Browse Topic: Metallurgy

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Specifications for Low Carbon Cast Steel ShotJ2175_202608 (Current)8/19/2026
This SAE Recommended Practice describes chemical analysis, hardness, microstructure, and physical characteristic requirements for low carbon cast steel shot to be used for shot peening or blast cleaning operations.
Surface Enhancement Committee
Design of Adaptive Overtorsion Sliding Mode Observer Based on Logarithmic Gain Law and Estimation of Satellite Disturbance Torque2026-99-03158/14/2026
The vigorous rate of new spacecraft being launched has made the accurate estimation of in-orbit environmental disturbances torques paramount to reducing attitude control performance corrosion. Leveraging telemetry from an asset in low-earth-orbit, we present a novel Adaptive Super-Twisting Sliding-Mode Observer, which interlinks three techniques heretofore decoupled: 1) saturation-constrained angular-acceleration adaptation; 2) Kalman-filter preconditioning of angular velocity; and 3) state-weighted logarithmic gain with dual leakage. Denoising of raw Euler angle sequences and detection of quasi-steady epochs are achieved with a customized Kalman update, while an adaptive band-pass stage isolates the torque-related acceleration signature. Casting these filtered data into the super-twisting form, we update the log gain on-the-fly, and twin leakage terms remove excess energy with accompanying chatter rejection—without compromising bandwidth. Head-to-head telemetry tests show a positive margin headroom on noise attenuation that has to be compared with the power-gain type counterpart and that increases with the signal roughness, thereby validating the fact that this technique refines environment torque estimates and hence strengthens robustness design envelopes in next-generation attitude-control systems.
Yin, Xu, Deng, Yuhui, Chi, Dongxiang
Study on Visible-Light-Driven Photocatalytic Degradation of Tetracycline Hydrochloride by g-C 3 N 4 /CoFe 2 O 4 Composite Photocatalysts2026-99-10078/7/2026
g-C₃N₄, a metal-free semiconductor photocatalyst, demonstrates remarkable potential, but its practical application in pollutant degradation is significantly limited by the rapid recombination of photogenerated electron-hole pairs and low photocatalytic efficiency. To address this, a series of magnetic recyclable g-C₃N₄/CoFe₂O₄ composite photocatalysts with different CoFe₂O₄ doping ratios were innovatively designed and prepared via thermal polymerization, sol- gel, and combined with ultrasonic and heat treatment processes. The novelty of this composite design lies in the effective integration of magnetic CoFe₂O₄ with g-C₃N₄ through a heterojunction structure. It substantially boosts the absorption of visible light. Concurrently, it effectively fosters the separation and mobility of photo-induced charge carriers. The composite materials were systematically characterized by X-ray diffraction, thermogravimetric analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy, photoluminescence spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy. Using tetracycline hydrochloride as the target pollutant, the photocatalytic activity of the composites was evaluated under visible light irradiation, and the effects of initial concentration, catalyst dosage, and the influence of solution pH on degradation efficiency were also examined. The results indicated that the composite with a CoFe₂O₄ to g-C₃N₄ mass ratio of 1:3 (denoted as 3-CN/CFO) exhibited the optimal performance: a TCH degradation rate of 80.29 % within 105 minutes and a total organic carbon removal rate of 61.63 %. After five consecutive cycling experiments, the degradation efficiency remained above 70 %, demonstrating good reusability and stability. The performance improvement is attributed to the formation of heterojunctions in the composite, which effectively facilitates charge separation, inhibits carrier recombination, and enhances visible light absorption. Furthermore, the inherent magnetism of the composite permits efficient recovery, streamlining its integration into practical applications. Toward the purification of antibiotic-contaminated water, this research proposes a viable method for fabricating highly effective and recyclable photocatalysts.
