Browse Topic: Body structures

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FITTING END, STANDARD DIMENSIONS FOR BULKHEAD FLARELESS TUBE CONNECTIONSAS33515E (Current)9/17/2026
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Simulation of Compression and Bending Performance of GFRP Rod of Composite Hollow Post Insulator2026-99-01077/31/2026
Composite hollow core station post insulators utilize fiber-reinforced epoxy resin as the core rod material, offering advantages such as high specific strength, high specific stiffness, and excellent fatigue resistance. This enables them to effectively meet the flexible, variable, and complex operational demands of modern power systems. However, composite materials exhibit anisotropic characteristics, resulting in complex mechanical properties. Additionally, the core rod of hollow pillar composite insulators is typically fabricated through a spiral-plus-circumferential winding process, which significantly complicates structural design and computational analysis. This study establishes a finite element model of the hollow pillar composite insulator core rod in ABAQUS. It analyzes the influence of fiber content on composite material parameters and performs finite element numerical calculations to examine the stress state of core rods with different winding angles under compressive and bending loads. The research findings provide theoretical support for the optimized structural design of hollow pillar composite insulator core rods.
Liu, Jianbiao, Du, Yijun, Quan, Xiaoxi, Zhou, Songsong
Measurement and Regulation of Residual Stress in Door Opening Welds of Wind Turbine Towers2026-99-01977/31/2026
Weld residual stress is a critical factor affecting the structural integrity and service life of wind turbine towers. In this study, a systematic investigation was conducted on the residual stress distribution and control methods for door corner welds of an in-service wind turbine tower after approximately 20,000 hours of operation. X-ray diffraction (XRD) measurements revealed significant tensile residual stress in the weld and heat-affected zone, with peak values reaching 315 MPa, particularly concentrated at depths of 5-7 mm. To mitigate these stresses, two post-weld treatment methods were employed: ultrasonic impact treatment (UIT) and localized heat treatment. UIT effectively transformed surface tensile stress into compressive stress, achieving a maximum compressive residual stress of -372 MPa within a depth of 3 mm, while simultaneously refining grains and increasing surface hardness. In contrast, localized heat treatment at 460 °C for 5 hours led to a broader stress relief effect, reducing residual stress by approximately 100 MPa without causing significant changes to the macrostructure, but inducing substructural rearrangements beneficial for stress relaxation. Mechanical testing confirmed that both treatments improved tensile strength, ductility, and toughness of the welds. The combined findings demonstrate that ultrasonic impact treatment is highly effective for enhancing fatigue performance at the surface, while localized heat treatment offers advantages for deep stress redistribution and long-term structural stability. This comprehensive approach provides valuable technical guidance for residual stress management in complex welded structures of wind turbine towers.
Sun, Wanting, Zhong, Zhenqian, Zhang, Bo, Liu, Hui
Analysis of Underbody Impact Scenarios in New Energy Vehicles2026-99-08277/30/2026
In recent years, with the rapid increase in the market penetration of new energy vehicles, safety issues in electric vehicles, particularly those characterized by thermal runaway of power batteries, especially fire incidents caused by mechanical abuse from underbody impacts, have become a major focus of industry attention and social concern. This paper systematically compiles key data from electric vehicle underbody collision incidents, covering core parameters such as impact location, geometric features of obstacles (shape and size), and vehicle speed during accidents. Based on this data, the study further reviews existing underbody scraping evaluation protocols both domestically and internationally, with a focused comparison of the differences in mechanical load and battery pack response between two typical test methods: horizontal underbody scraping and 3° inclined underbody scraping. The findings of this research aim to provide data support for the refinement of relevant evaluation standards and to offer theoretical foundations and practical references for automotive manufacturers in optimizing the design and validation strategies for underbody protection of battery packs.
Wang, Qinggui, He, Qike, Li, Wenbo, Li, Chun, Li, Xiaodong
Research on a Lightweight Door Based on an Approximate Model Constructed by a Differentiation Strategy2026-99-08127/30/2026
Taking the front door of a new energy vehicle as the research object, a finite element model was built based on HyperMesh to conduct stiffness and modal performance analysis, and clarify the characteristic differences of multiple responses of the door. To address the issue that traditional single approximation models are difficult to adapt to different response characteristics, a strategy for constructing differentiated approximation models is proposed, which is to select the optimal approximation model according to different response types. The results show that the approximation models for each response constructed based on the differentiation strategy have a fitting accuracy (R^2) of more than 0.99, close to complete fitting, which is significantly better than the overall adaptation effect of a single model. Finally, based on the approximate model established using this strategy, combined with a multi-objective optimization algorithm, the dimensions of the front door are optimized, while achieving lightweighting and performance improvement of the front door, which provides a new idea for constructing multi-response high-precision approximate models.
