Browse Topic: Materials

Items (66,466)

System-Level Simulation of Air Disc Brake under Dynamic Braking Conditions for Design Optimization

2026-01-5086

11/11/2026

Air disc brakes are commonly used in trucks due to their superior performance compared to conventional drum brakes. To validate the brake assembly, extensive physical tests are conducted for the required brake torque condition. The aim of the study is to correlate the physical test deformation and failure modes using finite element analysis (FEA) and to optimize the design variables. Initially, there was a correlation gap between the test and FEA as the braking event was simulated with estimated static loads at the interfaces. Though the geometry is symmetric, during brake application, there are unsymmetric loads acting on the assembly along the direction of the rotation of the rotor due to dynamic deformation as the torque is generated at the friction pad interface. To simulate this unsymmetric behavior, the dynamic implicit analysis procedure with a moderate dissipation approach in Abaqus/Standard is used. To correlate the clamping force required to generate the braking torque achieved in the physical test while rotating the disc, dry and sliding friction parameters and the modeling of other mechanisms are iterated. By using this approach, the tangential loads at the friction interface, load transfer through other contact interfaces, and corresponding changes in stress levels are well captured. With this improved method, the deformation modes and failure locations are well correlated with the physical tests with an optimized simulation time. As contact interactions are well captured in assembly-level simulations, further part-level design iterations can be carried out by mapping interaction loads from other parts. Due to the improved accuracy of the FEA methodology, topology optimization is also carried out to reduce mass by a considerable amount. This FEA methodology adds value to the organization as it helps in validating and optimizing the brake assembly at the initial concept phase itself to achieve the required fatigue performance at the design-rated torque.

Dhayaanidhi, K. V., Amirtharaj, D., Vasanth Bharath, S., Murugan, S.

Multi-Dimensional Suitability Analysis-Based UAV Platform Selection for Chemical Contaminant Detection Sensors

2026-99-2203

11/6/2026

Unmanned aerial vehicles (UAVs) equipped with chemical contaminant sensors offer an innovative approach for rapid and safe remote chemical reconnaissance. However, the proliferation of diverse UAV platforms presents a critical challenge: how to select the optimal platform for a given mission scenario. This paper establishes a systematic suitability analysis framework for deploying chemical contaminant sensors on three mainstream UAV platforms-multirotor, fixed-wing, and vertical take-off and landing (VTOL) types. We analyze payload capacity, endurance, flight stability, environmental adaptability, and mission system integration. To reduce decision subjectivity, we develop an Analytic Hierarchy Process (AHP)-based quantitative evaluation model incorporating expert surveys and consistency tests to validate the weighting process. Beyond the evaluation framework, we explore key engineering challenges in platform-sensor integration, including aerodynamic interference, vibration and electromagnetic compatibility, and power management. We compare quantitative measurements and qualitative features across platforms in simulated mission scenarios. The resulting selection criteria provide a theoretical basis and a reproducible decision-support framework for developing chemical detection systems applicable to emergency response, environmental monitoring, and public safety.

Liang, Ting, Wen, Hao, Qi, Yelin, Yang, Wen

Research on a Structured Modeling Method for Aero-Engine Complex Piping System Based on L-System

2026-99-0639

11/6/2026

This paper proposes a structured description and discretized modeling method for aero-engine complex piping systems based on the Lindenmayer system (L-system). By leveraging the grammatical rewriting rules and parametric extensions of L-system, a tree-like structural description and geometric discretization of piping are achieved, addressing the structural characteristics of both typical pipes (e.g., I-type, L-type) and complex three-dimensional pipes (e.g., bifurcated pipes, helical pipes). The proposed framework is further extended to integrate physical attributes, enabling the unified expression of geometry, topology, material, and cross-sectional properties within a single symbolic system. Furthermore, by comparing the dynamic characteristics of continuous and discrete structures in free modal analysis, the feasibility and accuracy of equivalent modeling using discrete straight segments are demonstrated. The discretization granularity is discussed, and the method’s adaptability for different analytical precision requirements is established. This approach successfully unifies the geometric description, structural discretization, and physical property assignment of complex piping, providing a new structured and automated pathway for rapid modeling, dynamic analysis, and optimization design of aero-engine piping. The inherent parameterization and automation advantages of the L-system also open avenues for automatic layout generation, integration with intelligent optimization algorithms, and future development towards a comprehensive “geometry compiler” for CAD/CAE interoperability and digital twin applications.

Zhao, Zhifang, Wang, Xin, Chen, Nan, Liu, Na, Li, Linjie, Wu, Feng

Experimental Investigation on the Failure Behavior of TMC Open-Hole Panels under Tensile Loading

2026-99-0602

11/6/2026

Investigating the load-bearing capacity of Titanium Matrix Composites (TMCs) open-hole panels and their mechanically connected components is of great significance for the application of titanium matrix composites in the aerospace field. This paper investigates the failure behavior of TMC open-hole panels with a [45°/45°/-45°/-45°] laminate configuration under tensile loading. Tensile tests were conducted in conjunction with finite element modeling to analyze the damage evolution process and identify the failure modes of the tensile samples. The results show that the simulation outcomes exhibit good consistency with the experimental results, providing a foundation for the structural optimization and theoretical study of TMC open-hole panels.

Gao, Ximan, Jia, Qiuyue, Liu, Shanshan, Meng, Fanling

Human–Machine Simulation of Lunar Surface Environment Maintenance

2026-99-0628

11/6/2026

In China's manned space programs, extravehicular activities (EVAs) of astronauts on the lunar surface include the assembly, maintenance, and repair of the space station, as well as the operation of extravehicular equipment. Scientific working postures can alleviate occupational fatigue, ensure the health of astronauts, and significantly improve operational efficiency. The human engineering of aerospace equipment based on virtual simulation technologies has long been a focus of attention in the aerospace field. The Jack Software can be used to conduct ergonomic simulation analysis of the comfort of the operating postures of different percentile operators, and thereby explore the rationality of aerospace maintenance operation postures. Based on this, the Jack virtual simulation technology is employed here to study the ergonomics of the entire process of aerospace maintenance operations. The rationality of the simulation results is verified through simulation–based optimization, and corresponding design improvements are realized according to the analysis results to improve the operational efficiency and comfort of operators. This study provides a reference for the ergonomic evaluation and design improvement of domestic aerospace maintenance operations.

Wang, Xi, Gan, Yu

An Interactive Click-Based UAV Path Planning Method for Anti-Corrosion Spraying Using BIM-SLAM Fused 3D Models

2026-99-0637

11/6/2026

To solve the critical challenges of uncoordinated operational node selection and premature mission termination caused by dynamic energy or coating depletion during anti-corrosion spraying on largescale steel structures, this paper proposes an advanced path planning methodology for UAVs. The proposed approach is built upon a BIMSLAM fusion model. Specifically, a high-fidelity three-dimensional (3D) environmental model is reconstructed by integrating offline BIM structural priors with real-time SLAM data. Furthermore, the framework implements the ICP algorithm and Kalman filtering simultaneously to eliminate point cloud noise and compensate for perceptual occlusions, thereby achieving a 5 cm localization accuracy in cluttered industrial environments. A dual-stage pipeline is established for pre-screening and dynamic evaluation. In the offline phase, geometrically inaccessible task points are identified and pruned via spatial accessibility analysis. During real-time operations, the onboard system continuously calculates the battery State of Charge (SoC), operational power, and remaining paint volume to eliminate inefficient flights. For the path generation stage, a hybrid search strategy is developed, which implements a Genetic Algorithm for task sequencing alongside a multi-objective cost function parameterized by four metrics: energy consumption, paint requirements, obstacle proximity, and task density. Additionally, Softmax is used to dynamically regulate the weight coefficients, enabling the system to balance operational safety and efficiency based on the instantaneous state vector. Finally, a fifth-order B-spline parameterization is used to maintain flight stability under complex wind disturbances and heavy time-varying payloads. Consequently, the results show that the proposed method significantly outperforms conventional baselines. The recorded 96.7% mission completion rate demonstrates its operational reliability for the maintenance of bridges and towers.

