Browse Topic: Safety testing and procedures

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Investigation on Dynamic Expansion Response and Structural Safety Assessment of Typical Polygonal Fabric Gasbags2026-99-2337To be published on 10/30/2026
The geometric structure of a gas bag has a profound effect on its effectiveness in transferring energy and reliability of its structure when rapidly expanding. Even though there have been considerable improvements in high-performance composite materials such as Kevlar, the transient dynamic reaction and possible rupture mechanisms associated with particular polygon shapes have been greatly unexplored. In this paper, we focus on conventional polygonal gas bags, and perform extensive inflation tests using high-accuracy transient data recorders to monitor the development of the dynamic pressure. In order to overcome the limitations of physical testing, a highly non-linear dynamic finite element model - based upon the application of the *MAT_FABRIC material model in LS-DYNA - is used. This technique allows the systematic examination of how changes in geometric parameters affect the performance of payload dispersion and membrane stress distribution. The results indicate unique ways of deploying depending on their geometry. The circular gas bags are capable of obtaining a velocity of the payload of 4.23 m/s but have high stress concentrations of up to 426 MPa due to the lack of geometric boundaries which make them prone to tearing failure. Rectangular gas bags with very large aspect ratios will experience a tubular expansion deformation that causes energy transfer efficiency to plummet; the release speed of these types of gas bags falls below 2.77 m/s. Ultimately, the optimal structural design is a regular hexagonal shape that optimally balances work performance and structural safety. It can keep good levels of energy transfer efficiency with a final release velocity of 4.12 m/s. Moreover, it successfully stops the continuous hoop tension and reduces the peak stress by around 46 percent through straight edge boundary constraints. This complete research offers an adequate scientific foundation to the anti-burst design of sophisticated polygonal gas bags.
Wang, Jinwei, Shi, Lv, Hou, Jingjing, Li, Yilong, Li, Dailin, Liu, Zhiyi
Trajectory Optimization for Non-Cooperative Target Spacecraft Based on Sequential Convex Programming2026-99-2330To be published on 10/30/2026
Autonomous operations near space targets that do not cooperate present great challenges because position and attitude planning must be linked. A target of this type lacks navigation aids or communication systems, which makes relative motion planning much more difficult. Although methods based on convex optimization work well for problems with three degrees of freedom, like planetary landing, their use in integrated operations with six degrees of freedom is limited by constraints that are not convex. To solve this problem, this paper proposes a new framework for servicing spacecraft using sequential convex programming. The primary contribution is the extension of convex methods to high dimensional trajectory planning while adding a robust trust region constraint based on trajectory deviation. This mechanism reduces the chance of finding no solution during convex approximations. It improves reliability and convergence when solving complex problems. The approach first creates a continuous optimal control problem with an index that balances energy use and the angle of the line of sight. Nonlinear dynamics are simplified using first order Taylor expansions. Constraints for the field of view and collision avoidance are modeled using spherical and ellipsoidal regions. The non convex problem is changed into a sequence of discrete convex subproblems and solved through iterations. Numerical simulations show that the servicing spacecraft can safely approach the target with stable attitude while meeting all physical limits. The method using sequential convex programming with a trust region demonstrates great potential in optimizing computational efficiency alongside strong numerical stability, laying a solid foundation for future real-time autonomous trajectory generation in complex orbital environments.
Wang, Yuzhi, Yao, Zihao, Wang, Qian, Han, Ziwen, Zhang, Chao, Zhang, Yumei, Li, Shunli
Optimization and Validation of a Lumbar Spine Model for Aviation Vertical Impact Simulation Based on THUMS2026-99-2371To be published on 10/30/2026
In assessing lumbar spine injuries of civil aircraft occupants under vertical impact, existing anthropomorphic test devices cannot accurately capture the injury mechanisms. Digital human body models, such as THUMS, are primarily developed for automotive crashes, and their default seated posture differs from that of real civil aircraft occupants. Although the THUMS model can be adjusted to better represent civil aircraft occupants’ seating posture, the mechanical response of the lumbar spine after adjustment has not been sufficiently validated. This limits the model’s reliable use in assessing lumbar spine injuries of civil aircraft occupants. To address this limitation, the THUMS lumbar spine model was modified to reflect aircraft seating posture and physiological lumbar lordosis, and the stiffness of key lumbar ligaments was systematically optimized. Following optimization, the model’s mechanical response curves under flexion, anterior shear, tension, and compression all fell within the post-mortem human subject (PMHS) response corridors, with deviations from the mean PMHS curves significantly reduced. Under the typical 14 g vertical impact specified by FAR 25.562, the optimized lumbar spine exhibited lower peak flexion moments at all lumbar levels, while the axial compressive load and predicted injury risk became more concentrated in the upper lumbar spine. These findings indicate that directly using the original THUMS model may underestimate injury risk in the upper lumbar region while overestimating it in the lower lumbar segments. Posture adjustment, lumbar curvature correction, and ligament stiffness optimization enhance model biofidelity, providing a more reliable basis for the assessment of occupant lumbar injuries.
Shi, Xiaopeng, Jiang, Zihao
Letter from the Guest Editors09-14-03-000810/26/2026
Letter from the Guest Editors
Mueller, Becky, Forman, Jason
Influence of Helmet Surface Protrusions on Youth Bicycle Helmet Impact Performance09-14-03-001910/26/2026
Youth bicycle helmet manufacturers often add shell protrusions to make helmets more attractive or fun for children, yet the safety implications of these features are not well understood. While prior work suggests protrusions may affect head impact kinematics, no study has evaluated their effectiveness in location-matched impacts between helmets with and without protrusions. Twelve youth bicycle helmet models, with protrusions intact and removed, underwent matched oblique impacts at three locations and 4.2 m/s to capture resulting peak linear acceleration (PLA) and peak rotational acceleration (PRA). A linear mixed model was used to quantify the effect of protrusion presence on PLA, PRA, and impact duration. The youth bicycle helmet models produced a wide range of kinematics. Protrusion presence had a strong effect on PLA, PRA, and impact duration. PLA averaged 103.0 ± 22.8 g for helmets with protrusions compared to 143.9 ± 21.4 g for helmets without protrusions, while PRA averaged 4432 ± 1570 rad/s2 for helmets with protrusions and 5177 ± 2110 rad/s2 for helmets without protrusions. These findings suggest that helmet protrusions can reduce peak head accelerations in youth bicycle helmet impacts.
Jung, Caitlyn, Stark, Nicole E.-P., Rowson, Steve
Failure Tolerance of Male and Female Lower Extremities under Pure Bending and Combined Loading Modes09-14-03-001410/26/2026
Lower extremity injuries remain common in frontal motor vehicle crashes, with evidence suggesting increased vulnerability among female occupants. While prior research has established failure tolerances of midsize male lower extremities under bending and combined loading conditions, limited data exist for small female specimens. This study aimed to characterize and compare the failure tolerance of small female and midsize male postmortem human subject lower leg specimens under combined axial compression and posterior–anterior (PA) bending using consistent boundary conditions. Twenty-four lower leg specimens, including the tibia, fibula, and surrounding soft tissue, were obtained from 50th percentile male (n = 12) and 5th percentile female (n = 12) donors. Dynamic tests to failure were conducted at 1.5 m/s using a test apparatus designed to apply three-point bending in the PA direction with varying levels of superimposed axial compression (0, 2, 4, and 6 kN). When paired left and right legs from the same donor were available, they were assigned to different loading conditions to assess the influence of axial compression magnitude. Fracture timing was determined using force, strain, acoustic emission data, high-speed video, and post-test CT imaging. Results indicated that 18 specimens fractured at the tibial shaft, 5 near the potting interface, and 1 did not fracture. Under pure bending, mean failure moments were 255 ± 57 Nm for males and 156 ± 15 Nm for females. At 6 kN axial compression, failure moments decreased to 195 Nm and 72 Nm for male and female specimens, respectively. Among matched pairs, increasing axial load resulted in an average 21% reduction in bending moment at failure. These findings demonstrate reduced failure tolerance with increasing axial compression and highlight sex-based differences. The data provide a foundation for developing improved injury risk functions and scaling methodologies for diverse occupant populations as well as informing anthropometric test devices and human body models.
