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This document describes guidelines, methods, and tools used to perform the ongoing safety assessment process for transport airplanes in commercial service (hereafter termed “airplane”). The process described herein is intended to support an overall management of safety. It is associated with showing compliance to regulations and also establishing and meeting internal company safety standards. The methods identify a systematic means, but not the only means, to assess ongoing safety. While economic decision-making is an integral part of the safety management process, this document addresses only the ongoing safety assessment process. To put it succinctly, this document addresses the “Is it safe?” part of safety management; it does not address the “How much does it cost?” part of safety management. This document also does not address any specific organizational structures for accomplishing the safety assessment process. While the nature of the organizational structure is significant to the quality of a safety program, this document focuses on the functions to be accomplished and does not attempt to define what the structure should be. The intent is to leave the greatest amount of flexibility to the organizations that use this document.
S-18C Ongoing Safety Assessment Committee
The main purpose of this SAE Recommended Practice is to verify that vehicles are capable of communicating a minimum subset of information in accordance with the diagnostic test services specified in SAE J1979, or the equivalent document ISO 15031-5. Any software meeting these specifications will utilize the vehicle interface that is defined in SAE J2534. SAE J1699-3 tests shall be run using an SAE J2534-1 (API Version 04.04) Interface. However, the use of an SAE J2534-2 (API Version 04.04) Interface shall be permitted if the following conditions are met: The number of 29-bit ISO 15765 OBD ECUs exceeds the capability of the SAE J2534-1 Interface. The SAE J2534-2 Interface meets or exceeds all of the SAE J2534-1 requirements and also supports the SAE J2534-2 feature “Mixed Format Frames on a CAN Network.”
Vehicle E E System Diagnostic Standards Committee
This SAE Aerospace Standard (AS) establishes the aerodynamic flowoff requirements and test procedures for AMS1424 Type I and AMS1428 Type II, III, and IV fluids used to deice and/or anti-ice aircraft. The objective of this standard is to ensure acceptable aerodynamic characteristics of the deicing/anti-icing fluids as they flow off of aircraft lifting and control surfaces during the takeoff ground acceleration and climb. Aerodynamic acceptance of an aircraft ground deicing/anti-icing fluid is based upon the fluid’s boundary layer displacement thickness (BLDT) on a flat plate, measured after experiencing the free stream velocity time history of a representative aircraft takeoff. Acceptability of the fluid is determined by comparing BLDT measurements of the candidate fluid with a datum established from the values of a reference fluid BLDT and the BLDT over the dry (clean) test plate. Testing is carried out in the temperature range at which the fluid, undiluted and diluted, is to be used in aircraft service. NOTE: No additional aerodynamic testing is required for non-glycol fluids at this time. For more information about non-glycol fluids, please refer to AMS1424 and AMS1428.
G-12ADF Aircraft Deicing Fluids
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, LuFang, YudongYang, JixingZhang, ChenHu, BinZhang, Mingyue
With the acceleration of population aging, the number of disabled older people is increasing, and the demand for home care is also rising. In the case of a narrow space and no gap between the bed and the ground, the transfer of patients between the wheelchair and the bed has become a challenge. Current solutions suffer from bulky designs, require caregiver assistance, and pose potential safety risks. In order to solve the above problems, this paper proposes an intelligent transfer wheelchair with voice interaction and autonomous navigation function. The wheelchair innovatively adopts a cantilever transfer device, which can enable safe and stable transfer without requiring bed-floor clearance, and has the dual functions of a wheelchair and a transfer device, effectively saving family space. The stability of the structure is verified by finite element analysis. Under the action of a 500 N load, the maximum stress and maximum displacement are within the safety limit of the material. The wheelchair is also equipped with an advanced human-computer interaction system with voice interaction and autonomous navigation functions. Users can control the operation of the wheelchair through voice. The navigation module of SLAM and the hybrid A*/Dynamic Window Approach (DWA) path planner realizes the high-precision docking of the wheelchair and the bed. The results show that the design can realize the safe transfer of disabled people between wheelchair and bed, and provide a solution for home intelligent nursing.
