Technical Papers - SAE Mobilus

SAE Technical Papers are written and peer-reviewed by experts in the automotive, aerospace, and commercial vehicle industries and provide the latest advances in technical research and applied technical engineering information.

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CFD Numerical Simulation Study on Flow Field Characteristics of Umbrella-Frame Combined Impeller2026-99-12089/4/2026
For the mixing of hydroxy-terminated polybutadiene (HTPB) with silicon dioxide particles, this study adopts the Computational Fluid Dynamics (CFD) method to conduct a visual analysis on the fluid flow field characteristics generated by the umbrella-frame impeller (UF impeller) and umbrella-frame combined impeller (UFC impeller). Comparative studies are carried out from the dimensions of particle concentration distribution, fluid flow trend, vorticity, and path line. The results show that compared with the UF impeller, the UFC impeller, equipped with an upper blade structure, enables its generated flow field to cover the entire stirred tank more effectively, significantly improving the solid-liquid mixing efficiency. In addition, the fluid-structure coupled numerical method is used to analyze the structural deformation characteristics and stress distribution law of the impellers. The research findings can provide a reference for the optimization of dispersion and mixing processes of solid particles in high-viscosity fluids.
Li, Ruizheng, Sun, Zhenxing, Zhang, Yan, Wu, Qiong
2025 6th International Conference on Applied Mechanics and Mechanical Engineering2026-99-12009/4/2026
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Tobolski, Sue
Ultrasonic Guided Wave Thickness Measurement of Cortical Bone with Soft Tissue2026-99-12209/4/2026
Early diagnosis of osteoporosis is crucial for preventing fractures and improving the quality of life of patients. In clinical practice, the mainstream diagnostic methods, such as dual-energy X-ray absorptiometry (DXA), are limited by high equipment costs and ionizing radiation, resulting in a low coverage rate of large-scale early screening. Only less than one-third of brittle fracture patients have received a DXA assessment. To address this issue, this study proposes an innovative diagnostic method based on ultrasonic guided wave technology. This technology is cost-effective and portable, and it overcomes the limitations of X-ray detection in terms of its unsuitability for large-scale early diagnosis. The Young’s modulus and Poisson’s ratio of water are similar to those of soft tissue, so this method utilizes water coupling to simulate the environment of soft tissue around the bone and combines the transverse isotropy of cortical bone, which is an important characteristic that most existing models ignore, to analyze the propagation of guided waves in anisotropic cortical bone. Through the processing of ultrasonic signals using two-dimensional short-time Fourier transform (2D-STFT), the local thickness of cortical bone can be inverted. By establishing a fluid-coupled orthotropic anisotropic plate model, deriving the dispersion equation, solving the theoretical method for the dispersion curve, using the bovine long plate to construct a water-coupled detection platform, and obtaining experimental data to invert the thickness of the bone plate, the local thickness of the bone plate was obtained, proving that this method can effectively reconstruct the thickness changes of anisotropic and variable cross-section cortical bone under simulated soft tissue conditions, with an average relative error of 13%. This lays the foundation for subsequent in vivo experiments and provides a reliable solution for large-scale early osteoporosis screening.
Nong, Kexin, Li, Bing
Scaling Behavior of Levitation and Dragging Force in Electrodynamic Suspension Systems2026-99-12109/4/2026
The geometrical and velocity scaling behavior of levitation and dragging forces in Electrodynamic suspension (EDS) systems was studied by both analytical and numerical methods, to provide comparisons between designs for both on-board and ground-mounted magnetic components. Effects of system dimension, levitation gap, magnetic field dependence of critical current density, and vehicle velocity were studied. The lift-to-self-weight ratio of two realistic EDS systems and their geometrical scaling were studied numerically.
Shao, Nan, Zhang, Chang, Shang, Liang, Yu, Wenjing
Experiments on Effects of Self-Locking on Mechanical Response of Origami Metamaterials2026-99-12069/4/2026
Motivated by the negative Poisson’s ratio tetrahedral-trihedral polyhedron (TMP), this study systematically examines the role of self-locking mechanisms in determining the mechanical response and energy absorption capacity of rigid origami metamaterials. Quasi-static compression tests were conducted on specimens exhibiting three distinct geometries (B19, B22, B23) and four wall thicknesses (0.8–2.0 mm). The results of these tests revealed two unique self-locking behaviors. Type I self-locking originates from inter-wall interlocking, characterized by progressively decreasing inter-wall spacing during compression; Type II self-locking originates from interlocking between creases, characterized by creases contacting each other during compression. The fabrication of the specimens was accomplished through the utilization of FDM-based additive manufacturing, employing PEEK material. The results obtained from this study revealed two distinct locking behaviors: It has been demonstrated that type I locking enables sustained deformation without load reduction. In contrast, type II locking has been shown to result in premature collapse and diminished energy absorption capacity. The B22 configuration has been demonstrated to trigger both locking mechanisms concurrently, thereby significantly enhancing performance metrics. This has been evidenced by improvements in both crush force efficiency (CFE) and specific energy absorption (SEA), whilst also delaying densification. In contrast, structures dominated by a single locking mechanism exhibit premature failure (B19) or inefficient energy absorption (B23). These findings emphasize the pivotal role of synchronized self-locking activation and geometric configuration in enhancing impact resistance and energy dissipation, thereby establishing a foundational theoretical framework for the design of advanced metamaterials in protective engineering.