Carbon, Maria, Nazari, Isabella, Edinger, Timothy, Shin, Jeesoo, Hanggi, Connor, Kerrigan, Jason, Forman, Jason
Preliminary Impact and Injury Response of Varied Anthropometry Postmortem Human Surrogates in Frontal Sled Tests09-14-03-000910/26/2026
Robust restraint system design requires effectiveness across varied anthropometries. Biofidelity reference datasets of postmortem human surrogates (PMHS), a necessary component of informing and assessing restraint system design, exist for the midsize males and small females, but there is limited research for other anthropometries such as the midsize female and obese populations. The goal of this study was to evaluate the kinematic and injury response of midsize female, elderly midsize female, obese female, and obese male PMHS in upright frontal impacts in a simplified restraint environment. The test condition in this study was a full-frontal 30 km/h impact. The test fixture consisted of a rigid seat, knee bolster, footpan, a custom 3 kN shoulder belt force limiter, and separate shoulder and lap belts. Twelve tests were performed with PMHS of varied anthropometries: three per occupant type (midsize female, elderly midsize female, obese female, and obese male). The restraint environment limited the movement of the lower extremities, isolating the thoracic response. Shoulder belt lengths and positioning varied by occupant type. Peak shoulder belt force values ranged between 2.8 and 4.4 kN. Differences in soft tissue distribution (including the hips, abdomen, and breasts) affected both the pre-test path of the shoulder belt on the thorax and the belt’s subsequent motion relative to the thorax during the test. Rib fractures were observed across all four occupant types ranging from 0 to 19 fractures. Occupant anthropometry affected the impact and injury response of the PMHS in this study, demonstrating the breadth of the population over which restraint system robustness is required.
Gallaher, Mary K., Donlon, John-Paul, Nazari, Isabella L., Mann, Logan M., Hollar, Reagan T., Sochor, Sara H., Noss, Junior R., Forman, Jason L.
Thoracic Biomechanical Responses of Small Female Postmortem Human Subjects in a Simplified Side-Impact Condition09-14-03-001010/26/2026
Biomechanical response targets for the thorax have largely focused on the 50th percentile male, limiting their relevance for smaller females. Previous studies have provided side-impact female postmortem human subjects (PMHS) data from either oversimplified or realistic boundary conditions. This study aimed to generate thoracic biomechanical responses of small female PMHS in a simplified side-impact condition with realistic components and compare responses between two input energy levels. Twelve small female PMHS were seated on a simplified seat with FMVSS No. 213a seat foam and fabric and impacted once on the left thorax with either a 14.0 kg (low energy) or 23.7 kg (high energy) pneumatic impactor at 4.5 m/s. A rectangular impactor face (22.9 × 25.4 cm) covered with FMVSS No. 213a armrest foam simulated an intruding door panel. Thoracic deflection was measured using a chestband. Inertially compensated force was recorded via a load cell. Spinal kinematics were captured using six-degree-of-freedom motion blocks. Biomechanical responses were compared between groups using two-sample t-tests. The high-energy group exhibited significantly higher peak forces (2.5 vs. 1.9 kN, p = 0.0001), greater thoracic deflections (41.0 vs. 33.9 mm, p = 0.016), and increased deformation energy (91.6 vs. 61.0 J, p = 0.0001). Effective stiffness did not differ significantly between groups (p = 0.734). Energy loss increased with impact severity (66.2 vs. 56.7%, p = 0.020). Kinematic responses also increased with increased input energy. Peak y-accelerations were significantly greater at T4 in the high-energy group (p = 0.049). The sternum exhibited significantly greater peak z-angular velocity in the high-energy group (p = 0.038). Mean BioRank System Score (BRSS) of the force–deflection corridors between groups was 0.93. In summary, these findings provide essential biomechanical data and establish an important foundation for developing improved testing conditions and advancing the evaluation of female human body models (HBMs) and anthropomorphic test devices (ATDs) in side-impact scenarios.
Anantharamakrishnan, Srinivas, Kemper, Andrew, Baker, Gretchen H., Guettler, Allison J., Rhule, Heather, Kang, Yun-Seok, Agnew, Amanda M.
Sex and Age Effects on Tibia Biomechanical Properties in Dynamic Four-Point Bending09-14-03-001510/26/2026
Globally, approximately 11 million pedestrian impacts each year result in injury or death. The lower extremity is the most frequently injured body region in pedestrian impacts, and these injuries often lead to long-term disability. To better understand lower-extremity injury risk, biomechanical testing of the leg and tibia has previously been conducted. However, this work has mainly focused on males, despite females having a higher risk of sustaining lower-extremity injuries in these loading events. This study aimed to evaluate the effects of sex and age on biomechanical properties of the isolated human tibia in a diverse sample. Sixty-six tibiae from 35 females and 31 males with similar age distributions (p > 0.05; females = 68.8 ± 3.4 years; males = 59.8 ± 4.0 years) were utilized. Tibial diaphyses were loaded to failure at 6 m/s in lateral–medial four-point bending to replicate vehicle bumper interaction in pedestrian impacts. Reaction forces were measured at each end of the bone. Proximal and distal moments were calculated as the product of reaction force and the distance from the axis of rotation to the nearest impact site. Peak bending moment at midshaft was further calculated as the maximum of the average proximal and distal moments. Strain at time of fracture was determined from axial strain gages on the lateral and medial bone surface between impactor locations. Maximum deflection was normalized by specimen length and area moment of inertia. Males exhibited significantly greater peak moments than females (p = 0.001). In the full sample, age demonstrated a weak but significant negative relationship with peak moment (p = 0.013, R2 = 9.3%); however, no significant age relationship was observed when males or females were analyzed separately. Male tibiae had a significantly greater deflection than female tibiae (p = 0.001), but no significant sex difference was observed with normalized deflection. Age was strongly and negatively associated with deflection in the full sample (p < 0.0001, R2 = 39.7%), and for males (p < 0.0001, R2 = 44.8%) and females (p < 0.0001, R2 = 25.4%) separately. No significant sex differences were observed for tensile strain at fracture. However, age had a significant negative relationship with tensile strain in the full sample and within each sex (p < 0.0001). Further investigation with larger sample sizes is needed to characterize the interacting effects of sex, age, and size. Overall, this work advances understanding of tibial biomechanics and provides insight for improving pedestrian safety tools including anthropomorphic test devices and human body models.
Spangler, Jonathon, Agnew, Amanda, Kang, Yun-Seok, Kemper, Andrew, Hunter, Randee, Baker, Gretchen, Guettler, Allison, Harden, Angela
Vehicle Front-End Architecture as a Driving Factor in Occupant Injury Risk during Vehicle-Guardrail Impacts: A Hybrid III Dummy-Based Numerical Study09-14-03-001110/26/2026
The performance of Midwest Guardrail Systems (MGS) during impact with electric vehicles (EVs) has raised concerns with recent observations demonstrating a higher susceptibility to rail failures. These failures are hypothesized to be related to EV-specific design, including variations in front-end geometry and inertial properties. Current guardrail evaluations rely on two vehicle types, a small car and a pickup truck, potentially overlooking sensitivity to front-end geometry variations, potentially leading to unanticipated impact responses. Additionally, the extent to which geometry influences occupant injury risks and trends during vehicle-guardrail impact remains insufficiently investigated. The objective of this study is to quantify the influence of vehicle front-end geometry on occupant injury risk during vehicle-guardrail impacts using finite element (FE) simulations. Occupant injury risk is analyzed using Hybrid III anthropomorphic test device (ATD)-based injury criteria and flail space-based vehicle severity metrics to identify trends and relationship between geometric variations and injury probability. Front-end geometry data from the Insurance Institute of Highway Safety (IIHS) were analyzed to identify parameters and ranges associated with adverse MGS performance. Based on vehicle alignment with the W-beam, hood leading-edge height, hood leading-edge angle, and bumper height were morphed on the Toyota Yaris model. A Latin Hypercube Design of Experiments generated 13 unique configurations for detailed analysis. Full-scale Manual for Assessing Safety Hardware (MASH) Test Level 3 FE simulations were then performed between the morphed vehicle models integrated with Hybrid III 50th percentile male ATD and MGS guardrail. Occupant injury metrics were evaluated alongside vehicle-based crash severity measures. All vehicle geometries fulfilled MASH criteria with occupant impact velocity (OIV) and occupant ride down acceleration (ORA) within tolerance with no rail rupture. Simulations suggest that probability of serious full-body injury (AIS3+) was estimated at 17.11% while probability of severe neck injury was the highest at 15.64% among the component level probabilities. While front-end geometry influences occupant kinematics, resulting injury metrics and vehicle-guardrail interaction characteristics, it does not independently govern occupant injury risk. Although, the MASH tests have the same outcome as the geometries studied, the changes in EV inertial properties could interact with the geometry leading to barrier failure, which will be explored in future work.