Wang, ShunliPeng, LiZhao, Liang
As special pressure-bearing vessels, spherical tanks are widely used in chemical, oil refining, and other fields. However, their safe operation faces the dual challenges of structural failure and leakage diffusion. Meanwhile, due to its low lower explosive limit and the low ignition energy required, propane will evaporate rapidly after leakage to form an explosive mixed gas, which may further trigger severe accidents such as combustion and explosion. Therefore, this paper takes a 3000 m3 propane spherical tank as the research object, comprehensively applies the finite element analysis method, and systematically researches stress distribution, aiming to provide theoretical support for the safety design of spherical tanks and accident prevention and control.
Huang, YuanxuanTao, GangZhang, Lijing
Fracture failure of girth welds in high-grade steel pipelines poses a critical threat to pipeline integrity. Leveraging enhanced digitalization in pipeline engineering, a statistical database has been developed to support reliability analysis based on actual operational data. This study utilizes real project data to analyze the failure probability and key influencing factors of girth welds containing crack defects, thereby providing theoretical support for safety design and risk management. To overcome the conservatism of traditional deterministic methods, a probabilistic reliability model was established, incorporating a modified PRCI-CRES ultimate tensile strain criterion. Addressing the inefficiency of standard Monte Carlo (MC) simulation in high-dimensional low-probability contexts, an efficient Hamiltonian Monte Carlo-Subset Simulation (HMC-SS) strategy was introduced. Results show that HMC-SS improves computational efficiency by 99.95% over MC, with only 0.90% relative error. Key findings include: crack depth has the strongest influence – variation from 0.92 mm to 3.68 mm, which increases failure probability by 103 times; the strength matching coefficient is dominant, and higher values reduce failure risk; strain demand exhibits a positive correlation with failure probability and couples with material properties. It is concluded that high- or equal-strength material matching should be emphasized in welding, and reliability-informed design should account for multi-parameter interactions to ensure global safety.
Yang, KaiWang, KaihongWang, BinShao, JiaYu, WeichaoZhang, Dong
In view of the problems that it is difficult to accurately control the spraying area of the mining sprinkler, and the resource waste caused by the mis-spraying material stacking area, as well as the failure of traditional radar monitoring in the complex electromagnetic environment, this paper proposes an anti-splashing system for the mining sprinkler. By combining millimeter wave radar and visual recognition fusion technology, the overall scheme of the anti-splash system is proposed. Then the control simulation of the whole system is carried out. The results show that the problem of poor control in traditional sprinkler operation can be effectively solved, and the sprinkler area can be adjusted intelligently. Finally, in order to verify the accuracy of the algorithm used in this paper, different algorithms are used for comparative experimental verification. The results show that the Modified YOLOv4 algorithm has a high accuracy of 98.75 %, which has good applicability and provides a theoretical basis for subsequent research.
Hou, Lin
Head-cover-to-stay-ring bolts in pumped-storage plants face fatigue fracture risks due to axial alternating loads, with catastrophic failure cases reported globally. In China, the absence of a unified design code in early projects produced widely divergent bolt designs. This study proposes a hybrid “field measurement and Computational Fluid Dynamics (CFD) correction” method to analyze bolt forces under turbine load-rejection transients (max. stress: 780 MPa, error <3.1%), benchmarks three Chinese standards (GB/T 22581-2024, NB/T 10135-2019, GB/T 15468-2020) for preload design, and refines their technical clauses to provide actionable guidance for future tender specifications and long-term bolt maintenance.
Long, ZheGuo, MeichaoKang, CainiLi, Chengjun
Gear-shift execution is critical to power delivery, vehicle acceleration, and driver workload in Formula Student racing vehicles. Conventional shifting solutions for sequential gearboxes are often limited by driver-dependent operation, insufficient actuator authority, incomplete torque coordination, or the absence of closed-loop gear-state confirmation. This study develops and validates a clutchless electro-pneumatic gear-shifting system for a CF700-powered Formula Student vehicle equipped with an integrated sequential dog-engagement gearbox. The system is treated as a shift-assist form of automated manual transmission, in which the driver retains gear-selection authority while shift actuation and engine torque coordination are performed electronically. Although pneumatic shifting systems are already established in motorsport applications, the present work focuses on their vehicle-specific integration through measured shift-load characterization, geometry-based actuator design, gear-position-based closed-loop control, and electronic-throttle-assisted torque intervention. Vehicle tests were conducted under straight-line acceleration, high-speed obstacle-avoidance, and endurance-oriented training conditions. Across 76 recorded shift events, no failed gear transition or missed target-gear confirmation was observed. In straight-line acceleration tests, the mean target-gear confirmation time for recorded upshifts was 96 ± 5 ms, and the representative gear-position transition interval was approximately 20 ms. The full Engine Control Unit (ECU)-controlled upshift event was 0.50 ± 0.10 s because it included the calibrated low-torque dwell and torque-recovery phase, and should therefore be interpreted as a control-event window rather than the mechanical shift duration. After powertrain-specific actuation and torque-control calibration, the developed system provides an implementation basis for similar electronically controlled sequential-gearbox racing platforms, with potential to reduce shift time and driver workload and to support improved autocross drivability and performance.