Qian, Lei, Huang, Chen, Tan, Libin, Huang, Tao

Research on Quantification Methods for Nonlinear Forming Length of Ultra-Thin Flat Wires in Flat Wire Motors

2026-99-1913

11/6/2026

Because of the imprecision of length quantification in the manufacturing of flat wire windings for flat wire motors, empirical allowances have long been a common practice in production, which in turn leads to considerable material waste and elevated production costs. This paper presents an integrated solution that fuses material experiments, reverse engineering, simulation iteration and parametric design, realizing accurate prediction and quantitative calculation of winding forming length. First, high-precision elastic-plastic constitutive relationships of flat wires are acquired through room-temperature uniaxial tensile tests. On this basis, reverse engineering is applied to derive the initial geometric characteristics and process motion paths of flat wire windings from the 3D model of finished products. Next, an innovative closed-loop iterative compensation algorithm is constructed, with the forming height of the innermost flat wire layer serving as an absolute reference; finite element simulation is then utilized to dynamically optimize the forming length of each flat wire layer. Finally, a parametric design system with a visual interactive interface is developed, which enables an intelligent workflow where precise cutting lengths and equipment motion curves are automatically generated upon input of key design parameters. Production validation results show that this method drastically reduces the length allowances of flat wires, markedly lowers the production scrap rate, and shortens the process debugging cycle of new motor models by more than 80%.

Li, Wenbin, Zhu, Ye

Anchoring Mechanics Analysis and Structural Optimization of Slip for Pipeline Plugging Robot

2026-99-1915

11/6/2026

Reliable anchoring of slip is essential for preventing axial slippage of pipeline plugging robots under high-pressure plugging conditions. However, excessive tooth penetration may induce furrow formation, local plastic deformation, and hard-contact damage on the inner wall of the pipeline. To balance anchoring capacity and pipe-wall protection, this study establishes a mechanical model for the slip–pipe interaction and analyzes the effects of key structural parameters on slip anchoring performance. The self-locking condition between the slip and slip bowl is first derived, and the minimum equivalent friction coefficient required for stable anchoring is determined. Subsequently, an explicit finite element model of the slip anchoring process is developed to evaluate the influence of bevel angle, tooth profile angle, and curvature radius on the von Mises stress and equivalent plastic strain of both the slip and the pipe wall. Based on the simulation results, an orthogonal parameter optimization scheme is conducted to identify the optimal structural combination. The results show that the optimized slip structure, consisting of a 20° bevel angle, a 90° tooth profile angle, and a 150 mm curvature radius, can effectively reduce pipe-wall damage while maintaining reliable anchoring performance. This study provides a theoretical and numerical basis for the structural design and optimization of anchoring slip in pipeline plugging robots.

Wang, Mingkuan, Zhang, Enchao, Gao, Ang, Shao, Hongyuan, Zhang, Shimin, Zhu, Xiaoxiao

Investigation on Interface Analysis and Process Simulation of Electromagnetic Pulse Welding for Automotive Copper Terminal/Aluminum Conductor Joints

2026-99-1922

11/6/2026

To suppress the formation of brittle intermetallic compounds typically generated during conventional joining of Cu/Al dissimilar materials in the automotive lightweighting sector, this study examines the interface properties and process simulation of electromagnetic pulse welding technology for connecting copper terminals to aluminum conductors. High-quality welds exhibit a wavy interface composed of interpenetrating metallic phases, according to microstructural research. To represent workpiece dynamics, magnetic field distribution, and impact behavior under discharge voltages ranging from 4 to 5.5 kV, a linked electromagnetic-structural finite element model was developed. According to simulation data, increasing the discharge voltage significantly enhances impact pressure, strain rate, and magnetic flux density, all of which support strong contact bonding. The study offers a reference for the lightweight production of automobile electrical connectors by demonstrating the impact of process factors on weld quality.

Li, Liang, Lei, Xiaokun, Fang, Cheng, Li, Yaxiong, Tang, Ming, Wang, Hu, Xie, Chong, Du, Changqing

Design and Analysis of a Continuous Drying Process and Equipment for 3D Hollow Polyester Fiber Production

2026-99-1903

11/6/2026

In the production of polyester fibers from recycled polyethylene terephthalate (rPET), the drying and crystallization of plastic bottle flakes are crucial for ensuring the consistency and strength of the finished fibers. Traditionally, rPET production lines still rely on vacuum drum dryers, which have been suffering from issues including agglomeration, uneven heating, and high energy demand. In this work, we developed a novel continuous system that is capable of achieving a total throughput of 1300 kilograms per hour. The design consists of a pulsating fluidized-bed crystallizer and two cylindrical drying towers operating in parallel. Structural performance of the main systems was analyzed using finite element analysis under material load, thermal expansion, and internal air pressure. Airflow behavior and temperature distribution inside the units were studied using Computational Fluid Dynamics (CFD) models, where the flake bed was treated as a porous medium based on experimental bulk density and pressure drop. Results showed that the drying tower maintained a minimum safety factor above 3 under full-load conditions, while the crystallizer also remained well within allowable stress limits. Additionally, flow-field analysis results indicated stable countercurrent airflow, adequate mixing near the inlet region, as well as acceptable axial temperature gradients for moisture removal below 50 ppm. Compared with conventional drum drying, we believe the continuous configuration simplifies operation and reduces heat loss. Our design approach has been combined with analytical calculations on structural and flow simulation, and can be beneficial when applied to similar rPET drying applications.

Wu, Ye, Wu, Tianqi, Ge, Yuchen, Ni, Hongjun, Tan, Linwei, Lv, Shuaishuai

Study on Corrosion of the Vehicle Body Sheet Metal and Exterior Chrome-Plated Parts in Typical Climatic Environments

2026-99-1907

11/6/2026

This paper examines the corrosion of vehicle body metal panels and external chrome-plated components under typical climatic conditions. Specifically, we analyse the potential corrosion mechanisms and influencing factors, and propose protective and improvement measures. The research indicates that corrosion at the interface between body sheet metal and exterior chrome-plated parts is predominantly characterized by galvanic corrosion and crevice corrosion. These problems are caused by the potential difference between the materials, assembly gaps, moisture retention, and the influence of contaminants. The authors analyse climatic data from seven representative cities in eastern, southern, southwestern, northeastern, and northwestern China. The study reveals the synergistic effects of environmental factors (such as NO2, SO2, precipitation, temperature, and relative humidity) on metal corrosion. The results show that the static corrosion rate of carbon steel is higher in the southwestern, southern, and eastern coastal regions (reaching over 98 μm/a at maximum) and lower in the northeastern and northwestern regions (approximately 10 μm/a). Field investigations of more than ten vehicle models in eastern coastal cities of China have found that chrome-plated parts in areas such as engine compartment cover plates, window trims, and trunk lid panels are prone to corrosion due to structural interference, assembly-induced damage, and poor drainage performance. Consequently, the authors propose protection measures through optimizing Chromium plating processes, improving structural designs (e.g., adding sealing strips, designing rounded transitions, and increasing drainage gaps), and adjusting assembly methods (e.g., adopting adhesive bonding or encapsulated clips), which effectively reduce corrosion risks. Finally, the authors conduct professional tests to verify the corrosion resistance of vehicle chrome-plated parts. This paper provides a reference framework for enhancing the corrosion resistance of vehicle exterior components, offering crucial guidance for improving the overall aesthetic quality of vehicles and enhancing customer satisfaction.