Wei, Yansai, Shen, Yongfeng
Experimental Study on the Temperature Impact of a Typical Cabin Fire on Adjacent Cabins2026-99-08667/30/2026
The cabins of ships are mainly made of steel. When a fire breaks out, the temperature inside the cabin rises rapidly, and an extensive body of heat spreads through the bulkheads to adjacent cabins. Understanding the variation law of the temperature field in adjacent compartments after a fire occurs in the compartments is of great significance for the research on the thermal safety of ship compartments. This paper designs an L-shaped cabin test system. We conduct fire tests of different scales and obtain the temperature distribution of adjacent compartments. The test results show that as the fire area in the pool keeps rising, the temperature in the adjacent compartments keeps rising. Due to the fact that an extensive body of high-temperature smoke produced by combustion is suspended at the ceiling of the compartment of fire, the temperature of the vertically adjacent compartments is higher than that of the horizontally adjacent compartments.
Hu, Wei-guo, Hu, Yang, Wei, Jin, Yuan, Ya-long
Analytical Analysis of Wellbore Stresses under Fluid Pressure and In-Situ Stress in Three-Dimensional Wellbores2026-99-08317/30/2026
During fluid injection operations such as fracturing and well killing, the casing, cement sheath, and borehole wall rock are subjected to three-dimensional in-situ stresses and internal pressure. If the equivalent stress exceeds the material’s yield strength, component failure may occur, leading to wellbore failure or even blowout accidents. In order to investigate the stress distribution in wellbores under specific working conditions, a three-dimensional mechanical model of curved wellbores was established. By adopting the superposition principle and stress function method, the influence of horizontal in-situ stress non-uniformity on the fourth equivalent stress of various components was analyzed. The study demonstrates that under three-dimensional in-situ stress, the fourth equivalent stress of each component increases with the rise of horizontal in-situ stress load non-uniformity and azimuth angle. Meanwhile, borehole azimuth angle and in-situ stress load non-uniformity exert a greater influence on the fourth equivalent stress of the casing, while internal pressure has a lesser impact on it. The effects of azimuth angle, horizontal in-situ stress load non-uniformity, and internal pressure on the fourth equivalent stress of the casing are more significant than those on the cement sheath and borehole wall rock. The research results can provide theoretical and technical references for wellbore design and safety improvement, as well as for the structural safety assessment of components such as automotive chassis and body frames under complex dynamic loads.
Zhang, Wenzhe, Jiang, Wu, Guo, Ziwang, Cao, Yinping, Dou, Yihua
Design of a Jamming Test Apparatus for Aircraft Cargo Door Latches2026-99-08337/30/2026
The reliability verification of cargo door latches for civil aircraft requires a safe, accurate, and controlled method for simulating jamming failures in lab settings. We adopt a crank-rocker mechanism with a variable degree of freedom (DOF) to construct a novel jamming apparatus that may be dynamically constrained in order to meet this requirement. The apparatus maintains two DOFs when not in use, which permits the latch mechanism to move freely. Both the guiding shafts and the rotation shafts are simultaneously constrained for a jamming test, reducing the mechanism’s DOFs to zero. This operation creates a precise and passive lock that immobilizes the mechanism without the need for an active external load. This approach offers a more realistic simulation of the sudden jamming brought on by wear, foreign object intrusion, or manufacturing tolerances. A theoretical kinematic analysis is then conducted to calculate the mobility of the mechanism and determine the theoretical conditions and transition paths to reach the two functional states. Moreover, the apparatus implements a real-time computational model based on classical planar linkage force analysis and integrates a multi-sensor system. This model converts sensor data into the torques and jamming forces that are actually delivered to the latch. The findings demonstrate that the proposed design accurately simulates latch jamming conditions while allowing for real-time monitoring and quantification of important dynamic characteristics. Thus, by offering a dependable and effective verification solution for cargo door latches, the apparatus greatly improves testing safety and the value of the data gathered.
Ren, Jie, Zeng, Xiaohu, Qiu, Xudong, Xie, Youshui
Adaptive Attitude Adjustment Mountain Transport Vehicle for Electric Tower Material2026-99-08507/30/2026
Transporting large steel materials for mountain electric towers is challenging due to steep gradients, narrow roadways, and uneven terrain. To address these issues, this study designs an adaptive attitude adjustment mountain transport vehicle. This mountain transport vehicle has a compact structure, measuring 1.4 meters in length and 1.1 meters in width, which enhances its suitability for confined mountainous environments. This vehicle adopts a design scheme that combines hydraulic lateral adjustment, load-bearing platform follow-up adjustment and frame adaptive adjustment mechanisms. The transportation of tower materials, measuring 12 meters in length and 1.2 tons in weight, is accomplished by employing two vehicles working in coordination. The three-dimensional model of the entire vehicle is established by using SolidWorks software. The lateral stability of the mountain vehicle and the limit working conditions of its adjustment mechanism are analyzed through theoretical calculation. The dynamic simulation of the virtual prototype is carried out using Adams software, including the processes of lateral leveling, follow-up adjustment and frame adjustment. The results show that the leveling mechanism can achieve an adjustment range of more than ±25°. The results confirm the vehicle’s excellent stability and adaptability to mountainous conditions. This study provides a more effective and more reliable solution for the construction of mountain electric towers than traditional manual or animal-powered transportation methods.