Bubna, Maheep, Buckland, Elijah, Riexinger, Luke E., Untaroiu, Costin
Performance of WC19 Wheelchairs in Static Aircraft Seating Tests09-15-01-000110/23/2026
The guiding hypothesis for this project is that wheelchairs compliant with RESNA WC19 voluntary standards for vehicle crashworthiness could meet aircraft seating crashworthiness standards specified by the FAA. This article documents methods and results of static testing. Companion efforts for dynamic horizontal and vertical dynamic testing are reported elsewhere [1]. Surrogate 4-point-strap tiedowns secured the wheelchairs in all tests, using the geometry specified for WC19 testing. Nine different commercial wheelchairs, representing a range of designs, were tested using adapted versions of FAA procedures for static loading in five directions. Occupant restraint conditions included both a wheelchair-anchored lap belt and a floor-mounted lap belt. Tested wheelchairs met static requirements for integrity and deformation, despite multiple tests conducted on the same wheelchair. These results support future use of personal wheelchairs as seating on aircraft, provided the wheelchairs meet WC19 requirements. Additionally, the wheelchairs must be secured with 4-point-strap tiedowns, and occupants should be restrained using both a wheelchair-mounted belt and a supplemental lap belt anchored to the aircraft.
Orton, Nichole R., Manary, Miriam A., Vallier, Tyler, Boyle, Kyle J., Klinich, Kathleen D.
Research on Satellite Constellation Selection Method for GEO Multi-Satellite Relay Systems2026-99-295010/19/2026
Geostationary Earth Orbit (GEO) satellites, as a crucial infrastructure for global communication and emergency support systems, are highly valued due to their wide coverage, long communication distances, and large transmission capacity. However, the scarcity of orbital slots and the difficulty in quickly identifying available satellites in actual user scenarios have become the main bottlenecks restricting the communication efficiency of multi-satellite relay systems in geostationary orbit. To address these issues, this paper proposes an accurate and efficient method for selecting the set of available satellites for multi-satellite relay applications. We construct a spatial coverage model based on the H3 hierarchical discrete global grid system and a geometric model that characterizes the visible orbital arc of the user station. By comprehensively considering the geographic locations of gateway stations and user stations, satellite beam coverage boundaries, and the visibility constraints imposed by user terminal antenna pointing, the proposed method can accurately screen out qualified satellite sets that satisfy the end-to-end link condition of “gateway–satellite–user station”. Simulation experiments are conducted in the Ku-band to validate the effectiveness of the proposed scheme, with performance metrics including coverage probability, accessible satellite quantity distribution, and selection efficiency evaluated. The results show that the H3-based modeling approach effectively reduces computational complexity while ensuring high accuracy in visibility judgment. The proposed method significantly improves the accuracy and efficiency of satellite selection, and supports dynamic updates in mobile user scenarios. This work presents a reliable satellite selection algorithm, which can be used to support efficient resource scheduling and provide a strong guarantee for GEO multi-satellite relay communication.
Yu, Xinyue, Jiang, Yanzi, Lu, Yi, Hou, Yucheng, Su, Xingyu, He, Wenxi, Zhang, Jie
Multilevel Bayesian Model Updating for Satellite High-Stability Brackets Considering Welding Uncertainties2026-99-292510/19/2026
The high-stability bracket is the primary component in remote sensing satellites responsible for carrying the camera and attitude control equipment; its dynamic behavior directly affects imaging quality and in-orbit service life. Welding-based connections introduce uncertainties during manufacturing and assembly, leading to significant discrepancies between finite element analysis results and experimental data. To quantitatively assess the impact of welding processes on the accuracy of the high-stability bracket’s finite element model(FEM), this study proposes a Bayesian parameter correction method based on Markov Chain Monte Carlo (MCMC) sampling and the Metropolis-Hastings (MH) algorithm. It employs a multilevel correction experimental framework—”material-level, component-level, and system-level”—to progressively refine material parameters and establish a high-fidelity FEM. First, the elastic modulus of the welded and non-welded regions were calculated using stress-strain curves obtained from static tensile tests on welded and non-welded plates; then, targeting the first two natural frequencies from dynamic impact tests on bar specimens, the material densities of the welded and non-welded regions were corrected using the Bayesian method; finally, the effectiveness of the correction method was verified through free vibration tests on the actual high-stability bracket. The results indicate that, compared to the undamaged region, the welded region exhibits a 13.87% loss in elastic modulus and a 55.32% loss in density. The relative errors in the first three natural frequencies of the corrected model were 0.59%, 0.01%, and 0.83%, respectively, verifying the high reliability of the proposed method in modal identification and providing a new technical approach for correcting spacecraft structural models.
Liu, Kun, Guo, Chongchong, Wu, Wenhua
Simulation of Liquefied Petroleum Gas Truck Accidents during Heatwave Periods Using the Areal Locations of Hazardous Atmospheres Program2026-01-507910/1/2026
In this study, the effects of heatwaves (HWs) on liquefied petroleum gas (LPG) leaks were analyzed using the Areal Locations of Hazardous Atmospheres (ALOHA) program. For this purpose, data from an accident at a gas station in the Eryaman District of Ankara in January 2024 were utilized. Approximately 40 m3 of LPG was released during the incident, but no explosion occurred. The accident was simulated using atmospheric data from the accident date in the ALOHA program. In the simulations, emissions of propane and butane—the primary components of LPG—were modeled separately. To simulate the LPG leak during a HW, a HW was first defined based on daily maximum temperature data. The threshold was set at the 90th percentile, and temperatures persisting for three or more consecutive days were classified as a HW. Using this definition, a four-day HW in Ankara in July 2024 was identified. The atmospheric conditions during this HW were input into the ALOHA program for simulation. The study compared the simulation results of the LPG leak in January with those during the HW period. The findings showed that the sub-explosion areas for propane and butane during the HW were 2% (95% CI: 0.91–1.15, p > 0.05) and 9% (95% CI: 0.84–1.42, p < 0.05) larger, respectively, than those during the accident in January. As a result, the study highlights the need for stricter safety measures during summer months when transporting explosive materials.
Öztürk, Yunus
Ai-Powered Safety Intelligence as a Decision Enabler for Ground Vehicle MBSE: The Digital Safety Twin Approach2026-01-75329/22/2026
Model-Based Systems Engineering (MBSE) has become a mandated practice for Department of Defense acquisition programs, yet measured benefits remain elusive. The 2024 Defense Science Board found that less than one percent of published literature actually quantified MBSE outcomes, and flagship ground vehicle programs such as the XM30 Infantry Fighting Vehicle have experienced schedule delays attributed directly to insufficient proficiency with model-based approaches. This paper presents the Digital Safety Twin concept: an AI-powered safety intelligence architecture that addresses three of the most labor-intensive and error-prone MBSE workflows. First, the architecture uses hybrid natural language processing and large language model (NLP/LLM) pipelines to auto-formalize unstructured natural language documents into formally structured, traceable requirements. Second, it auto-generates and continuously maintains traceability relationships across requirements, design elements, hazard analyses, and verification artifacts. Third, it provides continuous safety case completeness and confidence assessment through automated Goal Structuring Notation (GSN) synthesis connected to live evidence sources. The approach is grounded in Systems-Theoretic Process Analysis (STPA), the OMG Risk Analysis and Assessment Modeling Language (RAAML), MIL-STD-882E system safety practice, and the UL 4600 safety case framework. We present the methodology, its alignment to the DoD Digital Engineering Strategy, and its applicability to ground vehicle autonomy programs including next-generation infantry fighting vehicles and robotic combat vehicles. We also discuss the limitations, risks, and cultural barriers that must be addressed for AI-augmented safety engineering to achieve acceptance in mission-critical defense applications.