Liu, Peng, Zhuang, Mengmeng, Chen, Junjie, Wang, Jiayu, Wu, Weixing, Ren, Kaixu, Wang, Wentao, Li, Yan

Influence of Transversely-Isotropic Lining Elastic Constants on Brake Squeal in S-Cam Drum Brakes: An Optimization Framework

2026-28-0161

11/5/2026

Brake squeal in heavy-duty S-cam drum brakes remains a persistent NVH challenge, primarily driven by friction-induced modal instabilities. Existing studies on drum brake squeal mitigation largely emphasize geometric modifications, stiffness tuning, or the application of damping treatments, while the influence of directional stiffness characteristics of friction linings remains insufficiently explored. This research presents a novel, material-centric approach by modelling the brake lining as a transversely isotropic material, characterized by six independent elastic constants, and systematically quantifying their influence on squeal-prone unstable modes using Complex Eigenvalue Analysis (CEA). A validated finite-element model of a production S-cam drum brake assembly is developed and correlated through experimental modal analysis, ensuring close agreement between predicted and measured natural frequencies and mode shapes. The validated model is then integrated with a Design of Experiments (DOE) within commercially available FEA software to quantify both main effects and higher-order interactions across practical ranges of in-plane and out-of-plane elastic moduli and shear constants. To enhance the predictive accuracy of the surrogate models, a subsequent sampling–fit study is conducted, significantly improving the coefficient of determination (R2) of the response surfaces. The refined surrogate models are employed within a Global Response Surface Methodology (GRSM) framework to perform multi-parameter optimization aimed at minimizing squeal propensity under representative operating conditions. Finally, complex eigenvalue analysis quantifies the impact of the optimized transversely isotropic property combinations on modal stability, establishing a predictive, optimization-driven methodology for robust, noise-free drum brake design. The study culminates in the identification of an optimized transversely isotropic elastic-constants signature for the friction lining, providing actionable targets for friction material formulation and reinforcement alignment. Unlike prior research focused on isotropic material assumptions or component-level design changes, this first-of-its-kind methodology advances the state of the art by enabling friction material– centric NVH optimization for heavy-duty drum brake systems.

Philip, Rony, Muralidharan, Sudharsan, Mohanam, Gopalakrishnan

An Intelligent Computer Vision Framework for Duplicate Part Detection in Complex CAD Assemblies

2026-28-0173

11/5/2026

Duplicate components in large-scale Digital Mock-Up (DMU) assemblies present a significant challenge to product integrity within Digital Twin environments operating on integrated OEM Product Lifecycle Management (PLM) platforms. These duplicates, often referred to as structural redundancies or doubloons, are characterized by geometrically identical or equivalent components occupying the same spatial location without corresponding justification in the Bill of Materials (BOM). Such inconsistencies arise from increasing assembly complexity, tool integration issues, and limitations of conventional scripting-based validation approaches. Existing duplicate detection methods rely heavily on manual inspection and isolated tool functionalities, making them impractical for large-scale assemblies. While interference analysis tools can detect spatial conflicts, they cannot reliably distinguish between valid engineering overlaps and unintended duplicate conditions. Consequently, a more structured and automated validation strategy is required. This paper presents an automated computer vision-based methodology developed within an OEM Digital Twin environment to address these challenges. The proposed framework combines interference-data extraction, image-based overlap assessment, automated duplicate screening, Active Feedback Learning, and BOM-integrated validation within a unified workflow. The methodology transforms interference-derived information into structured analytical features and uses Red Percentage–based overlap evaluation to identify potential duplicate conditions. The proposed approach enables scalable duplicate detection across complex assemblies while reducing dependence on manual review. Validation on production-scale automotive DMU datasets demonstrated significant reductions in engineering effort and substantial filtering of non-actionable interference records. By integrating computer vision analytics, feedback-driven noise elimination, and product structure validation, the proposed framework improves Digital Twin data integrity and supports efficient engineering workflows in modern OEM PLM environments.

Gnanaprakasam, Hepshibha, Sridhar, Ashok

Advanced Semiconductor Derating Methodology for Electronic Circuits and Validation

2026-28-0172

11/5/2026

In current and futuristic electronic designs, ensuring the accuracy and reliability of electrical circuits over all component parameter variation and operating condition, requires validation across multiple domains - mathematical modelling, simulation, and physical measurements. Before committing to physical board fabrication, simulation has become a critical step in the circuit design process. With increasing design complexity, engineers rely heavily upon simulation tools to predict circuit behavior, optimize performance, and reduce the number of design iterations. The effectiveness of simulation lies not only in its ability to provide accurate representations of real-world circuit behavior, but also capturing key electrical characteristics such as voltage levels, frequency response, accurate modeling of component tolerances and coefficients, etc. It should also excel in efficiency-allowing rapid iteration, testing under varied conditions, evaluation of multiple scenarios without excessive computational costs, and quick comparisons of design alternatives. This paper presents an advanced semiconductor derating methodology that addresses the limitations of conventional approaches through automation. The derating algorithm has been developed and implemented using Maple (Mathematics based Tool) to generate precise worst-case values of semiconductor component parameters adjusted for specific circuit operating conditions. This automated tool significantly enhances both the efficiency and accuracy of mathematical analysis results, providing engineers with more reliable performance predictions for electronic circuit design. This paper also presents a comparative study that analyzes and correlates the performance of an electrical circuit obtained through worst-case mathematical analysis using internal tool, simulations using industry-standard tools, and the result collected during internal testing of the product. The objective is to evaluate how closely theoretical predictions and simulations align with real-world behavior and to identify factors contributing to any discrepancies.

Mishra, Anshul, M. S., Suhas

A Surrogate Modeling Approach for the Weight Optimization of a Two Wheeler Chassis with PSD Based Durability Validation

2026-28-0207

11/5/2026

As the global automotive industry pivots toward sustainable mobility, reducing vehicle curb weight remains a paramount objective for enhancing energy efficiency and range. This paper presents a robust and comprehensive methodology for the light weighting of a two-wheeler chassis through the integration of Design of Experiments based optimization and Power Spectral Density durability analysis. The study begins by establishing a baseline durability profile for the vehicle using frequency-domain durability simulations under random vibrational loading, ensuring a benchmark for structural integrity. To explore the design space effectively, frame tube thicknesses are parameterized, and a Design of Experiments design matrix is constructed using Modified Extensible Lattice Sequence technique. This design matrix is solved, and a response matrix is built. These two matrices are combined, and appropriate curve-fitting techniques are applied to construct a Reduced Order Model. This mathematical surrogate model enables the rapid evaluation of the frame’s response under varying frame thickness combinations, thereby avoiding computationally expensive traditional Finite Element Analysis iterations. The optimum combination of frame tube thicknesses is identified using the Global Response Surface Method. This configuration minimizes the overall mass of the vehicle while strictly maintaining predefined durability and safety targets. The final optimized frame is evaluated by a secondary Power Spectral Density durability analysis to validate the accuracy of the surrogate model’s predictions. The integration of this metamodel-based design approach results in a significant reduction in structural weight. Ultimately, this framework accelerates the design cycle by developing a lightweight, cost-effective, and durable structure, thereby minimizing the overall time-to-market for sustainable automotive products.

Chettiar, Alfred Selvamani, V., Vinothkumar, S., Deepak, Praveen, Kannan

Machine Learning Model for Stress Strain Behavior Extraction at Different Strain Rates

2026-28-0189

11/5/2026

Accurate representation of strain-rate dependent stress–strain behavior is essential for reliable structural analysis and crashworthiness assessment in automotive engineering as vehicle structures and safety-critical components experience a wide range of loading conditions, from quasi-static deformation during forming and durability events to high strain-rate loading during crash and impact scenarios. Conventional material characterization approaches rely on extensive experimental testing to generate strain-rate dependent constitutive data, including specialized high strain-rate techniques that are costly, time intensive, and require dedicated infrastructure, which often limits the availability of comprehensive material data during early vehicle development phases and supplier evaluation. This paper presents a data-driven methodology for predicting strain-rate dependent stress–strain behavior of automotive steels using limited experimental input data. The proposed approach integrates physically meaningful material properties with a machine-learning framework to construct a generalized stress prediction model that remains consistent with classical material mechanics principles. Fundamental parameters governing material behavior, including strain, strain rate, yield stress, density, Poisson’s ratio, and elongation limit, are used as inputs to capture the combined influence of deformation state, loading rate, and intrinsic material characteristics. A Random Forest regression algorithm is employed to model nonlinear relationships without relying on predefined analytical hardening or rate-sensitivity formulations. The methodology is developed and validated using experimentally obtained stress–strain data from multiple automotive steel grades under quasi-static and dynamic loading conditions, and model performance is evaluated through correlation analysis between predicted and experimental stress responses across the full strain range. The results demonstrate strong agreement with experimental observations and robust generalization capability across different materials and strain-rate regimes, with minor deviations observed at very high strain levels attributed to limited data density near fracture conditions. The proposed framework significantly reduces dependence on extensive physical testing while maintaining accurate representation of material behavior, providing a practical and efficient alternative for material characterization that supports faster material selection, reduced testing effort, and improved robustness of automotive computer-aided engineering simulations.