Zhang, Rui, Kong, Fanfang, He, Yuling, Lv, Jiahui, Chen, Changlong, Zhan, Lulin, Liang, Ke
Geometric Deep Learning–Based AI Framework for Nonlinear Crash Behavior of Extruded Rails15-19-03-00127/27/2026
Extruded Rails are critical energy-absorbing components in automotive structures designed to mitigate impact loads during the frontal collisions. Traditional crashworthiness design relies heavily on computationally expensive finite element simulations and iterative design exploration. This work proposes a machine learning–driven framework for rapid front extruded rails design using a trained geometric deep surrogate model. A design-of-experiments (DoE) was conducted by varying geometric parameters including width, height, and wall thickness of a thin-walled extruded rail structure. For each design variant, LS-DYNA simulations were performed to obtain performance metrics such as mean crush force and peak crush force. These simulation results were used to train an AI surrogate model capable of predicting crash responses directly from geometric parameters. The proposed approach significantly reduces computational cost by replacing repeated high-fidelity crash simulations with machine learning surrogate predictions. By enabling fast and accurate evaluation of crash response metrics, the workflow shortens design cycles and supports sustainability-driven crashworthiness assessment by reducing simulation resource usage. The framework establishes a scalable, simulation-driven engineering pathway across vehicle platforms and provides a foundation for future closed-loop, AI-assisted crash design workflows.
Kumar, Manik, Srinivasan, Sriram
Research and Application of Flush Adjustment for Multi-Link Retractable Hatch2026-99-16207/24/2026
The adjustment process for multi-link retractable hatches has long relied on personal experience, making it difficult to achieve precise and quantitative length adjustments. This limitation has consistently constrained the efficiency of the adjustment process. This paper aims to analyze the risks and shortcomings in the existing flush adjustment process, simplify the flush adjustment process into a mathematical model, and calculate the required adjustment amount of the actuator length. By simplifying the flush adjustment process and steps, the risk associated with the adjustment process can be reduced, and the efficiency of door step difference adjustment can be improved.
Deng, Qinwen, Shen, Yingdong, Wang, Zhihai, Li, Yixiao, Wei, Xingxu, Gao, Haosen
Accurate Control of Refueling Volume for a New Type of Oil Change Device in the Reducer of Tobacco Machinery Equipment2026-99-16187/24/2026
In order to achieve precise control of refueling volume, improve oil change efficiency, reduce oil pollution and waste, a new oil change device for the reducer of the range hood equipment is studied. We design a new oil change device that integrates oil discharge and refueling functions based on the operating characteristics of the reducer in the range hood equipment. Using the rotational speed of the power pump and the flow rate of the oil pipeline as variables, we determine the refueling flow rate using a one-dimensional quadratic formula. Based on direct control theory, we optimize the relative position parameters of each component of the device, establish a control matrix, and achieve precise control. The experimental results show that the new oil change device exhibits good performance during both one-time oil discharge and refueling processes, meeting the precise control standards for refueling volume. The design and application of a new oil change device can effectively improve the efficiency and accuracy of oil change in the reducer of the range hood equipment, and have practical application value.
He, Pengtao, Wei, Bo, Liang, Zhiyuan, Deng, Weiren, Liang, Wenbin, Xing, Yuquan
Lightweight Optimization Design of Subframe Structure Based on Sensitivity Analysis2026-99-16397/24/2026
In order to meet the needs of national energy conservation and environmental protection policies, a typical chassis structure lightweight method based on sensitivity analysis of 13 strength conditions was proposed. Firstly, the finite element model of the subframe of a certain model is established, and the impact strength and static strength of the subframe structure are analyzed by the finite element method. Secondly, the sensitivity analysis of 13 strength conditions was carried out for the 12 main sheet thicknesses in the finite element model. Based on the results of the sensitivity analysis, the plate thickness of the components that is conducive to lightweight and has little impact on the 13 strength conditions of the subframe was selected as the design variable. The size optimization was carried out with the goal of minimizing the mass of the subframe and the constraint that the maximum Von Mises stress of the unit, where each material is located, did not exceed the yield strength of the material. The optimization results show that the performance of the subframe under 13 strength conditions meets the requirements of the index, and the weight of the subframe is reduced by 1.37 kg / 9.6%.
