Numerical analysis and experimental research on Acoustic-vibration characteristic of 110 kV transformer tank

A vibroacoustic coupling model of the 110 kV transformer tank is constructed by using the finite element method. The structural vibration response under 100 Hz and 200 Hz sound source excitation is analyzed. Radiated sound field characteristics and sound transmission loss performance across the 0-400 Hz frequency range are evaluated. Then, a test system is established to measure vibration response and sound transmission loss through experiments. Simulation analysis and experimental test results show that the average sound transmission loss of the 110 kV transformer tank ranges from 30 dB to 40 dB. The simulation calculation results show good agreements with experimental test results, which prove the correctness of the vibroacoustic coupling model of the 110 kV transformer tank

Design and simulation of a cable-driven elbow rehabilitation device

With the increasing prevalence of neurological and musculoskeletal disorders, the demand for effective rehabilitation technologies has grown. This study presents the AlmatyExoElbow system with a cable-driven exoskeleton for elbow rehabilitation with two degrees of freedom. The device was designed in SolidWorks CAD and tested in SolidWorks Motion to evaluate flexion/extension and pronation/supination trajectories. The design is simple, adaptable, and cost-effective, making it a promising candidate for future clinical integration and personalized therapy

Study on vortex-induced vibration response of large-scale two-lay steel trusses bridge under large wind angle of attack

With the advancement of urbanization, two-lay trusses bridges are widely used because of their good traffic capacity and structural performance. However, the aerodynamic behavior of this beam type is still in the exploratory stage. The local microclimate characteristics at the bridge site in mountainous cities are obvious, and it is easy to form a large wind angle of attack, which has a significant impact on the vortex-induced vibration (VIV) performance of the bridge. Therefore, this study takes a long-span two-lay steel trusses bridge in a mountainous city as the engineering background, and uses wind tunnel test and numerical calculation methods to study the changes of the static three-component force coefficient and VIV response of the main beam in the construction and completion state under the action of high wind angle of attack. The results show that the three-component force coefficient curves under different wind speeds are close to each other, and the Reynolds number effect is not obvious. The vibration test shows that the vertical bending VIV first occurs at +3° and +5°, and then two torsional VIV with different amplitudes occur. Both vertical bending and torsional VIV are simple harmonic vibrations with a single frequency, and the vertical bending VIV frequency is locked at 2.227 Hz, and the torsional VIV frequency is locked at 4.289 Hz, which are close to the natural frequency of the test model. Compared with +3°, the maximum amplitude of vertical bending VIV under +5° increases by 30.0 %, while the maximum amplitude of torsional VIV under high and low wind speed increases by 16.6 % and 12.7 % respectively, and the locking range is longer. It can be seen that the wind angle of attack has a significant effect on the VIV response of the main beam in the completion state. Especially, the trusses beam at a large angle is more sensitive to VIV, and it is more prone to large-scale and large-amplitude VIV. The research results can provide a theoretical basis for the aerodynamic shape optimization and provide a reference for the design of related bridges

Review of chemical methods for road pavement stabilization: prospects for application in Uzbekistan

This article provides an overview of methods for stabilizing the subgrade soils of road pavements using nanomaterials and polymer additives. A theoretical‐comparative analysis is performed on both traditional stabilization methods and modern approaches that employ nanosilica, nanoclays, carbon nanotubes, and various polymers. The mechanisms of action of the stabilizers and their influence on the physico mechanical properties of soils are examined, along with the advantages and disadvantages of each method. Particular attention is devoted to the specific climatic and geological conditions of Uzbekistan. Based on an analysis of the literature and modeling results reported by both domestic and international researchers, recommendations are made for selecting optimal stabilization methods for different soil types and climatic zones in Uzbekistan. It should be noted that this study is a review and does not present the results of original experiments

Mechanical properties of nano-SiO2 modified ultra-high-performance concrete

This study experimentally investigates the effects of varying nano-silica (nano-SiO2) contents on the mechanical properties of ultra-high-performance concrete (UHPC) hardened paste, focusing on compressive and flexural strength improvements. Nano-SiO2, owing to its high surface area and reactivity, has potential to enhance UHPC performance by filling micro-pores and promoting cement hydration. In this research, UHPC hardened paste specimens were prepared with nano-SiO2 dosages of 0 %, 0.5 %, 1 %, 1.5 %, and 2 % by mass of cement, and their mechanical properties were evaluated and statistical features were analyzed. The results indicate that incorporating nano-SiO2 enhances both compressive and flexural strength of UHPC, with the optimal improvement observed at a 1 % dosage. Specifically, UHPC with 1 % nano-SiO2 exhibited a 5.1 % increase in compressive strength and a 6.3 % increase in flexural strength compared to control specimens. These findings suggest that a moderate addition of nano-SiO2 can effectively optimize UHPC’s mechanical performance, offering a promising approach for high-strength, durable concrete in demanding structural applications

