Browse Topic: Electrical systems

Items (16,793)
Driven by the growing demand for higher efficiency and load-bearing capacity in fields such as new energy vehicles and heavy-duty engineering machinery, planetary gear sets are increasingly operating at elevated rotational speeds, coupled with a corresponding expansion of their revolution radii. This dual trend directly induces a substantial surge in centrifugal acceleration acting on the internal needle roller bearings. Under the cyclic stress inherent to transmission operations, such enhanced acceleration not only accelerates the initiation of spalling faults on the inner bores of planet gears but also exacerbates the propagation and deterioration of these faults throughout the service life. To elucidate the influence mechanism of inner bore spalling on the dynamic response of planetary gear bearings, this study develops a specialized dynamic model. This model explicitly incorporates the compound kinematic effects of simultaneous rotation and revolution, thereby ensuring a high-fidelity reconstruction of actual operating scenarios. The research systematically investigates how different spalling types and dimensional parameters affect the system’s dynamic behavior. Numerical results demonstrate a positive correlation between the severity of the spalling defect and the dynamic response intensity. Specifically, the expansion of defect dimensions under harsh operating regimes markedly exacerbates both the contact impulses at the needle-roller interface and the overall vibration acceleration amplitudes. Notably, the amplitude increment of the needle rollers is far more pronounced than that of other components. These findings enrich the theoretical understanding of fault-induced dynamic responses in planetary gear systems and provide a solid theoretical and model-based foundation for optimizing the fault diagnosis, condition monitoring, and maintenance strategies of the associated needle roller bearings.
Zou, DeshengLai, JunbinGuo, WeiDong, PengXu, XiangyangSun, Qiang
Solid-state hydrogen storage is severely limited by poor thermal performance of storage reactors, which leads to non-uniform temperature fields and slow reaction kinetics. A numerical model for metal hydride hydrogen storage technology was implemented by means of COMSOL Multiphysics 6.3, based on hydrogen sorption behavior for LaNi5-based material. After experimental validation, a spiral-wound tube with embedded turbulators was introduced into the reactor. The influence of turbulator cross-sectional ratio and shape on hydrogen-absorption performance was then investigated. When the turbu-lator occupied 1/40 of the cross-section, the temperature distribution became more uniform and the reaction rate increased markedly; the time to achieve 80% conversion was reduced by approximately 9.29%. The study demonstrates that tailoring the turbulator geometry (circular vs. square) and exploiting its synergy with the spiral tube accelerates reaction kinetics and balances the temperature field. Under 0.8 MPa and 313 K, a hydrogen uptake of 1.4 wt% was achieved. The simple structure can be mass-produced by CNC (Computer Numerical Control) tube-bending, making it attractive as a portable hydrogen source for mobile devices such as unmanned aerial vehicles.
Lin, JiangnanJin, Tingxiang
Due to the interference of oscillatory components and noise, the periodic impulses associated with localized bearing faults become difficult to extract, leading to unreliable diagnostic performance. To solve this problem, the study proposes a simultaneous impulse and oscillatory component decomposition method (SIOCD). The method designs and solves a novel optimization model to decompose oscillatory components and fault impulse components from noisy vibration signals. To achieve component separation in the optimization model, distinct penalty functions are introduced for oscillatory and impulse components. For oscillatory components, a regularization term is applied to achieve their extraction by minimizing the component bandwidth in the frequency domain. For impulse components, a penalty function is designed to achieve their decomposition by enhancing both sparsity within groups (SWG) and sparsity across groups (SAG) in the time domain. Then, an iterative solver is derived using an alternating minimization framework and the majorization-minimization (MM) algorithm. Finally, the proposed method’s effectiveness is demonstrated through comprehensive simulation and experimental analyses, and the results demonstrate that it achieves superior performance over existing approaches in fault feature extraction and enhancement.
Sun, HaoranZhang, JinduoHan, TianyuShi, Xi
Railway wire harness connectors are critical elements in modern rail transport systems, ensuring reliable signal transmission, power distribution, and communications across the subsystems that govern traction, braking, and passenger information. The progressive deterioration of these connectors under harsh operating conditions, particularly temperature variations encountered during continuous railway operations, poses significant challenges to system reliability and operational safety. This paper presents a hybrid framework integrating an adaptive Wiener process with a deep generative model (DGM) for reliability assessment and remaining useful life (RUL) prediction of railway wire harness connectors under multi-temperature conditions. The proposed methodology combines Arrhenius-based temperature acceleration with a Wiener degradation model that characterizes temperature-dependent degradation kinetics. Specifically, a variational autoencoder (VAE) is employed as the deep generative network to learn the complex nonlinear degradation patterns that conventional parametric models may fail to capture. Furthermore, a particle filter algorithm is incorporated to enable real-time Bayesian parameter updating and state estimation, thereby allowing the model to be refined in an adaptive manner as new monitoring data become available. The effectiveness of the proposed method is validated through accelerated degradation tests on electrical connectors at four temperature levels (25°C, 55°C, 85°C, and 105°C), demonstrating that the RMSE is reduced by 23.5%, 18.2%, and 32.1% compared with the standard Wiener process, LSTM-based approach, and Gaussian process regression, respectively. The analytically derived reliability function and RUL distribution provide comprehensive uncertainty quantification to support maintenance decision-making in railway systems.