Shedolkar, Pravinkumar, Dudhewar, Swapnil, Shukla, Anurag, Mhaskar, Dnyaneshwar, Chavan, Avinash, Kakade, Ajit

2025–2026 Reviewers

05-19-04-0033

11/5/2026

2025–2026 Reviewers

Barkey, Mark

Steel, Maraging, Welding Wire, 18Ni - 8.0Co - 4.9Mo - 0.40Ti - 0.10Al (Maraging 250), Vacuum Induction Melted, Environment Controlled Packaging

AMS6501F (Current)

11/4/2026

This specification covers a maraging steel in the form of welding wire.

AMS E Carbon and Low Alloy Steels Committee

Steel Bars, Forgings, Mechanical Tubing, and Forging Stock, Nitriding, 3Cr - 1Mo - 0.2V - (0.29 - 0.36C), [3% Cr-Mo-V], Premium Aircraft-Quality for Bearing Applications, Double Vacuum Melted

AMS6481F (Current)

11/4/2026

This specification covers a nitriding grade of 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, Investment Castings, 15Cr - 4.6Ni - 0.22Cb (Nb) - 2.8Cu (15-5 PH®), Solution and Precipitation Heat Treated (H1000), 150 ksi (1034 MPa) Tensile Strength

AMS5347D (Current)

11/3/2026

This specification covers a corrosion-resistant steel in the form of investment castings, solution and precipitation heat treated to 150 ksi (1034 MPa) tensile strength.

AMS F Corrosion and Heat Resistant Alloys Committee

Electrostatic Spray Application of AMS3143 Powder Coating Materials

AS8485A (Current)

11/3/2026

This standard provides the recommended requirements for electrostatic spray application of AMS3143 powder coatings to aerospace components. Adherence to these requirements will facilitate satisfactory performance of the applied powder coating.

AMS G8 Aerospace Organic Coatings Committee

Steel, Sheet, Strip, and Plate, 0.75Mn - 0.78Cr - 1.8Ni - 0.35Mo - 0.20V (0.33 - 0.38C) (4335 Mod), Premium Aircraft Quality, Vacuum Consumable Electrode Remelted, Annealed

AMS6435J (Current)

11/3/2026

This specification covers a premium aircraft-quality, low-alloy steel in the form of sheet, strip, and plate.

AMS E Carbon and Low Alloy Steels Committee

Prediction of Aero-Engine Exhaust Gas Temperature Using iTransformer

2026-99-2335

10/30/2026

Exhaust gas temperature (EGT) is one of the key parameters for evaluating the thermal state of an aero-engine during flight operations. Precise EGT predictions are important in both managing engine health and optimizing performance. However, the nonlinear interactions among multiple operating parameters pose challenges for conventional prediction methods. An approach to EGT prediction presented in this paper is based on the iTransformer architecture. Unlike conventional time-series models that process temporal observations as tokens, this algorithm works with every single variable like a unique token and encodes the entire historical sequence of each variable. This design enables the model to capture inter-variable dependencies directly, thus increasing its power to capture multivariate time series. Two different datasets were used to validate the proposed approach and compared to various commonly used prediction models. The results indicate that iTransformer gives smaller prediction errors when the same conditions are met with MAE values of 0.5525°R and 0.4539K both on the two datasets. Despite the overall satisfactory performance, some prediction mismatches can be observed under extreme fast changing conditions of the engine operation. These results demonstrate that the proposed method can effectively characterize the complex interactions among engine variables and has potential for practical EGT prediction applications.

Hao, Mengfu, He, Yongbo, Li, Yifan

Investigation on Dynamic Expansion Response and Structural Safety Assessment of Typical Polygonal Fabric Gasbags

2026-99-2337

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

Process and Performance Optimization Design of Metal-3D Braided Composite Joint Structures

2026-99-2349

10/30/2026

The sleeve is the key assembly part of the high-speed internal electric spindle support of the high-precision CNC internal and external grinder, and its machining accuracy directly affects the running state of the spindle. The purpose of this study is to adjust the structural process to improve its bearing capacity in all directions. Combined with the refined mechanical simulation of 3D braided composites, the influence mechanism of joint thickness and surface pretreatment on the connection performance is studied from the aspects of stress distribution characteristics and damage failure mechanism. The overall performance analysis and design of the metal-composite sleeve are carried out. Experiments show that the thickness of the joint has a great influence on its bearing performance, and the effectiveness of the proposed pretreatment process is verified, which provides a reliable technical path for the realization of high-performance metal-3D braided composite connection structure.

Wang, Zijun, Chi, Xinfu, Li, Chengen, Li, Dinghua

Study on the High-Temperature Creep Behavior of Ti-1100 Alloy

2026-99-2344

10/30/2026

This study investigates the creep response of the high-temperature titanium alloy Ti-1100 over a temperature range of 550-700 °C under applied stresses varying from 150 to 450 MPa. Under different combinations of stress and temperature, the creep rate, stress exponent, and activation energy for creep were determined using the Arrhenius relationship, while the corresponding creep characteristics and microstructural changes were examined through optical microscopy (OM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The findings indicate that an alloy is highly sensitive to temperatures and stresses when subjected to long-term creep. At the temperature of 550-700 °C, the Ti-1100 alloy has relatively high creep activation energy when subjected to an applied stress of 300 MPa. For the Ti-1100 alloy, the stress exponent was determined to be 5.33 within the stress interval of 150-450 MPa at 600 °C. When considered alongside the observed microstructural characteristics, this result indicates that dislocation climb serves as the primary mechanism controlling creep during prolonged exposure. Within the investigated temperature and stress window, creep deformation in Ti-1100 gives rise to localized regions with elevated residual stress, and this tendency becomes more pronounced as both temperature and applied stress increase. These areas are likely to grow and evolve into microcracks, thus contributing to the microstructural instability of the alloy.

Yongquan, Yang, Lihui, Yang, Feng, Du, Baohui, Zhu, Xiaochen, Hu, Lihua, Shen, Jianfeng, Li, Shaofu, Kang

Self-Regulation of Force in the Space Truss-Type Deployable Structure Based on Magnetic-Electric Material

2026-99-2341

10/30/2026

Under on-orbit disturbances, large space truss-type deployable structures readily undergo vibration. Such vibration may degrade pointing accuracy and positioning precision. As a countermeasure, an internal-force self-regulation method is proposed using a magnetoelectric self-sensing actuator. This actuator combines Terfenol-D with piezoelectric material, thereby realizing force output and self-sensing. It can be placed at critical truss joints. By exploiting the ΔE and Villari effects of magnetostrictive materials, a resonant-force self-sensing mechanism is established. The actuator model is then integrated into the deployable truss’s dynamic model, and an LQR-based active vibration suppression strategy is derived. Simulation results show that the actuator detects static and dynamic output forces. Over a specific magnetic field range, sensing behavior exhibits an approximately linear dependence on the output force. Control outcomes confirm effective suppression of structural vibration, reduced response amplitudes at key nodes, and enhanced structural stability. Therefore, a novel method for vibration suppression in large deployable truss-type space structures is provided by these findings.