Jing, Min, Jia, Zhilong, Zhang, Hualei, Liu, Minjie, Gan, Xinhua, Gao, Jinyu
Multi-Frame Centroid Extraction Method for Optical Navigation During the Approach Phase of Small Body2026-99-18517/17/2026
Autonomous optical navigation is one of the important navigation methods for the small bodies approach phase. To improve optical navigation performance during the approach phase to a small body, this paper presents a method for extracting the target centroid from sequential optical images. The process begins with fitting a minimum enclosing ellipse to the detected contours in each frame to obtain an initial estimate of the centroid. Building upon this, edge corner points across adjacent images are matched using normalized cross-correlation, and their displacement is tracked using optical flow techniques. The observed pixel trajectories are analyzed, and a predictive model of pixel motion is formulated based on the geometric relationship between the detector and the small body. By combining the directly extracted centroids with the predicted motion of key pixels, a fusion strategy is developed to improve the reliability of the centroid estimation. Finally, numerical simulation results demonstrate that the method significantly improves the accuracy of centroid extraction, thereby enhancing the overall performance of optical navigation during approach operations.
Liu, Jing, Zhu, Shengying
Aircraft Evacuation Simulation Study2026-99-18457/17/2026
This study analyzed the evacuation process of aircraft cabin personnel, with a focus on the impact of emergency exit configuration on evacuation efficiency. The research results indicated that the number and location of emergency exits are key factors determining evacuation time. In the case of only one exit, the evacuation time was significantly longer than that of multiple exit configurations. Utilizing three exits could reduce the evacuation time to 76 seconds. Additionally, the age and gender distribution of passengers, as well as priority rules, also had a significant impact on the evacuation process. The study further demonstrated that the activation of emergency exits and rear cabin doors could significantly enhance evacuation efficiency, while the opening of the front cabin door had a relatively smaller effect.
Wang, Kai, Wu, Bin, Li, Guolin, Yue, Chaoyu, Zeng, Tai, Su, Zhengliang
Analysis of Structural Stiffness Indicators of Manned Lunar Vehicles2026-99-18277/17/2026
The structural stiffness of a manned lunar vehicle is a core indicator ensuring its stable operation in the complex lunar environment. The vehicle’s body structure must meet multiple requirements, including high stiffness, lightweight design, and adaptability to lunar surface conditions. Since lunar gravity is only 1/6 of Earth’s and the terrain is rugged and dusty, the body structure must employ a high-stiffness design to withstand driving impacts and resist deformation, thereby preventing mechanical failures or safety hazards for crew members caused by excessive structural distortion. However, excessive structural stiffness would result in an overweight vehicle body, conflicting with the spacecraft’s lightweight requirements. Thus, the structural stiffness index should be optimized to a lower value while ensuring safe operation during lunar surface driving without compromising performance. This paper calculates and determines the structural bending and torsional stiffness indicators for the manned lunar vehicle’s body through simplified model calculation and the FEA method.
Shen, Zhenghui, Wu, Yingjia, Yang, Jianfeng, Wang, Weijun, Zhang, Chongfeng, Han, Liangliang
Numerical Investigation of Inverted Airfoils in Ground Effect for Motorsport Applications01-19-01-00047/15/2026
Ground effect plays a critical role in enhancing the aerodynamic performance of race cars by increasing downforce without a proportional rise in drag. Despite its importance, the influence of airfoil geometry on inverted airfoils operating in ground proximity remains underexplored in open literature. This study addresses this gap through a detailed numerical investigation of chord-dominated ground effect using two-dimensional Reynolds-Averaged Navier–Stokes (RANS) simulations. A range of NACA four-digit airfoils is systematically analyzed to isolate the effects of camber, thickness, and camber location on aerodynamic performance in ground proximity. Results show that increased camber enhances downforce and efficiency both in and out of ground effect; thinner airfoils yield higher downforce and efficiency in ground effect; and forward camber locations outperform rearward ones in maximizing downforce contrary to out-of-ground-effect trends. Detailed pressure distribution and flow separation analyses explain the underlying mechanisms, offering actionable guidelines for optimizing ground effect airfoil design in motorsport.
Chowdhury, Rohan, Shukla, Dhwanil
Experimental Validation of Frame-Dependent Gyroscopic Frequency Splitting in a Freely Rotating Tire Using Wireless MEMS Accelerometers and Scanning Laser Doppler Vibrometer2026-01-07006/20/2026
Gyroscopic effects split circumferential traveling-wave resonances of rotating structures into forward and backward branches. This work first analyzes the splitting in the co-rotating (Lagrangian) frame to provide physical intuition for the evolution of the two branches with spin speed. A transformation to the inertial (Eulerian) frame is then derived, showing that the observed frequencies are shifted by a kinematic Doppler-like term that acts with opposite sign on the forward and backward waves, leading to different Campbell-diagram slopes depending on the observation frame. The resulting framework is validated experimentally on a freely rotating, unloaded tire using two complementary sensing modalities: wireless on-tire accelerometers (co-rotating view) and a scanning laser Doppler vibrometer (inertial view). A frequency-domain SVD-based identification (FDD/ODS-SVD) is used to extract poles and deformation patterns over a range of spin speeds, enabling Campbell diagrams in both frames. The application of the proposed transformation maps the co-rotating branches onto the inertial observations, yielding consistent forward/backward splitting between the two measurement systems.
