Browse Topic: Manufacturing

Items (45,833)
Find
Integrating MBSE with High-Fidelity Crash Simulation2026-01-75429/22/2026
Modern electrified ground vehicles introduce complex, multi-domain safety requirements, such as post-crash thermal runaway prevention, that expose the traceability limitations of Document-Based Systems Engineering (DBSE). This paper proposes a four-layer, bidirectional digital thread architecture that integrates Model-Based Systems Engineering (MBSE) with high-fidelity, non-linear Computer-Aided Engineering (CAE) crash simulations. Leveraging SysML, System-Theoretic Process Analysis (STPA), and Python-based orchestration middleware, the framework automates the translation of descriptive safety requirements into explicit finite element boundary conditions. The architecture programmatically extracts key performance indicators from massive binary solver outputs and injects them back into the SysML environment for automated compliance verification. Demonstrated through a simplified electric vehicle side-pole impact case study utilizing LS-DYNA and a 1D thermal model, the framework successfully eliminates manual data handoffs, accelerates multidisciplinary design optimization, and ensures robust, risk-driven requirement traceability across the engineering lifecycle.
Rye, Patrick J.
Decision Engineering: Applying Lean Production Principles to the Lifecycle Decision Factory2026-01-75259/22/2026
The Army’s transformation mandate is unambiguous: deliver warfighting capability 25–30% faster. Every Tier 2 metric published in support of that mandate – days between milestones, days to complete the requirements process, days to complete contracting, days to complete testing – is really a decision throughput measurement. Yet the systems engineering (SE) discipline that governs those timelines has no formal production framework for producing decisions. This paper proposes Decision Engineering as the framework. Grounded in lean production theory, applied to information work and anchored to the defense acquisition policy structure of DoDD 5000.01 and DoDI 5000.02, Decision Engineering reconceives SE as the discipline of designing, operating, and continuously improving the lifecycle decision production system. It introduces a formal decision ontology comprising six decision states (Latent, Declared, Active, Deferred, Closed, Reopened), four topology relationship types (Precedes, Enables, Constrains, Triggers), and five diagnostic biomarkers that measure production system health. The paper presents the Decision Factory model and describes how its application to ground vehicle system programs and across the Army acquisition enterprise can accelerate capability delivery without sacrificing rigor. Defense acquisition programs do not fail for lack of engineering rigor or digital tooling. They fail because the production system that converts information into decisions is ungoverned – no inventory count, no flow discipline, no throughput measurement. Decision Engineering names this production system, provides instruments to measure its health, and offers a practitioner framework for running it better.
Alexander, Eric, Foglesong, Matthew, Berklich, Louis (Bill)
An Assessment of Biomanufacturing in Forward Deployed Locations2026-01-75579/22/2026
Biomanufacturing uses microorganisms to produce chemicals or materials of interest, much like a brewery uses fermentation by yeast to produce the alcohol in beer. Biomanufacturing relies upon synthetic biology to reprogram yeast or other microorganisms to produce something of greater value, such as fuel, food, or pharmaceuticals. Industrial biomanufacturing has made significant advances and the products it can deliver include reactive coatings and textiles, sensors, optical materials that can bend light, and new therapeutics such as antimicrobials and vaccines. The convergence of synthetic biology, robotics, and artificial intelligence is opening the way to produce materials never before possible in the commercial market. These same technologies create the opportunity for the miniaturization of this technology to fit into ever more compact spaces, bringing forward deployment of these mini-factories closer and closer to the point of need.
Ahern, Brooke, Crumbley, Annie, Walker, Anne, Grodecki, Joseph
Decision-Centric Virtual Metrology for Geometric Deviation via Foundation-Embedding Retrieval2026-01-75549/22/2026
Modern defense manufacturing and sustainment require timely engineering decisions (e.g., inspection triage, rework/accept decisions, and process adjustment) based on the as-built geometric quality. Advanced machining systems generate rich multichannel controller and sensor streams, yet accurate geometric deviation labels remain costly and delayed because they depend on downstream metrology. This paper introduces ChronosGD, a retrieval-based virtual metrology framework. ChronosGD predicts pointwise geometric deviation from multichannel time series data by: (1) retrieving the most similar historical process windows in a frozen Chronos-2 embedding space, and (2) transferring deviation information through similarity-weighted aggregation. ChronosGD avoids plant-specific gradient retraining during deployment; adaptation is achieved by refreshing a labeled historical memory as new inspected parts become available, while preserving traceability through explicit neighbor provenance.
Hoang, Danny, Matthiessen, Ryan, Miller, Christopher, Mannan, Nasir, ElKharboutly, Ruby, Gorsich, David, Castanier, Matthew P., Imani, Farhad
Designing a Digital Twin–Enabled Requirement Verification Workflow within an MBSE Framework2026-01-75309/22/2026
Verification of functional requirements in Model-Based Systems Engineering environments remains fragmented across heterogeneous tools and manual processes. This paper presents a digital twin–enabled workflow that supports automated requirement verification through integration of SysML models, executable simulation environments, and verification evaluation functions. Within this scope, the objective is to formalize a verification workflow that preserves architectural abstraction while enabling automated, traceable, and simulation-driven evaluation of functional requirements. The approach establishes a continuous digital thread that maintains traceability between requirements, system architecture, and verification outcomes. The workflow is demonstrated using a differential-drive robotic platform, where sensor data availability and update rate verification are used as representative examples of digital twin-based functional requirement evaluation. Results illustrate the feasibility of incorporating digital twin-driven verification into model-centric engineering processes while maintaining consistent verification feedback within the system model. The demonstration produced both passing and failing verification outcomes, illustrating the workflow’s ability to surface requirement-design mismatches.
Zeki, Omar, Sahebsara, Farid, Torkjazi, Mohammadreza, Hieb, Michael R., Raz, Ali K.