Wagner, Michael, Santini, Nelson, Balakrishnan, Anoop
Global–Regional Energy Balance Climate Modeling Framework for Country-Level Temperature Projections Based on CO₂ Radiative Forcing2026-24-00219/21/2026
This study presents a computational framework for estimating country-level temperature projections based on global radiative forcing from CO₂ emissions. The methodology integrates a carbon-cycle accumulation module, a logarithmic radiative forcing formulation, and a dynamic one-box energy balance model (EBM) to simulate global mean temperature evolution. Atmospheric CO₂ concentration is computed from cumulative global emissions using an airborne fraction parameter. Radiative forcing is then determined using the established logarithmic relationship between concentration and forcing. The global temperature response is calculated dynamically by solving the transient energy balance equation, incorporating effective heat capacity and climate sensitivity parameters. To regionalize projections without relying on high-resolution General Circulation Models (GCMs), an empirical regional amplification factor is introduced. This coefficient is derived from historical regression between observed regional and global temperature anomalies. The resulting formulation enables country-level temperature estimation as a scaled response to global mean warming while preserving physical consistency with radiative forcing theory. The framework is computationally efficient and suitable for implementation in lightweight numerical platforms, enabling rapid scenario testing of emission pathways. Although the model does not resolve atmospheric circulation, precipitation changes, or nonlinear feedback variability at regional scales, it provides a transparent and physically grounded approach for comparative warming assessments across countries. The proposed methodology establishes a structured link between global climate energetics and regional temperature response, supporting engineering-oriented climate risk analysis and emission policy sensitivity evaluation.
Gutierrez, Marcos, Taco, Diana, Sampietro-Saquicela, Jose, Bermudez-Herrera, Leandro, Valencia-Ortiz, Nakira, Ulloa de Souza, Raul
A Multi-Body Dynamic Analysis of Click Noise Generated in Rear Brake Caliper2026-01-08159/14/2026
As customer awareness of brake-related NVH (Noise, Vibration and Harshness) continues to increase across the automotive industry, noise originating from braking systems is increasingly regarded as important indicator of vehicle quality. Among these issues, intermittent click noise from rear brake caliper is commonly noticed during low-speed driving and initial brake application and is frequently associated with customer dissatisfaction. In the automotive industry, this noise has primarily been addressed through empirical design modifications and component-level testing. However, due to its low reproducibility and impulsive response characteristics, making quantitative prediction and root-cause identification during the design phase difficult. While most previous brake NVH research has mainly focused on continuous vibration phenomena such as squeal and groan, fewer studies have examined single-event impact noise related to pad-to-carrier clearances, contact transitions, and frictional nonlinearity from a simulation-based perspective. In this study, rear brake caliper click noise is defined as a dynamic phenomenon inherent to conventional caliper mechanical architecture. A Multi-Body-Dynamic model was developed using RecurDyn to reproduce the observed behavior incorporating pad-to-carrier clearance, friction characteristics, and component compliance. Brake dynamometer testing was conducted to measure acceleration and noise response, and correlation with simulation results was performed. Simulation and tests were carried out using a caliper geometry whose improvement effectiveness had been confirmed in prior applications, demonstrating that the applied approach can qualitatively and reproduce the occurrence tendencies and key characteristics of rear caliper click noise. The simulation-test integrated approach is applicable to early-stage NVH risk assessment and to the validation of countermeasures for click noise in production vehicles. Future work will focus on improving analytical modeling and prediction of click noise through development of a new model incorporating key design parameters.
Choi, Hyeontae, Kim, Sangbum, Park, Ilho, Kim, Taeuk, Kwon, Yongsik, Yang, Soonhong, Ma, Jaehyeon, Kim, Jinwook
Evaluation Method for Driving Safety on Highway Successive Curves2026-99-15689/11/2026
To evaluate the driving safety performance of continuous curves, this study developed a safety assessment model using a human-computer interaction simulation platform. First, three indicators are selected, including the driver’s heart rate variability, the rate of change in steering wheel angle, and trajectory lateral deviation, which together form a driving safety evaluation indicator system. Secondly, through significance testing and range analysis. Through analysis, four key curve-related elements are identified as having a notable influence on the overall evaluation indicators. A global optimization algorithm using multivariate nonlinear regression is then applied to establish the driving safety model. Finally, taking a dual four-lane highway in Sichuan province as an example, the safety of the successive curve in the project is evaluated. Empirical results show that when the intermediate straight line section H ≤ 4.23, driving is hazardous; 4.23 < H ≤ 4.46, driving is relatively hazardous; 4.46 < H ≤ 4.78, driving is relatively safe; H > 4.78, driving is safe. For oval-shaped curve segments, when H ≤ 4.53, driving is hazardous; 4.53 < H ≤ 5.32, driving is relatively hazardous; 5.32 < H ≤ 5.86, driving is relatively safe; H > 5.86, driving is safe. Through this method, the driving safety of successive curves can be effectively evaluated, particularly with a focus on driver comfort and safety. This provides valuable references for assessing driving risks associated with different combinations of curve elements.
Huang, Yongheng, Zhang, Ruizheng, Sun, Chao, Zeng, Xinjie, Zheng, Liwen
Study on Low-Velocity Impact Damage of Glass Fiber Reinforced Composite Pipeline2026-99-14169/11/2026
Through low-velocity impact testing, the effects of punch shape (conical, hemispherical, and cylindrical) and impact energy (5, 10, and 15 J) on damage characteristics in glass fiber composite pipes were investigated. Ultrasonic A-scan inspection was employed to detect internal delamination damage at the impact points within the composite pipes. Test results indicate that the contact area between the punch and the pipe is a key factor influencing the severity of pipe damage. A smaller contact area results in a higher energy absorption rate, greater punch displacement, larger area under the load-displacement curve, and longer contact time, leading to more severe damage characteristics. When the conical punch delivered 15 J of impact energy, the energy absorption rate of the glass fiber composite pipe reached 91.6%, exhibiting multiple damage characteristics, including pitting, penetration, and cross-shaped cracks. As impact energy increases, the area of internal delamination damage caused by the three punch shapes exhibits near-linear growth. The conical punch induces severe damage characteristics in the thickness direction but results in the smallest delamination area. Blunt-shaped punches (hemispherical and cylindrical) disperse impact energy over a wider region, leading to increased delamination damage area.
Wang, Xuan, Cao, Yanzhen
Safety Assessment Model for Airborne Time-Sensitive Networking Based on Analytic Hierarchy Process2026-99-14149/11/2026
With the growing demand for high real-time performance and high reliability in airborne networks, Time-Sensitive Networking (TSN) has been widely adopted as a core technical basis for deterministic Ethernet for next-generation avionics systems. This paper proposes an AHP-based safety assessment model for airborne TSN, introducing a hybrid evaluation strategy that integrates both subjective and objective factors. By constructing a comprehensive evaluation index system, the model quantifies the weights of traffic attributes—including time sensitivity, priority level, and bandwidth guarantee requirements—and combines them with the degree centrality of network nodes to achieve a holistic assessment of TSN safety. The proposed model not only provides theoretical support for the safety-oriented design optimization of avionics systems but also offers practical guidance for the airworthiness verification of airborne networks. Feasibility and effectiveness are verified by applying the proposed method to a representative case scenario. Moreover, the model’s scalability supports its application in more complex network environments, meeting the broader assessment needs of airborne TSN safety.
Wang, Penghui, Mei, Yanan, Fu, Jinhua
Ultrasonic Frequency-Domain Reverse-Time Migration Imaging Incorporating Element Directivity Correction2026-99-14199/11/2026
The finite width of ultrasonic array elements results in a non-uniform angular radiation pattern of elastic waves in solids, deviating from the ideal point-source assumption commonly adopted in reverse-time migration (RTM). This angular radiation non-uniformity produces a crack tip-dominated imaging amplitude with weak crack flank representation, manifesting as a pronounced depth-dependent amplitude imbalance along vertically oriented defects. As a result, cracks may be misinterpreted as point reflectors, which compromises the reliability of characterization in ultrasonic nondestructive testing (NDT). This study proposes an ultrasonic frequency-domain reverse-time migration (FDRTM) imaging method incorporating element directivity correction. A longitudinal-wave directivity model in solids is formulated in the frequency domain and normalized at each frequency to ensure consistent scaling during multi-frequency stacking. During backward wavefield reconstruction using full matrix capture (FMC) data, the angular-dependent energy distribution associated with the receiving direction is explicitly corrected, rebalancing the angular energy distribution in the reconstructed wavefield. Defect imaging is then performed using a frequency-domain cross-correlation imaging condition, followed by stacking over frequency and normalization. Validation experiments were conducted on an artificially manufactured vertical crack in a 7075 aluminum alloy specimen. The results indicate that, relative to conventional RTM, the proposed method reduces crack tip dominance and enhances the relative visibility and continuity of crack flanks. Compared with conventional RTM, the peak imaging amplitude increases by 22.44%, and the amplitude at a depth of 6.8 mm is enhanced by 24.39%. In addition, the proposed method outperforms the total focusing method (TFM) in crack profile continuity and the relative visibility of crack flanks. The results confirm that incorporating element directivity correction into frequency-domain RTM mitigates depth-dependent amplitude imbalance and restores crack flank visibility, thereby improving the reliability of crack defect characterization in ultrasonic NDT.
