Browse Topic: Bodies and Structures

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Edge-Intelligent Real-Time Evaluation System for Aerospace Manufacturing Skill Training2026-99-292010/19/2026
The evaluation of practical skills in aerospace manufacturing, maintenance, repair, and overhaul (MRO) conventionally relies on examinations or observations from instructors. However, these methods deliver slow feedback, reduce the efficiency of skill acquisition and require substantial instructional workload. To overcome these challenges, this study proposes an edge-intelligent real-time evaluation system for skill training in the field of aerospace manufacturing. Specifically, the system comprises five sensing modalities, which are then processed through a hierarchical three-layer structure. Then, the neural architecture search (NAS) is introduced to identify the optimal network structure and the quantization-aware training (QAT) approach is employed to improve the inference speed. In addition, temporal modeling is used to realize real-time inference and multi-level evaluation. Moreover, a conflict-aware adaptive fusion algorithm is introduced to ensure robust scoring under harsh workshop conditions and deliver interpretable feedback. Finally, federated learning and the differential privacy mechanism are used for cross-institutional model improvement without raw data exposure. Empirical results on turbofan engine MRO assembly, airframe structural component CNC manufacturing, and aviation maintenance human factors training show that the system achieves low latency, high expert correlation, improved learning efficiency and strong robustness, which offers a scalable and privacy-aware solution for competency-based vocational training in the aerospace manufacturing field.
Li, Xin, Li, Zhaokang, Yu, Lina
Task Allocation and Trajectory Optimization for Mother-Daughter Satellite Clusters Observing Non-Cooperative Constellations via Improved Genetic Algorithm2026-99-291710/19/2026
Over the past decade, the rapid deployment of Low Earth Orbit (LEO) mega-constellations has significantly reshaped the spatial distribution of the near-Earth environment and increased orbital density to historically high levels. While popularizing space access, the accumulation of defunct or non-cooperative satellites raises severe concerns regarding space sustainability and the Kessler syndrome. Consequently, the ability to conduct active, multi-target close-proximity inspection is becoming an essential capability for Space Situational Awareness (SSA). Traditional monolithic servicing strategies rely on sequential point-to-point orbital transfers, which have to face heavy computation cost and restrictive fuel constraints when targeting multi-planar distributed networks requiring continuous out-of-plane maneuvers and phasing adjustments. In order to overcome these limitations, the paper proposes a coordinated mother-daughter satellite cluster architecture. A primary mother satellite serves as a deployment hub, while a swarm of highly maneuverable daughter satellites executes sequential "Observe-and-Return" missions, gathering high-fidelity SSA data. Assigning these multi-target inspection missions to a limited fleet creates an NP-hard combinatorial challenge, further compounded by strictly non-overlapping operational time windows and rigid propellant boundaries. To navigate this high-dimensional search space, the study introduces an improved Genetic Algorithm (GA) featuring a dynamic chronological decoding mechanism. Furthermore, to eliminate secular positional drifts during orbital integration, a high-fidelity five-impulse maneuver sequence is established, embedding an autonomous Lambert-based positional compensation mechanism. Simulation results indicate that the proposed method yields scalable, fuel-feasible, and load-balanced kinematic baselines for autonomous target characterization across large-scale constellations. Additionally, an event-triggered dynamic re-planning mechanism is utilized to robustly adapt to uncooperative evasive maneuvers in highly dynamic real-world space scenarios.
Sheng, Beining, Tian, Yang, Li, Tieying, Shan, Yiming
Noise Analysis and Circuit Optimization for the Drive Loop of Resonant Accelerometers2026-99-296710/19/2026
Resonant MEMS accelerometers are core inertial devices in precision measurement fields such as inertial navigation, aerospace, and seismic monitoring, characterized by frequency signal output, strong anti-interference capability, and high-precision potential. With the growing demand for sub-microg-level measurement accuracy in high-end industrial and scientific applications, noise suppression and detection sensitivity optimization have become key research topics for resonant accelerometers. This paper conducts a systematic modeling study on resonant accelerometers, analyzes their mechanical structure and acceleration sensing mechanism based on the force-frequency effect of double-ended tuning forks, and establishes corresponding mathematical models. Non-ideal noise models of the mechanical structure and drive loop are constructed separately, and key noise source analysis identifies mechanical thermal noise and 1/f noise of the front-end charge amplifier as the main contributors to system noise. To solve these problems, a dedicated low-noise charge amplifier is designed for the drive loop. Simulation results show that the input-referred noise of the low-noise operational amplifier used in the charge amplifier reaches 18.804 nV/√Hz @ 50 kHz. When applied to the drive loop and verified through tape-out testing, the system achieves a phase noise better than -119.904 dBc/Hz @ 20 Hz offset from the resonant frequency, with a corresponding acceleration noise density of approximately 0.477 μg/√Hz @ 20 Hz.
Cai, Hebin, Li, Zhaohan, Zhang, Qiukun, Liu, Guowen, Zhang, Wenbo, Yin, Liang, Gao, Naikun, Fu, Qiang
Research on 3D Cooperative Localization Method Based on Single-Auxiliary Node Maneuver Reconstruction2026-99-295910/19/2026
The demand for high-precision, real-time, and continuous localization in aerospace and low-altitude unmanned systems is steadily increasing. However, under weak GNSS availability, obstruction, and degraded ranging geometry, conventional 3D localization methods often suffer from insufficient observation constraints and severe accuracy degradation. To address observability degradation and localization error divergence in single-auxiliary-node systems, this paper proposes a 3D cooperative localization method based on maneuver reconfiguration of a single auxiliary node. Within a particle filtering framework, the method fuses target motion increments with single-shot range measurements to recursively estimate the target’s 3D position and heading. A geometric degradation metric and a radial-consistency metric are further constructed from the line-of-sight distribution and the alignment between target velocity and line of sight within a sliding window, enabling online detection of degraded observability. Once degradation is detected, the auxiliary node performs either lateral maneuvering or circular maneuvering to actively reshape the target–auxiliary relative geometry and restore observation diversity; meanwhile, the two metrics can also serve as feedback variables for adaptive maneuver adjustment. Comparative analyses are conducted under three modes, namely no reconfiguration, lateral maneuvering, and circular maneuvering, from the perspectives of 3D trajectory evolution, error time series, degradation-metric time series, and statistical error performance. Parameter sensitivity analyses and an additional nonlinear velocity-varying scenario are also included. Experimental results show that the no-reconfiguration mode exhibits clear error divergence under degraded conditions, whereas both maneuver-based strategies effectively reduce localization errors. Lateral maneuvering is more suitable for rapid recovery in the early degradation stage, while circular maneuvering achieves better overall accuracy and stronger post-degradation recovery capability. These results demonstrate the effectiveness and engineering feasibility of degradation-triggered active geometric reconfiguration for cooperative localization in low-configuration unmanned systems.
Wen, Yuanbin, Guo, Ziwen, Wu, Jian, Tu, Jiajun, Ma, Junteng, Wei, Jinyue, Zhou, Jihua
Research on Temperature Hysteresis Error Suppression Technology for Capacitive MEMS Accelerometers2026-99-296810/19/2026
The performance of MEMS accelerometers is highly sensitive to temperature variations, manifesting as zero drift, sensitivity drift, and hysteresis error. This paper presents a low-temperature-drift, low-noise interface ASIC for capacitive MEMS accelerometers. The circuit employs an analog closed-loop architecture comprising a small-capacitance front-end detection circuit, a variable gain amplifier (VGA), a correlated double sampling (CDS) circuit, a PID controller, and a feedback module. To suppress temperature-induced errors, key optimizations are implemented: the charge amplifier employs active and passive charge compensation techniques to reduce common-mode offset drift; the VGA uses switched feedback resistors for gain adjustment; a Class-AB unity-gain buffer enhances driving capability while isolating load interference; and a high-order compensated bandgap reference with pre-regulation achieves low temperature drift and high power supply rejection. Post-layout simulations demonstrate a system sensitivity of approximately 2.27 V/g, a sensitivity temperature coefficient of 74.55 ppm/°C, and a 1σ zero-bias temperature drift of 1.757 mg. Experimental results over the full temperature range from -45°C to 85°C show an output hysteresis error of only 0.6 mg. These results validate the effectiveness of the proposed temperature hysteresis error suppression technique, providing a valuable reference for the design of high-precision MEMS accelerometer interface circuits.
