The research aims to develop an original design and analytical model of a friction damper based on a slotted cylindrical shell with deformable filler for elastic suspension of sucker rod strings. The developed model should relate the geometric parameters of the "slotted shell – filler" contact system, the number of shell slots, dry friction force effects, and mechanical properties of materials to the desired stiffness-strength parameters of the damper.The damper design utilises the bending effects of the slotted shell during its frictional interaction with a slightly compressible, deformable filler. In developing the analytical model, the slotted shell is reduced to an equivalent Winkler foundation where each panel formed by slots acts as an independent elastic element resisting the radial pressure of the filler. The equivalent stiffness of the foundation is determined by calibration using the average deflection coincidence criterion. The filler is modelled as an isotropic material, considering the relationship between axial and radial deformations, which allows for closed-form relationships between contact pressure, axial stresses, and settlement.An original structural design for a friction damper to provide elastic suspension of sucker rod strings is presented. Compact analytical dependencies are developed for determining damper settlement, contact stresses in the friction pair, and ultimate stresses in the slotted shell. Design diagrams are provided for efficient parametric design of the damper structure.The results obtained are oriented toward small deformations and quasi-static regimes, with friction assumed constant. The assumptions correspond to the preliminary design calculation stage. Future research plans to apply boundary-integral approaches based on Green's functions for a more precise analysis of the contact interaction between the slotted shell and filler, and to verify the results through bench testing.A simple and low-maintenance damper design is obtained with high load capacity and effective damping while ensuring sufficient nominal settlement and compact transverse dimensions. The solution is technological – a steel slotted shell combined with a deformable filler forms a maintainable modular unit resistant to field conditions. The analytical results obtained provide engineers with direct tools for damper adjustment.The original shell damper design reduces axial stiffness without compromising load capacity and damping while maintaining compactness and simplicity. A comprehensive analytical model is developed that transparently relates damper geometry, number of shell slots, friction effects, and elastic properties of materials to settlement and stress state. A ready tool for parametric design of the damper for sucker rod string suspension, along with a methodology for calculating related shell-type shock absorbers, is obtained.

The paper aims to analyse the joint influence of laser power and machine type on the mechanical properties of metal parts manufactured by additive manufacturing, in particular via SLM/LPBF (powder bed melting) and DED (direct energy deposition) technologies. The study responds to a growing need to optimise manufacturing parameters for advanced alloys such as Inconel 718, Ti-6Al-4V and 316L stainless steel, particularly in bimetallic applications where mechanical performance is critical.Thie work is based on an in-depth comparative analysis of the data available in the literature concerning the tensile strength, yield strength and hardness of parts produced by different SLM and DED machines operating at various laser powers. The approach highlights the interactions between process parameters and the technical specificities of the machines (optical system, scanning strategy, thermal management), based on a literature study targeting the main alloys used in an industrial context.The results confirm that laser power has a decisive effect on densification and mechanical properties, but only up to an optimum threshold. Beyond this, excessive power can lead to over-melting, internal defects (such as microcracks and porosities), and microstructure degradation. At the same time, the type of machine plays a crucial role: for equivalent parameters, performance can vary considerably depending on factors such as beam quality, gas recirculation system, or thermal stability. Some moderate-power, well-calibrated machines outperform more powerful but poorly controlled systems.The study is based exclusively on a literature review, with no direct experimental validation. Future work is needed to validate the trends observed through controlled tests on bimetallic parts and to support numerical modelling of the process.The results provide concrete recommendations for selecting the optimal machines and manufacturing parameters to enhance the mechanical performance of parts in critical sectors, including aerospace, biomedical, and energy.The work provides an unprecedented cross-sectional reading of the combined impact of laser power and machine type in metal additive manufacturing. It provides a useful comparative basis for process engineers and researchers seeking technological optimisation.

