Maintenance, Reliability and Condition Monitoring
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Fault diagnosis of time-varying speed gearbox based on gated recurrent dropout attention unit
Full text linkIn response to the difficulty of fault diagnosis of gearbox under time-varying speed conditions, this paper presents a novel approach for diagnosing gearbox faults in time-varying speed, utilizing an improved gate recurrent unit (GRU), which adds attention gate mechanism and cyclic dropout learning strategies on the basis of the GRU, and constructs a new model named as gated recurrent dropout attention unit (GRDAU). By introducing attention gate mechanism to realize allocating weights dynamically, focusing on key features, and enhancing GRU’s ability to capture important information. In addition, the designed cyclic dropout learning strategy reduces excessive dependence on specific hidden states by randomly discarding some hidden state information. Finally, the robustness and excellent interference suppression ability of the proposed method were verified through case analysis of a gearbox under time-varying speed, and the diagnostic accuracy of the method is as high as 99.78 %. Comparative experiments were conducted to validate its superior performance and stronger generalization ability compared to existing advanced diagnostic methods
A new self-adaptive anti-galloping device in suppressing conductor galloping in transmission lines
Full text linkConductor galloping is a serious threat to transmission line integrity, inducing excessive conductor tension that may lead to catastrophic failures including conductor breakage and tower collapse. This study proposes a novel self-adaptive anti-galloping device (SAGD) to mitigate galloping amplitudes and reduce associated risks. In this paper a novel self-adaptive anti-galloping device (SAGD) to mitigate galloping amplitudes and reduce associated risks was proposed. The structural design scheme of the device is provided, and its operation sequence was verified through static loading experiments. Conductor free-falling experiments validated the SAGD's vibration control performance, with test results demonstrating its practical applicability for transmission line protection. A finite element model for the conductor-SAGD system was developed, enabling numerical simulation of galloping displacement time history and analysis of endpoint support reaction dynamics. The device's galloping suppression effectiveness is systematically evaluated under varying stroke lengths and threshold conditions
Experimental results of reducing harmful vibrodynamic effects caused by the interaction between rolling stock and track through the use of elastic under-sleeper pads in the rail joint zone
Full text linkIn the current era of independent development and market relations, the importance of railways continues to grow steadily. This, in turn, places great responsibility on the system of measures aimed at ensuring railway reliability. However, despite the advantages and advancements of the railway industry, it still faces technical complexities that can lead to track deterioration. In heavily loaded and high-speed railway sections, the interaction between the rolling stock and the track causes various issues in the rail joint zones – such as the development of defects and irregularities, deterioration of track geometry, reduction of track stability, as well as problems related to noise and vibration that must be mitigated. To address these challenges, scientific studies and experimental investigations have been conducted on the installation of elastic under-sleeper pads in the rail joint zones. These studies aim to modify the vertical stiffness transferred from the wheelsets of the rolling stock to the track structure, reduce harmful vibrations and oscillations, and thereby ensure uniform stability along the entire track. The conducted research, testing, and their results are presented in this article
Experimental and finite element analysis of the structural durability of special self-propelled rolling stock frames
Full text linkThe study presents an experimental-numerical assessment of the structural durability and residual life of the ADM-1 self-propelled railcar frame operating under cyclic and static loading conditions. A combined methodology integrating full-scale cyclic bench testing and finite element modeling (FEM) was developed to determine the frame’s stress–strain state and fatigue resistance. The experimental tests, performed at the accredited laboratory of “Quyuv Mexanika Zavodi” JSC using the ISRB-1000 hydraulic loading stand, simulated real operational loads up to 2×106 cycles, equivalent to approximately ten years of service. A detailed FEM model was created in SOLIDWORKS Simulation to replicate these loading conditions, analyze stress distribution, and validate experimental data. The numerical and experimental results showed strong correlation (r > 0.9) with a deviation below 8 %, confirming the accuracy of the proposed approach. The maximum equivalent (von Mises) stresses remained below 0.6σ0.2 for St3sp steel, indicating that the structure operated entirely within the elastic range and met the strength requirements of GOST 31846-2012. Fatigue life estimation using Miner’s cumulative damage rule yielded a damage factor of D= 0.72, corresponding to 8-12 years of effective service life, with a residual fatigue resource of approximately 35-40 %. The developed hybrid methodology provides a reliable framework for condition-based maintenance and life-extension of special self-propelled rolling stock