Zhao, Weiqiao, Liu, Guowen, Hao, Zhiwen, Li, Zhaohan, Gao, Naikun, Zhang, Wenbo, Fu, Qiang, Yin, Liang
Analysis of Structural Stress Distribution and High-Temperature Performance of Load-Bearing Components in External Fire Scenarios of Steel-Structured Aircraft Models2026-99-297510/19/2026
This paper focuses on three typical external fire scenarios in aircraft firefighting and rescue training systems: engine fires, external fuselage skin fires, and nose landing gear fires. Unlike internal fires, these external fires expose the load-bearing steel structure directly to flame radiation and high-temperature environments, and the cooling methods and stress conditions associated with each fire scenario differ significantly. Based on the ABAQUS finite element platform, this study established a three-dimensional finite element model comprising an engine model, a water-cooled thermal insulation structure, and a fuselage support system, fully accounting for the actual structural layout and cooling protection measures of the training system. Material parameters were derived from measured performance data for Q355NH steel. The calculation results indicate that under the three types of external fire scenarios, the steel structure model maintained sufficient structural safety margins, with a minimum safety factor of 4.49 and a maximum of 9.43. This demonstrates that the current design meets the safety requirements for prolonged external fire training, providing a reliable mechanical basis for the safe operation of the ARFF training system.
Gao, Jianwei, Xu, Xiaodong, Huang, Min, Wang, Shumin, Shi, Yajie, Zhang, Yun
Trajectory Planning for Heterogeneous Multi-Satellite Cooperative Proximity Operations2026-99-291410/19/2026
This study addresses the challenges in heterogeneous multi-satellite cooperative proximity operations, including functional heterogeneity, strong temporal coupling, and difficulties in unified planning. A functionally layered framework composed of observation, support, and servicing satellites is constructed. Considering the distinct mission characteristics of different satellite types, differentiated decision variables, objective functions, and constraints are designed, and a particle swarm optimization algorithm is employed for solution. Simulation results demonstrate that the proposed method can generate feasible cooperative trajectories satisfying constraints such as safety distance, temporal coordination, communication links, and mission windows, while maintaining system stability and operational safety. Parametric analysis indicates that mission duration, minimum access distance, and support effectiveness significantly affect system performance. Through functional decomposition and cooperative optimization, the system achieves an effective trade-off among different preferences, providing theoretical support for the mission design and control of heterogeneous multi-satellite proximity operations.
Xiao, Jinzhao, Zhang, Jin
Backstepping-Based Dynamic Sliding Mode Control for Tilt-Rotor Quadrotor UAVs in Transition Flight2026-99-291310/19/2026
The flight control problem of an H-shaped dual-wing tilt-rotor quadrotor UAV during positive tilt transition is investigated, where the rotor tilt angle varies continuously from 0° to 90° and the vehicle shifts from rotor-borne to wing-borne lift. A component-based partitioning approach is adopted to build a complete kinematic and dynamic model of the fuselage, wings, rotors, and main body, derived from the Newton–Euler equations and the momentum theorem so that major force and moment contributions can be explicitly integrated. Based on this model, a MATLAB/Simulink simulation platform is established for controller evaluation. To achieve stable tracking with practical implementability, a dynamic sliding mode control (DSMC) strategy is developed, which avoids the explosion of complexity caused by repeated differentiation and balances response speed and attenuation of residual oscillations, particularly in the altitude channel. Furthermore, the performance of both DSMC and conventional sliding mode control (SMC) is systematically examined through extensive simulations under representative flight scenarios, including different transition speeds, various tilt angles, external disturbances, and multi-UAV cooperative tracking tasks. Comparative simulations with conventional sliding mode control under identical transition settings show stable command tracking and faster error convergence, with particularly improved altitude steady-state precision, while the velocity response exhibits a trade-off in mean-square accuracy over the evaluation horizon.
Liu, Dantong, Li, Daochun
Assessment of Aircraft Wheel Sealing SystemsARP5146A (Current)10/9/2026
This SAE Aerospace Recommended Practice (ARP) is intended to provide guidance on verifying the integrity of inflation pressure sealing systems of aircraft wheel/tire assemblies.
A-5A Wheels, Brakes and Skid Controls Committee
The Impact of Observability Constraints on the Planning for Employment of Robotic and Autonomous Systems2026-01-75149/22/2026
Employment of Robotic and Autonomous Systems requires a different paradigm of mission planning. The GTRI Missioneer for Organic Collaborative Kill-Chains (MOCKS) effort was developed to mature the concepts of mission planning in light of autonomy, where the decision making is distributed across the battlespace and each individual entity has limited awareness of global state. The paper presents some initial characterizations of the impact of constraints on periods out of communication, or no-comms windows, on the number of resources required for missions of a certain operational area. This metric, along with the foundational metric of remaining effective range margin are foundational to robust a priori planning.
Spratley, Michael
Decision-Centric Virtual Metrology for Geometric Deviation via Foundation-Embedding Retrieval2026-01-75549/22/2026
Modern defense manufacturing and sustainment require timely engineering decisions (e.g., inspection triage, rework/accept decisions, and process adjustment) based on the as-built geometric quality. Advanced machining systems generate rich multichannel controller and sensor streams, yet accurate geometric deviation labels remain costly and delayed because they depend on downstream metrology. This paper introduces ChronosGD, a retrieval-based virtual metrology framework. ChronosGD predicts pointwise geometric deviation from multichannel time series data by: (1) retrieving the most similar historical process windows in a frozen Chronos-2 embedding space, and (2) transferring deviation information through similarity-weighted aggregation. ChronosGD avoids plant-specific gradient retraining during deployment; adaptation is achieved by refreshing a labeled historical memory as new inspected parts become available, while preserving traceability through explicit neighbor provenance.
Hoang, Danny, Matthiessen, Ryan, Miller, Christopher, Mannan, Nasir, ElKharboutly, Ruby, Gorsich, David, Castanier, Matthew P., Imani, Farhad
FITTING END, STANDARD DIMENSIONS FOR BULKHEAD FLARELESS TUBE CONNECTIONSAS33515E (Current)9/17/2026
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Thermomechanical Fatigue Life Prediction of Grey Cast Iron Brake Rotors Using Advanced Material Models and Elastic-Plastic Fracture Mechanics2026-01-08169/14/2026
A unified thermomechanical fatigue (TMF) life-prediction methodology is presented for lamellar graphite (grey) cast iron brake rotors operating under the severe transient thermal loads that arise in brake dynamometer durability testing. The workflow links four ingredients within a single rotor-level framework: transient nonlinear finite-element analysis, temperature-dependent inelastic constitutive modeling, a mechanism-based short-crack TMF damage model, and an elastic-plastic (nonlinear) fracture-mechanics crack-growth simulation. Two constitutive descriptions are exercised for the structural analysis — the standard rate-dependent Chaboche viscoplastic model available in Abaqus, and a user material subroutine (UMAT) that couples Chaboche viscoplasticity with continuum damage in order to reproduce the tension–compression asymmetry of cast iron. The resulting stress, strain, and temperature histories drive a multiaxial thermomechanical fatigue Damage (DTMF) computation that estimates crack initiation and early extension, after which a nonlinear fracture-mechanics procedure simulates crack-front advance toward through-thickness failure. Both constitutive models correctly localize the crack-initiation site on the rotor inner diameter, consistent with the dynamometer observations; for the loading histories examined, the standard Chaboche model yields lives in closer agreement with test. The crack-growth simulation reproduces the rapid post-initiation propagation seen experimentally and resolves branch-wise differences in crack-front evolution through the rotor section.