An AI-Ready Decision Digital Thread Schema for Digital Engineering2026-01-75339/22/2026
Digital engineering (DE) and model-based systems engineering (MBSE) improve traceability for requirements, architecture, and verification, but concept decisions—the governance events that turn evolving evidence into binding commitments—are poorly captured. Rationale, assumptions, alternatives, model baselines, and approval conditions are scattered across slides and minutes, limiting auditability, reproducibility, and automation. We propose a Decision Digital Thread (DDT): a typed graph schema that makes decisions governable by linking framing and scope, structured (including set-based) alternatives, uncertainty and risk, immutable evaluation-run provenance with reviewed evidence, and commitment events with machine-actionable conditions, authorized actions, and outcome feedback. DDT serves as the decision system of record and a contract between platform modules and enterprise policy while referencing MBSE/PLM/simulation artifacts via stable identifiers and configuration context. Policy-driven readiness gates block lifecycle transitions when evaluator coverage, evidence review, or bias checks are incomplete. An electric pickup range-extension case demonstrates auditable gates, evidence lineage, and safe AI-agent authority boundaries.
Chinnam, Ratna Babu, Murat, Alper, Rana, Satyendra, Rapp, Stephen H., O’Bruba, Joseph G., McGregor, Michael, Bechtel, James E., Costa, Laura W.
Powder Metallurgy Hot Isostatic Pressing: Titanium Done Differently for Defence2026-01-75569/22/2026
Powder metallurgy hot isostatic pressing (PM HIP) is a novel manufacturing process extensively utilized in oil & gas and aerospace industries. With the evolution of this advanced manufacturing process, many other industrial sectors including defence are benefiting from the clear strategic advantages of PM HIP compared to conventional manufacturing processes. This paper is intended to give an overview of PM HIP technologies and highlight the potential of this process for the manufacture of components for land based military systems. The study will focus on a brief introduction of PM HIP technology followed by more detailed description of some key benefits of adopting PM HIP in defence sectors. These include easier processability of Ti-alloys, generation of high-performance metal matrix composites (MMCs), manufacturing of complex shape parts and generation of multi-materials structures via HIP diffusion bonding (DB). Finally, the paper will focus on future prospectives of PM HIP.
Clark, Gerry, Sergi, Alessandro
Data-Driven System Dynamics and Chauvenet-Based Outlier Detection for Assessing Global CO₂ Emissions under Fossil Energy and Electric Vehicle Transition Scenarios2026-24-00209/21/2026
Understanding the structural drivers of global CO₂ emissions requires integrated analysis of fossil fuel production, total energy consumption, and electric vehicle (EV) deployment trends. This study presents a data-driven modeling framework combining system-dynamics formulation with statistical outlier detection implemented in Python to evaluate emission trajectories over a ten-year historical period. The methodology incorporates historical datasets of global CO₂ emissions, primary energy consumption, fossil fuel production, and EV manufacturing volumes. A computational routine developed in Python applies the criterion proposed by William Chauvenet to identify statistically inconsistent observations within the dataset, ensuring robustness prior to regression and correlation analyses. Carbon intensity (CO₂ per unit of energy) is calculated to assess decoupling behavior, while correlation matrices and elasticity indicators quantify the relative influence of fossil production and EV penetration on emissions. The dynamic structure expresses CO₂ emissions as a function of fossil energy share, total energy demand growth, and electrification rate. Sensitivity analysis evaluates the responsiveness of emissions to variations in these parameters. Results indicate that emission reductions are strongly dependent on carbon intensity evolution rather than EV growth alone. Outlier detection enhances model reliability by preventing anomalous years from biasing trend interpretation. The proposed framework provides a transparent and computationally efficient tool for emission diagnostics, transition scenario evaluation, and policy-oriented forecasting within the context of sustainable mobility and global energy transformation.
Gutierrez, Marcos, Taco, Diana
Development and Production of Weight-Reduced Steel Hat Brake Discs: A Contribution to Automotive Lightweighting2026-01-08219/14/2026
The automotive industry's transition towards electrification, particularly in the passenger car (PC) and light commercial vehicle (LCV) segments, has intensified the focus on vehicle lightweighting to maximize battery range and efficiency. Conventional brake systems in electric vehicles (EVs) are subject to minimal mechanical wear due to regenerative braking, making corrosion the primary cause of component failure and replacement. This paper details the development and production of an innovative lightweight brake, which addresses these challenges. The "Cast-In" brake disc combines a traditional gray cast iron friction ring with a pre-finished, deep-drawn steel hat through a specialized composite casting process. This design achieves a significant reduction in unsprung mass—1.6 kg per disc in a 390mm x 36mm example—directly contributing to improved vehicle dynamics and energy efficiency. Key manufacturing challenges, including ensuring a robust material bond, preventing casting defects, and sealing the steel hat during casting, have been overcome through advanced process controls, simulation, and a patented sealing system. Furthermore, a novel, enhanced corrosion protection system has been developed and validated to meet the required service life of over 10 years, addressing the specific demands of e-mobility. With production scheduled to begin in April 2026, this technology is a milestone for modern braking solutions in the era of electrification.
von Reth, Thomas
Correlation of Tribological Characteristics with Brake Emission Factors in Automotive Disc Brakes2026-01-08299/14/2026
Following the recent introduction of the Euro 7 regulations, research on non-exhaust emissions, including brake wear particles, has increased. However, full-scale dynamometer tests are affected by complex variables such as vehicle class and brake system specifications, which makes it difficult to analyze the unique characteristics of friction materials independently. Previous studies have predominantly focused on comparing emission levels by friction material composition or on disc surface treatments, and quantitative correlations, resolved by friction material type, between the physical wear mass of friction materials and the Brake Emission Factor (BEF), remain scarce. In this study, the brake emissions from various friction materials were precisely measured using a scale dynamometer reflecting the UN-GTR No. 24 standards. By applying the WLTP cycle, a quantitative correlation was derived between the friction characteristics and the BEF for each braking section. The results show that BEF varies with friction material type depending on the friction- and wear-related factor, while disc wear and total wear were confirmed, regardless of friction material type, to be common key indicators that exhibit a statistically high correlation with BEF.
