analyzed; it is shown that structural materials significantly affect the mass of the car, strength, reliability, corrosion resistance, fuel and lubricant consumption and the number of harmful emissions into the atmosphere. The analysis of structural carbon steels allows us to correctly formulate the requirements for steels of certain groups of automotive parts, and to select materials for the manufacture or repair of automobile parts, taking into account the properties of the material, purpose and operating conditions of automotive parts. Modern trends in the development of new materials for road transport are considered: high-strength steels, aluminum alloys, nanomaterials, composite materials. The possibilities of creating layered composite materials by explosion welding are investigated, and impact toughness tests are conducted. Originality. A comprehensive analysis of the problems of metal structural materials has been carried out, which allows us to identify their impact on the mass of the car, the consumption of fuel and lubricants and the number of harmful emissions into the atmosphere. The main trends in the development of metal structural materials have been highlighted; the approach to assessing materials according to the criterion of embodied energy has been considered. It is emphasized that the development of innovative technologies for creating new metal structural materials is an important step towards the transition to environmentally friendly transport in the country. The use of layered metal composite materials as materials with high fracture toughness has been substantiated. Practical value. An analysis of the main grades of structural carbon steels has been carried out, which allows us to correctly formulate the requirements for steels of certain groups of automotive parts, as well as to select materials for the manufacture and repair of automotive parts, taking into account the properties of steels, the purpose and operating conditions of automotive parts. The directions and problems of metal structural materials for automotive parts have been highlighted. Layered metal composite materials obtained by explosion welding have been proposed as materials with high fracture toughness.

Optimization of energy efficiency of a multi-profile medical center building

A. V. Radkevych — 2025-09-26

Purpose. Increasing the thermal efficiency of a multidisciplinary medical center building by optimizing architectural and planning solutions, taking into account climatic conditions and improving the parameters of engineering systems. The building is considered as a single energy system, the efficiency of which is determined by the interaction of external and internal factors. Methodology. Is based on mathematical modeling of heat and mass transfer, analysis of climatic data, and calculation of energy consumption in accordance with current standards. The study takes into account the effects of solar insolation, wind loads, outdoor air temperature, air infiltration, and thermal insulation of building envelopes. An indicator of the efficiency of a design solution is proposed, which assesses its deviation from the energy-optimal variant. Findings. Are based on the example of a multidisciplinary medical center located in the city of Dnipro. An analysis of insolation according to the orientation of facades was carried out, thermal gains through transparent and opaque elements were calculated, and heating and cooling loads were determined. Seasonal climate variability, thermal inertia of materials, and the operational regime were taken into account. The study confirmed that the building’s orientation, glazing area, ventilation system efficiency, and the quality of engineering equipment significantly affect energy consumption. A method for determining the optimal building dimensions is proposed, based on local climatic data and the potential of solar energy. Originality. lies in the substantiation of a systemic approach to energy-efficient design, which combines climatic factors, architectural constraints, and thermal characteristics into a unified model. A coefficient is proposed to evaluate the design solution in terms of its energy efficiency. Practical value. lies in the development of recommendations for reducing energy consumption. The proposed solutions make it possible to reduce thermal loads on engineering systems by 20–25%, lower operating costs, and improve comfort. The examined facility includes a ventilation system with heat recovery (up to 85%) and a heat pump with a COP of 3.5, which resulted in significant energy savings. The results confirm the effectiveness of integrating architectural design with modern engineering equipment and climate adaptation. The methodology can be applied to a wide range of public and residential buildings. Conclusions. Comprehensive energy-efficient design requires the integration of architecture, energy systems, and climatology. The proposed approach enables the development of projects that not only comply with standards but also ensure minimal energy consumption under real operating conditions.

Numerical Analysis of the Stress-Strain State of Two Unanchored Interacting Circular-Shaped Workings

O. L. Tiutkin — 2025-09-26

Purpose. The authors aim to perform a numerical analysis of the stress-strain state of two unsupported circularly influenced workings and determine the change in stresses and strains of finite element models depending on the distance between the workings. Methodology. We analyze analytical and numerical approaches to solving the problem of the stress-strain state of two unsupported circularly influenced workings. Within the framework of the analytical approach, two hypotheses of the occurrence of mutual influence based on the theoretical principles of geomechanics, but without a thorough generalization, are considered. In contrast to analytical methods, a more fruitful approach to the problem can be considered the use of numerical methods, in particular the finite element method. Using the professional calculation complex Structure CAD, three finite element models of two unsupported circular workings with a distance between them of one, three, and five diameters were developed. Findings. The analysis of the displacement components and normal stresses along the horizontal and vertical axes for different distances between two unsupported workings ranging from one to five diameters was performed. Moreover, in order to compare the stresses of the considered cases, a single working was also calculated, the stress-strain state of which is considered in this study to be the reference state. It was found that the stress isofields along the horizontal axis at a distance of one diameter (D) between the workings increased by 1.2...1.3 times compared to a single workings, which indicates a clearly expressed mutual influence. Originality. Based on the analysis of the obtained results, the change in stresses and displacements of two unsupported circularly influenced workings for different options of distances between them was estimated. Practical value. Proposals have been developed for the location of two unsupported circular workings in such a way that the influence between them is determined and controlled.