Lee, Heewook, Garcia, Arnoldo, Liu, Yi, Hazime, Radwan, Boughanmi, Heni, Kassir, Abdallah
Design and Validation of Lightweight Composite Load-Bearing Structures for Aircraft Using Topology Optimization and Multiscale Verification2026-99-14089/11/2026
Composite materials have become widespread for use in aircraft load bearing structures due to their ability of reducing structural mass without compromising the required stiffness, strength and safety requirements in the face of aerodynamic, inertial and thermal service loads. This work has addressed with success the development and validation of such an integrated lightweight-design framework applied to a representative composite aircraft load-carrying structure. The workflow exploits SIMP topology optimization and parametric modelling as well as Kriging and support vector regression surrogate models, Latin hypercube sampling and a multi-island genetic algorithm, to screen the low mass design space subject to stress, deformation, buckling and manufacture ability constraints. The optimized FE model contained 2.15M elements. It predicts a max prinicpal stress of 263.4MPa,a stress margin of 4.18, and a tip deflection of 1.24 mm under the 2.0 mm limit, and the minimum buckling factor was 3.47. The prototype test recorded maximum stress at 257.6 MPa, and thermal deflection of 1.27 mm while deviation between simulations and testing remained below 6%. In general, the above results indicate that the surrogate model based optimization coupled by the manufacturing feedback will be able to relate the aircraft composite structure design, fabrication and validation, and can be used as a realistic benchmark for digital engineering analysis of light-weight aircraft structures.
He, Haoming
Research on the Application of Multi-Source Data in Bus Route Network Optimization2026-99-15669/11/2026
This research aims to optimize the bus route network in Shiyan City using bus Origin-Destination (OD) data. By integrating multi-source data, including GDP, population, and bus OD big data from 2018 to 2022, short-term and long-term indicators are forecasted by time-series methods. Shiyan city is divided into 77 Traffic Analysis Zones (TAZs) considering its mountainous terrain, population-industry distribution, and urban planning. A conventional four-stage traffic demand model is applied, calibrated with bus OD data in 2021. The investigation reveals peak-hour bus passenger travel demand of 29,700 short-term and 31,800 long-term person-trips in the city center and key corridors. Bus passenger travel forms a four-vertical and five-horizontal layout in the short term, evolving to a five-vertical, five-horizontal, and two wings pattern in the long term with eastward urban expansion. Accordingly, an optimized and upgraded bus route improvement strategy is devised. In the short term, there are seventy existing bus routes that are adjusted, creating a five-layer bus route network with diverse functions. Long-term plans involve optimizing twenty bus routes and adding eight new routes to align with urban development. This research not only aids an integrated bus route network optimization framework using bus OD data in a time-consuming way, but also provides a sample of bus route network adjustment for a typical mountainous city.
Ye, Qian, Chang, Sheng, Shen, Yucan, Li, Tanfeng, Tian, He, Tian, Shimo, Cen, Jian
Vehicle Multi-Target Tracking Algorithm Based on Improved CenterTrack2026-99-11029/11/2026
With the rapid increase in the number of vehicles worldwide in recent years, multi-vehicle tracking has become a critical and challenging research topic in smart transportation. Although many researchers have constructed classical multi-object tracking (MOT) models, these models often lose trajectories of objects in challenging traffic environments with frequent occlusions and high object density. This significantly hinders the practical deployment of such tracking systems. In order to improve tracking robustness and accuracy when faced with these challenges, we propose a new multi-vehicle tracking algorithm built upon the CenterTrack framework. The core of our work lies in three key improvements. Each overcomes a distinct weakness in existing approaches, and together they work to improve performance. First, we use the Wise Intersection over Union (WIoU) loss to guide the model optimization and reduce the impact of label noise during training, which results in better convergence. Second, we apply an attention mechanism to reduce feature interference caused by multiple inputs (current frame, previous frame, and heatmap) of the model. Third, we employ the Sigmoid Linear Unit (SiLU) in the backbone network to further improve nonlinear feature representation. We evaluate our algorithm on the standard KITTI multi-object tracking benchmark. Experimental results show that our method achieves a Multi-Object Tracking Accuracy (MOTA) of 65.94% and an Identification F1 (IDF1) of 84.01%. This represents an improvement of 2.93% in MOTA and 2.36% in IDF1 over the baseline method. The results demonstrate not only the effectiveness of our method but also its practical usefulness and robustness in challenging road environments.
Zhang, Hao, Huai, Chongfei, Wang, Ziming, Zhao, Zexuan, Ye, Shuai, Du, Xiaobing, Sun, Shenghai
Study on Shaking Table Model Test of Seismic Dynamic Response of Loess Multi-Arch Tunnels2026-99-15849/11/2026
Taking the Nieye Multi-Arch Tunnel in Zhuoni County as the engineering background, this study systematically explores the seismic dynamic response characteristics of loess multi-arch tunnels through shaking table model tests. The test results show that: (1) The strain distribution of the surrounding rock is significantly different. Under a peak acceleration of 0.6 g, the maximum strain in the tunnel portal section is concentrated on the right side, which is related to the incident direction of seismic waves and the stress concentration at the bottom of the central wall; the maximum strain in the tunnel body section is located on the left side, affected by the propagation characteristics of seismic waves, burial depth, and unsymmetrical pressure. (2) The acceleration amplification factors in the Z and ZX directions show nonlinear changes. Under bidirectional excitation, the Wenchuan wave-ZX combination exhibits the strongest response. The variation trend of acceleration at the soil-rock interface varies with wave types, and the slope damage undergoes three stages: elastic stage, elastoplastic stage, and plastic damage stage. (3) The ratio ω of tunnel burial depth to central wall thickness is positively correlated with the strains at key positions. For the seismic design of loess multi-arch tunnels, special attention should be paid to sensitive areas such as the bottom of the central wall and the left side of the tunnel body. It is suggested to improve the structural seismic performance by optimizing the lining reinforcement and adapting to regional seismic wave types. The research conclusions provide a reference for the seismic design of such tunnels under complex geological conditions.
Han, Tao, Cao, Xiaoping, Zhang, Shulin, Yang, Zibin
Numerical Investigation of In-Plane Antisymmetric Failure Modes and Load-Carrying Mechanisms of Steel Portal Piers2026-99-15949/11/2026
A nonlinear finite element model was applied to study the in-plane instability of steel portal piers, in which initial geometric imperfections, welding residual stresses, and material nonlinearity were considered. The modeling procedure was compared with experimental results from box-section members, and consistent tendencies in load level and deformation evolution were observed. In the numerical analyses, the initial elastic buckling configuration exhibited an in-plane antisymmetric form. As loading continued beyond the elastic range, this deformation pattern persisted. With further loading, the deformation remained purely axial while combining compression with bending. During this stage, plastic hinges appeared near the column tops, while lateral displacement became clearly observable. Comparison models with different geometric proportions show that variations in the span-to-height ratio and the beam–column stiffness ratio influence how instability develops and where plastic deformation tends to localize. From a design perspective, these trends can be considered when distinguishing instability characteristics and selecting stiffness proportions between beams and piers.
Li, Jie, Shangguan, Bing, Cheng, Zhangxu, Ruan, Furong, Bai, Fan
Research on Interference Management of Shared Collection and Transportation Vehicle Scheduling of Bulky Garbage with Order Changes2026-99-15199/11/2026
This study presents a shared vehicle scheduling model designed to tackle scheduling conflicts arising from changes in orders for bulky waste collection and transportation. The model accounts for five types of interference events: alterations in the original order location, modifications to the time window, changes in waste size, the inclusion of new orders, and order cancellations. The goal of the model is to reduce variations in the frequency of collection and transportation, minimize costs, and meet the three requirements of three-dimensional loading for shared trucks, as well as satisfy user time windows. To solve this complex combinatorial optimization problem, the sparrow search algorithm is employed. Numerical studies indicate that the proposed method outperforms the genetic simulated annealing algorithm in objective function value and computational efficiency under the five interference scenarios. These results also confirm the model’s efficacy.