Wu, JiajunChen, Yongping
AE-8C2 Terminating Devices and Tooling Committee
The transition toward low global warming potential (GWP) refrigerants, driven by increasingly stringent environmental regulations and carbon reduction targets, has imposed new requirements on thermal management systems (TMSs) for electric vehicles (EVs). These systems must ensure efficient operation across a wide range of ambient conditions while maintaining high energy efficiency and environmental compatibility. Among potential alternatives, R290 (propane) has emerged as a promising natural refrigerant due to its favorable thermophysical properties and low environmental impact. In this study, an R290-based dual secondary loop TMS is proposed and evaluated for wide-temperature-range EV applications. A one-dimensional system model was developed using Dymola and validated through experimental testing on a dedicated performance test bench. TMS performance was investigated under multiple steady-state operating conditions, including high-load cooling, battery fast charging, and low-temperature heating, and benchmarked against a conventional R1234yf-based direct TMS. The results demonstrate that the R290-based dual secondary loop system achieves improved performance compared to a conventional R1234yf direct system, with a coefficient of performance (COP) increase of 4.29% under high-load cooling conditions at 43°C and up to 27.27% under high-load heating conditions at −10°C. Furthermore, under extreme low-temperature conditions (−18°C), the system delivers a heating capacity of 7 kW with a COP of 1.8, demonstrating strong low-temperature adaptability without the need for auxiliary heating. The results confirm that the proposed R290-based dual secondary loop system provides significant advantages in energy efficiency and wide-temperature adaptability, offering a promising solution for next-generation EVTMSs.
Zhang, YunpengMohammed, Mustafa MudassirGu, YiliangZhou, Guoliang
P2-type layered oxides are good cathode materials in high-performance sodium-ion batteries since they have desirable two-dimensional ion migration pathways. However, their instability at interfaces and their attenuation as cycles persist also remain a significant challenge. To increase their electrochemical stability, surface coating is also a good plan, but the balance between the coating and ionic conductivity is one of the key challenges. This study constructed an immensely thin layer of alumina (Al2O3) coating, and the influence of the amount of the coating (0.3-1.2 wt percent) on the working of the material was methodically examined. Electrochemical analysis showed that the lowest levels of Al2O3 (0.3 wt) provide the greatest improvement in performance. The optimized sample showed a retention capacity of 96.35 after 100 cycles of operation at 1C, significantly higher compared with samples that had increased coating contents. An analysis of cyclic voltammetry and impedance spectroscopy was subsequently done to corroborate the presence of a 0.3 wt% coating, which infected the electrode-electrolyte interface by inhibiting side reactions but minimally obstructing sodium-ion transport and thus promoting reaction reversibility and improved interfacial kinetics. These results highlight the importance of a less-is-more rule when it comes to surface coating and provide a novel understanding of how long-life sodium-ion battery cathodes can be designed by carefully engineered interfaces.
Hu, ChaoPeng, RuiZhou, YuZhou, DengmeiTian, Liangliang
This article focuses on the research and development of a remote cab controller for pure electric loaders, aiming to address the threats posed by traditional loaders operating in harsh and hazardous environments to drivers’ health and safety. First, the functional requirements of the controller were analyzed, based on which the hardware design with a multicore microprocessor as the core was completed, featuring functions such as signal acquisition, controller area network (CAN) communication, and H-bridge driving. On this basis, a control algorithm framework for remote driving was developed, including modules for signal input, analysis and processing, and signal output. Detailed control strategies were formulated for key components: For the pedal sensor, algorithms for opening degree calculation, automatic zero-position calibration, and dual-signal redundant fault diagnosis were proposed; for the steering module, precise angle calculation and force feedback feel simulation were achieved; and for the electric control handle, a hysteresis control algorithm was developed to suppress shocks caused by overly fast operations. In addition, a hierarchical fault diagnosis mechanism was established to ensure system safety. To verify the controller performance, a complete remote driving system was built. Field test results show that the system exhibits good signal following and control responsiveness in terms of traveling and working functions. Efficiency tests indicate that the remote driving efficiency can reach 80% of that of in-person operation under short-term test conditions, demonstrating the technical feasibility and control effectiveness of the developed controller. While the prototype exhibits promising performance for pilot deployment, long-term reliability metrics such as mean time between failures (MTBF) remain to be validated through extended field operation.