Xie, Dongjian, Ni, Xiaofeng, Cheng, Lei, Cui, Qifeng, Zhang, Yahui

Synergistic Enhancement of Impact Resistance in SiCw-Polymer Composite

2026-99-2325

10/30/2026

Addressing the performance degradation bottleneck of conventional impact-resistant materials under complex operating conditions, and the limitation of existing research focusing primarily on enhancing single properties while neglecting material equilibrium, this study employs silicon carbide whiskers (SiCw) as the reinforcing phase. Through surface modification techniques, SiCw/celluloid and SiCw/polyimide dual-polymer composite systems were constructed and systematically investigated. Surface modification of SiCw was achieved using titanate and silane coupling agents. Through mechanical testing and X-ray photoelectron spectroscopy (XPS) characterisation, the effects of SiCw loading and modification treatments on composite mechanical properties and interfacial bonding were analysed. Results indicate that SiCw introduction significantly enhances the tensile, flexural, and impact strength of the polymer matrix, with optimal addition ratios identified: 6% for the celluloid system and 1.0% for the polyimide system. Surface modification further optimises toughening effects by reducing surface oxide layers and impurities on SiCw particles while strengthening interfacial bonding. This study provides practical guidance for the system design of high-performance impact-resistant composites. The resulting materials hold broad application prospects in sectors demanding high structural impact resistance, such as aerospace and transportation.

Xue, Kaiming

Research on Dynamic Response and Impact Resistance of Airport Pavement Made of Gradient Carbon Fiber Reinforced Composites

2026-99-2346

10/30/2026

Aiming at the engineering problems of easy cracking and insufficient impact resistance of traditional airport concrete pavement under complex dynamic loads, this paper studies the application of functionally graded carbon fiber reinforced polymer ( FG-CFRP) in airport pavement. Based on the modified Halpin-Tsai model and the first-order shear deformation theory, the dynamic finite element control equation is established. Based on the COMSOL Multiphysics platform, the modal characteristics and transient impact response analysis are carried out, and the dynamic response of the aircraft under moving wheel load is simulated. The static bending test of FG- CFRP plate samples made in the laboratory was carried out, and the numerical model was calibrated. The relative error of test-simulation was controlled within 5 %, which verified the accuracy of predicting static response. The carbon fiber volume fraction gradient curve was parametrically studied to reveal the sensitivity of the gradient to impact and stress reduction. The key engineering factors such as long-term environmental durability and life cycle cost of FG-CFRP pavement are discussed, and targeted improvement and optimization strategies are proposed. The results show that the fundamental frequency of the gradient plate is about 1.93 % lower than that of the homogeneous plate, and the vibration mode characteristics are highly consistent. The peak displacement of transient impact is reduced by 9.4 %. Under the action of moving wheel load, the peak Von Mises stress decreased from 5.32 MPa to 2.15 MPa, with a decrease of 60 %. The gradient design realizes efficient load diffusion and impact hardening through the surface high modulus layer, and the gradual change of interlayer wave impedance promotes the dissipation of stress wave, which significantly improves the safety reserve and dynamic stability of pavement structure. This study verifies the application feasibility of FG-CFRP in high-performance airport pavement engineering, and provides innovative material solutions and theoretical support for the development of a new generation of long-life and high-reliability airport pavement.

Li, Zhenyue

Study on Fatigue Crack Growth of Sandwich Composite Panels with Opening

2026-99-2327

10/30/2026

Owing to their remarkable specific strength and stiffness, coupled with superior impact resistance and thermal/acoustic insulation, sandwich composite panels are extensively utilized in marine, aerospace, and transportation sectors. In contrast to conventional monolithic structures, the multi-layered architecture of sandwich panels introduces complex fatigue failure mechanisms that are not yet fully understood. This study experimentally investigates a U-shaped core sandwich panel featuring a rectangular hatch opening under uniaxial tensile fatigue loading, aiming to characterize its crack initiation and propagation behavior. Subsequently, a custom three- dimensional fatigue crack growth simulation code is developed, grounded in linear elastic fracture mechanics and the extended finite element method (XFEM). A comparison with experimental measurements reveals that the maximum relative error between the predicted and observed fatigue life is 15.7%. The findings offer a theoretical foundation and a technical reference for the fatigue design and life assessment of such sandwich structures.

Chen, Siyu, Xu, Yunze, Liu, Gang

Study on Interface Design and Functional Tolerance of Structured Composites for Zero Thermal Expansion Performance

2026-99-2323

10/30/2026

Structured zero thermal expansion composites demonstrate significant application potential in thermal deformation control for high-end equipment, particularly aerospace precision instruments, due to their unique ultra-low thermal expansion properties. However, during the transition from theoretical design models to manufacturing models, uncertainties at connection interfaces and manufacturing errors alter the thermal deformation coordination between heterogeneous components within the material, leading to significant degradation of its zero thermal expansion performance. To address this issue, this study focuses on lattice-structured zero thermal expansion composites derived from topology optimization. First, the connection interface design between heterogeneous lattice components was completed. Subsequently, two typical manufacturing errors—dimensional errors and assembly tolerances—were incorporated into the manufacturability model. Using Monte Carlo random sampling, a mapping relationship was established between the random and discrete manufacturing errors and the composite's equivalent thermal expansion performance. Building upon this foundation, a yield rate metric based on functional tolerance concepts was introduced. This metric was used to evaluate how different interface configurations affect the stability of zero thermal expansion performance. The results demonstrate that, under identical manufacturing precision conditions, different interface configurations exhibit significantly varying thermal expansion stability in response to manufacturing errors characterized by structural parameter dispersion. This research provides valuable insights for translating theoretical designs of such functional materials into manufacturable solutions that meet thermal expansion performance requirements.

Yan, Shaojie, Yang, Zihao, Zhang, Yongcun

High-Temperature Sealed Disc Spring Compression Load-Holding Performance Testing and Material Parameter Calibration

2026-99-2322

10/30/2026

In high-temperature sealed assemblies, disc springs provide sustained preload to suppress leakage. However, at elevated temperatures, material creep and stress relaxation may reduce elastic recovery and accumulate permanent deformation, thereby degrading sealing reliability. Because the material properties of commercially procured disc springs vary with suppliers and production batches, they are difficult to apply directly in the analysis of high-temperature components. This study investigates Inconel-800 disc springs. Sustained compression tests were conducted at 600–900 °C to systematically obtain load–time responses and the temperature dependence of permanent deformation. The results show that, as temperature increases, the rate of force decay accelerates significantly and the residual load decreases markedly. At 800 °C and 900 °C, the permanent deformation approaches the compression limit, indicating that time-dependent material deformation becomes the dominant factor. Based on these results, a finite-element model consistent with the test conditions was established. Material creep parameters were calibrated from component-level compression data by minimizing the discrepancy between simulated and experimental curves. The identified parameters were validated under different temperature conditions and loading cases. The simulation results agree well overall with the experiments, and the errors remain within engineeringly acceptable limits. This study provides baseline data and an engineering method for obtaining material parameters to support material selection and structural optimization of high-temperature sealed disc springs.

Yang, Yuyao, Cai, Xianhui

ME-YOLO: Aircraft Corrosion Defect Detection Model Based on Multi-Directional Edge Perception and Multi-Scale Feature Fusion

2026-99-2321

10/30/2026

Detecting surface defects on aircraft is critical to safety in the aerospace field. The current detection methods suffer from low efficiency, high false positive rate and poor adaptability to complex environment. Although the existing target detection algorithms have achieved notable performance in this field, at present, many models in this field still face considerable challenges. For example, due to the constraints of hardware platforms, machines that can be deployed on edge devices such as UAVs and robots need lightweight and easy-to-deploy models, but lightweight designs often a certain degree of accuracy degradation. At the same time, most of the surface defects of the aircraft are small targets, which impose higher demands on the model. In order to solve these limitations, this paper proposes an improved YOLO model ME-YOLO (multi directional edge fusion YOLO) based on edge enhancement and multi-scale fusion. Firstly, the EdgePyramid module is designed, which uses the rich edge responses extracted by the Multi Orientation Attention Sobel (MOAS) module and through the three-layer cascade pool structure to construct the three-scale edge features aligned with the backbone network. Then, the EdgeEnhance module is introduced to adaptively fuse the conventional convolution features and edge features at the corresponding resolution, effectively enhancing the sensitivity of the model to the corrosion boundary. Experimental results show that, compared with the baseline YOLOv11, ME-YOLO improves mAP@0.5 by 2.7% and simultaneously increases Recall by 2.3%, which helps reduce missed detections of corrosion targets. Although the introduction of multi-directional edge priors brings a slight increase in parameters (+3.66M) and a minor decrease in inference speed (--8.6%), the model still maintains a real-time detection capability of 97.54 FPS, meeting the deployment requirements for edge devices such as UAVs. This strategy of trading a modest computational overhead for improved detection rates in safety-critical tasks offers a potentially practical and robust alternative for intelligent operation and maintenance of aviation equipment.