Xu, Chen, Ma, Huimin
Research on Heavy-Haul Train Operation Adjustment Considering the Degree of Chaos in Train Timetable2026-99-15229/11/2026
Heavy-haul railway development is as important a strategic direction for China’s railway sector as high-speed railway development. With the continuous expansion of heavy-haul railway operational mileage and the growing transportation demand, the complexity of operational adjustment in heavy-haul railways continues to escalate. The operational adjustment for heavy-haul trains subjected to speed restrictions following maintenance windows, aimed at maximizing the restoration of timetable regularity and guaranteeing freight volume, constitutes a critical and urgent research problem. Grounding on the operational principle of heavy-haul railways that prioritizes freight volume preservation over strict punctuality, this paper proposes a rescheduling model that incorporates the timetable disruption level. By adopting the order entropy theory, the model is formulated to minimize the total system disruption level and freight time cost, thereby framing the rescheduling problem as an order entropy optimization problem. The train disruption level is a metric that quantifies the perturbation intensity of a rescheduled timetable relative to the original operational plan within a given railway section. By initializing the entropy value of the pristine operational order to zero, any subsequent entropy variation directly facilitates a systematic investigation into the evolution of train operational order. Effective timetable adjustment strategies are subsequently derived, contingent upon the available buffer time and freight volume constraints. Guided by actual operational timetables and sectional line characteristics, this research designs a case study. The Gurobi solver is employed to obtain a rescheduled heavy-haul train timetable that successfully restores the original freight volume. The proposed methodology contributes to the enrichment of railway transportation organization theory and provides robust decision-making support for the strategic deployment of heavy-haul train services.
Fu, Lu, Lin, Li, Xu, Shichao, Ji, Guanggang, Li, Zheng
Real-time Vehicle Speed Detection Based on YOLOv11 and DeepSORT2026-99-15959/11/2026
The technology of real-time and effective vehicle speed detection is considered a key technology to improve traffic monitoring efficiency and traffic safety management grade. To address the limitations of traditional speed detection schemes—including reliance on dedicated hardware, poor environmental adaptability, and high construction and maintenance costs—this paper proposes a r10eal-time vehicle speed detection system based on YOLOv11 and the DeepSORT algorithm. The proposed system uses the YOLOv11 target detection algorithm as its primary model. DeepSORT multi-target tracking technology is integrated to enhance tracking performance. Speed measurement is implemented using a virtual detection line. This approach enables accurate vehicle detection, continuous tracking, and real-time speed measurement within video frames. Through the experiments, the result shows that the improved YOLOv11n model reaches mAP@0.5 of 0.982 and a recall rate of 0.956 in the test set, higher than the YOLOv8n and YOLOv5s models. The speed detection error can be restricted to 3 km/h, satisfying the real-time detection need. There is no need for road surface modification, and the detection system has a flexible layout, providing a dynamic basis for traffic law enforcement and traffic data support for road construction and traffic control optimization.
Jin, Guowei, Ma, Wenlong, Jiang, Dali, Li, Nan
Study on Brake Efficiency Airworthiness Requirements and Verification of Transport Category Aircraft2026-99-14049/11/2026
Braking efficiency is one of the key indicators for evaluating the performance of braking systems on transport category aircraft. The value of braking efficiency is directly related to the safety of aircraft deceleration processes, especially during landing, and it is also critical for civil aircraft operators to improve operational efficiency on routes. This paper presents the airworthiness regulation requirements related to braking efficiency, requirements for aircraft wheels and tires, requirements for runway pavement types, major sources of contaminants, and specific requirements for simulating wet runway conditions using different contaminants. This paper analyzes effective methods for calculating braking efficiency, including the pressure method, torque method, and slip ratio method, and introduces the approaches for acquiring data of relevant parameters. Combining experience from braking efficiency verification work, the paper demonstrates the specific test procedures for the actual measurement of braking efficiency. Based on measured data such as braking pressure, wheel speed, and aircraft speed during braking, as well as the wheel dimensions and rotational inertia of wheels and brakes, the specific braking efficiency values under different calculation methods are derived. The paper compares the differences in braking efficiency values obtained by various calculation methods for similar braking processes, analyzes the causes of these differences, and demonstrates that the accuracy of braking efficiency calculated by different methods is acceptable. Additionally, the same calculation method is applied to compute the braking efficiency of multiple braking deceleration processes, which demonstrates that the method has good repeatability and can be stably used for braking efficiency calculation. This verification method provides a reference for the certification work to ensure that the braking efficiency of transport category aircraft complies with airworthiness and performance requirements.
Feng, Yibo
3D Dynamic Object Detection with Multi-Modal Temporal Fusion2026-99-11179/11/2026
This research aims to address the critical challenge of accurately detecting and estimating the state of dynamic objects in autonomous driving. Traditional 3D object detection methods often struggle with motion perception, particularly in velocity estimation, due to the lack of information in single frame perception. We propose a novel framework that enhances the BEV representation with temporal modeling. The core of our method is a two-stage temporal fusion process. First, we align historical BEV features to the current coordinate frame to eliminate the interference of ego-motion. Subsequently, a dedicated temporal fusion encoder, architected with residual connections and a Feature Pyramid Network, refines the aligned multi-frame BEV features to capture complex motion patterns and improve multi-scale object representation. This approach directly tackles the problem of motion decoupling. By aligning features, we disentangle object motion from ego-motion. The temporal fusion encoder then mitigates the positional ambiguity of moving objects in the fused BEV space, a common issue in simple feature concatenation, leading to more robust detection. We built a dataset following the structure of the nuScenes dataset, using data collected from an autonomous driving simulation platform. The evaluation results on our simulation dataset demonstrate that the proposed temporal module achieves a 13.0% improvement in NDS score and a substantial 29.7% reduction in velocity error (mAVE). These results demonstrate that our temporal fusion strategy effectively enhances 3D detection accuracy in dynamic scenarios.
Shao, Mengjia, Li, Wei, Bai, Jie, Zhu, Shaoxiong, Xu, Chenjie
An Analysis Method for the Static Stability of Helicopter Rotor in Level Flight Based on Flight Test2026-99-14029/11/2026
To provide better data support for the aerodynamic design, flight control system design, and parameter optimization of helicopters, it is necessary to obtain the aerodynamic derivatives of the helicopter rotor based on flight test data and analyze the static stability of the helicopter rotor. This paper breaks through the limitations of aerodynamic testing of helicopter rotors and establishes a quantitative analysis method for the static stability of helicopter rotors in level flight based on flight test data. Based on the flight test data of the helicopter, this study establishes an aerodynamic model of the helicopter rotor and employs a genetic algorithm for parameter identification to obtain the aerodynamic derivatives of the rotor in level flight. The identified parameters are then used to quantitatively analyze the static stability of the helicopter rotor. The results show that the method developed in this study can accurately and effectively obtain the aerodynamic derivatives of the helicopter rotor from flight test data. Furthermore, this method can reliably evaluate the static stability of the helicopter rotor, demonstrating significant value for engineering applications.