Chen, Si, Zhang, Yifeng, Ma, Tengfei, Xu, Zheng, Jiang, Jiansheng, Gao, Jiaqi
A Three-Dimensional Safety Domain Method for LNG Vessels in Ports Based on Human Factors and Speed Characteristics2026-99-15239/11/2026
To accurately assess the navigation safety status of LNG vessels in port waters and balance safety control with waterway capacity efficiency, this study constructs a 3D dynamic safety domain model for port LNG vessels, integrating human–ship–environment multi-factors. The model introduces the Weibull function to quantify the impact of drivers’ knowledge, skills, and physiological-psychological states on safety boundaries, combines a ship motion mathematical model to establish a 2D safety domain boundary equation, and incorporates hull subsidence to build a vertical dimension, forming a complete 3D model. Longitudinally, the safety distance is calculated using the car-following braking theory, while laterally, boundaries are determined by controlling the ratio of inter-vessel interference force to navigation resistance. Through static scenario analysis and dynamic simulation verification, results show that the safety domain scale is dominated by ship speed and environmental conditions, and its shape tends to shrink as the driver’s state improves, making it more suitable for actual port scenarios than traditional models. Verified with a specific LNG hub port as a case, the safety distance calculated by the model is significantly reduced compared with current specifications, while the delay impact rate and average delay time on other vessels are decreased. The research results establish a quantifiable framework for dynamic safety assessment, providing maritime administrations and on-board pilots with a scientifically-grounded tool to determine real-time safe navigation boundaries in complex port environments, balancing safety control with operational efficiency.
Wang, Yangang, Jia, Changsheng, Zhu, Jinshan
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
Stress-Strain Response Characteristics of Buried Gas Pipelines Under Landslide Action2026-99-12759/4/2026
Typically, triggered by geological hazards such as landslides, ground displacement acts as the main cause for the failure of buried pipelines. To maintain the structural integrity of these pipelines, an in-depth investigation is required to understand how these pipelines, subjected to landslide thrust, respond mechanically. During the research, a refined three-dimensional (3D) finite element model for soil-pipeline interaction was established, as evidenced by existing experimental data, which takes the elastoplastic behavior of the soil and complex contact conditions into consideration. According to a thorough parametric study, on the basis of the model, the effects of pipeline, landslide, and soil vary in their protection, detrimental, and complex trade-off levels. On the one hand, protective measures concerning wall thickness, steel grade, and other similar factors serve to improve resilience; on the other hand, detrimental factors such as burial depth and soil stiffness escalate the possibility of failure risk. Notably, the influences related to landslide extent and pipe diameter are not straightforward and monotonic. In other words, when one factor increases, risk may be reduced in one regime and amplified in another. Therefore, words like “wider” or “bigger” should not be equal to “safer” by default. To conclude, based on the results, train-based evaluation is supported, and some practical guidance can be provided for the design and risk assessment for pipelines in areas where geohazards may occur.
Zhang, Ruijia, Dong, Shaocan, Wang, Xinyu, Li, Yuxing, Hu, Qihui, Wang, Wuchang
Validation Study of the Jaguar Land Rover Aerodynamic Computational Fluid Dynamics Process Using Metric-Based Assessment Criteria2026-01-50729/3/2026
Credibility of simulation data has always been fundamental in aerodynamic vehicle development, as a significant amount of early design phase work is conducted virtually before a physical test property is made. As the automotive industry pivots toward artificial intelligence and machine learning techniques to assist in aerodynamic development, training these models with simulation data requires a comprehensive understanding of the accuracy and validity of the underlying simulation. It is critical these systems are trained from reliable data with a full understanding of both the limitations and predictive performance of the computational fluid dynamics (CFD) process and the wind tunnel facility it is benchmarked against. Validation and verification studies have been a long-established set of guidelines to determine if the simulation model appropriately reflects reality (validation) or if it has been set with robust numerical schemes, mesh settings, or boundary conditions (verification). The work presented here shows a comprehensive validation study with more than 400 test configurations and 18 vehicle properties. It evaluates Reynolds-averaged Navier–Stokes (RANS) and detached eddy simulation (DES) approaches using moving reference frame (MRF) and rigid body motion (RBM) to account for wheel rotation and comparing STAR-CCM+ CFD process and the FKFS Aeroacoustic Wind Tunnel (AAWT). The results demonstrate that DES—particularly when wheel rotation is modeled using RBM—provides the highest overall predictive performance, with a drag accuracy from −2% to +4% for 80% of cases with corrections applied, which gets to ±2% for over 95% cases with an additional calibration step. A metric-based assessment criterion that combines key performance metrics into a single detection event (DE) score derived from failure mode effects analysis (FMEA) principles is proposed with an example shown for the 2021 Range Rover Velar. The benefit being that it removes a more judgement-based, qualitative approach, aiding toolset selection and methods development gaps.
Beves, Christopher, Simmonds, Nicholas, Dalmau Graells, Eric
Better safety through collaboration at Toyota research center26AUTP09_079/1/2026
The gathered journalists cover their ears as a loud hydraulic ram begins to load and a warning alarm sounds. Less than a minute later… FOOSH… BAM! A 9.9-pound model of a human head is launched into the front-end structure of a test vehicle, deforming the hood and sending the head bouncing to the ground. The violence of the moment, which is part of pedestrian safety research, is a stark reminder of the seriousness of all the testing that happens at Toyota's North American Research and Development Headquarters in York Township, Michigan. The $187-million (in 2007 dollars) facility includes 180,000 sq.ft. of research and testing space.
Clonts, Chris
Research and Practice of Emergency Rescue Unmanned Patrol Flying Equipment2026-99-03378/14/2026
To enhance China’s disaster and accident emergency response capabilities and strengthen the digital battlefield system for emergency rescue, an integrated multi-payload unmanned aerial surveillance and communication support system has been developed for extreme weather conditions and ‘triple-disconnection’ disaster scenarios. This paper sets out to address the limitations of traditional emergency drones, including poor environmental adaptability, weak payload capacity, and operational inconvenience. The system’s resistance to wind and rain has been significantly enhanced through the optimization of its airframe design. The innovative design incorporates dual-station symmetric conjugate antennas with planar blind-spot coverage systems, integrating public and self-organizing network base stations to achieve three-dimensional signal coverage and heterogeneous network integration. This enhances ground cellular network resilience. Multi-functional reconnaissance payloads are integrated and compatible with day/night and smoke/rain scenarios, thus overcoming the limitations of single-source visual information perception. The system employs zero-length deployment and parachute recovery methods, thereby facilitating rapid deployment and terrain-independent take-off and landing capabilities. The simulation results obtained demonstrate excellent aerodynamic performance, thus permitting safe operation in wind conditions up to Force 8. The antenna system under discussion is innovative in nature and has been developed to achieve 360° three-dimensional signal coverage. The primary function of this system is to ensure sustained communication link integrity. The field trials further corroborate the aircraft’s stable low-altitude cruising capability in Force 8 winds, thereby averting congestion in constrained rescue airspace. The dual-base station design, incorporating symmetric conjugate antennas and blind-spot compensation antennas, has been demonstrated to reliably restore public ground network signals within a 6.7-kilometre radius. The development of this unmanned aerial patrol system addresses a significant gap in low-altitude rescue capabilities for intelligent unmanned equipment in harsh environments. It underpins the integrated emergency command and operations system for intelligence, command, and execution, as well as the integrated emergency communication support system spanning the air, land, and sea domains. This advancement has been demonstrated to enhance disaster response efficiency and auxiliary decision-making effectiveness under extreme conditions.