Lu, YueqiJi, ShaoboYu, QiuyeLi, MengXu, HaozhiAn, Meng
A modeling study was performed to find solutions to reduce the unburned hydrocarbons during cold start of a PFI (port fuel injection) SI (spark ignition) engine. Through modeling, the root cause for the high unburned hydrocarbons of the baseline engine during cold start was found. The slow combustion, which is due to the high amount of exhaust gas flowing back into the intake port and then becoming trapped inside the cylinder, is the root cause. A new valve lift, which can reduce the internal residual by 26%, was designed. Along with a fuel amount decrease of 35%, the UHC (unburned hydrocarbons) before the three-way catalyst can be reduced by 40%. The exhaust temperature using the new valve lift design increases by 400°C, which improves the performance of the three-way catalyst for further reducing UHC. In addition to the adoption of the new valve lift, an active SAI (secondary air injection) strategy was also investigated. Modeling results show that SAI can promote secondary combustion in the exhaust pipes to increase exhaust temperature and thus is beneficial for further oxidizing unburned hydrocarbons. The amount of active SAI mass flow rate should be controlled to less than 25% of the intake air flow rate to avoid the cooling effect dominating over the oxidation process. The duration of SAI should be from EVO (exhaust valve opening) to IVO (intake valve opening). For combustion modeling, a newly reduced iso-octane chemical kinetic mechanism was developed using carbon flux analysis to extract major reaction pathways for a wide range of practical engine temperature conditions. In the new reduced mechanism, a skeletal sub-mechanism for species starting from iso-octane to C4 is coupled with a recently updated H2/O2/CO/C1–C4 detailed sub-mechanism. Including a reduced NOx (oxides of nitrogen) sub-mechanism, the final mechanism has 681 species and 3332 reactions. Before the new reduced iso-octane mechanism was used, it had been validated with available experimental data of ignition delay times, laminar flame speeds, and important species profiles in the literature. Both the investigation of PFI engine unburned hydrocarbons reduction under cold start operating conditions and the development of a reduced chemical mechanism are the objectives of this work.
Guo, DongshaoZhang, LichengYang, ShiyouBourg, CyrusSun, YongAbidin, ZainalLin, Shujun
To provide test guidelines, recommendations, and referenced standards for insulation materials in a high energy system especially at high voltages (AC, DC, and PWM) and at operational altitudes, for the purpose of defining/measuring the effects of insulation aging. This document is a part of a family of documents related to the impact of ageing on insulating materials devoted to aviation applications. Aging mechanisms, and the markers to monitor them, have been defined in AIR7374. For sake of brevity, the main conclusions are used here. ARP7375 focuses on the ways to measure these markers on representative samples (either coupons or electrical insulation systems) for aerospace applications.
AE-11 Aging Models for Electrical Insulation in Hi-Enrgy Sys
This SAE Standard covers unshielded cable, 22 gauge and larger, intended for use at a nominal system voltage up to 600 V or 1000 V (ACrms or DC). It is intended for use in surface vehicle electrical systems.
Cable Standards Committee
AE-8C2 Terminating Devices and Tooling Committee
Inertial Friction Welding (IFW) equipment is essential for the welding process of aircraft engine shaft components. However, the absence of comprehensive fault-handling standards for domestically produced inertial friction welding equipment has hindered its further development. This study focuses on the connecting rod and motor of the 30T-IFW equipment, employing a model-based fault detection method. Through simulation, the deformation of the connecting rod and the frequency response of motor vibration acceleration under different working conditions are obtained. Additionally, a monitoring platform is proposed to collect real-time data on connecting rod deformation and motor vibration from actual welding equipment. By establishing a quantitative correlation model of connecting rod deformation-force and revealing the coupling mechanism between motor eccentricity faults and modal frequency vibrations, a hybrid diagnostic framework that combines simulation of primitive warning and measurement of calibration is proposed. At last, the simulation and experimental results verify the effectiveness of the fault diagnosis method proposed in this paper.
Yang, HaifengYuan, MingqiangSun, TaoLiang, WuGong, MaolinAn, XingyiWang, QisongLiu, Dan
Conventional aero-engine fault detection techniques tend to have problems simultaneously extracting local anomalies in sensor data and long-term temporal dependencies. To solve this problem, we propose a new fault detection scheme that only uses a Dual-Path Temporal Convolutional Network (Dual-TCN) and a Gated Recurrent Unit (GRU) module. The model, in turn, takes advantage of dual parallel branches of TCNs to extract local and global features and integrates these features with the GRU to model the progression of faults in time. Validated on the dataset of the National Aeronautics and Space Administration, called C-MAPSS, the proposed technique achieves a detection accuracy of 91.39%, which is better than CNN and LSTM baselines, demonstrating interesting improvements in the precision, recall, and F1-score. Experimental results further demonstrate the effectiveness of the dual-path feature extraction and GRU fusion strategy; this method is potentially useful to realize the real-time and accurate detection of faults in complex aero-engine systems.
Yan, ShaokaiZhang, Yongjian
With the continuous improvement of performance requirements for aviation equipment, the importance and complexity of hydraulic systems as the core carrier of flight control are becoming increasingly prominent. The cleanliness of aircraft hydraulic pipelines directly affects the reliability and flight safety of hydraulic systems, and it is necessary to use specialized cleaning and testing equipment during design and manufacturing to achieve efficient cleaning. The design of traditional cleaning equipment relies on experience-driven development, with mechanical, hydraulic, and electrical systems developed independently. There are problems such as unclear requirement definitions, low efficiency of interdisciplinary collaboration, and lagging validation, making it difficult to achieve the goal of forward design. Therefore, this study introduces Model-based Systems Engineering (MBSE) method in the development process of pipeline cleaning test equipment, proposes a modeling process based on RFLP (Requirements-Function-Logical-Physical), and uses SysML system modeling language to construct a top down design model system for aircraft hydraulic pipeline cleaning equipment. Through requirement analysis modeling, functional behavior definition, and system architecture design, the significant advantages of MBSE method in the development of complex aviation test equipment have been verified, effectively improving the bold design capability and top down design efficiency. MBSE method can not only improve the design efficiency of equipment, but also promote the intelligent and efficient operation of equipment, which has important significance for the development of intelligent manufacturing and electromechanical integration technology.