Cao, Yuanyi
Applicability of the CDTire tire model in vehicle handling and stability simulations is studied in this paper by comparison with the PAC2002 tire model. Based on the physical tire 245/50 R20, corresponding CDTire and PAC2002 models are established and assembled on the multibody dynamics model of an SUV. After simulating 5 handling and stability conditions, it is found that the CDTire calculation is more time-consuming compared with PAC2002, but the increased time cost does not exceed 10%. In addition, the relative errors of the 17 evaluation indices obtained based on CDTire compared to PAC2002 do not exceed 5%. Therefore, in terms of both computational accuracy and efficiency, CDTire is suitable for application in vehicle handling and stability simulation.
Gao, FenglingWu, WenwenFei, Yuanjun
In this research, the design of a digital twin system for a Robot-Assembled Workpiece Transfer Station (RAWTS) and virtual commissioning with it were detailed, aiming for debugging high-repeatability, high-precision robotic motions. The system employs a structured three-layer digital twin framework, Physical, Digital, and Information Fusion layers, interconnected via an OPC UA communication architecture to enable real-time virtual-physical data synchronization. The 6-axis industrial robot’s kinematic model is established using the D-H parameter method, and the translational end-effector’s kinematic relationships are configured with defined OPEN/CLOSE poses. A behavior-driven digital twin model is constructed within NX MCD, incorporating lightweight-processed 3D geometry from SolidWorks. Virtual commissioning involves PLC and robot program integration, OPC UA-based signal mapping, and kinematic path planning with reachability validation to avoid singularities and collisions. Key joint angles at critical path points are optimized, and virtual-physical integration debugging is performed, resulting in first-attempt success in physical operation. The study demonstrates that the NX MCD-based digital twin approach effectively validates control logic, optimizes robot trajectories, reduces on-site debugging time, and enhances operational precision and safety, offering a practical reference for digital twin applications in robotic systems.
Zang, YupingWang, YeFu, HudaiLi, WeiweiJiang, ZhiyuWang, Dayu
Assembly sequence planning is a crucial part of process preparation in aircraft final assembly. A scientifically designed assembly sequence can significantly improve assembly efficiency and reduce costs in aircraft production. Efficient planning not only streamlines the workflow but also minimizes potential errors and rework, which are critical in high-stakes aviation manufacturing. This paper examines the constraint relationships in aircraft assembly from the perspectives of cabin constraints and system constraints, covering both spatial layout restrictions and functional logical dependencies to ensure the comprehensiveness of constraint analysis. It establishes a directed graph for the aircraft assembly outline and generates the corresponding adjacency matrix, which converts the complex constraint relationships into a structured mathematical expression for easier subsequent algorithmic processing. The Warshall algorithm and Johnson algorithm are used to check and extract contradictory constraints from the directed graph. The adjacency matrix is then employed to calculate the reachability matrix, which helps identify redundant constraints and reduces the computational effort in assembly sequence planning. Finally, the optimized constraint relationships are used to calculate the aircraft’s final assembly sequence, which generates a Gantt chart for assembly sequence planning, guiding the on-site assembly order and accelerating aircraft development efficiency. The integrated approach effectively addresses the key challenges in complex aircraft assembly sequence planning.