Zhao, Jingchao
A Maritime Occluded Ship Detection and Tracking Method Based on Improved YOLOv8 Fused with AIS Trajectory2026-99-15499/11/2026
Typical maritime monitoring scenarios are usually constrained by factors such as multi-scale ship density, frequent motion overlap, and limited viewing angle of shore-based cameras. These challenges often lead to trajectory interruptions and identity mismatches in target detection and multi-target tracking tasks. In order to solve these problems, this study proposes a ship occlusion detection and tracking method based on the improved YOLOv8 model and further integrates an automatic identification system (AIS) trajectory reasoning. The method builds a unified perception framework with enhanced detection architecture, multi-source data fusion, and behavioral reasoning capabilities. First, in the target detection module, the improved SEConv structure is introduced into the YOLOv8 trunk network to address challenges caused by small-scale variations and severe occlusion in maritime scenes. The ReLU activation function in SEConv is replaced by the Swish activation function to enhance the nonlinear feature representation. In addition, the optimized SEConv is embedded in the C2f structure, and the convolutional block attention module (CBAM) attention mechanism is introduced to enhance the sensitivity of the model to the occlusion area. Next, for multi-target tracking, ByteTrack is used as the basic tracking framework. AIS trajectory data is introduced as auxiliary input to compensate for trajectory losses caused by occlusion. Finally, experimental results on the SeaShips public dataset and the self-built occlusion reference dataset show that the improved YOLOv8 detector achieves stable mAP gains in mild, moderate, and severe occlusion scenarios. The AIS enhanced tracking system improves the multi-target tracking accuracy (MOTA) and identification F1 score (IDF1) by about 6.3% and 8.1%, respectively, and the average occlusion reconstruction error is controlled within 1.4 seconds. The proposed method effectively enhances the perception ability of ships in complex occlusion environments and verifies the feasibility and superiority of the strategy of combining visual detection with AIS data assistance.
Guan, Keping, Chen, Miao, Zhou, Yue
Rolling Element Bearing No-Load Torque TestARP5483/1B (Current)9/9/2026
This test method outlines the recommended procedure for performing the no-load rotational starting torque test on airframe rolling bearings. Bearings covered by this test method shall be antifriction ball bearings and spherical roller bearings.
ACBG Rolling Element Bearing Committee
The Vacuum System of Arc Section Standard Cell for STCF Collider Rings2026-99-12389/4/2026
The Super Tau-Charm Facility (STCF) is a new-generation positron-electron collider planned in China. The core mission of STCF is to design a new generation of large-scale scientific facility featuring a center-of-mass energy between 2 and 7 GeV and a peak luminosity of more than 5×10^31 cm^–2s^–1. Given its high beam intensity and high luminosity characteristics. This will provide serious difficulties for the vacuum system’s design due to its high beam intensity and high luminosity features. The double-ring collider and the injector are the two primary components of the STCF. Each collider ring is divided into arcs, straight sections, and the interaction region. The arc sections adopt the same standard cell design. This paper primarily introduces the vacuum system of a standard cell for the arc section. This is related to the space simulation of aerospace on the ground, which requires a very high vacuum. By designing an overall scheme for the vacuum system, the structure and dimensions of the vacuum chamber are determined. The synchrotron radiation power and dynamic gas load distribution are calculated for the Arc Dipole Magnet. The placement scheme for vacuum components such as vacuum pumps, bellows, and BPMs is determined. At the same time, simulation analysis was conducted on the temperature, strength, and internal pressure of the vacuum chamber using finite element analysis software. Different vacuum chamber materials will have different calculation results, and the copper vacuum chamber is selected in this paper. The design specifications meet the technical requirements proposed by the physical system, providing a theoretical basis for the development of the next prototype and technical guidance for the design of vacuum systems in other sections.
Zhao, Lijuan, Zhang, Ruiyang, Sun, Kun, Gong, Hailiang, Jiao, Weijie, Zhang, Benfu, Mao, Mingyang
Aerodynamic Load Calculation and Prediction Method for Folded Wing Mechanism2026-99-12899/4/2026
The folding wing mechanism is widely used in aircraft design. Whether the folding wing surface can unfold smoothly determines whether the aircraft can fly normally. Therefore, studying the aerodynamic loads and structural deformations during the unfolding process of folded wing surfaces is very important. The motion process of a folded wing mechanism is a typical fluid-structure interaction (FSI) process. During deployment, the wing surface moves under the combined action of the actuator’s pull and the aerodynamic loads from the incoming flow, while the large deformation of the wing surface during its movement, in turn, affects the aerodynamic loads on the mechanism from the flow field. Considering the FSI effects during the unfolded motion process of the folded wing, simulation was conducted using the ALE algorithm in LS-DYNA to obtain the kinematic and dynamic parameters in the unfolded motion process, and also to get the aerodynamic torque on the wing under different angles and angular velocities. In practical engineering applications, the actuation force of the deployment mechanism can vary due to factors such as the amount and performance of the pyrotechnic material. Consequently, the final velocity and the whole motion process of the wing mechanism will also change. For the calculation of aerodynamic external loads under multiple operating conditions, using the ALE algorithm will consume a large amount of computational time and cost. Given the high computational cost and long computation time of finite element simulations, a BP neural network was established to calculate the aerodynamic loads on the wing surface under different actuation forces. This allows for a rapid assessment of whether significant deformation or damage will occur to the folding mechanism or nearby components during the deployment process.
Wei, Ting, Li, Naitian, Tong, Zongkai
Optimized Design of Vibration Reduction for the Frame Structure of Metering, Considering Ground Impact Load2026-99-12339/4/2026
To effectively mitigate the adverse effects of impact loads on the operational quality of a planter, this paper focuses on precision metering with dual planting chambers, and a novel approach is proposed to concurrently consider static and impact loads in the design of the frame structure, aiming to achieve a balanced design that combines load-bearing capacity and vibration reduction effects. The methodology employs a dual-layer cyclic process, where the outer layer calculates equivalent static loads based on the structural nonlinear dynamic response, and the inner layer introduces these equivalent static loads into the objective function of the optimization model using a weight method. The design of the frame structure, which simultaneously accounts for static and impact loads, is established through a topology optimization model based on the parametric level-set method. The simulation-optimization results indicate that, within the two-dimensional plane, the optimized seed metering frame achieves a marked reduction in volume fraction while its compliance remains almost unchanged. When the solution is expanded from 2-D to 3-D, and the optimized volume is increased to match the original volume, the optimized stiffness becomes 1.92 times the initial stiffness. This demonstrates that the frame is substantially lightened yet its stiffness is effectively enhanced, confirming that the design concurrently offers improved vibration attenuation and load-bearing capacity. The proposed structural optimization method can provide a viable design for improving the quality of precision metering. Although physical tests are still lacking, the soundness and consistency of both the simulation outcomes and numerical analyses provide strong evidence for the feasibility of the proposed method. Future tests can further verify its effectiveness.
Zhang, Wenpeng, Zeng, Shan, Zang, Ying, Wang, Yu
An Experimental and Numerical Study on the Optimization of Quasi-static Energy Absorption Performance in Aluminum Alloy Thin-walled Tubes with Varied Notch Configurations2026-99-12559/4/2026
Aluminum alloy thin-walled tubular parts play an important role in the energy absorbing elements of automotive passive safety. The number of geometry-trigger based notches is a factor in alleviate the initial force peak and shift the progressive buckling mode. However, until now, only limited work has been reported considering multiple notches. It is hard to clearly understand the impacts of the number of triggers on the buckling behavior and thresholds. Here, a mixture of quasi-static axial compression testing with high-fidelity finite element simulations is used to explore the influence of elliptical perforation number on AA6061-T6 tube crushing behaviour. For the first time, it is demonstrated that increasing the perforations leads to non-monotonic buckling evolution: from symmetry increasing → asymmetrical instability → optimal re-symmetrization → excessive weakening. We observe this transition from isolated holes to a collective “weakening hoop” controlling symmetric buckling as the number of holes increases. Our results give optima for separate objectives; T6 offers the best overall crashworthiness (45.2% less maximum force), with the other measures showing T4 with the best stiffness. We determine quantitative relationships between the number of holes and corresponding performance metrics. This gives practical design criteria for the design of energy absorbers.