Zhang, YuxinMa, ZichenLi, QiSong, GuoqiuLi, HaiweiZhang, Jingjing
This document covers cable, shielded and jacketed, intended for use at a nominal system voltage up to 1000 V (AC rms or DC). It is intended for use in surface vehicle electrical systems.
Cable Standards Committee
With the rapid development of the new energy vehicle energy storage industry, lithium-ion battery technology is undergoing a phase of rapid technological advancement. Enhancing battery energy density and safety remains a core challenge in overcoming industrial bottlenecks. During long-term cycling operations, deviations in state of charge (SOC), voltage, and temperature of individual cells inevitably occur, leading to reduced energy utilization efficiency. These deviations may also induce local overcharging and internal short circuits in individual cells, ultimately triggering thermal runaway incidents. While existing battery balancing strategies primarily focus on uniformity regulation, they fail to adequately address the coupling mechanisms of heat generation, heat storage, and thermal runaway propagation during balancing processes. Furthermore, the poor coordination between these strategies and thermal management systems makes it difficult to meet the complex safety requirements of high-energy-density batteries. To enhance the safety and energy utilization efficiency of battery systems during operation, this study focuses on the synergistic optimization of balancing strategies and thermal runaway prevention control. By establishing computer models of individual cells and battery packs in CATIA software, the research analyzes the evolution mechanisms of thermal runaway triggered by system state inconsistencies, while exploring the regulatory patterns of balancing parameters on thermal safety. Utilizing the ANSYS simulation platform, the study systematically examines the impact of three critical parameters—ambient temperature, discharge rate, and coolant flow rate—on battery temperature rise, providing theoretical support and technical references for the design of high-reliability lithium-ion battery pack systems.
Yu, ZhengGong, JiFan, YiLiang, WeiLi, YueweiLiu, FashenXie, MaojunCen, Zucai
This paper focuses on the parameter matching of key components and the improvement of overall vehicle performance for a certain front-wheel drive pure electric vehicle. Firstly, based on the target performance of the vehicle, the rated/peak power, speed, and torque of the permanent magnet synchronous drive motor, as well as the capacity, voltage, and series-parallel scheme of the LiFePO4 power battery, are systematically calculated. Meanwhile, the gear ratio of the transmission system is determined based on the dual constraints of the maximum speed and the maximum gradeability. Subsequently, the vehicle model is built using AVL Cruise, and the maximum speed, 0-100 Km/h acceleration time, maximum gradeability, and NEDC range are simulated and verified under steady-state and transient conditions. The results show that the maximum speed of the prototype vehicle reaches 139 Km/h, the 0-100 Km/h acceleration is 7.98 s, the maximum gradeability is 33.2%, the power consumption per 100 Km is 12.12 KWh, and the range is 485 Km, all of which are superior to the design indicators. The research verifies the rationality of the proposed parameter matching scheme and can provide a theoretical basis and engineering reference for the forward development of the power system of pure electric vehicles of the same level.
He, YuefanZhang, BaopingTang, ShujianChen, HanbangJin, Biao
SAE TOMORROW TODAY - SAE JA1016: Scaling the Future of UAVs with Battery Interoperability135798/6/2026
From drone delivery to public safety and defense, the next generation of uncrewed aerial vehicles (UAVs) will be powered not just by better batteries, but by better battery standards. Listen in as we sit down with Jeff Yambrick, Chair of the SAE Battery Cell Size Standardization Committee, and Lisa King, Director of Advanced Battery Strategy at Leap Manufacturing, to discuss SAE JA1016 -- a new standard designed to simplify battery integration, accelerate commercialization, and strengthen the UAV supply chain. During this conversation, you'll learn why common battery formats are essential for reducing development costs and creating greater interoperability across commercial and defense applications. We also explore the importance of domestic battery manufacturing, supply chain resilience, and how standardization can accelerate innovation without limiting future battery technologies. To join the SAE Battery Cell Size Standardization Committee, email Dante Rahdar at Dante.Rahdar@sae.org. We'd love to hear from you! Share your comments, questions and ideas for future topics and guests to podcast@sae.org. Don't forget to take a moment to follow SAE Tomorrow Today--a podcast where we discuss emerging technology and trends in mobility with the leaders, innovators and strategists making it all happen--and give us a review on your preferred podcasting platform. Follow SAE on LinkedIn, Instagram, Facebook, X, and YouTube. Follow host Grayson Brulte on LinkedIn, X, and Instagram.
Patterson, Lori
A research team led by Professor Lin Gui at the Institute of Physics and Chemistry, Chinese Academy of Sciences, reports the first fabrication of multi-layer flexible batteries using a combination of liquid metal microfluidic perfusion and plasma-based reversible bonding techniques.