Jang, Pan Gyu, Kim, Duck Hyeon, Jeong, Yoon Oh, Kwon, Sung-Wook, Jung, Kwang Ki, Lee, Jungju
Thermomechanical Fatigue Life Prediction of Grey Cast Iron Brake Rotors Using Advanced Material Models and Elastic-Plastic Fracture Mechanics2026-01-08169/14/2026
A unified thermomechanical fatigue (TMF) life-prediction methodology is presented for lamellar graphite (grey) cast iron brake rotors operating under the severe transient thermal loads that arise in brake dynamometer durability testing. The workflow links four ingredients within a single rotor-level framework: transient nonlinear finite-element analysis, temperature-dependent inelastic constitutive modeling, a mechanism-based short-crack TMF damage model, and an elastic-plastic (nonlinear) fracture-mechanics crack-growth simulation. Two constitutive descriptions are exercised for the structural analysis — the standard rate-dependent Chaboche viscoplastic model available in Abaqus, and a user material subroutine (UMAT) that couples Chaboche viscoplasticity with continuum damage in order to reproduce the tension–compression asymmetry of cast iron. The resulting stress, strain, and temperature histories drive a multiaxial thermomechanical fatigue Damage (DTMF) computation that estimates crack initiation and early extension, after which a nonlinear fracture-mechanics procedure simulates crack-front advance toward through-thickness failure. Both constitutive models correctly localize the crack-initiation site on the rotor inner diameter, consistent with the dynamometer observations; for the loading histories examined, the standard Chaboche model yields lives in closer agreement with test. The crack-growth simulation reproduces the rapid post-initiation propagation seen experimentally and resolves branch-wise differences in crack-front evolution through the rotor section.
Lee, Heewook, Garcia, Arnoldo, Liu, Yi, Hazime, Radwan, Boughanmi, Heni, Kassir, Abdallah
FITTING ASSEMBLY, 45° ELBOW, EXTERNAL SWAGE TO FEMALE FLARELESS, HYDRAULICAS6468A (Current)9/11/2026
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
FITTING ASSEMBLY, TEE, EXTERNAL SWAGE ON RUN, FEMALE FLARELESS ON BRANCH, HYDRAULICAS6489A (Current)9/11/2026
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
FITTING ASSEMBLY, 90° ELBOW, EXTERNAL SWAGE TO FEMALE FLARELESS, HYDRAULICAS6475A (Current)9/11/2026
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
FITTING ASSEMBLY, TEE, FEMALE FLARELESS TO EXTERNAL SWAGE ON RUN, EXTERNAL SWAGE ON BRANCH, HYDRAULICAS6471A (Current)9/11/2026
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Experimental Study on Partitioned Fruit and Vegetable Storage in Ships2026-99-15039/11/2026
After an investigation into a fruit and vegetable storage compartment on a ship, this paper proposes a method for creating different temperature zones within a single storage unit. To perform this approach, a top perforated plate air supply system should be implemented, and storage panels should act as partitions to make temperature control more accurate in different zones within the same compartment. This method ensures that fruits and vegetables can be stored for the best flavor at suitable temperatures, enabling fewer separate storage units on the ship. According to the experimental results, this solution can preserve various types of fruits and vegetables under different conditions during long trips, deal with the challenge of chilling or freezing injury due to mixed storage, and save the cold storage capacity on the ship. The proposed method has significant value in engineering applications.
Xie, Zhihao, Cui, Yonglong, Duan, Wenli, Li, Kun, Li, Qi, Wei, Shuaiju
Exploration of the Minimum Safe Transverse Distance for Ships Passing Through the Pier of Huangpu River Tidal Barrier Based on the Boundary Element Method2026-99-15469/11/2026
The Huangpu River tidal barrage is in a navigable reach where the quay wall greatly restrains the flow. Earlier studies focused on ship-structure interaction, but there aren’t many hard numbers on safe passing distance near the barrage pier. The purpose of this paper is to determine the lowest safe lateral gap for large vessels and to provide an engineering means of ascertaining the clear width of the main channel. A 20,000-ton oil tanker is used as the test vessel. Using the boundary element method (BEM), a 3D model is constructed to simulate the interactions between the ship and the pier under varying speeds, draft depths, and lateral offsets. Simulations were conducted for different speed levels, draft depths, and lateral offsets to observe the flow and the ship’s movement. Changes in side forces, yawing moments, and bow angles were recorded over time, and their maximum values were determined. Sensitivity and uncertainty analyses were also performed to evaluate how input variations affect the results and to assess model stability. Based on these results, simple limits were established for the three measures to serve as safety rules. Using these rules, the clear width of the main channel was calculated. The results indicate a minimum safe lateral distance of 14 m and a suggested channel width of 202 m, deviating by only 0.5 m, or approximately 0.25%, from the theoretical value of 202.5 m. These findings can also be applied in practice for pier layout and the determination of speed limits in narrow channels.