Wu, Baoji, Wang, Hairui, Jiang, Heng
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
A Novel Physics-Informed Graph Convolutional Reduced-Order Model for Fluid Flow on Unstructured Meshes2026-99-12459/4/2026
This study proposes a physics-informed graph convolutional reduced-order model, namely Phys-GCN, for high-fidelity and computationally efficient prediction of steady incompressible flow fields. In Phys-GCN, the incompressible Navier–Stokes equations are embedded into the loss function via residual constraints, such that the spatial feature extraction of graph convolutional networks is integrated with the physics-constrained learning strategy of physics-informed neural networks. This mixed design enables the model to capture complex nonlinear flow features while maintaining a clear level of physical interpretability. Benefiting from the node-edge encoding inherent to graph neural networks, Phys-GCN operates directly on unstructured CFD meshes to learn flow features from graph representations constructed using node attributes and adjacency relationships. In doing so, Phys-GCN dispenses with voxelization or SDF preprocessing and fully preserves the local geometric and topological characteristics of the flow domain. The proposed model is systematically evaluated on steady flows past circular and elliptical cylinders, where the predicted velocity and pressure fields are compared against reference CFD solutions in both interpolation and extrapolation scenarios. Results show that, for all physical quantities, the reconstructed steady flow fields achieve mean relative errors below 5%, exhibiting excellent agreement with the CFD benchmark solutions. After offline training, Phys-GCN achieves inference times that are several orders of magnitude faster than conventional CFD solvers, while maintaining comparable predictive accuracy. These findings demonstrate that Phys-GCN provides an accurate and efficient graph-based and physics-informed surrogate for steady flow-field reconstruction on non-uniform, unstructured meshes, thereby laying a solid foundation for future extensions to more complex three-dimensional and compressible flow configurations.
Xie, Haoran, Zhou, Hao, Yu, Changhao, Li, Qiang, Liu, Tianyu, Peng, Jiangzhou
Dynamic Characteristics Analysis of Needle Roller Bearings in Planetary Gear Trains with Consideration of Inner Bore Spalling Defects of Planet Gears2026-99-12799/4/2026
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, Desheng, Lai, Junbin, Guo, Wei, Dong, Peng, Xu, Xiangyang, Sun, Qiang
A Computing Method of Splitting Factor for 3D Non-Compatible Generalised Mixed Hexahedral Element2026-99-12119/4/2026
With the rapid development of the aerospace industry, FEM has been widely applied as a key tool. However, the high complexity of aircraft and spacecraft geometries and structures often leads to unavoidable distorted meshes in FEM, which significantly degrades the accuracy of analysis results. Both the splitting factor and the mesh distortion significantly affect the accuracy of the generalised mixed elements. The coefficient matrix deviation between the distorted element and the standard element was quantified. Thus, the computing equation for a three-dimensional (3D) hexahedral distorted element’s splitting factor was constructed. Examples were used to validate the proposed method. For distorted meshes, the accuracy of NCGME has been improved.
Shen, Ao, Qing, Guanghui
W 60 (FeCrNi 2.5 ) Alloy with High Strength and High Adiabatic Shear Band Sensitivity2026-99-12439/4/2026
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Lin, Jingchen, He, Jianye, Wang, Qiang, Wu, Shanghao, Zhang, Linbing, Ruestes, Carlos J., Li, Zezhou, Zhang, Zhaohui, Zhang, Fan, Wang, Lin, Cheng, Xingwang
A Coaxiality Measurement Method Applicable to the Three Holes of an Engine2026-99-12269/4/2026
To address the measurement challenges posed by the large diameters and wide spans of engine crankshaft holes, cylinder holes, and camshaft holes, as well as the abnormal laser measurement data caused by oil film adhesion and local protrusion structures on their inner walls, this paper proposes a non-contact coaxiality measurement method based on a laser displacement sensor (LDS) and a threshold-modified least squares ellipse fitting (TMLSE) algorithm. The method first preprocesses the data through median filtering and then employs an adaptive distance threshold based on maximum inter-class variance to eliminate outliers caused by oil film scattering and protrusions, achieving robust fitting of the cross-sectional centers. Subsequently, the datum axis is established using the least squares midline method, ultimately enabling the evaluation of coaxiality error. In the simulation experiments, a dual-hole model with an inner diameter of 100 mm and a spacing of 700 mm was simulated, where the right hole was translated by 1.5 mm to introduce coaxiality error. Each cross-sectional point cloud included 10% protrusion points (protrusion height of 10 mm) along with random noise and data loss simulating the effects of oil film. To assess the robustness of the method, a systematic analysis was conducted on the influence of laser incidence angles [80°,89°]on measurement accuracy. The results show that across different incidence angles, the maximum deviation between the coaxiality error obtained by the TMLSE method and the theoretical value is only 0.1582 mm, which is significantly better than that of the RANSAC, MZC, and MIC methods. Meanwhile, TMLSE demonstrates stable and efficient computational speed. The simulation verifies that this method offers higher fitting accuracy and robustness under both optical interference and variations in installation angle, making it suitable for the precision measurement of key engine hole systems.
Yin, Jiakuo
Application and Research of Steam Compressors in Heat Supply of Coal-Fired Power Plants2026-99-12419/4/2026
The application of steam compressors in heating supply of coal-fired power units demonstrates significant energy-saving benefits, while also effectively addressing the operational constraints of steam supply at low loads, thereby achieving thermoelectric decoupling.. This study analyzes and compares the performance characteristics and operational ranges of three distinct mechanical steam compression technologies. Although centrifugal compressors exhibit a low single-stage pressure ratio, their operational flow rate and temperature ranges are better suited for coal-fired heating requirements. Three typical application scenarios of steam compressors in industrial steam supply for coal-fired power units are proposed: Steam compressors enable waste heat recovery by compressing turbine exhaust steam for heating purposes, increase pressure in branch networks of steam supply pipelines to achieve high-pressure steam delivery, and enhance industrial steam extraction pressure under low-load conditions to realize thermoelectric decoupling. This enables substantial improvement in both the energy efficiency and steam supply capacity of coal-fired power units. Based on practical application cases of steam compressor systems, the objectives of steam pressure and temperature elevation can be achieved. Through collaborative adjustment of the drive motor frequency and the recirculation valve, dual-objective control of outlet flow rate and temperature can be realized. An analytical model was developed to simulate compressor performance, and validation against actual operational data confirmed the model’s applicability for guiding operational practices and control simulations. The centrifugal steam compressor in actual operation demonstrates normal performance across all operational indicators under high-speed conditions, confirming its technical reliability in coal-fired heating applications and providing crucial references for the widespread adoption of steam compressor technology in steam supply systems of coal power units. It expands the steam supply parameter range of electro-thermal conversion systems, thereby making a positive contribution to renewable energy integration.