Guo, Zifa, Jin, Ming
Simulation Modeling and Analysis of Landing Gear Brake-Induced Buffeting2026-99-12489/4/2026
This paper establishes a joint simulation model for landing gear vibration problems. Based on the model, the influence laws of different braking control methods, different runway conditions, and different positions of the rear strut on the main landing gear vibration are compared and analyzed. The results show that the runway conditions have a certain influence on the landing gear braking performance and heading vibration; the rear strut landing gear has better vibration response, and the vibration displacement is reduced by 10–20% in all simulation conditions compared with the strut in front.
Huang, Linyu, Lyu, Ning, Chen, Jie
Detection of Pipe Surface Coatings on Ultrasonic Guided Wave Propagation2026-99-12159/4/2026
Coating the surface of pipelines is one of the most crucial and effective methods for inhibiting corrosion and prolonging the operational lifespan of pipelines. The coating acts as a protective shield that isolates the pipeline metal from external corrosive environments. However, once the coating begins to peel off or deteriorate due to aging, mechanical damage, or environmental factors, the exposed metal surface becomes highly susceptible to corrosion. Statistics indicate that over 50% of external corrosion failures in pipelines are directly associated with coating defects. Despite the critical importance of coating integrity, research on the interaction between surface coatings and nondestructive testing methods—particularly ultrasonic guided wave techniques—has remained relatively limited in recent years. In this study, the impact of surface coatings on the propagation behaviors of ultrasonic guided waves in pipeline systems was systematically investigated. Coal tar pitch, a commonly used and cost-effective coating material, was applied to steel pipeline specimens with varying coating lengths. The attenuation rate of the guided wave signal amplitude was measured under different coating conditions to analyze the relationship between coating parameters and acoustic energy loss. The experimental results reveal that the coating significantly affects guided wave propagation, especially in terms of signal attenuation and boundary reflection. Furthermore, the study reveals that ultrasonical guided waves possess strong sensitivity to coating discontinuities and can accurately locate coating boundaries. These findings confirm the potential of guided wave technology for early detection of coating defects and quantitative evaluation of coating adhesion. Moreover, the outcomes provide useful insight for other transportation and aerospace structures that employ multilayer coatings or protective films, such as aircraft pipelines and composite fuselage components, where similar material interfaces and inspection challenges exist. This research provides theoretical and experimental references for improving the reliability of pipeline health status detection.
Xiao, Tianyi, Li, Bing
A Volume Coordinates System Generalized Mixed Element for Piezoelectric Structures2026-99-12169/4/2026
Prompted by the significant aerospace applications of piezoelectric materials, a novel 8-node hexahedral generalized mixed element is introduced for analyzing such structures. The element employs a volume coordinate system for its local frame, which maintains a linear transformation to the global Cartesian coordinates. Unlike conventional displacement-based formulations, the governing equations of this mixed element simultaneously include displacement and stress field variables, facilitating the direct solution of stress components. To address potential discontinuities in in-plane stresses across layers in piezoelectric laminates, a partial mixed method is further implemented. The model is applicable to flat or large-curvature-radius piezoelectric plates. Numerical benchmarks confirm the element’s robustness to mesh distortion.
Hou, Dianqiang, Liu, Yanhong
Nonlinear Modeling and Parameter Identification of Air Rudder System2026-99-12129/4/2026
The modeling accuracy of the air rudder system directly affects the quality of aircraft attitude control. However, the commonly used simplified second-order model cannot accurately represent its nonlinear transfer characteristics. To this end, a dynamic model of the air rudder system considering three types of nonlinear factors, such as saturation, clearance, and dry friction, was established. On this basis, a stepwise identification test modeling method based on frequency characteristic data was proposed. By designing two different excitation levels of test conditions to excite or suppress the influence of some nonlinear factors, the stepwise identification of each unknown physical parameter was completed. The identification results show that the air rudder system model established in this paper can accurately characterize its nonlinear transfer characteristics, and the transfer characteristic curve of the identification results is in good agreement with the measured data.
Wang, Ding, Nangong, Zi-jun, Liu, Bo
Fatigue Damage Analysis of a Wheeled Vehicle2026-99-12079/4/2026
This article studies the fatigue damage problem of vehicles under air drop and off-road conditions. First, a multi-body dynamics model of the entire vehicle is established in ADAMS/View to obtain loads and center-of-gravity acceleration under off-road conditions. Subsequently, a finite element model of the vehicle air drop is created in HyperMesh and LS-DYNA to simulate the landing impact and extract loads on key components. By superimposing and spectrum processing the loads from the two conditions, a vehicle load spectrum is compiled and used as input for fatigue analysis. Based on the Miner linear cumulative damage criterion and the material S–N curve, fatigue life predictions are made for key areas of the frame and suspension. The results indicate that the front cross beam and auxiliary longitudinal beam at the bottom of the frame are the most vulnerable components, with the auxiliary longitudinal beam reaching failure under both conditions, but having a limited impact on the overall vehicle operation. Although the peak acceleration under air drop conditions is higher, the off-road conditions lead to more severe cumulative damage due to higher impact frequency and duration. This study provides references for vehicle structural optimization and service reliability enhancement.
Lin, Qingpeng, Zhang, Qiang, Fu, Lei, Huang, Jianbing, Qin, Weiwei, Sun, Xiaowang
Dynamic Modeling and Robust Active Control of Graphene-Piezoelectric Composite Missile Wings with Elastic Boundary Constraints2026-99-12819/4/2026
To improve the stability and vibration suppression capability of missile wings under complex aerodynamic conditions, this study develops a dynamic model and explores the active control strategy for a graphene-reinforced piezoelectric composite missile wing subjected to elastic boundary constraints. An electromechanically coupled dynamic model with elastic boundary conditions is constructed by employing CLPT, the geometric nonlinearity following the von Karman assumptions, and piezoelectric coupling theory. The system is discretized and solved numerically using characteristic orthogonal polynomials and the Galerkin method. The influences of graphene distribution configurations, material properties, and boundary flexibility on the linear natural frequencies and nonlinear hardening characteristics are investigated. Results show that the X-type graphene distribution significantly enhances the equivalent stiffness and reduces nonlinearity. Boundary flexibility markedly modulates the vibration characteristics; in particular, increased structural flexibility strengthens geometric nonlinearity, leading to noticeable changes in frequency characteristics and hardening degree. A robust state-feedback controller together with a full-order observer is developed using the Linear Matrix Inequality (LMI) framework, and their performance is verified under different parameter disturbances and uncertainties. The control strategy effectively suppresses vibrations while maintaining good robustness, with the best performance achieved under X-type graphene reinforcement combined with thin piezoelectric layers. This study reveals the coupling mechanisms among material distribution, boundary flexibility, and robust control, providing a theoretical basis for the structural optimization and active control design of smart missile wings.
Qin, Shilong, Chen, Jie
Research on Online Zero-Point Calibration Technique for Ω-Shaped Coriolis Flowmeters in CCUS Applications2026-99-12379/4/2026
The Ω-shaped Coriolis flowmeter, owing to its suitability for high-pressure and wide-temperature conditions, has become the preferred device for CO2 metering in CCUS-EOR projects. In practical applications, however, the volatile nature of operating pressures and temperatures triggers a persistent zero-point drift. This instability creates a ripple effect: it not only degrades metering precision but also fundamentally undermines the equitable basis of carbon trading markets. This study, through theoretical analysis, fluid-structure coupling simulation, and experiments, deeply investigates the patterns of zero-point drift in Ω-shaped Coriolis flowmeters and corresponding correction methods. The research reveals that the asymmetry of the measuring tube structure is the primary cause of zero-point drift, with changes in the vibration frequency of the measuring tube directly influencing the zero-point value, leading to the establishment of a related zero-point drift model. Based on the asymmetric structure of a DN15 Ω-shaped Coriolis flowmeter, simulations were performed to model the zero-point variation patterns under different pressures and temperatures using CO2 as the fluid, thereby verifying the effectiveness of the zero-point drift model. To validate our approach, we executed targeted zero-point experiments, employing the proposed model to predict zero-point shifts across a broad spectrum of pressures and temperatures. By integrating these predictions into a refined correction framework, we successfully neutralized drift-induced errors. These findings offer both a robust theoretical pillar and a practical toolkit for high-precision CO2 accounting, ultimately safeguarding the economic integrity of carbon trading within CCUS-EOR initiatives.