del Fresno Zarza, Javier, Naets, Frank
Simulation and Analysis of Flow and Acoustic Induced Structural Vibration2026-01-06966/20/2026
For analysing flow and acoustic induced structural vibration, a fully run time coupled framework combining a hybrid CFD-CAA approach with a modal response simulation was validated and presented at the ISVNH 2022 (SAE Technical Paper 2022-01-0938). In this paper i We apply this CFD–CAA–modal coupling method to a series-representative bonnet geometry and demonstrate its capability to capture flow and aeroacoustically driven vibration with two-way coupling. ii We analyse the modal properties of the bonnet and show that confined air volumes beneath the bonnet can introduce significant fluid loading effects, which are already embedded in experimentally validated FE modal models and must therefore be treated carefully in two-way coupled simulations. iii We validate the fully coupled aeroelastic simulation against wind-tunnel measurements with undisturbed inflow, show close agreement with the measured vibration response and analyse that the dominant excitation is in this case from below the bonnet due to acoustic pressure fluctuations.
Schwertfirm, Florian, Ocker, Joerg, Hartmann, Michael
A Study of Improving Door System Sound Transmission Loss2026-01-06756/20/2026
Recent studies indicate that the door system plays a significant role in the interior noise levels of newly developed vehicles. This research investigates the noise transmission paths through the door system and identifies effective strategies for improvement through a combination of door buck testing and simulation. Specifically, in this study, the finite element method (FEM) was employed for door buck simulation, and the model was validated against vibration test results. Subsequently, acoustic analysis tools were utilized to correlate with noise testing, thereby establishing a process to ensure simulation accuracy. The sound insulation performance for the main areas of the door was experimentally evaluated, and a simulation model with good correlation to these test results was developed. By utilizing both experimental and simulation results, the principal transmission paths were identified, and appropriate improvement strategies for these paths were investigated. The validated improvement strategies are intended to be applied in the development of next-generation vehicles.
Chae, Ki-Sang, Jang, Jinung, Jeong, Hojung, Do, Hyuncheol, Han, Jinwoo, Yi, Jaebok, Bak, Seong-Jae, Jeong, ChanHee
Impact of Door Dynamics on Vehicle Interior Low-Frequency Vibro-Acoustics2026-01-06796/20/2026
Interior acoustics represent an essential component of driving comfort in electric vehicles. Numerical simulation is an effective approach for assessing design concepts and enhancing acoustic performance. However, a fully coupled vibro-acoustic model for an entire vehicle remains computationally infeasible. Our approach couples mechanical and acoustic modal models on non-conforming interfaces in the low-frequency range, allowing independent mode combinations. Modal coupling reduces the computational effort significantly from full-order systems with millions of degrees of freedom to a selection of modes of the acoustic and mechanical systems. Modal models of the vehicle structure are derived from measurements with a laser-vibrometer and accelerometers while the interior acoustics are simulated numerically. Since laser-vibrometer measurements are restricted to the vehicle’s exterior surfaces and vibro-acoustic coupling occurs between the inner structural surface and the interior fluid, the structural behavior of the vehicle’s inner surface needs to be determined. We performed modal testing on both the exterior and interior surface of a front door within an entire vehicle due to volume source excitation on the inside of the vehicle. The modal structural behavior of the exterior and interior surfaces for the frequency range of interest already showed an indication of a door dynamic. For a mathematically consistent application of modal coupling method, the eigenvectors of the acoustic and mechanical subsystems must be correctly scaled, i.e. they must be mass-normalized. While the acoustic modes obtained from numerical simulation inherently fulfill this requirement, the mechanical modes extracted from experimental data generally do not. To address this challenge, we investigated a flat plate in numerical simulation and derived a method to determine scaling factors for obtained mode shapes. Proper scaling of the mechanical modes was achieved by applying the scaling method on our measured door modes. The coupled simulation reveals an inherent dynamic behavior of the door.
Gutbrod, Manuel, Gabriel, Christoph, Müller, Gregor Johannes, Toth, Florian
Vibro-Acoustic Simulation for Vehicle Audio Design2026-01-06706/20/2026
Acoustic user interfaces and audio experiences are among the leading comfort factors in new vehicle interior designs. OEMs are more and more focusing on loudspeaker design and positioning, to provide the most immersive experience to the customers. The industrial target is to be able to predict the performance of an audio system in early design phases. This paper presents an integrated vibro-acoustic methodology enabling early-stage prediction of loudspeaker performance in real vehicle conditions. The approach combines electromechanical characterization, a hybrid loudspeaker calibrated model valid across the audible range and coupled FEM/BEM/SEA simulations to capture the loudspeaker response in the vehicle’s cabin considering door-installation effects and cabin acoustics. The method is validated experimentally on a rear-door loudspeaker installed in a production vehicle, showing strong correlation with measured SPL. A final application case demonstrates its capability to assess the impact of alternative speaker mounting positions during the design phase.