Bian, Lu, Fang, Yudong, Yang, Jixing, Zhang, Chen, Hu, Bin, Zhang, Mingyue
Numerical Simulation Study on Fire Prevention in Aero-Engine Fuel Tube2026-99-03038/14/2026
Transient gas-liquid two-phase flow in aero-engine fuel pipelines was examined using numerical simulations, focusing on the influence of flow rate on phase change behavior. Under low-flow conditions, phase change occurred repeatedly near the pipe wall, where vapor layers formed and collapsed in an intermittent manner. These processes introduced noticeable unsteadiness in the local mass flow and pressure fields. When the flow rate was increased, vapor generation was largely confined to a narrow region adjacent to the wall, and the overall flow exhibited a more stable character. The results suggest that flow-rate-dependent phase change plays an important role in determining the stability of fuel transport and should be considered in the fire safety assessment of aircraft fuel systems.
Wu, Bin, Xin, Bo, Zeng, Tai, Su, Zhengliang
Structural Design and Mechanical Performance Analysis of Key Components of Deicing Robots for Transmission Lines2026-99-03468/14/2026
Extreme winter weather often leads to ice accretion on transmission lines. Manual removal is inefficient, costly, and poses safety risks. To address this issue, this paper presents the design of a de-icing robot to replace manual operations for transmission line de-icing. The main content focuses on the detailed structural design of the robot, including the mobile platform, de-icing mechanism, and adaptive adjustment module. Finite element simulations are conducted on key components to verify the structural rationality and the correctness of material selection. The proposed de-icing robot enhances the safety of the de-icing process, improves operational efficiency, and provides a valuable reference for transmission line de-icing methods, demonstrating significant practical value.
Chang, Hao, Zhen, Chen, Han, Fengmei, Li, Cheng
Pelvis Lap Belt Engagement of Small-Sized Females in Frontal Impacts Using Seat-Integrated Restraints and Vehicle Seats for Alternative Seating Positions2026-22-00088/14/2026
Non-traditional vehicle seating postures challenge traditional occupant protection paradigms that promote pelvis lap belt engagement. Seat-integrated restraints may promote pelvis lap belt engagement in alternative seating postures but have not been evaluated with post-mortem human subjects (PMHS) in vehicle seats. The goal of this research was to perform three 38.8 g, 56 km/h frontal impact sled tests with small-sized female PMHS in a crash environment with a vehicle seat designed for alternative seating positions. PMHS pelvis kinematics, lap belt engagement, and submarining response were compared to that of the Hybrid III 5th female (HIII-5F) in the same environment. The seat was in the rearmost seat track position, reclined 40° from vertical, and incorporated a leg rest, which elevated the feet off the floor. A seat cushion airbag (SCAB), large passenger airbag (PAB), shoulder belt pretensioner (SB P/T), and seat-integrated belt (BIS) were incorporated into the testing environment. The SCAB restricted initial downward translation of the pelvis and induced 7.7°–11.8°of initial pelvis rearward rotation. Lap belt loading of the abdominal soft tissue occurred in each test via three distinct interactions: (1) initial pelvis lap belt engagement followed by pelvis fracture and subsequent submarining; (2) lack of initial pelvis engagement and direct abdominal loading; (3) initial pelvis lap belt engagement followed by submarining. In a matched test environment, the HIII-5F did not submarine nor reproduce the entire lap belt pelvis interactions observed by the PMHS. Future research must develop better tools for predicting lap belt engagement in alternative seating positions.
Newman, Rachel, Shin, Jeesoo, Sochor, Sara, Morgan, Neal R., Gepner, Bronislaw D., Kerrigan, Jason R., Kim, Yongtae, Kim, Sung Rae
Analysis of Critical Issues in the Assembly and Deployment Techniques of Unmanned Aerial Vehicles2026-99-09068/7/2026
With the complexity of chemical warfare threats and the diversification of battlefield environments, traditional toxic agent detection methods are facing bottlenecks such as response delays, coverage blind spots, and personnel safety risks. This research focuses on the application of unmanned aerial vehicle (UAV) carried toxic agent sensor systems, aiming to analyze the methods of mounting and deploying the sensors on the UAVs, and to construct a rapid response, high-precision, and highly resistant toxic agent monitoring system. Its significance lies in two aspects: 1. Tactical value: It breaks through the time and space limitations of manual reconnaissance, realizes real-time dynamic perception and early warning of toxic agent contamination, and provides key decision-making support for battlefield command; 2. Application expansion: The research results can be transferred to counter-terrorism, nuclear, biological, and chemical emergency response fields, providing theoretical support and engineering paradigms for the development of unmanned and intelligent chemical defense equipment.
Liang, Ting, Wen, Hao, Qi, Yelin, Yan, Rui, Ma, Tengbo, Yang, Wen
Accelerometer Mass Compensation on Frequency Response Functions in Impact Testing Based on the Substructure Method2026-99-09118/7/2026
Impact testing utilizing instrumented hammers and accelerometers is a widely adopted technique in dynamic testing. The mass loading effect of the accelerometer alters the dynamic response of the test structure, leading to deviations between the measured frequency response functions (FRFs) and their true values. Furthermore, the effects on the FRFs are contingent upon the positioning of the accelerometer, thereby causing the measured FRFs between two points to fail to meet the principle of reciprocity. This paper investigates the compensation method for the mass of a single accelerometer in impact testing. Compensation formulas for both origin–FRF and cross–FRF are derived using the frequency domain substructure decoupling method. Numerical simulations on a cantilever beam and experimental tests with milling tools validate the proposed methodology. The compensation formulas for FRFs presented in this paper are expected to enhance the measurement accuracy of FRFs in modal testing of small structures, particularly relevant for lightweight components in aerospace, aircraft, and transportation systems, where precise dynamic characterization is critical.
Tang, Zhenrong, Yao, Zhenqiang
Study on Penetration Damage Characteristics of Honeycomb Non-pneumatic Safety Tiree2026-99-01677/31/2026
To improve the mobility and reliability of special-purpose vehicles that are operated in extreme conditions and to minimize the influence of tire failure on the vehicle’s mobility, this paper investigates how the mechanical properties of honeycomb non-pneumatic tires are affected after high-speed impacts from external projectiles. A prototype of a network non-pneumatic honeycomb tire was initially developed, which was made of polyurethane material. The five parameter model of the Mooney-Rivlin model was selected as its constitutive relation and the experimental study was performed to validate three-dimensional stiffness simulation model for the tire. Secondly, a LS-DYNA-based finite element model was developed to describe the dynamic behaviors of the tire under an external impact at various locations (e.g. tread, single spoke plate and joints), and to investigate the influence of local damage and spoke plate fracture on the stiffness of the tire. The results indicate that the tire has better performance of resisting the impacts at small and medium levels, with the decrease of radial stiffness of the tire less than 4% after experiencing the ultrahigh load; after the spokes plate is broken, the radial stiffness of tire drops significantly by comparing with the intact tire, that is 24.17%, which has a great effect on the support performance of the tire. The findings of this work offer theoretical support and design guidelines for the structural optimization and properties improvement of NPTS.
Yao, Tuzao, Sun, Xiaowang, Zhang, Qiang, Fu, Lei, Huang, Jianbin
Microstructure and Property Evolution of T91 Steel under Deep Peak-Shaving Service Conditions2026-99-01687/31/2026
To address the safety assessment challenges of T91 steel heating surface components in the context of coal-fired power plant transformation toward deep peak-shaving, this study systematically investigates the evolution laws of microstructure and mechanical properties of in-service T91 pipes from different positions in a power plant after peak-shaving operation. Material properties were evaluated in accordance with standards such as GB/T 5310-2017 through metallographic analysis, tensile testing, impact testing, and hardness measurement, while the mechanisms linking microstructure to property degradation were explored. Results show that oxidation and decarburization occur on the outer surface of T91 pipes at all positions, with differences in the thickness of oxide/decarburized layers between the fire-facing and back-fire surfaces; the oxide layer exhibits fracture characteristics. After service, the tensile strength, yield strength, elongation, and hardness of the material still meet national standards. The performance at the platen and final superheater inlet is superior to that at the final reheater inlet, consistent with differences in operating temperature and pressure. This study indicates that the T91 steel provided in this study is in the early stage of its service life, providing a theoretical basis for the safe operation of the unit.