Guan, Keping, Yu, Min, Zhan, Qingan
Intelligent Mold Library System for Copper Tube Drawing Process2026-99-11089/11/2026
With the continuous and in-depth advancement of automotive lightweighting, the quality issues of automotive components have become increasingly prominent. Copper tubes, as an important component of automotive air conditioners, also need to ensure their quality level. In the production process of copper tubes, the multi- pass moving core head disc drawing process is one of the commonly used processing techniques. The relevant drawing dies determine the drawing effect and the quality of the finished copper tubes, so it is necessary to make a reasonable combination of drawing dies. At present, many copper tube processing enterprises overly rely on manual experience for mold matching work. Moreover, mold inventory information, usage records of matching molds, and mold size measurements are all completed by different operators. The operation procedures are not standardized, the standardization of mold matching operations is insufficient, there are too many uncertain factors, and the degree of human influence is too high. The intelligent mold library system for copper tube drawing process is designed to address the problems of weak stability, poor reproducibility, and insufficient precision in the existing manual mold matching. It facilitates accurate computation and control of process parameters. Compared with the estimation and rough adjustment based on manual experience, it can more accurately achieve the best parameter combination required by the process, thereby improving product quality and production efficiency. By integrating the mold matching methods of drawing pass process parameters such as the double decreasing method, the minimum pass method, the empirical pass method, the ZBL method, and the KD-KS coefficient method, and combining the inventory information in the system, it is ensured that the mold matching scheme generated by the algorithm is the best one, thereby improving the production level of the production process.
Yue, Fengli, Meng, Dezhi, Cui, Haitao, Zhang, Jiakun, Sun, Hongyun
Experimental Study on Ultrasonic Drilling of CFRP Based on Ultrasonic Tools2026-99-14139/11/2026
To investigate the influence of laws of rotational speed, ultrasonic vibration, and feed speed on burr length, splitting length, and hole roundness of carbon fiber reinforced plastic (CFRP), drilling experiments using ultrasonic tools designed based on the dagger drill principle were carried out on CFRP materials. This study aims to explore methods for improving the hole-making quality of CFRP and further enhancing its hole-making efficiency. The results show that a high rotational speed can effectively reduce the burr length by 60% and the splitting length by 50%. Ultrasonic vibration can reduce the burr length and splitting length by about 70% and increase the hole roundness by about 10%. The higher the feed speed, the lower the hole-making quality, while an excessively low feed speed will impair the hole-making efficiency. In this study, the optimal hole-making quality was achieved when the rotational speed was set at 18500 r/min, ultrasonic vibration was activated, and the feed speed was controlled at 40 mm/min. The research results provide valuable references for the research, popularization, and application of ultrasonic tools and related technologies.
Xiang, Hui, Xiao, Liuwei, Song, Jinhui, Chen, Songlin, Liu, Zhichun, Liu, Yihong, Xiao, Huan, Zhang, Cheng, Ran, Qiuyue, Luo, Jiang
Impact of Transient Driving Characteristics on Bench-to-Road Emission Consistency of Light-Duty Vehicles2026-99-15739/11/2026
The thalweg at the outlet of the Yuxikou Waterway transitions from right to left, forming a 90-degree bend. It then merges with the Xihua Waterway after passing Xiliang Mountain, creating a main-branch confluence water area. Taking a typical main-branch confluence water area in the lower reaches of the Yangtze River as the research object, this paper reflects the current navigation status and existing problems of ships in the area through the analysis of ship traffic flow. It classifies the risk levels of passing ships, proposes suggestions for route reform and optimization, and uses a model to verify the probability of collision accidents in the area after the implementation of the round-island navigation method, providing a reference for the navigation safety of passing ships.
Qiao, Jiajun, Jin, Zhenhua, Huang, Qi, Li, Guohui, Zhang, Xinguo
Numerical Investigation of In-Plane Antisymmetric Failure Modes and Load-Carrying Mechanisms of Steel Portal Piers2026-99-15949/11/2026
A nonlinear finite element model was applied to study the in-plane instability of steel portal piers, in which initial geometric imperfections, welding residual stresses, and material nonlinearity were considered. The modeling procedure was compared with experimental results from box-section members, and consistent tendencies in load level and deformation evolution were observed. In the numerical analyses, the initial elastic buckling configuration exhibited an in-plane antisymmetric form. As loading continued beyond the elastic range, this deformation pattern persisted. With further loading, the deformation remained purely axial while combining compression with bending. During this stage, plastic hinges appeared near the column tops, while lateral displacement became clearly observable. Comparison models with different geometric proportions show that variations in the span-to-height ratio and the beam–column stiffness ratio influence how instability develops and where plastic deformation tends to localize. From a design perspective, these trends can be considered when distinguishing instability characteristics and selecting stiffness proportions between beams and piers.
Li, Jie, Shangguan, Bing, Cheng, Zhangxu, Ruan, Furong, Bai, Fan
Research on Interference Management of Shared Collection and Transportation Vehicle Scheduling of Bulky Garbage with Order Changes2026-99-15199/11/2026
This study presents a shared vehicle scheduling model designed to tackle scheduling conflicts arising from changes in orders for bulky waste collection and transportation. The model accounts for five types of interference events: alterations in the original order location, modifications to the time window, changes in waste size, the inclusion of new orders, and order cancellations. The goal of the model is to reduce variations in the frequency of collection and transportation, minimize costs, and meet the three requirements of three-dimensional loading for shared trucks, as well as satisfy user time windows. To solve this complex combinatorial optimization problem, the sparrow search algorithm is employed. Numerical studies indicate that the proposed method outperforms the genetic simulated annealing algorithm in objective function value and computational efficiency under the five interference scenarios. These results also confirm the model’s efficacy.
Xu, Chen, Ma, Huimin
Linkages and Propagation Mechanisms of Risk Sources during Electric Vehicles Transportation2026-99-15289/11/2026
This study addresses safety issues in three representative logistics scenarios for electric vehicles (EVs) as cargo-car carriers, roll-on/roll-off (Ro-Ro) vessels, and containers. To address the heterogeneity across these modes, we develop an integrated “process–spatiotemporal load–risk factor” framework that embeds operational steps and confinement conditions into the indicator system, overcoming the limitations of single-scenario or single-factor studies in explaining chain-type propagation. Building on process mapping and spatiotemporal load characteristics, we develop a risk indicator system spanning “person-equipment-transported object-operation & environment-system management.” Expert judgments are then analyzed using an integrated DEMATEL-ISM approach to quantify inter-factor linkages and transmission pathways. The results indicate that regulatory oversight and carrier-side emergency equipment constitute the deep root causes of thermal runaway. The most hazardous transmission route is “regulatory oversight, procedural compliance and skill-experience match”, while “battery type, road/sea conditions and hoisting impacts” forms the shortest path. These findings reveal weaknesses in management and equipment that are amplified by operational execution and limited personnel capability, ultimately precipitating severe transportation incidents.