Zerrad, Mehdi, Errico, Fabrizio, Mordillat, Philippe
Design of Acoustical Features for a Quitter Aero-Engine Test Facility2026-26-07876/1/2026
It is a general practice to test aero engines to evaluate their performance in specially designed indoor test facilities after assembly, repaired or overhaul. Acoustic features are provided in the test facility to attenuate the noise level to a comfortable and acceptable level. Design of these features specially air intake and exhaust silencers are a challenging task in a flow field like aero-engine test facility considering the very high sound pressure level generated by them during test containing a very wide frequency band. Moreover, growing population and location of these facilities in the vicinity of residential areas has added this challenge in multifold. Also, the capital investment in building these facilities is huge due to their large size and longer construction time. Hence, the correct execution at first shot including design, fabrication and commissioning is very important. An attempt has been made to reduce design errors or improve the accuracy in the design stage by using commercially available acoustics analysis tools followed by laboratory measurement of sample features, which will reduce the lead time and cost of the project in design and implementation of the acoustic features for aero engine test facilities used for military application. This paper outlines the design of acoustics features such as air intake silencers, air cooled exhaust silencer, acoustic panels, sound proof doors and bullet resistant view window, which has produced significant improvement of noise level in and around the test facility.
Gouda, Bansidhar
Zero Waste Manufacturing in Aerospace: Circular Design Approaches from Concept to End-of-Life2026-26-07756/1/2026
Achieving zero-waste manufacturing in aerospace requires a shift from end-of-pipe waste mitigation toward circular design principles embedded early in product development. This paper presents a practical framework for integrating circularity into aerospace systems through five design pillars: design for modularity and disassembly, material substitution to enhance recyclability, waste segregation and characterization, component-level circularity readiness scoring, and collaborative supplier engagement. To operationalize this approach, a Circularity Readiness Assessment Tool (CRAT) is developed to evaluate design alternatives against criteria such as disassembly ease, material recyclability, manufacturing waste potential, end-of-life recovery pathways, and supplier take-back mechanisms. The framework supports multi-criteria decision-making by complementing traditional aerospace design drivers including weight, performance, cost, and safety. The methodology is demonstrated through a case study of an aircraft seating system. Scenario-based analysis indicates that targeted circular design interventions can reduce material waste and lifecycle carbon emissions while maintaining functional and regulatory requirements. Emphasizing practical engineering workflows rather than exhaustive lifecycle modeling, this work provides a scalable foundation for embedding circular design into aerospace product development and advancing zero-waste manufacturing objectives.
S, Chaitra
A Simulation Method for Automotive Door Jitter Containment10-10-03-00225/21/2026
This article describes multi-body dynamics simulation to investigate door jitter issues caused by the limiter during door operations. A simulation model integrating a rigid limiter and a flexible door-body system was developed to replicate the dynamic process of wide-angle door opening/closing. Through iterative refinements—including correlation of simulation results with test data, optimization of internal door connection methods, and solid-element hinge modeling—simulation accuracy was improved to over 89.7%. Using the validated model, quantitative metrics were established to evaluate door jitter severity. Key parameters that influence the door operation smoothness were identified, and an optimization scheme was proposed for a specific vehicle model, incorporating slope-holding performance requirements under hill-parking conditions. Finally, prototype testing validated the approach’s effectiveness. The developed simulation method provides a technical foundation for virtually resolving door jitter issues during vehicle development.
Xiao, Yongfu, Deng, Jianjiao, Li, Jingtan, Yang, Tao, Hou, Hangshen, Han, Chao, Gao, Meng, Wang, Yiqi, Liu, Yihong
Design of a Modular High-Power High-Repetition-Rate Semiconductor Pulsed Laser Power Supply2026-99-07165/15/2026
Pulsed lasers serve as critical components across a diverse spectrum of modern applications, ranging from precision manufacturing and medical equipment to advanced defense systems. Their performance is fundamentally governed by the pulsed power supplies that act as their energy source, where output characteristics such as stability, rise time, and efficiency directly dictate the quality and reliability of the laser output. Aligned with the prevailing industrial trend towards miniaturization and digital control in semiconductor laser pump drivers, this paper introduces a high-power, high-repetition-frequency pulsed laser power supply. The proposed design is architect ed around a phase-shifted full-bridge charging network for efficient energy transfer and a modular, switched-mode constant-current pulsed discharge network for precise output shaping. This integrated architecture provides versatile and independent control over key output parameters, including current amplitude, pulse width, and repetition frequency, offering significant flexibility for various operational requirements. The adopted switched-mode constant-current driving technique presents a substantial advantage over conventional linear constant-current methods. It drastically reduces conduction losses inherent in linear regulators, which is a decisive factor for enhancing overall system efficiency, particularly in demanding long-pulse application scenarios where thermal management is challenging. This work comprehensively details the systematic modeling, in-depth analysis, and tailored control design undertaken for both the front-end charging network and the rear-end pulse-forming modules. To validate the design methodology and practical performance, a functional prototype was developed and subjected to rigorous testing. Experimental results confirm that the prototype achieves a maximum constant-current pulsed output of 400 A, featuring a remarkably fast rise time of less than 10 μs. Furthermore, it demonstrates a wide range of operable pulse widths up to 1000 μs and sustains a maximum repetition frequency of 1000 Hz, thereby meeting the stringent demands of advanced high-power pulsed laser systems.