As the energy density of electric vehicle power batteries continues to increase, efficient and uniform heat dissipation has become critical to their safety and performance. The liquid cooling plate serves as the core component of the battery thermal management system, with its flow channel structure directly impacting heat dissipation efficiency and system energy consumption. Current liquid cooling plate flow channel designs often rely on empirical methods, making it challenging to simultaneously optimize both heat dissipation uniformity and flow resistance performance. This paper focuses on a single lithium battery as the research subject, employing a topology optimization approach to design the liquid cooling plate flow channel structure. Optimization targets include minimizing pressure drop at the inlet/outlet and minimizing temperature difference across the contact surface between the plate and the battery. Under constant inlet cross-sectional dimensions and flow velocity, numerical simulation of fluid heat transfer processes revealed an 11.17% reduction in temperature difference across the contact surface. This enhances lithium battery heat dissipation uniformity while reducing inlet/outlet pressure drop by approximately 10.98%. This approach reduces the system energy consumption of liquid cooling. It enables multi-objective co-optimization design for power battery liquid cooling plate structures. It provides new technical references for the refined design of cooling systems in automotive power battery packs.
Ma, HonghuiZheng, YuqingYang, Minghao
This study investigates the suppression of lithium-ion battery (LIB) fires using composite aqueous extinguishing agents, with a 20 Ah lithium iron phosphate battery as the experimental subject. Based on the functional selection of coverage-isolation and cooling-smothering, three aqueous extinguishing agents, S-E-1, S-E-2, and S-E-3, were designed and developed using hydrocarbon surfactants. The results indicate that all three aqueous fire extinguishing agents can effectively suppress LIB fires. Through a comprehensive evaluation of extinguishing time, cooling rate during extinguishing agent release, and physical and chemical parameters of the extinguishing agents, the optimal formulation was determined to be 2% SDS (sodium dodecyl sulfate), 1% SDBS (sodium dodecyl benzene sulfonate), 3.5% CAB (cocamidopropyl betaine), 1% APG0810 (alkyl polyglycoside), 1% CDEA (coconut oil acid diethanolamine), 0.32% CH4N2O (urea), 1.5% NH4H2PO4 (ammonium dihydrogen phosphate), 0.5% C2H6O2 (glycol), 1.5% Na3PO4 (sodium phosphate), and deionised water, demonstrated the best performance. Reducing the extinguishing time to 14 seconds, a 41.7% reduction compared to pure water, and increasing the cooling rate to 0.816 °C·s^–1, which is 4.4 times that of pure water, with no reignition observed. This work contributes to the theoretical principles needed to engineer next-generation fire suppression materials for lithium-ion batteries that are both efficient and eco-friendly.
Yu, TaoZhu, ShunbingLi, KeZhang, Menglan
The inconsistency in bearing data distributions under diverse conditions often affects the representations of the faulty data and leads to indistinct decision boundaries and even negative transfer resulted from overlapping class distributions, greatly limiting the accuracy of the diagnosis model. To cope with the challenge, a pseudo-label-guided dual-supervised alignment (PDSA) method is developed for bearing fault diagnosis across diverse operating scenarios in this paper. To address the fixed alignment strategy issue, an adaptive distribution alignment layer is incorporated to ResNet18 to achieve dynamic data distribution alignment under varying condition, To enhance classification performances, a dual-supervised mechanism, comprising shallow-layer supervised contrastive learning is introduced through target domain pseudo-labels in target domain and deep-layer regularization class consistency. Experiments on two publicly available bearing datasets demonstrated this model realizes refined class-level alignment, strengthens fault states representation, and shows notable superiority in both accuracy and robustness.
Sun, HaoRen, ShijinGu, Zhangqing
The rotary storage mechanism is a critical component responsible for transferring cylindrical units. To accurately simulate the nonlinear dynamics characteristics of the rotary storage mechanism, a dynamics model incorporating uncertain parameters is established based on the Lagrange method. Utilizing an optimization approach, uncertain parameters of the rotary storage mechanism are identified based on test data. The Stellar Oscillation Optimization (SOO) algorithm is employed, which balances exploration and exploitation by simulating the periodic expansion and contraction of stars to achieve optimal solutions. The results show that the output of the identified dynamics model under two operating conditions closely matches the test data, validating the accuracy of the model and the effectiveness of the identification process. This provides strong support for subsequent reliability analysis and fault diagnosis studies of the rotary storage mechanism.
Li, AngChen, GuangsongHuang, PengLi, Hanning
With the development of the power industry, 10kV switchgear (circuit breaker switches) are increasingly widely applied in power grids. When performing power-off maintenance or testing on 10kV switchgear (circuit breaker switches) at substations, maintenance personnel require transport carts to move the equipment to suitable locations for operation. Traditional transfer carts suffer from structural design flaws and significant shortcomings. These include difficulty operating in the confined spaces of switchgear cabinets, high risks associated with manual handling, low efficiency in secondary transfers, and poor adaptability across multiple workstations. These issues collectively pose safety hazards during power-off maintenance or testing. When operating in a 3m×5m high-voltage room, traditional maintenance carts achieve less than 0.5 units transported per hour, with equipment damage rates reaching 3% annually due to drops, resulting in low work efficiency. To address these challenges, a 10kV switch cart maintenance platform has been developed. This standardized equipment facilitates 10kV switch cart maintenance, supporting the intelligent upgrade of power grid operation and maintenance.