Digital solutions for the transition to a sustainable public transport system in Tashkent
Full text linkThe purpose of this study is to analyze the prospects for transitioning the city from automobile-dominated mobility to a public transport-oriented system. The methodological framework is based on the analysis of transport infrastructure. The research is conducted on the example of Tashkent – the capital of Uzbekistan – characterized by a high level of motorization and significant commuter migration. The study concludes that a successful transition to public transport requires a phased implementation, involving infrastructure modernization, digitalization, regulation of motorization, and transformation of citizens’ mobility behavior. The novelty of this study lies in developing a digital transition model for Tashkent that integrates international best practices (Berlin, London, Singapore) with the local transport and socio-economic conditions
Graphical analytical modeling of the kinematic scheme of a rock-piston pump
Full text linkTwo kinematic diagrams are presented, consisting of two combined toggle mechanisms and a piston pump. Kinematic calculations of the moving link parameters for both kinematic diagrams resulted in the determination of the displacement of the working and idle stroke lengths S of the piston as a function of the toggle mechanism swing angle φ and the change in the toggle length and crank radius of the piston pump. The numerical value of the coefficient K of the average toggle mechanism slider velocity, K= 2, and the displacement of the piston stroke S were obtained: for a toggle-piston pump, S= 1.25, and for a crank-toggle mechanism, SK= 0.7 m. Various asymmetric phase angles were calculated for the working φp and idle φx strokes of the slider during rotation of the toggle mechanism crank for both kinematic diagrams. The relationship between the center distance α and the position of the fixed support point O1 of the crank axis of rotation to the support point O2 of the rocker arm is obtained. The numerical values of the stroke displacement SD, linear velocity VD, and acceleration αD of the pump piston for both kinematic diagrams of the rocker-piston pump mechanism are presented in tabular form by numerical values and in kinematic diagrams
Cooling analysis and innovative design to increase heat transfer in sealed electronic devices
Full text linkOne of the most important problems of electronic devices is heating. Especially high-performance processors and electronic cards can draw significant power and therefore reach critical temperatures. Heating can lead to functional loss or failure of devices. Sealed systems are used in many areas today. Sealing is defined as not allowing two substances, water and dust, into a closed space. The purpose of our thesis is to design a new cooling system related to the cooling of sealed electronic devices. External flow ventilation will be used as active cooling, and a heatsink structure will be used as passive cooling. Then, the efficiency of this new design will be analyzed using CFD method. By keeping the device at reasonable temperature values, a new design example will be created, especially for cooling sealed structures. Analysis studies have been conducted according to different ventilation channels. As a result of these studies, reference data on how much heat can be drawn by different fin structures will be obtained. These reference data are aimed to provide an approximate cooling capacity estimation in projects where sealing is required. The data obtained as a result of the study are compared and presented in tabular form
Analysis of the influence of vibration phenomena in pump systems on electrical energy consumption and operational efficiency