Huang, De, Lu, Jiawei, Yang, Zhiqing, Xv, Ziyi, Xing, Hui
Effects of Vehicle Speed, Category, and Front-End Design on Full-Body Injury Risks of a Midsized Male Pedestrian09-14-01-00175/4/2026
This study investigated how vehicle front-end geometry, impact speed, and vehicle category influence injury risk to a midsize male pedestrian. Eighty-one generic vehicle (GV) models representing sedans, sport utility vehicles (SUVs), pickup trucks, and minivans sold in the United States were developed by morphing three base models using an automated pipeline. Front-end parameters that were varied included ground clearance (GC), bumper height (BH), hood leading-edge (HLE) height, hood length (HL), bumper lead angle (BLA), hood angle (HA), and windshield angle (WSA). Each vehicle impacted the Global Human Body Models Consortium 50th percentile male simplified pedestrian (GHBMC M50-PS) model at 30, 40, and 50 kph, totaling 243 simulations. Boundary conditions followed the European New Car Assessment Program (Euro NCAP) pedestrian test protocol. Thirty-five injury metrics were extracted across the head, neck, thorax, abdomen, pelvis, and lower extremities. Linear mixed-effects regression models assessed relationships between vehicle front-end geometry, impact speed, and injury outcomes, with predictor selection guided by principal component analysis (PCA) and collinearity diagnostics. Impact speed was the strongest predictor of injury severity across all body regions. GC and HLE height were also dominant predictors. Wrap-type trajectories were common at lower speeds and in SUVs, trucks, and minivans, while sedans and minivans showed roof vaulting at higher speeds. Head injury severity increased with speed and was influenced by HA and BLA. Minivans showed elevated brain injury criterion (BrIC) and cumulative strain damage measure (CSDM25) values, indicating increased diffuse brain injury risk. Trucks produced the highest thoracoabdominal injury metrics, which correlated with HL, HA, and HLE height. Sedans showed higher right-side (trailing leg) femur forces, slightly lower left-side femur forces than SUVs and minivans, and lowest tibia moments. Trucks had greater tibia bending moments, while SUVs and minivans had higher left femur moments compared to sedans. GC and impact speed exacerbated lower extremity injuries, varying by vehicle category. These effects are driven by geometry: Higher GC increases the unsupported span below the knee, promoting tibial bending, while lower HLE heights shift impact forces above the knee, elevating femur injury risk.
Poveda, Luis, Miller, Logan E., Edwards, Colin C., Pollock, Madeline, Armstrong, William M., Hsu, Fang-Chi, Gayzik, Scott F., Weaver, Ashley A., Stitzel, Joel D., Devane, Karan S.
Advanced MES Capabilities for Semiconductor Front-End ManufacturingTBMG-550835/1/2026
Finding Hidden Damage in Cold-Formed Steel with Radar and AITBMG-550695/1/2026
A University of Houston engineer has developed a method to detect possible damage in concealed cold-formed steel construction framing materials hidden behind walls, without having to tear the walls open.
Hierarchical Control Strategy Evaluation and Migration for a Four-Degree-of-Freedom Quarter Commercial Vehicle02-19-03-00144/9/2026
In order to improve the comfort performance in commercial vehicles, this study proposes a hierarchical control strategy that integrates the evaluation and migration of control algorithms. First, a quarter-vehicle model with four-degree-of-freedom (4-DOF) is constructed, incorporating the dynamics of the wheel, frame, driver’s cab, and seat. The key modal characteristics of the model are then verified through amplitude–frequency analysis, confirming their consistency with the typical vibration patterns observed in actual commercial vehicles, which provides the foundation for subsequent control strategy evaluation and migration. Then, based on a standard two-degree-of-freedom (2-DOF) suspension model, a weighted comprehensive evaluation function is developed to account for comfort, structural safety, handling stability, and both time- and frequency-domain performance indicators. Using this evaluation function, various control algorithms—including Skyhook control (SH), acceleration-based damping control (ADD), and proportional–integral–derivative control (PID)—are systematically assessed. The control algorithm is migrated to the 4-DOF model to carry out the hierarchical collaborative control. The results show that this method can effectively inhibit vibration transmission to enhance ride comfort and improve structural safety at the same time, while maintaining an acceptable level of handling performance. The transferability and applicability of the hierarchical control method are validated for the considered vertical dynamics scenarios. This article provides a new theoretical method and technical pathway for the comfort-oriented performance optimization of commercial vehicles.