Zhou, Xing, Li, Yuan

Multiscale MD-FEA Investigation on Large-Deformation Mechanical Behaviors of Hydrogels Modified with Ionic Liquids

2026-99-2306

10/30/2026

Hydrogels incorporated with ionic liquids (ILs) demonstrate broad application prospects in the fields of wearable flexible sensors and human physiological monitoring. Nevertheless, the intrinsic correlation between microscale intermolecular interactions and macroscale nonlinear mechanical responses under large tensile deformation has not yet been fully clarified. In this work, a coupled numerical framework integrating molecular dynamics (MD) and finite element method (FEM) was adopted to explore the mechanical behaviors of poly(acrylic acid)/N,N’-bis(acryloyl)cystamine/ionic liquid (PAA/NB/IL) hydrogels under large deformation. A series of molecular models with graded IL doping levels were established to characterize the structural rearrangement and energy change characteristics during uniaxial tension. Numerical results from MD simulations reveal that the addition of ILs strengthens non-covalent interactions such as van der Waals forces and electrostatic attractions, and further drives covalent bond stretching and angular deformation to bear external loads under high-strain conditions. Meanwhile, a generalized Maxwell constitutive model, whose Prony-series parameters were fitted by experimental stress-relaxation data, was introduced into FEM numerical calculations. The simulated quasi-static tensile properties are highly consistent with experimental measurements. Comprehensive analysis demonstrates that the mechanical enhancement induced by ILs stems from the synergistic effect of covalent structural deformation and the reconstruction of non-covalent interactions, which offers valuable theoretical guidance for the development of hydrogel materials applied in large-deformation engineering scenarios.

Li, Sitan

A Two-Time-Scale Model Predictive Control Framework for Precise Strain Control of Shape Memory Alloys

2026-99-2307

10/30/2026

Precise strain control of Shape Memory Alloys (SMAs) is challenging due to their strong nonlinearity, hysteresis, and thermomechanical coupling. To address the needs of real-time control system design, this paper proposes a two-time-scale decoupling control framework based on Model Predictive Control (MPC). First, a transient physics-based model considering one-dimensional heat conduction and latent heat under electrical excitation is established and then reduced to a lumped-parameter model suitable for controller design. To balance prediction accuracy and computational efficiency posed by the model nonlinearity, an innovative two-time-scale MPC strategy is designed: a fast inner-loop temperature MPC is used for efficient thermal management outside the phase transformation plateau, while it switches to an outer-loop strain MPC for precise trajectory tracking and hysteresis compensation during the critical phase transformation period. Simulations demonstrate that this strategy significantly reduces computational burden while maintaining accuracy. Compared to a single-time-scale MPC, the proposed method reduces the settling time by 26%, the root mean square error by 16%, and the single-step computation time by 19.6% for a step reference strain. This work provides an effective and engineering-friendly solution for high-performance, real-time control of SMA-based actuators.

Ding, Shaozhe, Liu, Longbin, Zhang, Shifeng

Experimental Investigation on Flame Characteristic for Civil Aircraft Propulsion System Fireproof Test

2026-99-2317

10/30/2026

In order to meet the airworthiness regulations, the civil aircraft propulsion system needs to carry out the necessary fireproof test. The measurement of the flame temperature is very essential for the certification and validation of fire protection thermal simulation models, and also helps to establish the empirical understanding of complex flame behaviors. In order to investigate the influence of the specimen on the flame temperature distribution, the two dimensional flame temperature distribution of the free burning test and several fireproof tests, including titanium panel fireproof tests, stainless steel panel fireproof tests, composite laminated panel fireproof tests, honeycomb sandwich panel fireproof tests, were experimental investigated in this paper. The test results shows that panel specimens significantly alter the temperature distribution of the standard flame and interfere with radiation heat transfer measured by thermocouple, resulting in a significant reduction in the temperature gradient of the flame and a obvious increment in the temperature of the surrounding non-flame-impinging zone. The central flame-impinging zone exhibits minimal temperature variation compared to the baseline flame at 1093 °C, with temperature elevation restricted to approximately 40 °C (within 4% deviation). Both metal panels and composite panels demonstrate consistent trends in affecting flame temperature distribution. However, compared to metal panels, composite materials induce smaller temperature gradients and more uniform temperature fields. Multiple burning tests on same panel progressively intensify the oxidation on the specimen surface, leading to a gradual decrement in flame temperature. Especially, this temperature reduction becomes statistically significant as early as the second time burning test.

Chen, Fang, Guo, Junxian, Peng, Sen

An Improved ResU-Net for Thermally Grown Oxide Layer Segmentation in Thermal Barrier Coatings

2026-99-2361

10/30/2026

Thermal barrier coatings (TBCs) serve as the critical protective layer for gas turbine components. In complex service environments, the thermally grown oxide (TGO) layer formed between the top coat (TC) and the bond coat (BC), along with the evolution of its microscopic morphology, is a key factor determining the service life of TBCs. To address the complex morphology of TGO layers that challenges conventional segmentation methods, this paper proposes MSF-SA ResU-Net, a multi-scale feature fusion self-attention model based on the ResU-Net architecture, for the image segmentation of thermally grown oxide layers. Building upon residual connections, this model incorporates two key enhancement modules at the bottleneck layer: Multi-Scale Fusion (MSF) and Self-Attention (SA). During the feature processing stage, the MSF module effectively captures the multi-scale morphological features of the TGO layer through receptive fields of different sizes, solving the difficulty of extracting long-strip and irregular morphologies. Subsequently, the SA module recalibrates the fused features by calculating the global dependencies between them, enhancing the network's attention to TGO boundaries and micro-defects. Comprehensive experiments on an in-house dataset of 3,000 SEM images demonstrate that MSF-SA ResU-Net outperforms standard U-Net and contemporary segmentation architectures. Furthermore, due to the feature extraction capability of the ResNet backbone network, the model maintains high accuracy and exhibiting good convergence performance. This makes the architecture an effective solution for the microscopic analysis of thermal barrier coatings.

She, Weicen, Song, Yan

Multi-Objective Robust Optimization Method for CFRP Laminates Based on a Dual Dimensionality Reduction Strategy

2026-99-2345

10/30/2026

This paper presents a robust multi-objective optimization method for a symmetric carbon fiber reinforced polymer laminate under uniaxial tension. The study focuses on the combined design problem of failure strength and failure displacement under material uncertainty. A fast structural response model is built by using classical laminate theory, and the Hashin failure criterion is used to predict the first-failure state of the laminate. The model takes uncertain material properties into account, so it can describe the effect of random changes in stiffness and strength on the structural response. To reduce the computational cost, the method uses a dual reduction strategy. The first step reduces the parameter space. Latin hypercube sampling is used to generate random samples, and Spearman correlation analysis is used to identify the key uncertain parameters. The second step reduces the sample space. K-means clustering is used to group the reduced samples and generate representative scenarios. Based on these scenarios, the study defines robust failure strength and robust failure displacement by combining the mean value and the standard deviation of the responses. A multi-objective genetic algorithm is then used to search for the Pareto solution set. After that, two single-objective optimizations are carried out to obtain the best strength and the best displacement, and these two values are used to form an ideal point. The two objectives are normalized, and the Pareto point with the smallest distance to the ideal point is selected as the final design. The results show that the proposed method can capture the positive relation between failure strength and failure displacement, identify the main uncertain parameters that control the response change, and provide a balanced design with good strength and displacement performance under uncertainty.