Hua, Longjun, Chai, Tian, Wang, Yiming, Zhang, Jing, He, Ting
Research and Application of Mechanical Voltage Stabilization Control Device2026-99-01197/31/2026
This study carefully designed and successfully developed a mechanical voltage stabilizing control device. The device uses silicone oil as the key component material of the liquid spring and 1Cr13 as the main material of the pressure control unit, enhancing its high-pressure resistance (up to 35 MPa), oxidation resistance, and acid-alkali corrosion resistance. By optimizing the transmission mechanism and simplifying the pressure regulation module, the device achieves a pressure regulation range of 0.1–21 MPa with an accuracy of ±0.01 MPa, significantly broader and more precise than traditional devices. To address manufacturing challenges, advanced CNC machine tools, ceramic cutting tools, and optimized heat treatment processes (e.g., quenching and tempering) were adopted, ensuring component machining accuracy within ±0.02 mm. Field applications in 13 oil wells demonstrated a 15.6% increase in daily oil production (from 25.5 t/d to 29.5 t/d) and a 17.9% increase in daily gas production (from 2800 m^3/d to 3300 m^3/d), with stable casing pressure control at 5.3 MPa. The device has created 1.225 million yuan in economic benefits while eliminating safety hazards, providing critical technical support for efficient and environmentally friendly oil and gas production.
Wang, Gang, Liu, Cuicui, Tong, Deshui, Cao, Jian, Mu, Taiji, Han, Baidong
Research on a Multilayer Membrane Electrothermal Microdriver Based on MEMS Process2026-99-01657/31/2026
Based on the principle of the bimetallic effect of the electrothermal microdrive, polymer SU-eight glue is used as the functional material, nickel metal is used as the structural material, and copper metal is used as the sacrificial layer to make the electric heating microdrive. We process and manufacture them based on specific MEMS processes such as lithography, mask plating, and magnetron sputtering, and perform basic characterization, observation, and electrical signal analysis on the samples. The results show that the overall electrothermal micro-driver device is complete, the electrode and resistance wire structure is complete, and the I-V signal is normal.
Xue, Yunhao, Tan, Xiaolan, Jiang, Xin
Docking Methodology for Large-Sized Irregular Castings via Industrial Robot Manipulation2026-99-01707/31/2026
Large-sized irregular castings are critical components extensively employed in large-scale equipment manufacturing. Due to their substantial dimensions and complex geometries, the assembly and docking processes between different components present significant challenges. To address the docking problem between large-scale irregular castings, this study proposes a casting docking method based on relative pose, along with a modeling approach for irregular castings, and accomplishes the docking process through the control of an industrial robot. Firstly, the current poses of feature points on the docking surfaces are measured. Based on these measurements, the relative pose transformation relationship between the center point of the docking surface and the robot’s Tool Center Point (TCP) is established, thereby constructing the docking model. This model calculates the relative deviation between the current pose and the theoretical pose. Subsequently, the robot motion is controlled according to this deviation to achieve precise docking. Finally, a simulation environment was built using KUKA. Sim Pro with Office Lite to simulate the docking process of large-sized irregular castings. The results demonstrate that the relative pose-based docking method effectively accomplishes the docking task. This study provides an effective solution for the docking of large-sized irregular castings.
Liu, Haoran, Jia, Haili, Wang, Aimin, Xigang, Fan, Peidong, Su
Measurement and Regulation of Residual Stress in Door Opening Welds of Wind Turbine Towers2026-99-01977/31/2026
Weld residual stress is a critical factor affecting the structural integrity and service life of wind turbine towers. In this study, a systematic investigation was conducted on the residual stress distribution and control methods for door corner welds of an in-service wind turbine tower after approximately 20,000 hours of operation. X-ray diffraction (XRD) measurements revealed significant tensile residual stress in the weld and heat-affected zone, with peak values reaching 315 MPa, particularly concentrated at depths of 5-7 mm. To mitigate these stresses, two post-weld treatment methods were employed: ultrasonic impact treatment (UIT) and localized heat treatment. UIT effectively transformed surface tensile stress into compressive stress, achieving a maximum compressive residual stress of -372 MPa within a depth of 3 mm, while simultaneously refining grains and increasing surface hardness. In contrast, localized heat treatment at 460 °C for 5 hours led to a broader stress relief effect, reducing residual stress by approximately 100 MPa without causing significant changes to the macrostructure, but inducing substructural rearrangements beneficial for stress relaxation. Mechanical testing confirmed that both treatments improved tensile strength, ductility, and toughness of the welds. The combined findings demonstrate that ultrasonic impact treatment is highly effective for enhancing fatigue performance at the surface, while localized heat treatment offers advantages for deep stress redistribution and long-term structural stability. This comprehensive approach provides valuable technical guidance for residual stress management in complex welded structures of wind turbine towers.