Pan, Ting, Pang, Jianzhong, Wu, Jinglai, Zhang, Jiuxiang, Kang, Gong, Zhang, Yunqing
Development and Application of CAE Methods for Predicting Snow Accumulation on Floor Undercovers During Snowy Road Driving.2026-01-04824/7/2026
This study presents a simulation method for reproducing slush accumulation on underbody components, with a particular focus on the floor undercover, during vehicle operation on slush-covered roads. As electrified vehicles become increasingly important in the pursuit of carbon neutrality, the adoption of aerodynamic undercovers to improve driving range has accelerated. However, these components are exposed to various environmental stresses, including water, chipping, and especially snow and slush, which can lead to damage and performance degradation. While previous research has addressed water and chipping stresses through simulation, studies on slush-induced stress have been limited. To address this gap, the Moving Particle Semi-implicit (MPS) method was applied, incorporating a power-law model to represent the non-Newtonian flow characteristics of slush. Parameter identification was conducted through steel ball drop tests and tire scattering tests, ensuring both qualitative and quantitative agreement between experimental and simulation results. The simulation’s accuracy was further validated by comparing the scattering direction and accumulation locations with those observed in actual vehicle tests. The method was also applied to different floor undercover specifications and multiple vehicle models, demonstrating its versatility and independence from vehicle type. Quantitative evaluation of slush accumulation was achieved, and the simulation results showed excellent agreement with experimental data across all tested conditions. This Computer-Aided Engineering (CAE) approach enables efficient and highly accurate assessment of underbody component stress during slush road driving, supporting both aerodynamic performance and environmental durability in the development of electrified vehicles. Remaining challenges include the variability of slush properties under real-world conditions, the limitations of the power-law model, and computational costs associated with the MPS method. Further research is required to enhance the method’s accuracy and applicability.
Matsuura, Tadashi, Annen, Teruyuki, Harada, Takeyuki, Ueno, Shigeki, Asai, Mikio, Watanabe, Haruyuki
Determining Video Frame Capture Rate through Reverse Engineering2026-01-05434/7/2026
The timing of video recordings, along with the spatial positioning of objects, is a fundamental parameter for calculating the speed time history. If the task involves determining the average speed of an object moving at approximately constant speed, it may be acceptable to average the speed over several to a dozen frames, using the fps (frames per second) parameter as the basic time unit.. However, if the objective is to compute speed from individual frames, the reliability of the timing becomes crucial. Without access to DVR hardware documentation, proprietary algorithms, or software – and considering the frequent hardware modifications and software updates - the most effective way to solve the problem is through a reverse-engineering approach. This study discusses several aspects of timing analysis, including: (1) making a test recording of a calibrated LED lightboard; (2) analyzing the relationship between the lightboard time and the presentation time stamp (pts) extracted from the file metadata; (3) investigating frame skipping and frame timing errors due to frame rate changes; (4) modeling the composite motion of the rolling shutter and the lightboard LEDs; (5) identifying the DVR’s actual frame capture rate; and (6) compensating the timing of the evidentiary recording. Establishing the timing scheme of the test recording enables reliable speed analysis based on two or three adjacent frames of the evidentiary recording, as well as the determination of the velocity time history over a short segment of the recording.
Wach, Wojciech
A Study on the Relationship between Impact Conditions and Head Injury Criterion (HIC) in Powered-Two-Wheeler to Car Crashes2026-01-05714/7/2026
Road Traffic crash statistics highlight the importance of reducing fatalities among Powered-Two-Wheeler (PTW) riders, and suggest the necessity of a robust method to evaluate PTW crashworthiness performance. The objective of this study is to clarify the relationship between impact conditions and the Head Injury Criterion (HIC) to establish a fundamental basis for determining representative crash configurations for safety. A total of 1,272 PTW-front to car-side impact simulations were conducted by using production car and PTW models. HIC was used as a metric indicating likelihood of head injury. Velocities, impact angle, and impact locations were varied to create response surfaces. The surfaces were evaluated in terms of their accuracy in identifying the representative impact conditions. In addition, head trajectories were analyzed to clarify the kinematics until head impact. The Finite Element (FE) simulations produced the following findings. The HIC distribution by Head Impact Target can be categorized into 2 groups by the height of the car roof. Some of the low-roof car group results show a phenomenon of partial helmet removal, causing large variation in HIC. High HIC values are observed when the Y-direction displacement at the head impact is small. Structural stiffness and roof height may need to be considered when investigating a future test method that provides stable safety evaluation. These findings establish a fundamental basis for determining the representative crash scenario through an analysis of the relationship between crash conditions and the HIC.
Yanaoka, Toshiyuki, Gunji, Yasuaki, Zulkipli, Zarir Hafiz, Matsushita, Tetsuya, Carroll, Jolyon, Puthan, Pradeep, Mohd Faudzi, Siti Atiqah, D-Wing, Kak, Miyazaki, Yusuke
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