Yu, Haobo, Hua, Chenquan, Yu, Wenxin, Zhao, Zerun
Research on Multi-Condition Topology Optimization of Transport Ship Pillar Structure2026-99-12289/4/2026
Structural optimization in shipbuilding represents a significant research focus within the fields of naval architecture and marine engineering. This study investigates multi-condition topological optimization for the deck pillar region of a transport ship's sectional structure. A mechanical model incorporating six typical load conditions was developed, and the Analytical Hierarchy Process (AHP) was employed to quantify the weighting coefficients for each condition. This enabled multi-condition collaborative topological optimization of the pillar layout. The optimized configuration underwent model reconstruction and finite element verification. Results demonstrate that the proposed multi-condition collaborative topology optimization method effectively balances structural performance and weight reduction requirements while satisfying strength specifications. This method yields optimal pillar layouts meeting multi-condition constraints, providing a reference for multi-condition topology optimization studies in ship structures.
Pei, Zihao, Wei, Yi, Feng, Ruge, Liu, Kun
Numerical Analysis of the Frequency Acceleration Effect on the Aerodynamic Efficiency of 3-DoFs Flapping Wing2026-99-12889/4/2026
This study examines how frequency acceleration affects the aerodynamic efficiency of a forward flying airfoil by establishing a kinematic model and conducting numerical simulations using the NACA0012 model. Since the aerodynamic force coefficients have been obtained in previous studies, this paper directly utilizes these coefficients to evaluate the effects of different frequency acceleration combinations on aerodynamic efficiency. It is concluded that under the condition of no pitch frequency acceleration, the combination of positive plunging frequency acceleration and sweep frequency acceleration significantly reduces the lift efficiency from 89.7% (under no frequency acceleration) to 18.1%, and can increase the propulsion efficiency from 44.1% (under no frequency acceleration) to 75.5%. Furthermore, under the AM-8 condition, the lift efficiency shows a decreasing trend as the acceleration factor increases. The analysis and investigation of frequency acceleration effect provide a theoretical foundation for enhancing the aerodynamic performance and optimizing the structural design of flapping wing drones.
Kong, Fanwei, Qu, Ligang, Li, Zhandong, Li, Jing, Lao, Yile
Shimmy Dynamics Analysis of a Dual-Wheel Main Landing Gear Considering Side Stay Angular Coupling01-19-02-00078/31/2026
Main landing gear shimmy is jointly affected by tire forces, structural elasticity, damping, and geometric coupling. To investigate the influence of side stay angular coupling on shimmy stability, this article establishes a shimmy dynamic model of a dual-wheel main landing gear considering side stay angular coupling. Numerical continuation bifurcation analysis, Hopf bifurcation frequency mapping, and local sensitivity analysis are then employed to study its influence mechanism on stability boundaries, dominant modes, and multistable behavior. The results show that the horizontal inclination angle of the side stay introduces additional structural coupling between strut torsion and longitudinal bending, causing the longitudinal motion to evolve from a passive response into an important mode participating in shimmy instability. A small horizontal inclination angle can induce the coexistence of multiple stable periodic responses, whereas a larger inclination angle changes the connectivity of Hopf bifurcation curves and forms a new instability branch involving longitudinal motion. Further analysis indicates that adjusting the orientation angle to make the local horizontal inclination angle approach zero can weaken the direct structural coupling between torsion and longitudinal motion and reduce the sensitivity of the longitudinal response to variations in the horizontal inclination angle. These results indicate that the angular design of the side stay should comprehensively consider the coupling effect between the horizontal inclination angle and the orientation angle, so as to avoid multistability and mode transition induced by the side stay angular arrangement.
Wei, Jian, He, Jipeng, Zhang, Jiahao, Zhu, Shixing, Li, Shuangbao, Zhu, Hengjia
Effect of Copper Valence and Content in Copper Red Glaze on Its Color Appearance2026-99-04208/28/2026
Copper red glazes have received considerable attention due to their perfect decorative effects and vivid coloration. This paper selected four different formula copper red glazes with different colors of bright red, violet blue, dark red, and gray blue as the samples. Based on the analysis of the colorimeter, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscope (SEM), a possible coloration mechanism was proposed to explain the variation of glaze colors. The results indicated that the glaze layers were mainly composed of amorphous phases with few quartz diffraction peaks and mainly presented a granulous structure and phase separation. Increasing the content of CaO could cause color changes of the glaze due to the high ionic potential of calcium ions, which could form a unique feature in the glaze melt. In addition, a small amount of calcium phosphate could greatly change the color of the glaze. The phase separation structure of the blue samples was more obvious than that of the red samples, with a phase separation size of less than 100 nm. The formation of droplet phase separation structure in the glaze could lead to Rayleigh scattering and Mie scattering, which made the color of copper red glazes blue and opacified. Increasing the content of Cu0 and decreasing Cu+ could weaken the structural color, which contributes to a* value of the glaze changing from 26.93 to 22.93. At the same content of Cu0, the higher the ratio of Cu+ /Cu2+ is, the less a* value of the glaze is. Finally, the existence of CuSiO3 in the glaze could also make the blue color.
Ding, Erbao, Yang, Mengli, Liu, Nannan, Li, Yabo, Zheng, Ruimiao, Xu, Yan
Finite Element Analysis of New Energy Vehicle Chassis Using ANSYS2026-99-03438/14/2026
Amid the rapid development of the new energy vehicle industry, the vehicle frame, as the core load-bearing component of the entire vehicle, plays a direct role in the vehicle’s safety, lightweight design, and power performance through its design and performance. Although research on new energy vehicle frames has matured, issues related to the lightweighting of drive shaft-associated structures and the balance between weight reduction and strength/stiffness still require in-depth exploration. This study focuses on the chassis of new energy vehicles, utilizing Q295 low-alloy high-strength steel. Based on the vehicle’s dimensions and mass parameters, a simplified 3D model was constructed using SolidWorks. Static analysis under bending and torsion conditions, along with a 6th-order modal analysis, was conducted using ANSYS software. Based on the analysis results, optimizations were implemented at both structural and material levels: structurally, the central crossbeam was widened, holes were opened on the crossbeam’s vertical plane to reduce weight, and the longitudinal beam welding process was optimized; materially, Q295 steel was retained in high-stress zones, while aluminum alloy replaced it in low-stress zones. The optimized frame achieved a 15% reduction in torsional stress, a 16% decrease in bending stress, a 2% reduction in torsional deformation, and a 3% decrease in bending deformation. Total mass decreased by 12.7 kg, with both strength and stiffness meeting design requirements. This approach synergistically enhances frame lightweighting and performance, providing technical support for optimizing the overall performance of new energy vehicles.
Guo, Lihong, Wang, Yiyou, Yang, Zihao
Bi-Directional Evolutionary Topology Optimization Design for Rib Structures2026-99-03148/14/2026
The performance of modern high-speed aircraft is intrinsically linked to structural mass. As a key component that generates lift, the shape and lightweight of the wing are crucial for improving aircraft performance. This study employs the bi-directional evolutionary structural optimization (BESO) method to perform topology optimization on the wingrib structure of a modern high-speed fighter aircraft. Minimize the overall strain energy as the objective and use the wing rib volume fraction as the constraint to perform topology optimization design on the wing ribs. Based on element stress/strain energy density criteria, the method iteratively adds or removes material to efficiently construct optimal load-transfer paths within the rib configuration. Following the redesign according to the optimized topology, the structural mass was reduced by 39.236% while satisfying strength and stiffness constraints. Results demonstrate that the BESO methodology effectively generates high-efficiency load-bearing configurations for wing ribs, significantly improving material utilization efficiency and structural performance while substantially reducing wing mass. This research provides an effective approach for lightweight design and performance enhancement of critical load-bearing structures in modern high-speed aircraft.