Yuan, Libo, Jiang, Huifu, Qin, Xiao
Analysis of Traffic Capacity at the Intersection of Xiyou Road and Qianshan Road in Hefei City2026-99-15519/11/2026
With the advancement of urbanization and the popularization of automobiles, the traffic load on urban roads is becoming increasingly heavy, resulting in many traffic problems. Road intersections serve as crucial linchpins in the urban transportation grid, wielding considerable influence over the overall traffic capacity of a city’s road network. Enhancing intersection efficiency and cutting down on delays stand at the heart of tackling urban congestion challenges. This study zeroes in on the crossroads where Xiyou Road intersects with Qianshan Road in Hefei City. Employing hands-on observation and photographic documentation, the research examines traffic flow and signal configurations during the peak demand period (7:30-8:30). The analysis evaluates traffic capacity and utilization rates for through, left-turn, and right-turn lanes at this intersection. Findings reveal that the right-turn lane at the southern entrance and the left-turn lanes at both northern and eastern entries show relatively low saturation levels, while the saturation of other lanes is greater than or close to 1. Therefore, this intersection does not have sufficient capacity. The actual traffic operation at the intersection, particularly during peak traffic times, is analyzed to identify the reasons for congestion Finally, improvement plans for optimizing traffic organization at intersections are proposed, such as optimizing signal timing schemes and transforming traffic channelization. Simulation analysis using VISSIM shows a 9.34% reduction in total intersection parking time, a 34.26% decrease in average queue length, and an 8.12% reduction in average vehicle delay. These results provide a reference for future optimization work, including intersection signal timing and channelization.
Wang, Yanmei, Wang, Chen, Fu, Ziyue, Meng, Xianglong
Dimensional Adaptability and Traffic Organization Analysis of Ships in Group Lockage2026-99-15109/11/2026
Aiming at the technology of electric intelligent working boat towing 4 ships in group lockage during the construction period of the Gezhouba Shipping Capacity Expansion Project, this paper, starting from ship dimensions, conducts an adaptability analysis on electric intelligent working boat towing ships in group lockage for all ships passing through Gezhouba No. 1 and No. 2 Ship Locks throughout 2024, based on the two-dimensional packing model, ship lock chamber scheduling model and algorithms, navigation scheduling rules and safety management regulations, the results show that ships unsuitable for being towed in group lockage through Gezhouba No. 1 Ship Lock account for approximately 26% of the total number of ships passing through it, while those unsuitable for being towed in group lockage through Gezhouba No. 2 Ship Lock account for approximately 57% of its total passing ships. Meanwhile, ships passing through the three Gezhouba ship locks on a specific day are selected, and an adaptability analysis on the dimensional suitability of electric intelligent working boat towing these ships in group lockage is carried out under the scenario where these ships only pass through Gezhouba No. 1 and No. 2 Ship Locks. The results show that the number of ships with suitable dimensions for group lockage accounts for the majority of the ships passing through the locks on a selected specific day. On this basis, combined with the operation modes of Gezhouba No. 1 and No. 2 Ship Locks, an analysis is carried out on the traffic organization, potential risks, corresponding countermeasures, and the required quantity of electric intelligent working boats for towing ships in group lockage, targeting the three main collaborative operation modes. The results can provide a basis for the future practical application of electric intelligent working boat towing ships in group lockage during the construction and operation periods of the Gezhouba Shipping Capacity Expansion Project.
Huang, Shaowen, Yang, Xi, Wang, Jian
Research on Planting Concrete Preparation and Alkali Reduction Technology2026-99-15189/11/2026
Planting concrete has drawn much attention due to its great potential in highway slope protection and ecological restoration. However, its practical application has been limited as its highly alkaline environment imposes severe restrictions on the germination of plant seeds and the growth of seedlings. To address this key issue, this paper conducted a systematic study on planting concrete preparation and alkali reduction technology. First, planting concrete samples that meet the basic physical and mechanical property requirements are prepared by optimizing the raw material ratio, mixing, molding, and curing processes. On this basis, the post-molding concrete samples are soaked in calcium superphosphate solution, so that the phosphate ions in it can have chemical reactions with the free calcium hydroxide in the concrete to make insoluble calcium phosphate salts, thus realizing chemical alkali reduction.
Liu, Ying, Yang, Wanting, Ma, Lijie
Loosening Behavior of Flared Tube Fittings under Transversal Vibration Conditions2026-99-11139/11/2026
Flared tube fittings are extensively utilized in pipeline systems due to their effective connection and sealing capabilities. However, during practical service conditions, transversal vibration frequently induces thread loosening, subsequently leading to seal failure and other malfunctions. Current research lacks a systematic investigation into the loosening behavior of flared tube fittings under transversal vibration conditions. This study establishes a precise finite element model of the flared tube fitting and systematically examines its loosening behavior under stress redistribution, plastic deformation, and fretting wear conditions by simulating the assembly process and applying cyclic transversal vibration loads. The research findings demonstrate that the loosening process of flared tube fittings occurs in two distinct stages. The initial stage primarily involves preload reduction caused by non-rotational factors such as stress redistribution, while the subsequent stage features continuous preload attenuation resulting from relative rotation between internal and external threads. Notably, a critical amplitude has been identified. When the actual transversal amplitude remains below this critical value, only non-rotational loosening occurs in the flared tube fitting, with no rotational loosening taking place. Further investigation into factors affecting the critical amplitude, including preload, friction coefficient, material properties, and thread type, reveals that preload, friction coefficient, and material elastic modulus significantly influence the critical amplitude, whereas thread type demonstrates a negligible impact. These findings provide valuable insights for enhancing the reliability of flared tube fittings in vibration-prone applications.