Zhang, Pan, Liu, Yan
Research and Analysis of Civil Aircraft Radio Altimeter Malfunction2026-99-12359/4/2026
The radio altimeter is an important navigation instrument on an aircraft, capable of accurately measuring the aircraft's true height above the ground or sea to ensure safe flight. This capability is crucial for ensuring normal flight operations, especially during critical phases such as takeoff, approach, and landing. Polar terrain is complex and continually changing. The vast, endless ice fields, crisscrossing glacier crevasses, towering icebergs, and weather conditions all add significant uncertainty to air travel. In such environments, the aircraft's navigation system is particularly important as a core device to ensure flight safety. This article provides a brief overview of the aircraft radio altimeter system. Using data and observations from production flight tests, it studies the specific challenges posed by radio altimeter failures encountered during these critical validation flights. The study synthesizes these findings and proposes a relatively general troubleshooting approach to address such issues. Furthermore, the effectiveness of this method has been rigorously validated through its application in solving a complex real-world radar altimeter failure case.
Song, Mingming, Mi, Yujie
Development of Engine Nozzle Characteristic Determination System2026-99-12429/4/2026
The determination of flight thrust for aircraft engines is an important means of evaluating engine and aircraft performance. The characteristics of the tail nozzle of the tested engine are an important data support for calculating flight thrust. In order to accurately evaluate the flight thrust of a certain type of engine, an “engine nozzle characteristic determination test system” is developed to obtain the thrust characteristic curve and flow characteristic curve of the nozzle. A calibration device and calibration process were designed for the experimental system to achieve in-situ calibration of the system.
Ren, Boyang, Jia, Wenjie, Song, Jiangtao
Study on the Vehicle Unsteady Vibration Control with a Semi-Active Strut2026-99-12319/4/2026
Unsteady vibrations of vehicles, which can be easily perceived by the human body, may affect the driving experience and compromise driving comfort. However, the conventional three-point powertrain mounting system (PMS) often fails to offer a satisfactory solution. Here, a novel four-point PMS was proposed by introducing a semi-active strut (SAS), which can provide stronger damping in a low-frequency range to resolve this problem. Specifically, a thirteen degrees of freedom (DoFs) vehicle dynamic model (VDM) with four mounts was constructed, and the evaluation indices for unsteady vibration responses of the vehicle were determined and analyzed; Next, the PMS optimization design approach was employed to identify the proper position of installation and dynamic stiffness of the SAS, and meanwhile the 13 DoFs VDM and the force-sharing principle were used to identify the structural parameters of the strut; Last, comparative experiments were performed to analyze the effect of the strut on alleviating the unsteady vibration of the vehicle under varied unsteady vehicle states. The results showed that the SAS has significantly reduced the seat rail peak acceleration, verifying the effectiveness of our novel PMS in alleviating the unsteady vibration. The research provided a feasible solution to alleviate the unsteady vibration of vehicles and improve the driving experience.
Wang, Daoyong, Liu, Yongjiang, Ma, Bo
Experimental Testing and Finite Element Simulation on Tensile Mechanical Behavior of Nickel-based Superalloys2026-99-12249/4/2026
The accurate prediction of high-temperature mechanical behavior of GH3230, as a core material for the new generation of combustion chambers in China, is a key technical prerequisite for promoting engineering applications. This article is the first to conduct a systematic study on the tensile properties of the alloy at three typical service temperatures of 200°C, 550°C, and 900°C, combining high- temperature tensile testing with numerical simulation. Through metallographic observation, the excellent microstructure characteristics of the alloy, including no grain boundary defects, inclusion phase size less than 5 μm, and uniform distribution, were clarified. Based on this, a multi-temperature adaptive tensile simulation model was established. Experimental verification showed that the model can accurately reproduce stress-strain tensile curves at different temperatures, with prediction errors controlled within a reasonable range, effectively breaking through the limitations of traditional single-temperature simulation. This study not only provides an efficient and accurate new method for the performance analysis and safety evaluation of GH3230 in a wide temperature range but also provides practical technical means to support the component-level engineering application of this material. At the same time, the research results also provide a reference technical path and research ideas for the multi-temperature mechanical performance prediction of other nickel-based high-temperature alloys.
Qiao, Yongle, Xie, Jiahui, Li, Lei, Zhou, Jie, Zhu, Yankun, Wang, Yifei
Molecular Dynamics Simulations of Microstructural Evolution in Pure Titanium under Laser Shock Peening2026-99-12859/4/2026
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Zhao, Congshan, Zhang, Linbing, Xu, Yidi, He, Jianye, Fang, Jing, Li, Zezhou, Ruestes, Carlos J., Cheng, Xingwang
Strain Analysis of Buried Pipelines in Trench Models Crossing Strike-Slip Faults2026-99-12809/4/2026
Long-distance buried pipelines are the core type in pipeline transportation; the technical indexes and requirements for protection are stricter. In the previous coupling model of pipe and soil, the in-situ soil and backfill soil are treated as a unified continuous medium, and the actual geometric shape and boundary effect of the pipe trench are ignored through simplification of the calculation model. In this study, a new coupling model of in-situ soil, backfill soil, and pipeline is proposed to analyze the actual strain state of buried pipeline with different backfill soil and in-situ soil materials. A model was established based on the ANSYS software to simulate and investigate the mechanical behavior of strike-slip fault-crossing buried pipelines under real trench conditions. By varying multiple parameters, this study analyzes the effects of different operating conditions on the strain distribution and magnitude of buried pipelines. The findings of this study can serve as a reference for the design, construction, and protection of buried pipelines traversing active faults.