Mechanics of composite fiber pull-out from concrete with fly ash using the DCB test

This study explores novel concretes where cement is partially replaced by oil shale ash (OSA), reducing CO2 emissions, and incorporates patented composite fibers for enhanced mechanical performance. The mechanics of fiber pull-out and interfacial bond strength in concrete reinforced with short fibers, where cement is partially replaced by either fly ash or OSA, using the Double Cantilever Beam (DCB) test. The research aims to assess how these eco-friendly additives impact the fiber-matrix bond and crack propagation resistance in fiber-reinforced concrete. In the experimental setup, two partially sawn concrete beams were joined along their length by a thin, fiber-reinforced concrete layer and subjected to a tensile force, simulating crack opening. Concrete specimens (400×210×100 mm) with varying ash contents were tested, focusing on key parameters such as peak load, energy absorption, and interfacial toughness. Findings indicate that both fly ash and basalt enhance the mechanical properties of the concrete, with significant improvements in load transfer and fiber pull-out resistance observed, particularly at higher ash contents. Analysis of force-displacement curves and fracture surfaces demonstrated a shift from brittle to more ductile behavior as ash content increased, enhancing the fracture resistance of the composite. This research supports the use of alternative cementitious materials like fly ash and basalt in developing sustainable, high-performance fiber-reinforced concrete, with potential applications in structural engineering and eco-friendly construction practices

Almaty ankle exoskeleton: comparative analysis and structural improvements of versions V.1 and V.2

This paper presents a comparative analysis of the V.1 and V.2 versions of the Almaty Ankle Exoskeleton. The main objective of the study is to identify the structural and functional shortcomings observed in the first version (V.1) and to develop an improved prototype in the second version (V.2) by addressing these issues. The paper compares the kinematic schemes, CAD models, and physical prototypes of both versions, highlighting their structural differences and technical advancements. In addition, the results of a static structural analysis performed on the V.2 prototype using the Finite Element Analysis (FEA) method are presented. This analysis allowed for the evaluation of stress, strain, and displacement distribution within the structure. The results demonstrated that the exoskeleton can effectively handle applied loads, although additional reinforcement is required in certain critical regions. Overall, the findings provide a foundation for engineering solutions aimed at enhancing the functional performance of the ankle exoskeleton and its application in rehabilitation processes

AI-driven VIN verification and RFID integration for error-proofing in automotive manufacturing

This paper presents an automated solution that combines deep learning-based computer vision with radio-frequency identification (RFID) technology to verify Vehicle Identification Numbers (VINs) during automotive production. The approach utilizes a YOLO-based object detection model for VIN localization and optical character recognition (OCR) for text extraction. An RFID tag linked to each component provides a reference VIN from the production system. A programmable logic controller (PLC) compares the AI-detected VIN with the RFID data in real time, halting the process if inconsistencies are detected. Otherwise, validated information is used to retrieve precise build instructions. This system enhances traceability, prevents assembly errors, and reduces rework, contributing to Industry 4.0 initiatives. Experimental validation confirmed the effectiveness of this integrated solution

Research on expansive soil characteristics – taking Ankang Tunnel as an example

This paper takes the Ankang Tunnel as an example to conduct research on the mechanical characteristics of swelling and shrinkage deformation of expansive soil, such as the free swelling ratio, unloaded swelling ratio, axial load swelling ratio, and swelling pressure, hoping to provide guidance for the construction of similar expansive rock and soil tunnels. The research shows that: (1) The free swelling ratio of the expansive soil in the Ankang Tunnel is relatively low, at 49.7 %, with weak-medium expansiveness. (2) The unloaded swelling process of the expansive soil can be divided into the rapid swelling stage in the initial swelling stage, the swelling transition stage and the slow swelling stage in the middle swelling stage, and the swelling stable stage in the later swelling stage. (3) With the increase of the water content, the swelling pressure of the soil gradually decreases

Enhancing the mechanical and functional characteristics of structural spring steel through the advancement of heat treatment technologies

The article discusses the improvement of the technology of heat treatment of springs made of structural spring-spring steel grade 55Si2, used in rolling stock of railway transport. The authors conducted extensive experiments to study the effect of different temperatures and duration of heat treatment on the mechanical properties of springs. During the research, optimal quenching and tempering modes were identified, which significantly improved the strength characteristics, wear resistance and stability of the springs. The results of the work formed the basis of new technological instruction aimed at improving the quality and increasing the yield of usable products, which is important for improving the reliability of freight wagons operation