Liu, Chang, Li, Muxiao, Chen, Hanlin, Xu, Dong, Gong, Zhengchao
Reliability Evaluation of Transmission Accuracy for RV Reducers Based on Uncertainty Theory2026-99-11019/11/2026
In reliability evaluation of RV reducers using accelerated degradation tests, practical constraints (e.g., test costs and resource shortages) often lead to insufficient test iterations or small sample volumes. This results in limited insights into the product’s overall degradation trajectory, inadequate data for reliability analysis, and notable epistemic uncertainty. Conventional accelerated degradation models—rooted in probability theory—depend on the large numbers, rendering them ill-suited to address such uncertainty in small-sample scenarios. Uncertainty theory, a modern mathematical framework developed to characterize epistemic uncertainty, has garnered broad academic interest for its strong adaptability to small-sample contexts. Accordingly, this study explores the evaluation of RV reducer reliability using accelerated degradation data and uncertainty theory, aiming to mitigate epistemic uncertainty arising from small sample sizes. Specifically, this work develops a transmission accuracy degradation model for RV reducers based on the Liu process—a core component of uncertainty theory—that incorporates both inter-sample individual variability and the epistemic uncertainty inherent in the degradation process. This study also assesses the reducer’s reliability and service life; comparative analysis against probability-theoretic models confirms the proposed model’s advantages in small-sample scenarios.
Luo, Min, Huang, Jinxing, Dai, Jinzhen, Shu, Ke
Current Situation of Ship Navigation and Research on the Route Reform Scheme in Typical Tributary-Confluence Waters of the Lower Yangtze River2026-99-15729/11/2026
The thalweg at the outlet of the Yuxikou Waterway transitions from right to left, forming a 90-degree bend. It then merges with the Xihua Waterway after passing Xiliang Mountain, creating a main-branch confluence water area. Taking a typical main-branch confluence water area in the lower reaches of the Yangtze River as the research object, this paper reflects the current navigation status and existing problems of ships in the area through the analysis of ship traffic flow. It classifies the risk levels of passing ships, proposes suggestions for route reform and optimization, and uses a model to verify the probability of collision accidents in the area after the implementation of the round-island navigation method, providing a reference for the navigation safety of passing ships.
Liu, Ka, Xu, Yerong
Integration of Configuration Management into the RFLP Process in the Development of Civil Aircraft2026-99-14179/11/2026
In the forward development process of civil aircraft, traditional configuration management, which primarily focuses on the physical implementation end, often leads to inconsistencies between functions, requirements, design configurations, and physical realizations. This study optimized the principles of configuration item identification by refining the logic, timing, and sequence for identifying different types of configuration items. It proposed a product structure centered on the Logical Identification Number (LIN), which explicitly represents the mapping relationships from functional to physical elements. Additionally, the research established the logic for change propagation and validity calculation. Using an air-conditioning refrigeration system as a case study, the model was validated, demonstrating its advantages for improving the efficiency of change-impact analysis, enhancing compliance verification, and ensuring scenario reproducibility.
Xie, Xiang, Meng, Xu, Zhang, Xinyuan, Wu, Binbin
Mechanical Properties and Freeze-Thaw Resistance of Modified Portland Cement-Stabilized Soil for Road Engineering2026-99-15809/11/2026
Subgrade soil is related to the load on the upper part of the road, and its properties will affect the road surface conditions. Frost-thaw action will damage the soil in cold regions. This study focuses on the fine-grained sand in Jilin affected by seasonal frost-thaw, and explores the effects of mixing amount (0% - 6%), curing time (7 days, 28 days), and frost-thaw cycle times (0, 5, 10, 20 times) on the DRM (dynamic resilient modulus) and UCS (unconfined compressive strength) of Portland cement-stabilized soil. The results are: the increase of mixing amount and the extension of curing time will both increase the UCS and DRM; frost-thaw cycles will reduce the UCS and DRM. Roads in cold regions need to use 4% modifier mixture for maintenance for 28 days to achieve strength stability. Heavy subgrades use 6% modifier to obtain the best stiffness load - bearing. This study has insightful guidance for subgrade material improvement in seasonal frozen soil regions.
Wang, Shujuan, Duan, Yonggang, Qin, Weijun, Shen, Ruoting, Jin, Chenguang
Optimization of Order Picking in an AMR-Assisted Picker-to-Parts System2026-99-15679/11/2026
With global retail sales expanding and same-day delivery demand on the rise, efficient order picking operations in warehouses have become critical to success. To improve order picking processes, warehouse managers increasingly rely on autonomous mobile robots (AMRs), which improve the performance of traditional picker-to-parts systems. This paper investigates an AMR-assisted picker-to-parts system in which a set of customer orders must be fulfilled. The orders are first batched, and the resulting batches are assigned to individual pickers. Each picker works in a batch-by-batch manner, manually retrieving items from picking aisles and handing over the completed batch to an AMR waiting at the cross aisle. After receiving a full batch, the AMR transports it to the designated depot before returning to serve the next batch. The objective is the minimization of the total tardiness of all orders. The problem is formulated as a mixed-integer programming (MIP) model, and several effective heuristic algorithms are developed. Extensive computational experiments are conducted to evaluate the performance of the proposed algorithms and compare them with a commercial MIP solver.