Li, Yuxiang, Wang, Guang, Zhang, Chengbin, Wang, Ke, Bi, Haisheng
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
Simulation and Structural Optimization Design of Thermal-Mechanical Coupling Performance of Supporting Components2026-99-12939/4/2026
This research aims to develop a high-performance composite material support component that meets extreme performance requirements. It is used to solve the problem of protecting critical electronic control units (ECUs) and flight data recorders in aerospace and automotive safety systems under harsh combined conditions of high temperature and high shock. Its internal dimensions are 0.14 m × 0.08 m × 0.08 m. In addition, it is required to withstand a constant temperature of 65°C for 3600 seconds, with the internal core temperature not exceeding 35°C. It can withstand a static load of 1.8 kg and a transient impact acceleration of 1400 G. The dual-layer composite structure based on functional decomposition solves the problems of thermal insulation and load-bearing/impact resistance. The inner layer uses ultra-low thermal conductivity aerogel to form a thermal barrier. The outer layer is a load-bearing frame made of high-strength/high-modulus quartz fiber reinforced epoxy composite material. The study employs a systematic numerical simulation method to verify the optimized design parameters. The results show that the internal temperature remained stable at 34.173°C. The outer layer deforms only at the micrometer level under static load. The inner layer is under zero load and there is no distortion in the internal space. The integrated design method of “material-function-structure-simulation” proposed in this paper provides a research approach for the survivability design of mechanical structures of new-generation aircraft and ground vehicles under complex multiphysics constraints.
Liu, Jiaxin, Wang, Yi, Zhao, Xiaorong, Wu, Chaofu, Zhao, Zhuo, Chen, Long
Application of Two-Component Flocculant Underwater Non-Dispersible Concrete in Ship Lock Engineering2026-99-12829/4/2026
To tackle the challenges of pronounced dispersion and inadequate cohesion of concrete in the underwater repair of ship lock engineering, this study presents a novel approach involving acrylate copolymer emulsion (PAE) and waterborne polyamine curing agent (WE) as the two-component flocculant, integrated with fiber modification technology, to fabricate non-dispersible concrete tailored for ship lock underwater rehabilitation. Mechanical property tests and elastic modulus analyses demonstrate that the resultant concrete exhibits significantly improved scour resistance, endowing it with robustness against erosion in complex subaqueous environments. This work thus offers a dependable technical solution for the structural repair and toughening of ship lock structures.
Li, Jun, Zhu, Xunsong, Yang, Ning, Meng, Xingyu, Zong, Jiawei
High-Precision Micro-Satellite Attitude Control: Design and Testing of an Ultrasonic Motor-Driven Control Moment Gyroscope2026-99-12919/4/2026
The issues associated with the traditional single-gimbal control moment gyroscope (SGCMG) driven by electromagnetic motors, such as complex structure, significant gear backlash, weak anti- interference capability, poor adaptability to space environments, and large volume and weight, make it difficult to meet the attitude control requirements of micro/nano satellites. To address these issues, this paper proposes an SGCMG design based on a rotary traveling wave ultrasonic motor (RTWUM) drive. Ultrasonic motors offer advantages including high torque, fast response, self-locking upon power-off, immunity to electromagnetic interference, and simple structure, making them suitable for spacecraft attitude control systems. This paper elaborates on the working principle and structural design of the ultrasonic motor, covering the entire process from stator modal optimization, flywheel and gimbal structural design to system integration and control system implementation. Through finite element analysis and experimental verification, the designed ultrasonic motor-driven SGCMG meets the requirements of micro/nano satellites in terms of output torque, speed control accuracy, and structural compactness, demonstrating the promising application prospects of ultrasonic motors in aerospace attitude control.
Wu, Jintao, Zhang, Jiyang, Li, Huafeng, Pan, Song
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
Numerical simulation of downwash airflow of rescue helicopter rotor2026-99-12949/4/2026
The helicopters conducting carrier deck operations and performing maritime rescue missions experience significant impacts from the downwash generated by their rotors, affecting both landing performance and the surrounding environment. Addressing the unclear mechanisms of downwash effects during water rescue operations, this study employed Computational Fluid Dynamics (CFD) methods, including overlapping grids, to investigate the operational characteristics of helicopter rotor airflow. Numerical simulations were conducted under various operating conditions, including different inflow velocities and rotor speeds. Based on the calculation results, the implementation process of helicopter rescue operations is proposed. These findings provided valuable guidance for helicopter water rescue operations. The results showed that as the rotor speed of the rescue helicopter gradually increased, the force of the rotor downwash flow on the water surface was greater. Moreover, when the rescue helicopter had an incoming flow velocity, the interference of the rotor downwash flow on the water force could be reduced accordingly.
Feng, Xu, Cui, Jia, Zhang, Yi, Han, Qingtian, Liu, Wei, Xing, Li, Wang, Jingyu
Traffic-Load Fragility Assessment of Prestressed Concrete Hollow Slab Bridges Considering Load Characteristics2026-99-12999/4/2026
Assessing the vulnerability of bridges to traffic loads is critical for ensuring their long-term operational safety. The reliability of bridges under design vehicle loads or simulated random traffic flows constitutes the primary focus of existing research. Current research often lacks analysis that incorporates actual traffic load conditions. This paper proposes a traffic-load fragility assessment method for prestressed concrete hollow slab bridges considering load characteristics. The methodology integrates Metropolis-Hasting sampling algorithm with Copula functions to simulate random traffic flow, calculates resistance levels corresponding to structural cracking, yield, and failure states, and employs Monte Carlo sampling for failure probability calculation. Finally, a case study of four prestressed concrete hollow slab bridges is conducted to analyze their traffic load fragility. The results show that, under the same traffic load characteristics, different bridges have varying vulnerabilities corresponding to different failure states. The traffic-load fragility assessment approach put forward in this study can offer important technical support for both bridge design work and the development of vehicle load restriction policies.