Yang, SenZhou, HanSu, HainanYu, XinHu, YutaoWang, Xisheng
Conveyor belt fault detection is critical for ensuring the safety and efficiency of industrial material transportation. In this study, a screen-printed flexible strain sensor based on a thermoplastic polyurethane (TPU) substrate and graphene conductive ink was fabricated. The sensor exhibited excellent flexibility, mechanical robustness, and stable electromechanical performance. Comprehensive evaluations were conducted, including microstructural analysis, strain sensitivity, hysteresis, dynamic response, and long-term cycling stability. The results demonstrated that a two-layer graphene configuration achieved an optimal balance between sensitivity and structural stability, showing high gauge factor, fast response, and reliable cyclic performance. Furthermore, the sensor was applied to conveyor belt fault monitoring. Experiments validated its ability to detect both halting faults and foreign object intrusions, with distinctive resistance signal features enabling not only fault occurrence detection but also identification of fault location, type, and severity. These findings highlight the potential of the proposed flexible sensor system as a promising solution for intelligent conveyor belt monitoring in harsh industrial environments.
Zhang, BoAi, ShigengZhang, XiaoboSun, WantingLi, Pengfei
The space cable-rod deployable articulated mast is a type of space-deployable structure with high storage efficiency. As a critical component, the pretension in the cables directly affects the stiffness and dynamic characteristics of the mast. However, research on the modeling of cable assemblies remains limited, and the relationship between cable tensions and the natural frequencies of the system has not been reported, leaving a lack of design and manufacturing guidelines for such assemblies. In this study, a dynamic model of the X-configuration cable–strut assembly consisting of a central locking device and four cables was developed, and its applicability was investigated. Guided by the characteristics of the actual structure, the assembly was simplified into a central mass–spring system, and the governing equations of motion were derived using the Newton–Euler formulation. A finite element (FEM) model based on spring elements is constructed to validate the proposed formulations. In addition, another FEM model employing beam elements is developed, and modal analyses are conducted to compare with theoretical predictions, thereby assessing the applicability of the model. The results demonstrate that the equivalent spring model can accurately capture the first, fourth, and fifth natural frequencies of the system, while its prediction of in-plane frequencies is limited due to the neglect of cable bending effects. Based on the characteristics of the three out-plane modes, explicit relationships between natural frequencies and cable tensions are derived. This work provides new insights into the simplified modeling of cable assemblies and offers valuable references for further refinement and practical applications.
Zhang, ShichengWang, YufengZhang, XiaochengSun, ChaoHe, HuadongWu, Zhiqiang
With the goal of enhancing diesel engine adaptability to low-temperature environments and exploring cold-start potential at - 50 °C, this paper develops a one-dimensional simulation model for the cold-start system. The model is based on a method that utilizes a diesel heater to warm the coolant, which in turn heats the engine block and oil. The heating condition of coolant and oil of a 10-cylinder V-type engine within a specified time under a -50 °C environment is studied through simulation. We further optimized the cold-start process by enhancing the coolant flow distribution within each circulation circuit to improve overall thermal management and start-up efficiency. The results show that: at an ambient temperature of -50 °C, with a heating power of 80 kW, a total flow rate of 110 L/min, and an engine block flow rate of not less than 54 L/min, the diesel engine can raise the coolant temperature at the engine outlet to 40 °C and the oil temperature to -35 °C within 20 minutes. Through flow optimization, by maximizing the flow rate of the engine block heating circuit and reducing the flow diversion of the intercooler, the coolant temperature at the engine outlet can reach 40 °C in 18.9 minutes, while the oil is heated to -34.9 °C, and the final heating coolant temperature reaches 44.4 °C at 20 minutes. Compared to the situation without flow optimization, the time for the engine outlet coolant temperature to reach 40 °C was shortened by 0.55 minutes, and the final heating coolant temperature increased by 2.2 °C. Based on relevant experiments and the dynamic viscosity curve of 5 W engine oil, this paper holds that the starting conditions of a diesel engine can be met when the engine outlet coolant temperature reaches 40 °C, and the engine oil temperature reaches -35 °C.
Wang, JingfeiXie, PengWang, ZhuoXia, YingqiuZhang, XiaodongChen, KeWang, Guodong
Laser welding technology for aluminum alloy electrode and busbar connections: addressing challenges in battery module assembly. In this work, a CFD framework was built in ANSYS Fluent using a Gaussian rotating heat-source representation, while a VOF approach was used to capture the transient gas–liquid interface in deep-penetration welding. A three-dimensional, transient, thermal-fluid coupled numerical model of the dual-layer heterogeneous aluminum alloy laser deep penetration weld pool was established concurrently with laser deep penetration welding experiments. Results indicate: Peak flow velocities in the weld pool during welding are concentrated along the weld centerline, with flow vectors predominantly directed axially along the weld. Once a quasi-steady keyhole regime is established, vaporization-induced recoil pressure becomes the primary driver governing melt circulation. The liquid metal first impinges on the pool bottom along the keyhole wall and then recirculates upward near the pool boundary, producing strong vortical motion. These findings are intended to support parameter selection and process optimization for laser welding of layered dissimilar aluminum components used in battery tab–busbar assemblies.