Wang, Yaoqiang

A Study on the Tribological Behavior of Silicon Nitride-Based Multiphase Ceramics Under Different Lubrication Systems

2026-99-2339

10/30/2026

To address the urgent need for high-performance self-lubricating ceramic materials for rolling bearings under high-speed operating conditions in the aerospace sector, this study employs Si3N4 as the matrix and incorporates nano lignin and graphene nanoplatelets (GNPs) to develop a self-lubricating composite ceramic system. This paper systematically studies the tribological characteristics and wear mechanisms of the composites. The results indicate that nano lignin undergoes pyrolysis during sintering, forming nitrogen-doped graphene quantum dots (N-GQDs). These structures are uniformly distributed at grain boundaries and participate in the formation of a lubricating film during the friction process, thereby significantly improving the material’s friction and wear properties. Under the special conditions (10 N, 1000 r/min), the composite material exhibited optimal tribological performance when the nano-lignin content was 2 wt.%, The friction coefficient decreased to 0.22 and a significant decrease in wear rate, demonstrating excellent friction- reducing and wear-resistant effects. In contrast, the introduction of GNPs failed to effectively improve friction performance, which may be attributed to their poor dispersion in the matrix and weak interfacial bonding. Mechanistic analysis indicates that during friction, Si N hydrolyzes to form SiO, which, together with the metal transfer layer and N-GQDs, forms a composite lubricating film; under shear stress, the N-GQDs undergo oriented alignment, reducing interfacial shear strength and achieving a synergistic effect of friction reduction and wear resistance. This study gives a new perspective into the application of biomass-derived lubricating phases in high- performance ceramics.

Chen, Wei, Zhao, Wenzhuo, Zhou, Ao, Li, Yetong, Wang, Chao, Yang, Yongqiang, Lou, Rui

Machining Deformation Control of 5A06 Aluminum Alloy Aircraft Skin

2026-99-2343

10/30/2026

Aircraft skin is a critical external structural component that provides aerodynamic profile, sustains and transfers aerodynamic loads, and protects internal systems from harsh environments. High machining precision is essential to ensure assembly accuracy and flight performance. However, large scale thin walled skin components are prone to significant machining deformation due to their low stiffness. Traditional deformation control methods, which relying heavily on experiments and full-process simulations, are inefficient and costly for industrial applications. To address this issue, this paper establishes a correlation model among machining parameters, residual stress, equivalent bending moment, and machining deformation. Single-factor experiments are conducted to reveal the effects of spindle speed, feed rate, and cutting depth on surface residual stress. Based on plate-shell theory, the relationship between residual stress and equivalent bending moment is established. The quantitative relationship between equivalent bending moment and machining deformation of the skin is obtained via finite element simulation modeling. Finally, a deformation control strategy for the skin during finish machining is established by optimizing the cutting depth. Experimental results show that after parameter optimization, the overall machining deformation of the 5A06 aluminum alloy skin is reduced by 81%, and the maximum deformation is controlled within 0.17 mm, which fully meets the aeronautical assembly requirements. This work provides an efficient and low-cost process optimization strategy for the machining deformation control of large weak-stiffness thin-walled components.

Chen, Shu-Guang, Wang, Jing-Kai, Wu, Chao, Wang, Tian-Rui, Yuan, Hao

Friction Stir Welding Process and Cryogenic Mechanical Properties of 2219 Aluminum Alloy Thick Welded Blanks

2026-99-2363

10/30/2026

To prepare reliable thick aluminum alloy tailor welded blanks for cryogenic forming, 2219 aluminum alloy friction tailor welded blanks that has the thickness of 12 mm were selected as the research object in our study. Vickers hardness tests were employed to clarify the property distribution across the weld cross-section. Room temperature uniaxial tensile tests have been used to reveal through- thickness deformation behavior under tensile loading. The mechanical tests at room and cryogenic temperatures were employed to investigate the effects of welding parameters of the friction tailor welded blanks on the mechanical properties, and evaluate the cryogenic formability of the welded blanks. Results show that the single-sided FSW specimens exhibit decreased hardness values from the top to the bottom surface, causing more severe deformation in bottom region and macroscopic bending under tension stress condition. In contrast, the double-sided FSW specimens exhibit a more uniform hardness distribution across the weld cross-section, resulting in nearly symmetric deformation and no significant bending. Lower welding speeds combined with higher rotational speeds significantly improved the ductility of the tailor welded blanks. The optimal welding parameters are identified as 200 mm/min and 800 rpm, showing a 321.1 MPa tensile strength and a 22.2% elongation, at room temperature after water quenching and solution treatment. These values increase to 385.5 MPa and 33.5% at liquid nitrogen temperature, showing a more than 20% enhancement in strength and around 50% enhancement in ductility, indicating excellent formability. This study offers a reliable material and process basis for the integrally forming of ultra-large components.

Liu, Hanyu, Yang, Guang, Zhang, Zhichao, Li, Yajun, Hu, Lan, Fan, Xiaobo

The Effect of Arc Ion-Plated Chromium Coatings on the Thermal Shock Behavior of Steel at 900°C

2026-99-2342

10/30/2026

To improve the thermal shock resistance of the shell steel, a Cr coating was deposited on its surface using arc ion plating technology. The protective capability of the Cr coating on the shell steel at 900 °C following a water-cooling cycle was investigated. Automatic scratch tester, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) were employed to characterize adhesion to the substrate, the microstructure, phase composition, and elemental composition of the shell steel and the Cr coating. The results indicate that the adhesion strength of the Cr coating is approximately 26.21 N, which is about 20.16% lower than the 32.83 N adhesion strength of the original Cr coating. At 900 °C, Fe₃O₄ and Fe₂O₄ form on the surface of the shell-and-tube steel. The oxide film exhibits cracking, peeling, and thermal fatigue, while oxidation defects accumulate within the steel, accompanied by significant precipitation of Ni. A dense Cr₂O₃ oxide film formed on the surface of the Cr coating, releasing thermal stress in the form of grid-like cracks. Under 10× magnification, no oxidation defects were observed within the Cr coating, and Fe from the substrate did not diffuse into the Cr coating; Under 100× magnification, the Cr coating exhibits fewer oxygen channels than the steel tube body. Oxygen is concentrated within these channels, and the Cr coating demonstrates significant resistance to thermal fatigue, providing markedly superior protection against thermal shock compared to the steel tube body.

Sun, Huixian, Lu, Xudong, Zhang, Rui, Guo, Cean

Deep Damage Detection of Plain Weave CFRP Using Microwave Rectangular Open-Ended Waveguide

2026-99-2334

10/30/2026

To address the challenge of detecting internal deep damage in plain woven carbon fiber reinforced polymer (CFRP), a microwave nondestructive testing method based on a WR-112 rectangular open-ended waveguide is proposed. Based on the weaving structure characteristics of the material, a discrete electromagnetic model within the 6.57-9.99 GHz frequency band was established. The microwave reflection response characteristics of backside circular damage with different dimensions were investigated through finite element simulation. Simulation results demonstrate that the proposed method can effectively detect backside damage with a minimum detectable diameter of 6 mm and a minimum detectable depth of 0.3 mm on a 2.4 mm thick plate, based on a signal-to-noise ratio (SNR) criterion of 3 dB. Furthermore, the amplitude of the reflection coefficient is sensitive to the variation of damage depth, while the resonant frequency remains stable. A microwave detection experimental platform was set up, and damage specimens were fabricated for verification. The experimental results are in good agreement with the simulations, confirming the effectiveness of the proposed method for damage detection and depth identification.

Chen, Xiaoyuan, He, Yongbo

Contact Mechanics and Release Dynamics Analysis of the Test Mass

2026-99-2332

10/30/2026

The test mass is a cube made of a gold-platinum alloy that serves as the inertial reference for space-borne gravitational wave detection; its final residual velocity after locking and release must not exceed 5 μm/s. During the release process, multi-degree-of-freedom disturbances caused by the pull-off effect between the release mechanism and the test mass are the key factors affecting the residual velocity of the test mass. This paper focuses on the designed release mechanism to conduct research on the interaction relationship between it and the test mass. Three contact configurations are proposed, and corresponding contact mechanics models are established to analyze the impact of release on test mass disturbances under plunger offset and deflection, leading to the selection of the optimal configuration. Based on adhesion effects, a one-dimensional impulse transfer model and Lagrange dynamic equations are constructed to analyze the disturbance transfer mechanism during the release process. Minimal release impulse is achieved through systematic parameter optimization. It is concluded that the plunger-sphere/test-mass-plane configuration is optimal for disturbance decoupling and technical feasibility, with an optimized plunger radius of 10 mm and mass of 0.8 g, which significantly reduces adhesion and residual preload. Furthermore, simulation verification demonstrates that the residual velocity of the test mass after release is on the order of 10^–7 m/s, satisfying the low-disturbance requirements. The aforementioned conclusions provide significant theoretical support and design references for enhancing the release success rate of test mass release mechanisms and reducing release residual velocity.