Zhou, Yihang, Yang, Gan
Compact Design and Simulation of a Four-Degree-of-Freedom Articulation Mechanism for Articulated Tracked Vehicles2026-99-12929/4/2026
To address the compact design requirements of articulation mechanisms for articulated tracked vehicles, a collaborative design methodology integrating kinematic modeling and configuration optimization is proposed. First, kinematic models of the steering and pitching devices are established, and analytical relationships between hydraulic cylinder stroke and vehicle body articulation angles are derived, along with an analysis of how articulation point positions affect kinematic characteristics. Second, a calculation method for minimizing the longitudinal dimension of the articulation mechanism is established, with the constraint that the front and rear vehicle body tracks do not interfere during motion. On this basis, an integrated layout strategy and design procedure for the four-degree-of-freedom articulation mechanism are proposed by optimizing the cylinder connection method and installation angle. The proposed method is applied to the design of an unmanned articulated tracked vehicle, and a virtual prototype is developed for simulation verification. The results demonstrate that the articulation mechanism achieves a steering angle of 45.2°, a pitching angle range of −47.9° to 48.7°, and enables the vehicle to negotiate obstacles of at least 900 mm in height, which validates the effectiveness and feasibility of the design approach.
Li, Ningyi, Zhang, Chuanqing, Zhang, Shaoliang, Liu, Xixia
Fluid-Structure Interaction Analysis of 150 m Wind-Turbine Concrete Tower2026-99-12959/4/2026
Wind turbines equipped with large blades significantly enhance power generation efficiency. For large turbines reaching 150 meters in height, concrete towers offer an effective means of cost savings. Nevertheless, the stability of such structures must be carefully considered, given that wind perturbations are amplified with increased height. In this study, we aim to develop a numerical approach for conducting fluid-structure interaction (FSI) analysis on a 150-meter wind turbine concrete tower. A two-way FSI analysis method has been developed using the immersed boundary method, effectively addressing the coupling effects between the structural and fluid models without the need for body-fitted meshing. Our numerical results demonstrate that the proposed method achieves stable convergence and accurately captures dynamic structural responses under high-speed wind conditions. This method will contribute to the numerical design and safety validation of wind turbine infrastructure in engineering projects.
Gan, Shishun, Li, Hao, Chu, Hao, Lin, Yiyang, Wang, Ban
Numerical Simulation and Optimization Study of Direct-Fired Hot Blast Stove Based on Computational Fluid Dynamics2026-99-12309/4/2026
Shantui Janeoo Machinery Co., Ltd developed a new direct-fired hot blast stove. However, experimental research was costly and failed to adequately capture the internal temperature distribution patterns. Therefore, computational fluid dynamics (CFD) was employed to conduct a numerical simulation of its three-dimensional model, analyzing its flow and heat transfer performance. The results indicated that the swirling cold air intake method caused local vortices and outlet backflow, leading to uneven temperature distribution. To address this issue, numerical simulation was used to investigate the influence of key geometric parameters on the stove’s performance. An improved design was proposed, and the performance differences between the optimized and original structures were compared and analyzed. The optimized hot blast stove showed a significant improvement in temperature distribution uniformity, with the outlet air temperature increasing by 59°C compared to the original structure.
Wu, Guoqing, Zhong, Wenzheng, Shen, Yuanlin, Chen, Ziyun
Johnson-Cook Model Calibration of 10# Steel and Dynamic Mechanical Behavior Analysis under High Strain Rates2026-99-12019/4/2026
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Tian, Yumo, Zhang, Longhui, An, Fengjiang, Feng, Bo
The Flexibility Coefficient Fitting of Bolt in Metal-Composite Hybrid Joint Structures Based on L-M Method2026-99-12679/4/2026
This study used the L-M (Levenberg-Marquardt) algorithm to analyze the fitting of the flexibility coefficient of fasteners in the mixed connection structure of metal composite materials to address key challenges in aircraft structural design. Through parametric modeling and finite element simulation of single lap joints, the system evaluates eight key factors, including the direction of the composite material layer, the elastic modulus of the metal plate, the plate thickness ratio, the fastener diameter, the elastic modulus of the fastener, the Poisson’s ratio of the fastener, the magnitude of the preload force, and the type of bolt configuration, covering convex and countersunk variants. Advanced material modeling techniques are introduced in the study to accurately capture the anisotropic behavior of the composite material layer and its interaction with metal components under different load conditions. The results show that the higher modulus and thickness of the composite material plate and metal plate significantly reduce the flexibility of fasteners, and larger fastener diameters are associated with reinforcement. The elastic modulus further reduces flexibility. The flexibility of convex head bolts is significantly lower than that of countersunk head bolts, while Poisson’s ratio, preload force, and humidity have little effect. Based on these findings, a new flexible calculation formula containing nine undetermined parameters is proposed. The L-M algorithm is used for nonlinear regression to derive formulas with physical significance. The verification shows that the proposed formula is highly consistent with the finite element results, with a corrected coefficient of determination of 0.956. Among 864 test sample points, 73.61% have an error of less than 5%, and only 0.23% have a deviation of more than 15%. Comparative analysis with twelve existing methods, including the Delft University and Boeing formulas, confirms that the proposed method has better accuracy. This method effectively expands the applicability of traditional flexible formulas, provides solid theoretical support for advanced aircraft connection design, and realizes diverse mixing in aerospace engineering and accurate calculation of connection configuration.