Jin, Bo, Peng, Jianxin
An Improved Genetic Algorithm for Multimodal Hinterland Empty Container Repositioning Considering Demurrage and Detention charges2026-99-15279/11/2026
The imbalance of global trade exacerbates the mismatch between supply and demand of empty containers, requiring rapid repositioning from import to export regions, so empty container repositioning has long been a focus of research. Compared to maritime repositioning, hinterland empty container repositioning is more complex because it occurs over a sophisticated multimodal transport network. Rail and inland waterways typically offer high capacity at lower cost, and hinterland container operators often consolidate containers and move them in batches to achieve economies of scale. In addition, demurrage and detention (D&D) charges, imposed on operators for delayed container returns, have remained high in recent years. Traditional hinterland empty container repositioning approaches that focus solely on transportation costs often overlook these time-related penalties, leading to higher total repositioning costs. To address this, we first develop a generic hinterland empty container repositioning optimization model that integrates both transportation costs and demurrage and detention charges while capturing batch-based dispatching characteristics observed in practice. Second, due to the model’s non-convex and combinatorial nature, traditional solvers struggle to provide efficient solutions. We further develop an improved genetic algorithm (GA) to solve this non-convex MINLP problem. The results of numerical experiments showcase the benign performance of our improved GA. Finally, we conduct a real-world case study based on a 2025 operation in China. The results demonstrate that minimizing transportation costs alone results in higher total repositioning expenses, while jointly optimizing transportation and D&D costs leads to more balanced and cost-effective repositioning strategies. This highlights the practical necessity of incorporating D&D considerations into HECR decision.
Yu, Mingzhu, Yang, Haoran, Zhang, Lingge
A Maritime Occluded Ship Detection and Tracking Method Based on Improved YOLOv8 Fused with AIS Trajectory2026-99-15499/11/2026
Typical maritime monitoring scenarios are usually constrained by factors such as multi-scale ship density, frequent motion overlap, and limited viewing angle of shore-based cameras. These challenges often lead to trajectory interruptions and identity mismatches in target detection and multi-target tracking tasks. In order to solve these problems, this study proposes a ship occlusion detection and tracking method based on the improved YOLOv8 model and further integrates an automatic identification system (AIS) trajectory reasoning. The method builds a unified perception framework with enhanced detection architecture, multi-source data fusion, and behavioral reasoning capabilities. First, in the target detection module, the improved SEConv structure is introduced into the YOLOv8 trunk network to address challenges caused by small-scale variations and severe occlusion in maritime scenes. The ReLU activation function in SEConv is replaced by the Swish activation function to enhance the nonlinear feature representation. In addition, the optimized SEConv is embedded in the C2f structure, and the convolutional block attention module (CBAM) attention mechanism is introduced to enhance the sensitivity of the model to the occlusion area. Next, for multi-target tracking, ByteTrack is used as the basic tracking framework. AIS trajectory data is introduced as auxiliary input to compensate for trajectory losses caused by occlusion. Finally, experimental results on the SeaShips public dataset and the self-built occlusion reference dataset show that the improved YOLOv8 detector achieves stable mAP gains in mild, moderate, and severe occlusion scenarios. The AIS enhanced tracking system improves the multi-target tracking accuracy (MOTA) and identification F1 score (IDF1) by about 6.3% and 8.1%, respectively, and the average occlusion reconstruction error is controlled within 1.4 seconds. The proposed method effectively enhances the perception ability of ships in complex occlusion environments and verifies the feasibility and superiority of the strategy of combining visual detection with AIS data assistance.
Guan, Keping, Chen, Miao, Zhou, Yue
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
Steel, Bars, Forgings, Mechanical Tubing, and Forging Stock, 1.45Cr (0.93 - 1.05C) (SAE 52100), Aircraft Quality For Bearing ApplicationsAMS6440U (Current)9/10/2026
This specification covers a low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
AMS E Carbon and Low Alloy Steels Committee
Steel, Corrosion- and Heat-Resistant, Bars, Wire, Forgings, Forging and Ring Stock, Mechanical Tubing, and Rings, 12Cr (410 MOD), Ferrite Controlled, Annealed, Consumable Electrode MeltedAMS5611H (Current)9/10/2026
This specification covers a premium aircraft-quality, corrosion- and heat-resistant steel in the form of bars, wire, forgings, mechanical tubing, flash-welded rings, and stock for forging or flash-welded rings.
AMS F Corrosion and Heat Resistant Alloys Committee
Cobalt Alloy, Corrosion- and Heat-Resistant, Investment Castings, 60Co - 29Cr - 4.5W (Stellite® 6), As CastAMS5387G (Current)9/10/2026
This specification covers a corrosion- and heat-resistant cobalt alloy in the form of investment castings.
AMS F Corrosion and Heat Resistant Alloys Committee
Steel Bars, Forgings, Mechanical Tubing and Forging Stock 1.75Cr - 4.0Ni - 0.5Mo - (0.35 - 0.40C) Premium Aircraft Quality Consumable Electrode Vacuum RemeltedAMS6551B (Current)9/10/2026
This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.
AMS E Carbon and Low Alloy Steels Committee
Steel, Corrosion-Resistant, Bars, Wire, Forging, and Forging Stock, 13Cr (0.30-0.40C) (420), AnnealedAMS5621J (Current)9/10/2026
This specification covers a corrosion-resistant steel in the form of bars, wire, forgings, and forging stock.
AMS F Corrosion and Heat Resistant Alloys Committee
Steel, Corrosion- and Heat-Resistant, Bars, Wire, Forgings, Mechanical Tubing, Rings, and Forging Stock, 18Cr - 10Ni - 0.40Ti (SAE 321), Solution Heat TreatedAMS5645U (Current)9/10/2026
This specification covers a corrosion- and heat-resistant steel in the form of forgings, wire, bars, mechanical tubing, flash-welded rings, and stock of any size for forging or flash-welded rings.
AMS F Corrosion and Heat Resistant Alloys Committee
Aluminum Alloy, Sheet and Plate, 4.4Cu - 1.5Mg - 0.60Mn (2024; -T3 Flat Sheet, -T351 Plate), Solution Heat TreatedAMS4037S (Current)9/10/2026
This specification covers an aluminum alloy in the form of sheet and plate from 0.008 to 4.000 inches (0.20 to 101.60 mm) in thickness, inclusive (see 8.5).