Kang, Mingdi, Si, Jixing, Ouyang, Junyong, Lu, Yifan, Yue, Honghao, Yang, Fei

Microstructure and Properties of CoCrFeNi/WC Cemented Carbides

2026-99-2308

10/30/2026

Traditional cemented carbides struggle to simultaneously improve hardness and toughness, and cobalt scarcity further limits their industrial production. To address these limitations, we utilize CoCrFeNi (with good ductility) as the binder phase to fabricate CoCrFeNi/WC cemented carbides, and regulate sintering temperature (1100-1200 °C) and holding time (3-10 min) to tailor the microstructure and mechanical properties, focusing on the occurrence of residual binder phase. The results indicate that sintering parameters significantly affect the morphology and content of residual binder phases: elliptical phases form at 1100 °C, while strip-like phases dominate at 1150-1200 °C. Specifically, the MEA3 sample sintered at 1200 °C for 10 min achieves the best mechanical balance (Vickers hardness: 2281 HV; fracture toughness: 12.2 MPa·m^1/2), attributed to reduced residual binder phase fraction and enhanced densification, which improve interfacial bonding. In contrast, a relatively high content of residual binder phases induced by lower temperatures (e.g., 1100 °C) or inappropriate holding times degrades mechanical properties. Microstructure analysis confirms that rational sintering optimization is key to controlling residual binder phase evolution and realizing high-performance cemented carbides. This study provides an experimental basis for the industrial production of high-performance WC-based carbides.

Sun, Yifeng, Li, Pengyan, Ma, Zhaolong

Multi-Criteria Optimization of Cutting Parameters for Energy-Efficient Turning of AISI 4340 Steel under Dry, Minimum Quantity Lubrication, and Nanofluid-Assisted Minimum Quantity Lubrication Conditions

05-20-01-0001

10/29/2026

Achieving energy efficiency and high surface quality in the turning of hard-to-machine materials such as AISI 4340 steel requires effective decision-making frameworks. While single-objective optimization techniques are widely reported in the literature, comparative studies evaluating the consistency and reliability of multi-criteria decision-making (MCDM) methods remain limited. This study considers different machining conditions, including cooling strategies, cutting speed, and feed rate, and evaluates multiple performance indicators, namely tool wear, surface roughness, sound pressure level, and current consumption, using evaluation based on distance from average solution (EDAS), complex proportional assessment (COPRAS), grey relational analysis (GRA), weighted aggregated sum product assessment (WASPAS), and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) methods. Objective criterion weights were determined using the criteria importance through intercriteria correlation (CRITIC) method. All five MCDM methods consistently identified Experiment 8 (nanofluid-assisted minimum quantity lubrication [nano-MQL], 150 m/min cutting speed, and 0.10 mm/rev feed rate) as the optimal parameter combination. This condition achieved the lowest surface roughness (0.81 μm), minimum tool wear (0.150 mm), lowest sound pressure level (88.1 dB), and minimum current consumption (4.18 A) among all experimental trials. The consistency of the ranking results confirms the robustness and reliability of the proposed decision-making framework for energy-efficient machining applications.

Toprak, İnayet Burcu, Fedai, Yusuf

Behind-Helmet Blunt Trauma Deformation Geometry under Different Helmet Materials

09-14-03-0016

10/26/2026

Modern combat helmets improve wearer survivability through preventing ballistic penetration via delamination or deformation of the shell material. However, this deformation may impinge upon the skull and present a risk of behind-helmet blunt trauma (BHBT). While legacy aramid helmets from the late 1970s–1980s inform current NIJ testing standards, the advent of lower areal density ultra-high molecular weight polyethylene (UHMWPE) and modern suspensions may incur unknown changes that present an unknown effect on BHBT risk. This study investigates whether current standards relying on a peak acceleration threshold and residual clay deformation may not reflect changes in deformation geometry seen in newer shell materials and suspension designs. Thirty-eight helmets categorized into three groups, older aramid, newer aramid (with new suspension), and prototype UHMWPE (with old suspension), were mounted on Hybrid III ATD head-necks and impacted on the temporal surface with 9 mm NATO projectiles at velocities between 388 and 482 m/s. Flash x-ray imaging captured deformation geometry. Deformations were digitized to measure maximum depth, volume, and surface area recruited. Multiple linear regression identified the influence of shell material and suspension on geometry. Results indicated that shell material significantly affected deformation volume and area (p < 0.05). Notably, UHMWPE exhibited a qualitatively more “pointed” deformation profile compared to aramid, recruiting material differently as depth increased. In contrast, suspension type and helmet design did not significantly influence deformation geometry. These findings suggest that the BHBT geometry in UHMWPE helmets differs fundamentally from aramid helmets. As UHMWPE helmets encounter higher-energy threats, current acceleration threshold or depth-based standards may not fully capture the risk of skull fracture. To future-proof helmet validation, testing standards should evolve beyond current standards to include area recruitment and other geometric measures.

Pang, Derek Y., Salzar, Rober S., Boggess, Brian M., Bass, Cameron R.

Multi-Objective Optimization of Face Milling Parameters for DIN 2714 Hardened Steel: Hybrid Taguchi–Analysis of Variance and Artificial Intelligence-Based System Modeling

2026-01-5070

10/23/2026

The face milling process for hardened steels used in die and mold manufacturing involves precise parameter settings to achieve high-quality surfaces with high productivity. However, due to the nonlinear relationship between the machining parameters, it becomes challenging to optimize the machining process. This paper focuses on optimizing the face milling parameters for the DIN 2714 hardened steel by employing experimental approaches and AI-based modeling techniques. Taguchi’s L9 orthogonal array-based design of experiments with machining parameters of depth of cut, cutting speed, feed rate, and step-over is employed for the optimization. The material removal rate (MRR) and surface roughness (Ra) were considered as output responses. The results showed that surface roughness is significantly affected by cutting speed, while depth of cut primarily controls MRR. To improve the precision in predicting the output responses, two artificial intelligence (AI) based intelligent models were developed using hybrid modeling techniques—namely, PSO-FIS and GA-FIS. The experimental results demonstrated that the GA-FIS model was accurate in predicting the output response for surface roughness (Ra), with a lower error value (0.0162 μm), while the PSO-FIS model was accurate in predicting MRR with a high R2 value (0.9997), proving that fuzzy modeling techniques can be effectively used to optimize machining operations with high precision.

Tripathy, Chitta Ranjan, Moudgil, Prince Kumar, Katyayn, Arvind, Kumar, Aman

Aluminum Alloy, Sheet and Plate, 6.3Cu - 0.30Mn - 0.18Zr - 0.10V - 0.06Ti (2219-O) Annealed or, When Specified, “As Fabricated” (2219-F)

AMS4031L (Current)

10/21/2026

This specification covers an aluminum alloy in the form of sheet and plate 0.020 to 2.000 inches (0.51 to 50.80 mm), inclusive, in nominal thickness, supplied in the annealed (-O) condition. When specified, product shall be supplied in the “as fabricated” (-F) temper (see 8.6).

AMS D Nonferrous Alloys Committee

Aluminum Alloy Sheet, 6.0Cu - 0.40Zr (2004-F), As Rolled

AMS4208E (Current)

10/21/2026

This specification covers an aluminum alloy in the form of sheet less than 0.250 inch (6.35 mm) thick (see 8.5).

AMS D Nonferrous Alloys Committee

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