Fan, Zhuotao, Wang, Xu, Wang, Tong, Li, Xianchao
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
Design and Simulation of Mobile Straw Carbonization Equipment2026-99-12659/4/2026
Straw is one of the major biomass energy sources. It has low economic benefits by conventional disposal methods, such as returning to the field, using as feed, pressing into block fuel, gasification power generation, papermaking, and manufacturing building materials. With the surplus of crop straw, a large amount of straw resources will be burned, resulting in severe resource waste, soil structure damage, and air pollution. Straw carbonization technology and equipment are effective measures to solve the problem of straw surplus. This paper proposes a mobile straw carbonization technology, studies the principles and processes of straw carbonization, and designs a high-efficiency mobile carbonization equipment that can be used in the field to reduce the costs of straw collection, transportation, and storage and realize the transformation of straw from waste to valuable resources. A mathematical model for the pyrolysis process of straw pellets was established. The structure of the mobile straw carbonization equipment was designed based on the research on the mechanism of straw pyrolysis and carbonization. A multi-layer sleeve rotary structure of the reactor is adopted, and the furnace body solves the problem of uneven heating of carbonization with a mixed feeding design of screws and scrapers. Simulation and experiments were conducted using corn straw as the raw material to analyze the variation law of temperature inside the furnace and verify the feasibility of the equipment designed for straw carbonization.
Shang, Chunmin, Yu, Jiadong
A Method of Hamiltonian System for the Vibration Problem of Cracked Plates with Piecewise Boundaries2026-99-12599/4/2026
This paper focuses on analytical solutions for studying the vibrations of partially cracked orthotropic plates with piecewise boundaries using the symplectic elasticity method. Crack compliance coefficients are derived from the line spring model and introduced into the governing equations. In this paper, by establishing the Hamiltonian system and solving the Hamiltonian canonical equations, the vibration problem of cracked plates with piecewise boundaries can be reduced to finding the symplectic eigenvalues and symplectic eigensolutions. In the Hamiltonian system, the problem is transformed into seeking the solution of an algebraic equation system by the aid of symplectic eigensolutions and the adjoint symplectic orthogonal relations between the eigensolutions. Thus, for orthotropic plates with cracks under piecewise boundary conditions, this work presents a set of analytical solutions. Specifically, expressions for the free vibration behavior are derived. Furthermore, the steady-state response is determined. Finally, the transient dynamic response is also formulated and solved. The numerical results show that this method is effective and the natural frequency obtained in this paper is consistent with experimental results. A parametric investigation is performed, with the aim of comprehensively investigating the dynamic behavior of cracked plates subjected to piecewise boundaries. Significant findings include how aspect ratio, piecewise boundary conditions, and crack length affect structural vibration characteristics. For the plates containing cracks under piecewise boundaries, the frequency-response and the time-history curves for the forced vibration are plotted. These curves clearly illustrate the corresponding vibration characteristics of the plates. Some of the results can provide benchmarks for validating numerical or approximate methods. The method presented in this paper can provide a pathway for solving similar problems in the field.
Qu, Jianlong, Yu, Qinyu, Jia, Jufang, Xu, Xinsheng
Design and Performance Verification of a Wheel-Track Transformable Mobile Platform Based on a Four-Bar Mechanism for Rescue Scenarios2026-99-12469/4/2026
Contemporary disaster rescue operations face challenges due to complex and hazardous terrains. Existing rescue robots with single locomotion mechanisms (wheeled, legged, tracked) and some hybrid ones have limitations in adaptability, efficiency, or structure. To meet the dual demands of complex terrains and limited space, this paper proposes a wheel-track transformable mobile platform based on a four- bar mechanism, which adopts a modular structure. A servo motor drives the active link to adjust the spatial position of the movable link (equipped with movable wheels), enabling smooth switching between wheeled and tracked modes. Key link lengths are determined via kinematic analysis, and a two-stage gear transmission system is designed. Adams simulation verification shows the platform completes wheel-track mode conversion on flat ground without component interference and can lift the center of gravity (CG) to surmount obstacles during slope climbing. The platform's feasibility is verified, providing a technical reference for designing highly adaptable rescue robots suitable for small spaces and complex terrains in post-earthquake or post-disaster scenarios.
Ma, Shangyuan
Numerical Investigation of Spiral Tubes and Turbulators for Enhanced Metal Hydride Reactors2026-99-12589/4/2026
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, Jiangnan, Jin, Tingxiang
New Nonlinear Buckling Solutions of Piezoelectric Truncated Conical Shells2026-99-12629/4/2026
Piezoelectric materials are highly valued in engineering for their electromechanical coupling. With these characteristics, structural applications utilizing such materials are increasingly being employed across a variety of disciplines. Among these structural configurations, piezoelectric conical shells have garnered significant interest owing to their inherent electromechanical coupling behavior, making them ideal for applications in various devices such as actuation systems, sensing mechanisms and energy harvesting solutions. To ensure the structural safety of these devices, assessing the stability of such shell structures is essential. This study conducts an analysis of the buckling stability of truncated piezoelectric conical shells. To this end, a theoretical buckling model for piezoelectric truncated conical shells is established, based on first-order shear deformation theory combined with nonlinear pre-buckling deformations. Utilizing a novel set of displacement trial functions within the Galerkin framework, this study derives precise critical buckling loads along with their associated mode shapes. The accuracy of the model is verified through comparative studies in the numerical section. Subsequently, the influence of key parameters—including applied voltages, semi-apex angles, and shell thickness—on the buckling behavior is investigated. The findings indicate that including the nonlinear pre-buckling deformation in the analysis is essential for ensuring reliable predictions. This research offers a theoretical foundation for the dependable design and assessment of piezoelectric truncated conical shells. Moreover, they also create opportunities for smart structures in aerospace, civil, and robotics, where accurate predictions of stability under electromechanical loading are critical.