The primary objective of the study is to estimate the global porosity within 3D-printed parts, which significantly influences the mechanical properties, using a numerical method. Today, 3D printing has become increasingly valuable for various domains, including automotive, aeronautics, and medicine. Still, the main challenge is the weakness of mechanical properties compared to other processes, and the weakness is caused by the presence of porosity between printed layers in printed parts.To deal with this, the study begins by analysing the variation in dimensions of 3D-printed specimens as a function of speed and temperature. Subsequently, the dimensions are compared with those obtained from ImageJ software, which is used to scale and calibrate images to estimate the area and volume of the printed specimens. Finally, the density of the specimens is calculated to assess the porosity percentage as a function of the speed and temperature.The study demonstrates the relationship between temperature, printing speed, and porosity in 3D-printed parts. The results advance our knowledge of how these variables affect the 3D printed part performance. The study establishes a foundation for optimising printing parameters, such as print speed and nozzle temperature, to achieve a specific porosity percentage.Our study provides a valuable technique for making a relationship between printing parameters such as print speed and nozzle temperature and porosity; future research could focus on testing other materials and printing conditions. Additionally, it could explore the impact of other print parameters on porosity and mechanical properties.The study provides practical implications for industries that rely on 3D printing for production, such as the automotive and medical sectors. The findings can be used to optimise printing parameters to reduce porosity.The work is unique because it uses both dimensional analysis and image-based software tools to assess porosity and its relationship to printing temperature and speed. The study is useful for additive manufacturing engineers and researchers because it offers a new method for predicting and improving the quality of 3D-printed parts in terms of optimising porosity.

The study aims to investigate the impact of raster angle and filament configuration on crack propagation mechanisms in 3D-printed PLA parts. Although numerous studies have addressed surface quality, stiffness, and strength, there is still a lack of understanding regarding fracture behaviour and damage propagation in printed polymers. This paper aims to fill that gap by analysing how specific printing parameters affect fracture resistance.An experimental approach was adopted using Single Edge Notched Tension (SENT) specimens printed in PLA. Two filament configurations were considered: parallel and crossed between layers. Each configuration was tested under three raster angles (0, 45, and 90). The critical stress intensity factor (KIC) was used to evaluate and compare resistance to crack propagation. The measured KIC values ranged from 0.75 MPa√m (90/90) to 4.52 MPa√m (45/-45).The results show that both raster angle and filament configuration significantly influence crack propagation behaviour. Crossed filament configurations generally demonstrated higher resistance to crack propagation compared to parallel ones. Raster angle also played a critical role: toughness decreased with increasing angle in the α/α configuration, while the 45/-45 configuration achieved the highest resistance (KIC = 4.52 MPa√m). Overall, crack propagation mechanisms varied between filament breakage at 0/0 and filament separation at larger angles.The study is limited to PLA material and specific raster angles. Future research should investigate a broader range of materials, environmental conditions, and loading types to generalise findings and enhance predictive models for fracture in printed parts.The findings provide practical guidance for optimising print parameters to improve fracture resistance in functional parts. The knowledge can be applied to the design of lightweight structural components, biomedical implants, and customised mechanical parts where fracture toughness is critical.The paper contributes original insights into the underexplored area of fracture behaviour in 3D-printed materials, supported by quantified fracture toughness values. It is particularly valuable to researchers and practitioners seeking to improve the structural performance of additively manufactured components.

The study aims to justify and determine rational, energy-efficient operating modes of gas transmission systems (GTS) under conditions of partial load, based on minimising total gas consumption for transportation.The study employs an analytical approach to modelling energy consumption in the linear sections of gas pipelines, considering both fuel gas and process gas. Mathematical dependencies are proposed to estimate the mass of process gas and energy losses as functions of operating pressure, temperature, and hydraulic efficiency. The influence of the parameters on total energy consumption is analysed.It has been established that the optimal operating mode of the GTS corresponds to the minimum total consumption of fuel and process gas. The results show that there is a specific outlet pressure of the compressor station at which the energy consumption for gas transportation is minimised. An increase in the volume of process gas leads to higher operating pressures, which in turn reduces the amount of fuel gas required for transportation.The results contribute to a deeper understanding of energy optimisation in GTS operations under changing load conditions. They may serve as a foundation for further research in the mathematical modelling of pipeline energy consumption.The proposed approaches can be implemented in the operational practices of gas transmission companies to reduce operating costs and enhance the energy efficiency of gas transportation systems under variable load conditions.The scientific novelty lies in the identification and justification of process gas as a distinct component of total gas consumption and in the formulation of an optimality criterion for GTS operation based on the minimisation of total fuel and process gas usage. A new approach to determining the optimal pressure, which takes into account hydraulic efficiency and temperature conditions, is proposed.