Guo, JingjingCun, WenyuanZhao, JiongYu, YangYang, RuiYu, Long
The shuttle vehicle is a critical piece of handling equipment in automated logistics warehouses. As its primary load-bearing component, the load plate is subject to spatial constraints, requiring both a compact structure and effective prevention of structural deformation that could compress the battery. For a shuttle vehicle load plate developed by a company—with a rated load of 1500 kg and a maximum allowable deformation of ≤ 2 mm—this study first adopts the finite element method (FEM) to analyze its structural characteristics and establish a hybrid mesh model consisting of 1D beam elements, 2D shell elements, and 3D solid elements. Symmetry constraints are applied to reduce the computational scale. The structural deformation and stress under two constraint schemes (fixed constraints and surface-to-surface contact constraints) are compared and analyzed. The results indicate that surface-to-surface contact constraints should be adopted under this working condition, and potential design risks are identified. During the analysis, mesh independence is verified to determine an appropriate mesh size, thereby avoiding errors induced by mesh dimensions. Finally, an optimization design is conducted with the goal of lightweighting. Taking the cross-sectional dimensions of the load plate’s stiffeners and the thickness of the load plate as variables, and deformation as the constraint condition, the overall structural weight is reduced from 32.7 kg to 29.6 kg through multiple gradient-based iterative optimizations, effectively achieving the lightweighting objective. Experimental results show good consistency with the computational predictions. Additionally, the manufacturing process requirements and cost impacts of the optimized scheme are analyzed, and a manufacturing solution that meets technical requirements while ensuring economic feasibility is proposed.
Liu, RuiShen, JieChen, Meng
The range energy consumption testing of electric vehicles is usually completed in an environment where the environmental chamber and chassis dynamometer are built. The vehicle is bound to the chassis dynamometer to simulate the range performance on a real road, and the vehicle's fixing method is particularly important, as it even affects the test results. In order to investigate the impact of vehicle fixation as a key testing factor on the range test results of electric vehicles, this study conducted comparative experiments using rigid fixation test vehicles at different positions. By relying on a chassis dynamometer to simulate road resistance and following the Chinese Light Vehicle Test Code (CLTC-P), a range test is conducted on the same electric vehicle under strictly controlled environmental conditions. The experiment collected data on endurance mileage, total energy consumption, and segmented energy consumption. By comparing the differences in simulated resistance and electric energy change trends of chassis dynamometer under different binding methods of test vehicles during the test process, the comprehensive energy consumption results were different. The results showed that the rigid fixation at different positions significantly affected the sliding results of the test vehicle chassis dynamometer, leading to differences in the comprehensive endurance energy consumption results. The comprehensive endurance mileage difference reached 24 kilometers, and the comprehensive energy consumption difference reached 4Wh/km. This study reveals potential sources of system bias in laboratory testing and analyzes the impact of vehicle fixation methods on comprehensive range energy consumption results. The research conclusions can provide a theoretical basis and empirical reference for improving the current standards for energy consumption and range testing of electric vehicles, and enhancing the accuracy and reproducibility of test results.
Zhou, MengJiang, ZhijieGeng, Peilin
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, BinXin, BoZeng, TaiSu, Zhengliang
Quayside container cranes (QCCs), essential for cargo handling in seaport operations, are particularly vulnerable to damage under strong wind conditions. This study investigates the wind-induced dynamic behavior of QCCs equipped with active anti-wind systems, focusing on the mechanisms that govern cable stress and sliding instability. A five-degree-of-freedom mathematical model is established, incorporating nonlinear cable stiffness, restricted sliding through a Kelvin-Voigt collision model, and a combined Stribeck-Coulomb friction model for the wheel-rail interface. Parametric studies are conducted to evaluate the influence of three key factors, the anti-wind cable diameter, the sliding displacement of the QCC wheel, and the wheel-rail friction coefficient, on cable stress responses. The results show that increasing the cable diameter and friction coefficient significantly reduces peak cable stress, whereas greater sliding displacement increases stress accumulation and structural vulnerability. Sensitivity analysis reveals that cable diameter has the most dominant effect on cable stress, followed by sliding displacement and friction coefficient. This work might provide theoretical foundations for the design and optimisation of wind-resistant QCC structures, as well as for the development of more reliable anti-wind protection systems in extreme conditions.