AMS D Nonferrous Alloys Committee
Laser PeeningAMS2546B (Current)9/9/2026
This specification covers the requirements for computer-controlled laser peening of metal part surfaces to induce residual compressive stresses at and beneath the surface.
AMS B Finishes Processes and Fluids Committee
CRIMPING TOOL AND ACCESSORIES, HAND OPERATED, DIE TYPE, WIRE SIZES 8 TO 0000 UN-INSULATED AND INSULATED CRIMP BARRELSAS5259/3C (Current)9/9/2026
AE-8C2 Terminating Devices and Tooling Committee
Compound, Corrosion-Preventive, Thin Film, Fingerprint RemovingAMS3065J (Current)9/9/2026
This specification covers corrosion-preventive organic substances dissolved or emulsified in a volatile solvent and supplied in the form of a ready-to-use liquid.
AMS B Finishes Processes and Fluids Committee
Titanium Alloy, Investment Castings 6Al - 4V, 130 UTS, 120 YS,6% EL, Hot Isostatically Pressed, Anneal Optional or When SpecifiedAMS4985F (Current)9/9/2026
This specification covers a titanium alloy in the form of investment castings (see 8.6).
AMS G Titanium and Refractory Metals Committee
2025 6th International Conference on Applied Mechanics and Mechanical Engineering2026-99-12009/4/2026
TOC
Tobolski, Sue
Experiments on Effects of Self-Locking on Mechanical Response of Origami Metamaterials2026-99-12069/4/2026
Motivated by the negative Poisson’s ratio tetrahedral-trihedral polyhedron (TMP), this study systematically examines the role of self-locking mechanisms in determining the mechanical response and energy absorption capacity of rigid origami metamaterials. Quasi-static compression tests were conducted on specimens exhibiting three distinct geometries (B19, B22, B23) and four wall thicknesses (0.8–2.0 mm). The results of these tests revealed two unique self-locking behaviors. Type I self-locking originates from inter-wall interlocking, characterized by progressively decreasing inter-wall spacing during compression; Type II self-locking originates from interlocking between creases, characterized by creases contacting each other during compression. The fabrication of the specimens was accomplished through the utilization of FDM-based additive manufacturing, employing PEEK material. The results obtained from this study revealed two distinct locking behaviors: It has been demonstrated that type I locking enables sustained deformation without load reduction. In contrast, type II locking has been shown to result in premature collapse and diminished energy absorption capacity. The B22 configuration has been demonstrated to trigger both locking mechanisms concurrently, thereby significantly enhancing performance metrics. This has been evidenced by improvements in both crush force efficiency (CFE) and specific energy absorption (SEA), whilst also delaying densification. In contrast, structures dominated by a single locking mechanism exhibit premature failure (B19) or inefficient energy absorption (B23). These findings emphasize the pivotal role of synchronized self-locking activation and geometric configuration in enhancing impact resistance and energy dissipation, thereby establishing a foundational theoretical framework for the design of advanced metamaterials in protective engineering.
Wu, Baoji, Wang, Hairui, Jiang, Heng
Application of Two-Component Flocculant Underwater Non-Dispersible Concrete in Ship Lock Engineering2026-99-12829/4/2026
To tackle the challenges of pronounced dispersion and inadequate cohesion of concrete in the underwater repair of ship lock engineering, this study presents a novel approach involving acrylate copolymer emulsion (PAE) and waterborne polyamine curing agent (WE) as the two-component flocculant, integrated with fiber modification technology, to fabricate non-dispersible concrete tailored for ship lock underwater rehabilitation. Mechanical property tests and elastic modulus analyses demonstrate that the resultant concrete exhibits significantly improved scour resistance, endowing it with robustness against erosion in complex subaqueous environments. This work thus offers a dependable technical solution for the structural repair and toughening of ship lock structures.
Li, Jun, Zhu, Xunsong, Yang, Ning, Meng, Xingyu, Zong, Jiawei
The Flexibility Coefficient Fitting of Bolt in Metal-Composite Hybrid Joint Structures Based on L-M Method2026-99-12679/4/2026
This study used the L-M (Levenberg-Marquardt) algorithm to analyze the fitting of the flexibility coefficient of fasteners in the mixed connection structure of metal composite materials to address key challenges in aircraft structural design. Through parametric modeling and finite element simulation of single lap joints, the system evaluates eight key factors, including the direction of the composite material layer, the elastic modulus of the metal plate, the plate thickness ratio, the fastener diameter, the elastic modulus of the fastener, the Poisson’s ratio of the fastener, the magnitude of the preload force, and the type of bolt configuration, covering convex and countersunk variants. Advanced material modeling techniques are introduced in the study to accurately capture the anisotropic behavior of the composite material layer and its interaction with metal components under different load conditions. The results show that the higher modulus and thickness of the composite material plate and metal plate significantly reduce the flexibility of fasteners, and larger fastener diameters are associated with reinforcement. The elastic modulus further reduces flexibility. The flexibility of convex head bolts is significantly lower than that of countersunk head bolts, while Poisson’s ratio, preload force, and humidity have little effect. Based on these findings, a new flexible calculation formula containing nine undetermined parameters is proposed. The L-M algorithm is used for nonlinear regression to derive formulas with physical significance. The verification shows that the proposed formula is highly consistent with the finite element results, with a corrected coefficient of determination of 0.956. Among 864 test sample points, 73.61% have an error of less than 5%, and only 0.23% have a deviation of more than 15%. Comparative analysis with twelve existing methods, including the Delft University and Boeing formulas, confirms that the proposed method has better accuracy. This method effectively expands the applicability of traditional flexible formulas, provides solid theoretical support for advanced aircraft connection design, and realizes diverse mixing in aerospace engineering and accurate calculation of connection configuration.
Fan, Zhuotao, Wang, Xu, Wang, Tong, Li, Xianchao
Items per page:
1 – 50 of 45833