To develop a mathematical wear model for bevel gears with biconvex-concave teeth and to confirm the accuracy of the modelling through experimental validation.Analytical relationships between tooth wear and meshing parameters (profile shift coefficients, module, number of gear teeth, gear face width) have been established using mathematical models of meshing and wear for biconvex-concave teeth of bevel gears. In the wear model, the determination of the contact point coordinates of the curves describing the tooth profiles is carried out using a geometric-analytical method. The result of the method is the solution of a transcendental equation with one unknown. The determination of the radius of curvature and the first derivative of the interpolation function was performed using a hypothesis that enabled the application of Hertz's formula for calculating contact stresses in gear teeth. Based on this hypothesis, the contact of profiles with variable curvature is replaced by the contact of two touching circles (cylinders) with radii equal to the curvature radii of the profiles at the contact point. It is assumed that the width of the contact deformation band of the actual profiles and the replacing circles is the same, as well as the distribution law of the contact stresses. The stress-strain state of the tooth was modelled using the finite element method to determine the stiffness of the teeth. Rolling and sliding velocities were determined using known formulas that depend on distance, time, and angular velocity. The experimental determination of wear on biconvex-concave teeth of bevel gears was defined as the difference between the initial coordinates of the points on the lateral surface profile of the teeth and the actual coordinates measured using a laser scanning method.A mathematical wear model for bevel gears with biconvex-concave teeth has been developed, considering wear in the pole of gear meshing and a decrease in the hardness of the contact surface due to the wear of the carburising layer. The models consider changes in the geometric, kinematic and strength parameters of gear meshing caused by alterations in the shape of the lateral profile surface due to wear after each loading cycle. Experimental wear measurements, conducted under production conditions, confirmed the reliability and adequacy of the theoretical models developed. The modelling approach provides sufficient accuracy in calculating the wear of the tooth working surfaces, with the relative error not exceeding 10% and the mean squared error is 0.021 mm.The results of wear modelling for bevel gears with biconvex-concave teeth have been validated by operational data from such gears used in coal shearer drives.The results of tooth wear modelling can be used to increase the service life of bevel gears in coal shearer drives by selecting rational meshing parameters.The selection of rational meshing parameters during tooth wear modelling will increase the durability of gears in coal shearer drives.

Prosthetic pylons are the columns that connect the prosthesis to the person’s body and play a vital role in providing stability, comfort, and functional performance to prosthetic users. Improving the properties of the columns contributes significantly to enhancing the user experience. The research aims to develop prosthetic pylons’ mechanical properties using natural and synthetic fibres.We could achieve these objectives by performing the composite prosthetic pylon materials used to replace conventional prosthetic pylon materials made of titanium, aluminium, or stainless steel.The results demonstrated that the type and quantity of reinforcement layers had a substantial effect on the mechanical properties of laminated composites. The results showed that the samples made of two layers of synthetic hybrid (glass and carbon) fibers gave better properties in terms of tensile strength, Young’s modulus, hardness, and compressive strength were 123 MPa, 6.5 GPa, 86 shore D, and 80 MPa, respectively compared to the samples made of three layers of ramie natural fiber. At the same time, the percentage of elongation was higher for ramie reinforced composite samples.The vacuum method was used to produce specimens with polyester as the matrix, and varying numbers of synthetic hybrid (carbon and glass) and natural (ramie) fibre layers as reinforcing materials. The mechanical characteristics (tensile strength, elongation percentage at break, Young’s modulus, compressive strength, and hardness) of each type of composite material were tested and evaluated.The effect of both materials gave acceptable results and proved their suitability for use instead of some metal materials that cause fatigue, exhaustion, and discomfort to users.