Huang, Liming, Li, Zutao, Zhang, Jie, Liu, Yaoren
Design of an Automatic Device for Snow Clearing of Solar Greenhouses2026-99-01467/31/2026
Solar greenhouses in winter or mountainous areas can be at risk of roof snow accumulation, leading to collapse, poor lighting, and sudden drops in temperature. The snow removal technologies presently employed on these greenhouses have the disadvantages of being cumbersome to adjust, being intricately structured, having a high cost, having high energy consumption, and being poorly adaptable to the curvature of the plastic. An intelligent snow removal device for removing snow on a northern solar greenhouse roof, and an automatic alarm safety system were designed to solve the problems. The device consists of a snow-clearing mechanism, a traversing mechanism, and detection-alarm modules. The mechanism for snow removal consists of a crank-slider with a curved guide rail. The snow removal rod is driven by the gear motor, which goes back and forth on the arched top. A bevel gear transmission system drives the gear motor mechanism. Due to this, the transverse mechanism moves with an interrupting jump-action on transverse rails around many different zones. The system for monitoring snow pressure has a distributed sensor that is programmed as a shield using an Arduino software system. The sensors detect the pressure of the snow in real-time. When the snow pressure hits the threshold, it activates the mechanism for coordinated functioning. This mechanism triggers snow clearing when the pressure threshold is achieved to avoid energy consumed through “premature clearing”. It also fits well on the curved surfaces of the greenhouse without any jamming. The snow removal machine’s various components and operations would accomplish full span snow removal and make it possible to overcome high labour intensity, slow manual response, energy waste, and others. The technology can enhance the safety of winter production of northern greenhouse crops and improve the disaster-resistant capacity of modern agriculture facilities. This technology has been granted a patent for invention.
Fu, Chengguo, Wei, Shanxiang, Zhang, Rongxian, Ding, Xuefeng, Gao, Yulan
Research on Ultrasonic Measurement Technology for Submarine Pipeline Deformation2026-99-02237/31/2026
Aiming at the measurement of buckling deformation defects of submarine pipelines in turbid waters, a precise measurement method for submarine pipeline deformation was proposed based on ultrasonic ranging technology. A unified underwater coordinate system for submarine pipelines and measurement sensors is established, and a three-dimensional model of the pipeline outer surface is constructed on this basis to provide a basis for calculating pipeline deformation elements. On the basis of underwater ultrasonic velocity correction, measurement accuracy control measures were proposed. Two types of ultrasonic measurement transducers and measurement systems were designed, and engineering applications were carried out to measure the deformation of submarine pipelines in the project. The measurement results indicate that the ultrasonic measurement system operates well under harsh sea conditions such as high turbidity, low visibility, and high flow velocity in the construction sea area, with high measurement accuracy. The three-dimensional model of the deformed pipeline is constructed accurately, and the deformation characteristics of the pipeline can be accurately calculated, meeting the requirements of engineering applications and providing effective data support for submarine pipeline maintenance.
Wang, Kekuan, He, Yazhang, Wang, Hong, Zhang, Tao, Cheng, Peiliang, Sun, Xinyan, Bai, Qian
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
Dynamic Assessment and Optimization of Bridge Resilience under Multi-Hazard Coupling2026-99-08297/30/2026
Traditional methods for assessing bridge resilience often focus on single hazards or static conditions. Yet bridges today face more complex multi-hazard threats. To address this, this research develops a dynamic model to evaluate bridge resilience under multi-hazard conditions, which is intended to provide scientific support for decision-making to improve resilience. The study first establishes an index system that measures a bridge’s ability to absorb impacts, adapt during an event, and recover afterward. We also propose a method to calculate the coupling degree, which quantifies the amplification effect of multiple hazards, such as an earthquake followed by a flood, on each other’s impacts. Next, we clarify the interrelationships among key resilience factors. Using this understanding, we construct a system dynamics model that simulates the variation of bridge resilience over a full disaster cycle. Finally, a numerical simulation is carried out for a concrete continuous girder bridge in China’s coastal areas as a case study. The results confirm the model is valid and clearly show the differences in bridge resilience between single-hazard and multi-hazard events. More importantly, they prove that combined hazards make the bridge system much more vulnerable. The model also identifies the best strategies for intervention: a strategy that coordinates actions across all disaster phases performs best, as it most effectively reduces the impact of compound hazards and keeps the resilience curve smoother. In short, this study presents a new method for assessing bridge resilience and provides engineers and managers with a practical tool to identify structural weaknesses and optimize resource allocation for resilience improvement.
Lin, Jiachen, Chai, Liang
Design and Analysis of a Lightweight Offshore Gangway2026-99-08517/30/2026
During offshore wind power operation and maintenance activities, personnel transfer and boarding procedures involve numerous safety risks. is a highly effective solution for enhancing safety during ship transfers at sea. This paper designs a compact active motion-compensating lightweight gangway capable of compensating for multi-degree-of-freedom motions induced by sea waves, including roll, pitch, yaw, and heave. The structural design is first established, and based on this configuration, the output forces of the rotary electric cylinder, roll electric cylinder, and pitch electric cylinder are analyzed. A finite element method was employed to conduct a static analysis of the gangway under extreme loading conditions. Analysis of the first six modal orders revealed that the first natural frequency of the designed gangway is significantly higher than the wave frequency, thereby effectively preventing resonance phenomena. The forward transformation matrix of the gangway was simulated using the Denavit-Hartenberg (DH) method. Simulation results indicate that the working space of the lightweight gangway meets the preset motion range requirements, thereby validating the design’s feasibility. The designed compact passageway features simple operational control, high cost-effectiveness, minimal installation footprint, and low installation and control complexity, demonstrating high practicality.
Yu, Zhigang, Fu, Wanli, Zheng, Bowen, Wang, Zhuoqun, Fang, Jiwen
Design and Construction Technology for Remotely Deployed Sacrificial Anode Supports of High-pile Wharves2026-99-08157/30/2026
In port construction, high-pile wharves—a primary structural form—are constantly exposed to marine environmental erosion, making corrosion a particularly prominent issue. Traditional anode installation typically relies on underwater diving operations, which suffer from low efficiency, high risks, and significant costs. To address these challenges, a novel installation technique requiring no divers has been developed. Through specialized equipment design and optimized construction processes, this technology enables remote, efficient, and safe anode installation. Research focuses on the design of non-diver anode support installation equipment, safety validation, and construction methodologies. Through theoretical analysis, numerical simulation, and field construction trials, this technology significantly enhances construction efficiency while reducing operational risks and costs. It provides a reliable solution for corrosion protection in high-pile wharves and holds significant importance for advancing port construction technology.
Lan, Jinping, Zhang, Shoulong
Design and Application of A Pressure Measurement System Based on Spacecraft Chemical Propellant Engine Plume Test2026-99-16237/24/2026
Spacecraft with chemical propellant engines, especially spacecraft for exploring extraterrestrial objects, need to carry out plume tests on the ground in order to determine the influence of engine plumes on spacecraft. An important purpose of the plume test is to accurately measure the pressure field in key parts of the spacecraft. In this paper, according to the pressure measurement requirements of the spacecraft plume test, the design of a pressure measurement system is carried out, which mainly includes a pressure measurement sensor, a pressure difference measurement sensor, a pipeline, a cable, a measuring instrument, a data acquisition instrument, upper measurement software, and so on. The designed pressure measurement system was successfully applied to the plume impact test of Chang'e VII, which provided important technical support for the development of the spacecraft.
Wu, Yue, Guo, Qinliang, Wu, Dongliang, Liu, Xiaoning, Tao, Dongxing, Lin, Boying, Xie, Zheng, Wei, Xi, Niu, Tong
Structural Fatigue Life Prediction and Safety Performance Evaluation of Adjustable-Angle Dental Implants2026-99-16547/24/2026
Adjustable-angle dental implants are favored by many patients due to the advantages they provide, such as high chewing force, aesthetics, comfort, and no harm to the adjacent teeth. This paper proposes a finite element modeling method for adjustable-angle dental implants by changing the material used for manufacturing the implants and predicting the life span of the dental implants with the help of Pro/E and ANSYS Workbench software, which provides biomechanical data reference for the selection of new implant parameters for industrial production and clinical use. The results show that the structural life of the implant is almost 764 years for pure titanium, 821 years for Ti6Al4v, and 1,274 years for βTi. From the analysis of the safety factor diagrams of the structures, it can be obtained that the smallest safety factor of the entire implant system occurs in the part where the abutment and the connection are in contact with each other during loading. In contrast, the smaller safety factors occurred in the abutment bumps, the ear stacks of the two grooves of the connector, and in the area of contact between the connector and the implant.