Lv, WenjunWu, Yan
In recent years, with the rapid increase in the market penetration of new energy vehicles, safety issues in electric vehicles, particularly those characterized by thermal runaway of power batteries, especially fire incidents caused by mechanical abuse from underbody impacts, have become a major focus of industry attention and social concern. This paper systematically compiles key data from electric vehicle underbody collision incidents, covering core parameters such as impact location, geometric features of obstacles (shape and size), and vehicle speed during accidents. Based on this data, the study further reviews existing underbody scraping evaluation protocols both domestically and internationally, with a focused comparison of the differences in mechanical load and battery pack response between two typical test methods: horizontal underbody scraping and 3° inclined underbody scraping. The findings of this research aim to provide data support for the refinement of relevant evaluation standards and to offer theoretical foundations and practical references for automotive manufacturers in optimizing the design and validation strategies for underbody protection of battery packs.
Wang, QingguiHe, QikeLi, WenboLi, ChunLi, Xiaodong
Hydrogen-powered aircraft primarily utilize the conversion of liquid hydrogen into gaseous hydrogen to replace aviation kerosene, where hydrogen is directly combusted to provide propulsion. This study applied Amesim software to establish a complicated model simulating the liquid hydrogen to gaseous hydrogen conversion and ignition combustion processes. The simulation contains converting liquid hydrogen into gaseous hydrogen through a heat exchanger and simulating the mixture of gaseous hydrogen and air in the engine combustion chamber, and then igniting the mixture. The pressure, temperature, and flow rate of gaseous hydrogen and air during the ignition and combustion process in the engine combustion chamber, as well as the outlet temperature of the combustion chamber, are simulated and analyzed. The results demonstrate that during the simulation process, the internal pressure of the liquid hydrogen storage tank, the outlet pressure and flow rate of the liquid hydrogen pump, and the pressure and flow rate of gaseous hydrogen meet the requirements of the ignition combustion test. In addition, varying gaseous hydrogen flow rates had significant impacts on the temperature of the combustion chamber during combustion.
Gao, PengfeiWang, Lijian
During the high-speed operation of packaging machines, if the abnormal components evolve into faults, the packaging machines often stop for inspection or even damage, causing production stagnation and huge economic losses. If key variables are predicted and faults are identified before the evolution of packaging machine failures, it is of great significance to ensure equipment safety and reduce maintenance costs and losses for enterprises. The purpose of fault prediction is to use the information modeling of equipment historical data to output the changes in key features before component failures in the future. Firstly, for the redundant data of multiple measurement points of the same variable in the packaging machine process variables, Pearson correlation analysis is used to obtain more accurate variable data. We reuse adaptive empirical mode decomposition (EEMD) for signal processing and feature extraction, reduce redundant information, use convolutional neural network (CNN) models for spatial feature learning, and then use bidirectional long short-term memory models to capture temporal dependencies of CNN information for capturing time series data. A model is established on the normal training set to fit the normal state of the packaging machine, identify different types and degrees of equipment fault characteristics through normal test set data, and send the predicted results of the equipment state to the fault classifier for judgment to determine whether to issue a fault warning. The results indicate that this article has validated the effectiveness of the model in fault feature extraction and high-precision fault classification through training on equipment status data.
Wu, AiminLiu, ShixianZhao, LihuiLiu, ZhaoWu, TaoLi, Lianbing
Due to the constraints of manufacturing costs and cycles, it is difficult to simulate the full-scale operating conditions of aircraft electrical power systems. Usually, scaled-down low-power systems are used for prototype development and experimental research. This paper puts forward a systematic framework for developing scaled physical models of aircraft electrical power systems by using similarity theory. In this paper, according to the general design principles of DC-DC converters, a 10-kW low-power DC-DC converter and a 250-kW high-power DC-DC converter are designed. Mathematical models for both systems are developed, and a time-domain performance index analysis is carried out using the per-unit dynamic equivalence principle. A metric conversion model is established and equivalently mapped to a high-power DC-DC converter simulation model. The waveform consistency between the converted model and the aforementioned 250-kW high-power model is verified, which shows the validity of the proposed conversion method.
Ma, HuanAi, FengmingBi, WenyanPei, XiaoningLiu, Liangliang
This study aims to solve the trajectory optimization problem of multi degree of freedom micro air vehicle (MAV) with the aim of improving its flight performance through technological innovation. A multi degree of freedom trajectory optimization (MDFTO) method with sideslip angle and angle of attack as the core control variables was proposed for multiple complex constraints in combat environment, such as terminal accuracy and overload limitation. This method can more accurately characterize and adapt the strong nonlinear, dynamic coupling and time varying characteristics of the MAV in high-speed maneuvering flight. In order to solve this MDFTO problem with multiple constraints and strong nonlinear characteristics efficiently, the hp adaptive pseudospectral method is used in this study, and is verified by simulations based on the GPOPS-II optimization platform. The algorithm has the advantages of highly accurate discrete state and control variables, efficient processing of path and terminal constraints, and adaptive adjustment of the distribution point density. GPOPS-II is able to efficiently adapt to the MDFTO method. The simulation results show that the GPOPS-II can accurately capture the MAV’s dynamic response. Its adaptive node adjustment mechanism effectively balances computational efficiency with solution accuracy, especially during flight phases where state changes drastically, ensuring the reliability of results. The MDFTO method successfully achieves the optimal solution, and the generated trajectory strictly follows the laws of vehicle dynamics and kinematics. This method provides an effective and engineering feasible technical approach for the trajectory optimization of the MAV under complex constraints, and has important theoretical and practical value for improving its strike accuracy, maneuverability and comprehensive combat effectiveness.