Full text linkDespite the long-standing recognition of vibration phenomena as a critical factor affecting both mechanical reliability and energy performance, yet their influence on electrical energy consumption remains insufficiently quantified. Excessive vibration, originating from rotor imbalance, shaft misalignment, bearing wear, and hydraulic instabilities, can result not only in accelerated component degradation but also in significant increases in energy demand and reductions in hydraulic efficiency. Understanding the quantitative relationship between vibration intensity and pump energy performance is therefore essential for both predictive maintenance strategies and energy efficiency improvements in pumping systems. This paper presents an experimental investigation of the effect of vibration on the electrical energy consumption and operational efficiency of centrifugal pumps. Five industrial pump types, with rated powers ranging from 15 to 75 kW and capacities from 100 to 320 m3/h, were tested under controlled conditions. Measurements were carried out using UT310A vibration testers, an ultrasonic flow meter, and a Fluke 1777 Power Quality Analyzer. Vibration signals, volumetric flow rates, pressure heads, and three-phase electrical parameters were simultaneously recorded under partial load, nominal load, and overload conditions. Hydraulic power and efficiency were then calculated, while statistical analyses-including correlation and regression models-were applied to determine the relationship between vibration intensity and electrical performance. The results revealed a strong positive correlation between increasing vibration levels and higher electrical energy demand. In particular, RMS vibration acceleration was found to be a reliable predictor of additional energy losses, while efficiency was observed to decrease as vibration intensity increased. These findings not only confirm the detrimental effect of mechanical instability on energy consumption but also provide a methodological framework for integrating vibration monitoring into energy management practices. By bridging the gap between mechanical diagnostics and energy performance analysis, the study contributes new insights that can support the development of predictive maintenance systems, improve pump reliability, and promote more sustainable operation of pumping stations
Enhancing the strength of steel grade 45 guide rails for ball rolling using the chemical-thermal carbonitriding method
Full text linkThe enhancement of guide rail strength for ball rolling applications is crucial to improving the durability and operational efficiency of the manufacturing process. One effective method for achieving this is carbonitriding, a chemical-thermal treatment that forms a hardened surface layer by saturating the material with both carbon and nitrogen at relatively low temperatures. This study was aimed at improving the mechanical properties of the guide bar used to hold balls on the rolling axis in ball rolling mills by chemical-thermal strengthening-carbonitration. Specimens of mild and medium carbon steel were used as tests. The process consisted in immersing the specimens in a bath with molten salts at a temperature of 570 °C and holding for 1.5 hours. The samples were then cooled in oil and then cleaned with high-pressure water. The study showed that the melt of salts based on urea and potassium carbonate saturates the steel surface with nitrogen and carbon, forming a hardened layer. The depth of the hardened layer depends on the exposure time, but after one hour, the penetration of diffusing substances slows down. This is due to the saturation of the steel crystal lattice with alloying elements (carbon and nitrogen) during carbonitration. The maximum hardening depth for high-alloy tool steels is 0.05-0.12 mm, for carbon steels 0.1-0.6 mm. Carbonitration can be used to increase the hardness, strength, wear resistance of balls without increasing the brittleness of the part
Numerical modeling of reinforced concrete structures made of lightweight concrete using ANSYS
Full text linkIn this paper, extensive numerical investigations into reinforced concrete beam made of lightweight concrete are given, through the ANSYS finite element program. The main aim was to assess the load carrying capacity, stiffness and deformation characteristics of the beams of different concrete densities. There were seven beam specimens, which vary in the percentage ratio of lightweight to normal aggregates, and the material properties were duly incorporated in the model. Three-dimensional nonlinear finite element analysis was used to simulate the beams with a mesh size of 25 mm, and the results were compared with the experimental results. Results showed that when the concrete density was reduced the loadbearing capacity decreased gradually, as the concrete became normal weight (95 kN) and then fully lightweight (85.7 kN). Nevertheless, the plastic zone transition happened later in lightweight beams and this implies that the deformation resistance was more difficult than in normal-weight concrete. The load-deflection curve demonstrated the fact that lightweight concrete beams though less stiff in nature, are structurally reliable and competitive. This study highlights the possibility of the lightweight concrete to be used as a structural material in contemporary engineering practice and therefore seismic zones where minimized self-weight improves the overall safety and efficiency. The results are useful in understanding how to optimize and design the reinforced lightweight concrete members