Zhang, Junlin, Chen, Lide, Jia, Jufang, Zhou, Zhenhuan
Ant Colony-Artificial Potential Field Fusion Path Planning Algorithm Based on a Maneuver Action Library2026-99-12579/4/2026
The traditional Ant Colony Algorithm has defects such as easy entrapment in local optima due to a simplistic heuristic function and slow convergence due to excessive search directions. A fusion path planning algorithm integrating ant colony optimization and artificial potential field based on a maneuver action library is proposed. Firstly, a mathematical model for UCAV path planning is established. Considering the maneuverability constraints of UCAVs, and drawing on the concept of basic maneuver action libraries for fighter aircraft, an ant colony-potential field fusion path planning algorithm based on a maneuver action library is introduced. Simulation results demonstrate that compared to two other algorithms, the proposed method significantly improves the number of waypoints and planning completion time.
Li, Ruishen, Chen, Xiaogang
Study on the “Vibration-Differential Pressure” Coupled Environment Test Technology for Airborne Equipment Vibration Isolation Systems2026-99-12519/4/2026
The stable operation of airborne equipment determines the functionality and performance standards of aircraft. Installing vibration isolation systems on such equipment aims to improve its performance. With the advancement of aircraft capabilities, future evaluations of airborne equipment’s vibration isolation systems will require increasingly real-world experimental assessment. Achieving a ground-based simulation of the complex coupling environment encountered by airborne equipment at high altitudes presents a huge challenge. This paper proposes a method utilizing air springs to simulate differential pressure forces, successfully enabling ground-based testing of “vibration-differential pressure” coupled environments for airborne equipment. The results verify the effectiveness of this approach, and it can be used for this type of environmental testing.
Qin, Xiaomeng, Xing, Xiaoming, Mou, Haowen, Wang, Jianzhong
Research on Scalelike Adaptive Suction Flow for Wide-Speed Range Hypersonic Inlets2026-99-12529/4/2026
As critical components of aircraft, hypersonic inlets utilize shock wave compression effects to pressurize incoming flow. The interaction between shock waves and the boundary layer tends to generate separation zones, and it adversely affects inlet performance. As a method to significantly enhance inlet performance, suction technology can substantially reduce the size of separation zones when they form in the inlet. However, when the inlet is started and operating normally, suction configurations may cause mainstream leakage and make it difficult to meet the requirements of inlets with wider speed ranges. This paper designs an adaptive scaliform suction structure that utilizes a lift-generating design to induce a slight upward deflection of high-speed near-wall flow. It can reduce high-speed mainstream leakage without compromising the effectiveness in low-speed separation zones. Numerical simulations are employed to evaluate its suction performance in both inlet separation zone flow fields and supersonic mainstream flow fields. The internal flow mechanisms of the scaliform suction structure are investigated, and differences in its behavior across various suction flow fields, as well as its interference with the mainstream, are discussed. The study reveals that when the height of the scaliform suction structure is approximately 1/8 of the incoming flow’s velocity boundary layer height, the suction flow coefficient in the separation zone is twice that in the hypersonic mainstream. Furthermore, the loss in Mach number and total pressure recovery coefficient of the near-wall supersonic mainstream is controlled within 5%. This structure exhibits an adaptive suction capability for separation zones, thereby extending the starting speed range of the inlet.
Zhao, Xuening, Zhao, Yilong
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
Research on Online Zero-Point Calibration Technique for Ω-Shaped Coriolis Flowmeters in CCUS Applications2026-99-12379/4/2026
222
Yu, Haobo, Hua, Chenquan, Yu, Wenxin, Zhao, Zerun
Design and Analysis of Transmission Line Tower Erection Equipment2026-99-12409/4/2026
In response to the industry's problems of transportation difficulties, low efficiency, and high safety risks during the erection of high-voltage transmission line towers in mountainous areas, this paper proposes a light tower erection device that integrates connection, assembly, and fixing functions. The device adopts 180 mm Q345 equal-angle steel tower legs and is equipped with a hydraulic drive system. The tower body is raised through the coordinated work of the main and secondary hydraulic cylinders. In contrast, the vertical and horizontal hydraulic cylinders are used for auxiliary descent and precise fine adjustment. Its modular and lightweight structural design meets the transportation needs in narrow spaces in mountainous areas. The specifications of the hydraulic cylinder are determined by mechanical calculation, and the structural strength of the square tube and the main and secondary hydraulic cylinder connecting rods is verified by finite element analysis. Kinematic simulation confirms that the operating performance of the device is stable. This device provides an efficient and reliable piece of technical equipment for the construction of transmission lines in mountainous areas, which has important engineering application value and broad promotion and application prospects.
Li, Hailong, Chen, Zhen, He, Longping, Wang, Zhongpan, Li, Cheng
The Vacuum System of Arc Section Standard Cell for STCF Collider Rings2026-99-12389/4/2026
31–2–1
Zhao, Lijuan, Zhang, Ruiyang, Sun, Kun, Gong, Hailiang, Jiao, Weijie, Zhang, Benfu, Mao, Mingyang
Research on the Evaluation of Uncertainty in Roundness Measurement2026-99-12449/4/2026
Accurate evaluation of measurement uncertainty is crucial for precision manufacturing. This paper proposes a two-stage Bayesian-Monte Carlo method for assessing roundness measurement uncertainty in online inspection. The method separates machining errors from measurement system errors by first establishing a prior distribution via calibration with a standard artifact and then updating it with workpiece measurements. To validate the method, measurements were conducted on a certified roundness standard, showing close agreement with the reference value. The method demonstrates effective uncertainty quantification with small sample sizes and provides a foundation for intelligent evaluation in dimensional metrology.