An, ZhichaoMing, ChaoWen, Guangbao
This article focuses on a wide range of high-precision storage and supply systems. Under the rated flow rate of 2.928 mg / s of the proportional flow controller, the instantaneous flow fluctuation range of the BangBang valve reaches 2.963 mg / s, exceeding the control accuracy requirement of 1% for the proportional flow controller. By establishing mathematical models of the BangBang valve, proportional valve, and proportional flow controller for simulation analysis, the trend of the simulation results is consistent with the experimental results. Furthermore, considering the spatial layout and weight of the storage and supply system, this paper proposes a method to improve the accuracy of flow output by adding 180 mL of air capacity between the proportional valve and the proportional flow controller. Ultimately, the maximum flow fluctuation of the proportional flow controller at the moment of the BangBang valve opening and closing is 2.941 mg / s, which meets the control accuracy of the proportional flow controller. Moreover, the error between the output flow rate of the proportional flow controller and the rated working flow rate is minor after increasing the air capacity.
Li, ZhongLi, ZongliangYan, ZelongHuang, Tiankun
Terminal guidance is critical for ensuring strike precision in the final phase of flight. However, traditional methods, such as proportional navigation and optimal guidance laws, face significant challenges regarding real-time performance and adaptability to dynamic targets. To address these issues, neural networks offer a promising solution by enabling adaptive adjustments to guidance parameters, thereby improving performance under various constraints.
Ma, HengweiWang, YongfengWen, HongLiu, DiWei, YuanhangDong, LonghaoLuo, Ying
To ensure the successful implementation of the separation, evacuation, and return processes of manned spacecraft after long-term docking at the space station, regular on-orbit health assessments must be conducted. Based on this requirement, a technical method for evaluation through autonomous on-orbit testing is proposed. First, the docking status and characteristics of the manned spacecraft’s systems, such as information management, crew environmental control, thermal control, power management, docking function, attitude, and orbit control function, are described. Then, the functional requirements for the separation, evacuation, and return of the manned spacecraft, such as the relative measurement, the relay communication, TT&C and data transmission, image and voice, instrument display and alarm, and the attitude measurement, are analyzed. Subsequently, the on-orbit testing system, test items, test procedures, and test methods for health assessment are detailed. It also provides the design of TT&C support, the design of energy support, and the main principle explanation for autonomous on-orbit testing of the system.
Cheng, WeiNan, HongtaoTian, YeZhao, Zheng
In recent years, drone technology has seen widespread application in both civilian and military fields. By 2025, China will introduce supportive policies from multiple dimensions, including industrial development, technological innovation, and application promotion, to significantly increase the number of UAVs in use and their frequency. However, drones are prone to malfunctions due to factors such as bad weather and electromagnetic interference, which may result in serious consequences, including property damage and casualties. Therefore, improving the accuracy of fault detection and the response time of drones is of great significance. Although current research has made progress, there are still deficiencies: First, most of them rely on a single or limited data source, resulting in incomplete information and vulnerability to interference, which leads to low detection accuracy and reliability; Second, traditional methods are mostly based on fixed thresholds or simple rules, lacking real-time dynamic monitoring and adaptive analysis capabilities, making it difficult to issue timely warnings of potential faults. To this end, this study proposes a multi-scale time series prediction model based on multimodal and multi-branch, integrating multimodal data, constructing a dual-branch architecture, and combining deep learning and attention mechanisms to enhance the anomaly detection effect of unmanned aerial vehicles. A dual-branch anomaly detection model based on 1DCNN-BiLSTM and continuous wavelet transform is proposed, including a trajectory prediction difference branch and a full time series data branch. In the dual-branch output stage, the attention gating mechanism is utilized to fuse features and improve the detection performance. The experimental results show that this model performs excellently in both normal trajectory prediction and anomaly detection, providing an effective solution for drone anomaly detection.
Pu, ZhenglinZhang, Lin
Flexible cables are widely used in aircraft and are essential for ensuring the proper functioning of critical systems and flight safety. The design and validation of these cables represent a foundational technology in enabling the transmission of electrical power and signals throughout the entire aircraft. To achieve their intended service life, appropriate protective measures and experimental verification must be implemented. Drawing on the development experience of flexible cables for a specific domestic aircraft model, this paper proposes a combined protection method designed to extend the service life of flexible cables. Experimental analysis demonstrates the practicality and reference value of this approach.
Shi, LiqingHu, HuanghuaGe, Zengwen
Items per page:
1 – 50 of 16793