Zhou, Lei, Wang, Wei, Gong, Quanwei, Zhou, Jingchao, Guan, Shenxiaoge
Design Study of the Landing Gear Door Assembly Unit for the Aircraft2026-99-03408/14/2026
Against the backdrop of the rapidly developing aviation manufacturing industry, there is an increasingly urgent demand for the high-volume and high-quality delivery of aircraft landing gear doors, which are critical components for ensuring flight safety. Traditional assembly methods face numerous bottlenecks, making it difficult to meet the industry’s evolving requirements. Consequently, a design study has been conducted on the assembly units for aircraft landing gear. By analyzing the structural characteristics and assembly process flow of the landing gear doors, the assembly procedures were optimized and reorganized. A pulsatile assembly unit incorporating dual-attitude modular assembly devices, an automatic transportation system, curing devices with heating, and module storage facilities was designed. Digital simulation technology was employed to perform a simulation analysis of the assembly process, verifying the feasibility of the proposed scheme. This production addressed issues such as long curing cycles for liquid gaskets, low efficiency in layered hole-making, and difficulties in transporting modular fixtures. It achieved semi-automation and intelligence in the assembly, curing, and transportation processes of landing gear doors. Compared to the production mode during the development phase, the production cycle for individual products was reduced by 50%, and annual delivery capacity increased by 100%. The research findings provide effective technical support for achieving efficient and high-quality assembly of aircraft landing gear doors.
Bo, Donghai, Gao, Chunlin, Zhou, Houchao, Chen, Yilong
Relevant vehicle front-end components for pedestrian laboratory testing to address real-world pedestrian injuries when struck by passenger vehicles with high hood heights2026-22-00098/14/2026
In the United States, pedestrian deaths account for 18% of roadway fatalities and have increased 78% since their lowest point in 2009. U.S. consumers are increasingly purchasing larger vehicles that are responsible for a disproportionate number of pedestrian injuries. This study examined a dataset of pedestrians struck by passenger vehicles in Michigan from 2015 to 2024 to identify the unique characteristics of the tallest vehicles, large SUVs and pickups, which are contributing to increased injury. Vehicle height was categorized as the hood leading edge (HLE) height compared with the estimated pedestrian hip and waist heights from anthropometric measures. Maximum abbreviated injury scale and injury sources by body region were tabulated for three vehicle height categories. Typical kinematic patterns were observed for each relative height category and the corresponding injury frequency and impact locations. For vehicles with high hood heights, head and torso injuries were commonly from the front of the vehicle —the grille, headlights, and HLE. In contrast, head injuries sustained when pedestrians were struck by medium-height and short vehicles were primarily from the vehicle hood and windshields. Even among the tallest vehicles where the bumper was much higher than the pedestrian’s knee, leg injuries from the vehicle bumper and valance were frequent, suggesting that evaluating these vehicle components is also necessary to address lower extremity injuries. This study identified the unique pedestrian impact locations associated with the tallest vehicles, which can help guide vehicle designers when considering impact attenuation strategies to reduce injury in crashes with pedestrians.
Mueller, Becky, Jermakian, Jessica
Review of Semi-Active Shock Absorption Mechanisms in Landing Systems01-19-02-00068/13/2026
Effective shock absorption is essential for maintaining stability during landing events. Aerospace systems traditionally rely on oleo-pneumatic struts, while robotic platforms utilize lightweight compliant joints for impact mitigation. Recent advances have shifted attention toward adaptive solutions, including magnetorheological and electrorheological dampers, which can adjust their damping characteristics in real time through sensor feedback and control algorithms. By integrating established mechanical design principles with advanced materials and intelligent control strategies, modern landing systems can achieve improved energy dissipation and enhanced performance under variable and unpredictable conditions. This work evaluates the transition from passive to adaptive shock absorption technologies by examining landing dynamics, the mechanical architectures of conventional and semi-active systems, and the control strategies that enable adaptive damping. The findings indicate that, although passive systems offer reliability and simplicity, they lack the adaptability required for highly variable environments, while semi-active systems provide enhanced performance through real-time modulation enabled by advanced control algorithms. However, challenges related to power requirements, system complexity, material durability, and long-term reliability continue to limit widespread implementation of adaptive technologies. Overall, this review highlights the limitations of passive designs, evaluates the tradeoffs between MR and ER damping technologies, examines the evolution of semi-active control strategies, and identifies the key technical barriers that must be addressed before adaptive shock absorption systems achieve broader operational adoption.
Shah, Rajesh, Patel, Parth, Mittal, Vikram
Airplane Design and Test Considerations for Tire Spray SuppressionARP1904 (Current)8/10/2026
This SAE Aerospace Recommended Practice (ARP) relates considerations and recommendations for design test procedures and test data evaluation for qualification of tire spray deflection devices.
A-5 Aerospace Landing Gear Systems Committee
Spectral Transmission TestJ1796_202608 (Current)8/10/2026
The scope of this SAE performance standard is to define the test method by which the direct solar and visible transmittance of safety glazing materials for road vehicles shall be measured. Adherence to this performance standard will facilitate writing, use, and referencing of reports by government, industry, and other organizations.
Glazing Materials Standards Committee
Research on the Intelligent Design Method of Roof Frame Based on the Middle Layer and Component Technology2026-99-09078/7/2026
This study proposes an intelligent automotive roof frame design method based on the middle layer and component technology on CATIA. It aims to solve core roof modeling issues: determining geometric input quantity but uncertain attributes (tangent vectors, normal vectors, number of curve segments, number of surface patches, and boundaries), high manual interaction dependence, and poor knowledge reuse, to realize efficient design knowledge reuse. Methodologically, it builds a feature-driven parametric template, develops a knowledge rule-embedded componentized UDF library (reducing repeated modeling and geometric reconstruction needs), and integrates knowledge engineering for geometric input verification and operation direction control, eliminating curve/surface attribute uncertainty impacts. Verification shows the template stably generates roof crossbeams under simple/complex inputs, improving model robustness and reuse rate, reducing design workload, shortening verification cycles, and providing an extensible solution for white body design.
Jin, Chunning, Fu, Xinyu, Hou, Wenbin
Experimental and Mechanistic Study on Current Carrying Friction of Sliding Ring Slide in Shaft-Type Oil Distributor under Different Oil Environments2026-99-10058/7/2026
The issue of current-carrying friction wear in the sliding ring slider of a controllable pitch propeller (CPP) oil distributor under shaft current conditions was addressed through the development of a specialized wear test device. Comparative tests were carried out with and without the application of electrical current in order to assess lubrication performance in bio-oil, mineral oil, and gear oil. Under conditions of low electrical current, the device exhibited significant signs of current-induced friction wear, in addition to substantial oil oxidation and the accumulation of deposits within the bio-oil. Conversely, the level of wear experienced was minimal in both mineral oil and gear oil conditions. These results imply that CPP systems utilising bio-oil encounter a considerable risk of wear under current-carrying circumstances. Quantitative analysis revealed that the wear depth of the friction pair in bio-oil under energized conditions reached 0.02 mm, accompanied by the formation of a phase-transformed layer up to 11.2 μm thick, which was approximately twice that observed in mineral or gear oils. Metallographic evidence confirmed severe arc erosion as the dominant wear mechanism, which was significantly exacerbated by the inferior oxidation stability and higher electrical conductivity of the bio-oil. In engineering practice, the utilisation of alternative lubricants is to be given precedence, and the shaft-type oil distributor is to be electrically insulated.
Xia, Miao, Li, Jiyue, Chang, Long, Wu, Rongjia
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