Gu, Tingting, Qian, Xiaoming, Qian, Li
Experimental Study on Heat Transfer Performance of Gravity Heat Pipes in Green Highway Construction2026-99-12399/4/2026
Gravity heat pipe technology offers an innovative solution for utilizing shallow geothermal energy to melt pavement snow and ice in winter, aligning with the requirements of green highway construction. By leveraging the evaporation and condensation of internal working fluids, these heat pipes efficiently transfer underground thermal energy to the ground surface, delivering a continuous and stable heat supply for road pavements in cold weather. To explore the factors affecting heat transfer efficiency, this study built an indoor environmental simulation platform and systematically examined the impacts of heat pipe shape, working fluid type (R-134a, R245fa), heating temperature (15°C–25°C), and working fluid filling rate (15%–30%). A winter pavement snow- melting simulation experiment was conducted to quantify key indicators such as pipe wall temperature and heat transfer power under medium-low temperature conditions. Experimental results show that R-134a heat pipes outperform R245fa counterparts in heat transfer power under simulated shallow geothermal snow-melting conditions. Low filling volumes tend to induce temperature gradients in the condensation section of L-shaped heat pipes, reducing overall efficiency. Straight heat pipes work best at a 15% filling rate, while L-shaped models achieve optimal performance at 25%. Comparative experimental analysis yielded parameter-effect diagrams for heat transfer power and thermal conductivity, which clarify the variation rules of heat pipe performance and provide engineering guidance for gravity heat pipe applications in green highway construction.
Wang, Zhen-kun, Yuan, Zhi-ming, Wang, Kang, Zhang, Wen-jun, Wu, Xiang-song, Liu, Guang-bo
CFD-Based Aerodynamic Stability Analysis of a Quadrotor UAV2026-99-12539/4/2026
This study analyzes the aerodynamic stability of a typical quadrotor UAV during hover and vertical flight using Computational Fluid Dynamics (CFD). A fitted relationship between single propeller rotational speed versus lift and torque was obtained through simulation. Rotor speed input parameters were determined by combining this relationship with force analysis under ideal conditions. Lift and torque variation data for each rotor under two typical flight conditions were subsequently acquired. The research examines changes in lift and torque caused by aerodynamic interference between rotors, which induces UAV instability. To address the additional rotor lift from airframe obstruction of airflow, a “Reduction Value Method” is proposed to correct the lift data. Kinematic simulations conducted in Adams show significant displacement and angular displacement fluctuations in both hover and vertical flight states. Instability is more pronounced during vertical motion. This research provides a theoretical basis for understanding UAV flight stability mechanisms and optimizing control strategies.
Zhao, Haiyuan, Li, Jia, Song, Jiafeng
Optimal Design of the Driving Axle Housing of a Heavy-duty Automobile2026-99-12259/4/2026
As one of the important freight modes, heavy trucks need a high- strength and high-reliability drive system to carry huge goods. Therefore, the drive axle housing, a key component, significantly influences the performance and service life of vehicles, and its design and optimization have high practical significance. Firstly, this study begins by creating a geometric model of the axle housing using SW and analyzes its stress distribution under four typical operational conditions. Through static analysis, it is concluded that the most critical operational conditions are the maximum deformation of 2.151 mm and the peak stress of 272.3 MPa; in the fatigue analysis of ANSYS Workbench, the minimum life is 820,000 times. Results from both static and fatigue assessments indicate that the initial axle housing design satisfies stiffness, strength, and fatigue requirements. There is a large margin in the structure, which has certain optimization space. Considering the most dangerous working condition, the response surface optimization module of ANSYS Workbench is used with the objective of mass reduction. Finally, the axle housing is reduced by 4.09 kg; the corresponding maximum deformation is 2.262 mm, meeting stiffness criteria, while the peak equivalent stress reaches 280.3 MPa, remaining below the material's yield strength. The minimum life is about 620,000 times, and the maximum fatigue life is 1 million times, which still meets the requirements of the vertical bending fatigue test. This lightweight redesign reduces material and manufacturing costs while maintaining the requirements for deformation, stress, and fatigue strength.
Zhao, Shenglian, Zhong, Weijie, Zhang, Jian
A Simple and Efficient THINC Scheme for Multiphase Flow via Dominant-Material Selective Reconstruction2026-99-12299/4/2026
αkαkNm
Wang, Wei, Zhong, Yanxu, Hu, Qinghua, Yang, Canqun
Synergistic Optimization of Geometry and Properties of Al-CF/PEEK Hybrid Curved Beams Formed via One-Step Hot Stamping2026-99-12099/4/2026
Fiber metal laminates (FMLs) are widely used in high-end transportation equipment due to their excellent lightweight characteristics and high strength. Among various fabrication methods, the one-step hot stamping process offers an advanced and efficient approach for manufacturing FML hybrid components. The critical process parameters of this method have a decisive impact on the final component's mechanical properties and geometric accuracy. In this study, Al-CF/PEEK hybrid curved beam components consisting of 6061-T6 aluminum alloy, PEEK films, and CF/PEEK prepregs were fabricated using the one-step hot stamping forming process. Mechanical testing, digital image correlation (DIC) technique, and scanning electron microscopy (SEM) were employed to investigate the effects of forming process parameters (forming pressure and stamping speed) on the mechanical properties and geometric accuracy of the hybrid components. Results indicate that stamping speed has minimal impact on component thickness but significantly affects the spring-in angle and mechanical properties. As the stamping speed increases, the spring-in angle decreases; however, mechanical strength also declines. Higher forming pressure results in reduced spring-in angles, with the smallest value (0.73°) observed at a pressure of 4 MPa. However, excessive pressure introduced interface damage, causing mechanical properties to deteriorate after a certain threshold. Optimal performance was achieved at a stamping speed of 10 mm/s and a forming pressure of 3 MPa, yielding a strength of 244.82 N·mm/mm and a critical fracture energy of 5.002 N·m, along with high geometric accuracy. These findings offer valuable guidance for optimizing the process.
Deng, Yulong, Li, Yibo, Huang, Minghui, Dong, Lei, Lu, Yan, Peng, Jingquan
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
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