The purpose of the work is to develop software to solve problems of forecasting and planning the operation of underground gas storage (UGS) facilities and the use of their capacities depending on the level of consumption, demand for natural gas storage services, and maximum daily productivity.Based on the analysis of various output data from technological units, as well as the study of wells digitised and entered into the database, software for predicting UGS operation modes has been developed. The developed software enables users to conveniently customise the user interface, allowing them to quickly locate the necessary information in the database and perform predictive calculations for various technological units, ensuring the efficient and uninterrupted operation of the UGS facility.The software is designed for easy use by specialists, enabling the prediction of gas extraction and injection modes in the shortest possible time and monitoring the primary indicators of stable UGS facility operation. The developed software significantly simplifies the work with large data sets, as well as the calculation of parameters of process equipment and UGS facilities.To increase the efficiency of UGS operation, it is advisable to implement the developed software necessary to calculate the predicted operating modes of technological units, wells, and UGS in general, in order to select a rational mode of gas storage operation. In addition, it is necessary to plan a strategy for the development and of underground gas storage facilities (reconstruction and modernisation), and determine the need for additional investments aimed at increasing the UGS facilities (active volume and/or capacity).The work results enable specialists to create design schemes for UGS facilities that allow for a detailed, facility-by-facility analysis of the performance characteristics of individual process units. It also allows the forecast performance of both individual process facilities and UGS facilities as a whole to be determined.The software enables specialists to make accurate predictions regarding gas storage capacity under specific conditions, ascertain the maximum feasible gas withdrawal volumes, and determine the requisite time for withdrawing a given volume of gas.

During pit-flare blowdowns of flowlines and wells at depleted gas and gas-condensate fields, a liquid-laden gas stream is vented. Most wells lack gas meters, and the existing calculation methods rely on dry gas flow rates that ignore the liquid content in the stream. It leads to inaccuracies in calculations and managerial decisions. The study aims to establish the regularities of the liquid phase's influence on the blowdown-gas flow rate and to derive a universal mathematical dependence for engineering calculations.A three-dimensional model has been developed, and CFD modelling of gas-liquid outflow under blowdown conditions typical of flowlines and wells at depleted fields has been carried out. Based on the obtained CFD data, a regression analysis was performed to investigate the influence of the volumetric fraction of liquid on the gas flow rate.It has been shown that during blowdowns of flowlines and wells, even a small amount of liquid in the stream markedly reduces the gas flow rate compared with the outflow of dry gas. Within the investigated parameter range, a regression dependence of the gas flow rate on the volumetric fraction of liquid and the working pressure has been determined.It opens prospects for further research aimed at improving the proposed methodology for modelling the influence of the liquid volume fraction on the gas flow rate, extending its application to a wider range of liquid-phase volume fractions and working pressures.A regression equation has been developed to calculate the volumes of gas lost during blowdowns of flowlines and wells at depleted gas and gas-condensate fields.To determine the gas flow rate during the outflow of a gas-liquid mixture from a pipeline, a regression equation has been obtained that explicitly accounts for the volumetric liquid fraction in the flow, thereby markedly increasing calculation accuracy.

This study investigates oil jet lubrication’s effects in different-speed machining, testing injection angles (15 and 40) and pressures (6–12 bar) on surface roughness and wear.We can achieve these goals by performing the oil jet lubrication used throughout the turning process, with two different injection angles (15 and 40) included in the lubrication conditions.Results show optimal performance at 15 and 6 bar, reducing roughness and temperature. The findings aid in selecting lubrication parameters for improved machining efficiency. One of the more significant findings from this study is that at 40 and 6 bar of pressure, the cutting speed ranges from 48 to 264 meters per minute, with the highest temperature reaching 134%. In contrast, under 15 and 6 bar, the highest temperature is 118%.We suggest that you carry out a quality surface, it is necessary to experiment with the cutting speed that significantly impacts the tools’ and workpiece’s wear and surface roughness. As the workpiece undergoes more plastic deformation at a higher cutting speed, a greater amount of mechanical energy is converted into heat energy, resulting in a notable increase in temperature. Low-carbon steel and various cutting tools were used in the studies.The effect of variables studied was cutting speeds (48, 88, 180, 264) m/min, feed rates (0.03, 0.043, 0.075) mm/rev, depths of cut (1) mm, and injection angles (15 and 40). Lubrication pressures ranged from 6 bar to 12 bar. No one has certainly facilitated improvements in the tribological properties of (AL-Rashid Oil) SAE 15W_40 through Oil jet lubrication, which was used throughout the turning process, with two different injection angles (15 and 40) included in the lubrication conditions.