Xiang, LeiJi, HuanyuLiu, ZhiweiWang, ZiyouXu, Xinyue
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, LihongWang, YiyouYang, Zihao
To safely, efficiently, and high-quality complete the mechanical testing of batch-produced manned spacecraft during the China Space Station (CSS) phase, a series of optimization measures were proposed based on system engineering principles. These measures cover the entire mechanical testing process from preparation to implementation, including: establishing a standardized mechanical testing documentation system; reducing the number of mechanical sensors that do not affect result evaluation; pre-identifying and measuring background noise; digitizing test notching and evaluation methods; and standardizing and automating testing procedures. Additionally, targeted measures for test safety and quality control were implemented, including regular inspections of reusable spacecraft components, strict control of test hazards and operational risks, and standardized management of ground support equipment (GSE) through regular inspections. The proposed optimization and control measures have been validated through applications in batch-produced manned spacecraft during the CSS phase. The results show that: the generalization rate of mechanical testing documentation exceeds 80%; the number of mechanical sensors has been reduced by more than 10%; the test preparation period has been shortened by over 4 days; test efficiency has been improved by 30%; the single-direction test duration has been reduced by more than 50%; and the total test cycle has been shortened by 25%. These results indicate that the proposed optimization and control measures are reasonable and feasible, which effectively reduces redundant test operations and items, lowers potential test risks, improves test efficiency, shortens the overall test cycle, enhances test safety, and ensures the high-quality completion of mechanical testing for batch-produced manned spacecraft.
Peng, HuakangWang, Mengchen
Aiming at the inherent instability, strong nonlinearity, and high dynamic characteristics of normal-conducting maglev suspension systems, this paper adopts a composite supervisory control scheme integrating PD control and an RBF neural network. First, a high-speed maglev train-track coupled dynamics model considering track elasticity is established. On this basis, a phased control strategy is designed: the initial phase employs a PD controller to ensure system stability, after which control is seamlessly handed over to an RBF neural network. The weights of this network are continuously refined online via a gradient descent algorithm, enabling progressive enhancement of control precision. Simulation results validate the effectiveness of this approach, confirming its superior performance in both precise suspension gap regulation and robust disturbance rejection. Consequently, the proposed method not only underpins the stable operation of maglev trains but also constitutes a reliable intelligent control framework for high-speed maglev systems.
Yu, YongZhang, JieWang, YuLiang, Shi
The construction of overhead power transmission lines in remote mountainous regions frequently relies on aerial ropeway systems, as conventional ground transportation is often impractical. However, complex terrain conditions combined with highly variable wind environments can significantly threaten the operational stability and structural safety of these cargo ropeway systems. To investigate these effects, a refined finite element model of a ropeway support was developed in ANSYS, and stochastic, time-varying wind fields were generated in MATLAB. The simulated wind time histories were applied to the numerical model to perform nonlinear transient dynamic analyses, enabling the evaluation of wind-induced displacement responses under different wind angles of attack. Based on the simulated response histories, critical stress- and displacement-sensitive regions of the support structure were identified, and the implications for structural detailing and design optimization of cargo ropeway supports were discussed.
Lv, YanfengYang, ZhonglvSun, MinggangJin, Hengdong
The vigorous rate of new spacecraft being launched has made the accurate estimation of in-orbit environmental disturbances torques paramount to reducing attitude control performance corrosion. Leveraging telemetry from an asset in low-earth-orbit, we present a novel Adaptive Super-Twisting Sliding-Mode Observer, which interlinks three techniques heretofore decoupled: 1) saturation-constrained angular-acceleration adaptation; 2) Kalman-filter preconditioning of angular velocity; and 3) state-weighted logarithmic gain with dual leakage. Denoising of raw Euler angle sequences and detection of quasi-steady epochs are achieved with a customized Kalman update, while an adaptive band-pass stage isolates the torque-related acceleration signature. Casting these filtered data into the super-twisting form, we update the log gain on-the-fly, and twin leakage terms remove excess energy with accompanying chatter rejection—without compromising bandwidth. Head-to-head telemetry tests show a positive margin headroom on noise attenuation that has to be compared with the power-gain type counterpart and that increases with the signal roughness, thereby validating the fact that this technique refines environment torque estimates and hence strengthens robustness design envelopes in next-generation attitude-control systems.
Yin, XuDeng, YuhuiChi, Dongxiang