Gu, Wei, Cheng, Siyuan, Liao, Jifei
Simulated Ice Accretion Stall Flight Test Technology for Civil Aircraft with High Angle of Attack Restriction Function2026-99-16347/24/2026
In response to the current airworthiness regulations’ inability to cover the stall flight test requirements under icing conditions of civil aircraft with high-angle-of-attack restriction function and the lack of relevant flight test technologies in China, a study was conducted on the differences in airworthiness provisions for stall characteristics under icing conditions of such aircraft. Key technologies, including simulated ice accretion stall flight test methods, ice installation strategies, and data analysis techniques, are proposed and successfully applied to a specific civil aircraft. The results demonstrate that the methodologies proposed in this paper can effectively support simulated ice accretion stall tests, providing valuable insights for other similar aircraft.
Zhang, Haini
North American CAV Performance Data StandardWP-00157/22/2026
As the deployment of connected and automated vehicles (CAVs) expands, the need for a consistent, cross-industry approach to performance relevant CAV data exchange is becoming more pressing. Vehicle developers, infrastructure owners and operators (IOOs), and technology providers generate and consume data that support safety, mobility, and operational efficiency, yet much of the data remains fragmented, inconsistently formatted, and difficult to reuse across systems. To address these gaps, the Society of Automotive Engineers (SAE) and the Canadian Standards Association (CSA) convened a multi-stakeholder workshop on November 3, 2025, with participants representing original equipment manufacturers (OEMs), automated driving system (ADS) developers, state and local agencies, standards bodies, and technology partners. The workshop focused on identifying challenges, clarifying needs, and outlining a path toward a North American CAV Performance Data Standard. Key themes from the workshop included: -The need for a shared data language to support safe and interoperable CAV operations. -The lack of consistent formatting, labeling and visibility regarding who produces and consumes data. -A “start small, iterate and scale” approach beginning with well-defined use cases. -The need for technical harmonization and governance structures that build trust and support sustained coordination. This white paper summarizes the key findings and outlines a practical approach to developing a Version 0.1 base-layer data standard that can support measurable progress in 2026 and beyond.
Nesheli, Mahmood
Automated Driving Fallback Test Driver Skill CertificationJ3300/3_202607 (Current)7/20/2026
This document is intended to establish a procedure to certify AD fallback test driver skill levels as an endorsement to SAE J3300 foundational level certification. The SAE J3300/3 endorsement can be used by the individual driver to qualify their skills as a test driver of vehicles with automated driving features. The SAE J3300/3 endorsement levels may also be used by test facilities or other organizations when seeking test or professional drivers with these skills. This document provides directions for obtaining the endorsement, including associated AD fallback test driving skill examination requirements, through SAE J3300-certified Examiners (refer to SAE J3300 for definition). Endorsement registration and associated records are administered through Probitas Authentication®. Probitas Authentication® is the current Independent Program Administrator for the SAE J3300 series. This document is a supplement to SAE J3300, providing information specific to the AD fallback test driver skill endorsement and clarifying the application of the rules set forth in SAE J3300 to the AD fallback test driver endorsement. While the references, definitions, rules, and guidelines presented in SAE J3300 Sections 1 through 5 apply to the AD fallback test driver endorsement, they are not repeated in this document.
Driving Skills Standards Committee
Experimental Analysis of Human Head Dynamic Response and Injury under High-G Landing Shock2026-99-18617/17/2026
This study looks at how the human head reacts and gets injured during high-G landing impacts in spacecraft return capsules. We used a vertical drop tower system for the experiments. A standard crash test dummy, called the Hybrid III 50th, was used to imitate how astronauts sit during landing. We applied two common safety standards—the Head Injury Criterion (HIC) and the 3 ms cumulative acceleration rule—to measure head response under high-G impacts. The results show several things. First, head acceleration increases linearly as seat acceleration increases. Second, the peak total acceleration of the head is much higher than the seat acceleration. In particular, acceleration in the X and Z directions is much stronger than in the Y direction. Third, when seat acceleration went over 47.71 g, HIC exceeded the safe limit of 700, and the 3 ms head acceleration also passed the 80 g limit. This suggests that 40 g should be considered a safe upper limit for seat acceleration. This work provides experimental support for improving landing systems to protect astronauts’ heads during high-G impacts.
An, Hao, Wang, Yafeng, Guo, Yazhou
Numerical Simulation Study on the Transformation Process of Multiple Droplets into Liquid Films2026-99-18337/17/2026
The numerical simulation of the transformation process of multiple droplets into liquid films is a complex problem involving multiphase flow, interface dynamics, and heat and mass transfer. It usually requires the combination of fluid mechanics, interface science, and numerical calculation methods. Based on the smooth particle fluid dynamics method, this paper establishes a multiphase fluid-solid coupling interaction model among droplets, surrounding air and solid walls, and studies the dynamic change process of multiple raindrops dispersed in different grooves. The results show that when the contact Angle is small, the boundaries of multiple raindrops do not come into contact. The multiple raindrops evolve in their respective grooves and eventually form multiple raindrops that approach the steady-state contact Angle. The second situation is that the boundaries of multiple raindrops do not come into contact, the raindrops start to fuse, and multiple raindrops form a larger one. At this point, the contact point of the gas-solid-liquid phase disappears, that is, the "regulating force" of the contact Angle is 0. This paper provides important numerical simulation references for flight safety, aerodynamic performance and anti-icing/de-icing technologies during the flight of aviation aircraft.
Huo, Ye, Chen, Yongheng, Sun, Cunxiang
Risk Assessment after Tin Whisker ObservationARP7505 (Current)7/13/2026
This document contains information and guidance on assessment of the risk posed by observed tin whiskers for aerospace, defense, and high-performance (ADHP) products or other products that demand high reliability.
G-24 Pb-free Risk Management Committee for ADHP
Automatic Synthetic Road Network Drivability Evaluation2026-01-50427/13/2026
Simulation plays a significant role in the validation and verification of Automated Driving Systems (ADS). In a scenario-based validation strategy, the road and the actions of the traffic participants must be captured in a portable and flexible format for simulation. XML-based parametric models constitute a common combination upon which the static and dynamic aspects of the environment are captured. Although there are plenty of tools for generating these XML files there are few alternatives to verify their content. This paper suggests a method for converting and simplifying a synthetic road network into a graph for which the Chinese Postman Problem is solved. The resulting sequence can be converted back into a route that can be sampled to verify the drivability of the whole network. Once the network is verified, it can be safely used for simulation, increasing the speed at which ADS systems are developed. The graph representation can also be used to provide interactive feedback to LLMs (Large Language Model), which are increasingly used for automatic generation of roads and scenarios.
Vargas Rivero, Jose Roberto, Kern, Andreas, Menken, Stefan, Harth, Michael, Kuipou, Franck Russel
Fifteen Instrumented Motorcycle Crash Tests into a Barrier and Stiffness Comparison of Standard and Upside-Down Forks2026-01-50597/10/2026
Fifteen instrumented crash tests were performed using a 2005 Yamaha R6 motorcycle. Seven tests were performed with upside-down (USD) forks and eight tests were performed with standard forks. The 2005 Yamaha R6 provided a platform where both types of front forks could be interchanged. For all tests, the motorcycle was delivered into a concrete block at speeds varying between 5 and 23 mph. Seven tests were conducted at low speeds to determine the onset of permanent deformation. Eight tests were conducted at higher speeds to observe the wheelbase reduction of the motorcycle and its relationship to impact speed. This paper summarizes the data from these tests related to wheelbase reduction, impact dynamics, and post-impact movement, allowing comparison between two different suspension systems and historical datasets.
Lucernoni, Anthony, Boyd, Dusty, Wahba, Ronny, Taeuber, Andre, Stoner, Jacob, Law, Trevor
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