Sun, Wanting, Zhong, Zhenqian, Zhang, Bo, Liu, Hui
Ultrasonic Assisted Room Temperature Welding of Liquid Gallium Indium Alloy Brazing Material and Its Solidification Behavior at the Cu-Cu Interface2026-99-01967/31/2026
Considerable the gallium-based alloys low melting point coupled with easy to synthesize intermetallic compounds with diverse metallic elements, employing liquid gallium-based alloys as the soldering medium and leveraging ultrasonic as assistance are effective to construct pure copper joints under atmosphere condition. The investigation delves into the characterization of the reaction products, interface microstructure, elemental distribution patterns, and evolution of shear strength within the welds. Furthermore, the pivotal role of ultrasonic waves and constituent element diffusion mechanisms during the solidification phase is elucidated. Thus, the initial one-day occurred during solidification showed the 2.6 MPa shear strength but with the time increased to four and a half days, the shear strength raised to 8.4 MPa at room temperature. Thereinto, the results indicate the weld seam has achieved metallurgical connection. This innovative welding technique operates at room temperature provides significant guidance for designing a novel perspective low-temperature joining for applications. It is not only augments the repertoire of material connection methodologies but also presents a viable joining strategy for sensitive elevated temperature materials. Therefore, such process possesses substantial practical significance and promises avenues for future applications.
Guo, Manying, Qu, Yingying, Fang, Qiuyue, Yang, Shen
Optimization of the Stewart Platform Based on Improved Genetic Optimization2026-99-01057/31/2026
Based on the improved genetic optimization, a new Stewart platform optimization design method is proposed in this paper. Through introducing chaotic mapping and simulation annealing strategy, combining the kinematic analysis of the Stewart platform and the constraint conditions of the workspace, aiming at maximizing the workspace and minimizing the motion error, the structural parameters of the platform are optimized. The experimental results show that the improved GA significantly improves the workspace and motion performance of the Stewart platform compared with the traditional ant colony optimization and basic genetic optimization.
Zhu, Ming, Wang, Baichao
Microstructure and Properties of 316L Stainless Steels Modified with C and Cr Elements2026-99-02177/31/2026
SiC-based power devices are favored for high-voltage and high-power applications due to their superior material properties. However, the demand for higher breakdown voltages and improved channel mobility presents significant challenges to the etching process, especially the micro-trenching effect. In this study, etching results from inductively coupled plasma (ICP) have been presents, which focused on using various SF6/O2/Ar gas ratios to eliminate micro-trenching effect. The profile analysis of micro-trench was taken by cross-sectional scanning electron microscopy (SEM). The results demonstrate that micro-trenches primarily originate from the coupling effect between ion multi-reflection from sidewalls and redeposition of etch byproducts. Based on this mechanism, we propose a quasi-Bosch process: a combined polymerization and etching step in oxygen-fluorine-rich plasma deposits polymer on exposed SiC and the mask, while removing it from the structure bottom via ion bombardment to enable etching and passivation; then alternates with a short fluorine-plasma step, which consumes sidewall polymer through ion incidence and prevents SiFxOy charge accumulation, cycle etching gradually deepens the structure without micro-trenches. Different gas ratios and etching time not only change the plasma energy distribution but also affect the temporal synchronization between etching and passivation steps. This approach reduces the special demands on ICP equipment capabilities while achieving superior trench profiles. The optimal etching conditions produced a micro-trench-free SiC structure with a vertical sidewall angle and a surface roughness of less than 1 nm. This methodology and resulting structures significantly advance the manufacturability of high-performance SiC power devices, enabling next-generation applications in electric vehicles and grid infrastructure where device yield and reliability are paramount.
Zhao, Yingfan, Dong, Shuang, Sun, Xiaoxu, Chang, Xiangpeng, Liang, Yiwei, Tong, Weiping
A Data-Driven Model for Predicting Casting Solidification Time and Mold Thermal Stress2026-01-50557/31/2026
This study proposes a data-driven surrogate modeling framework for predicting solidification time and mold thermal stress during low-pressure die casting (LPDC) of aluminum alloy wheels. The methodology employed an optimal Latin hypercube design (OLHD) to sample key parameters including cooling channel geometry and process conditions. A sequential simulation methodology combining ProCAST and Abaqus was implemented to generate a comprehensive dataset of solidification times and thermal stress distributions. Based on this dataset, surrogate models were developed using Support Vector Regression, Kriging, and Polynomial Response Surface Methodology, with their hyperparameters automatically tuned through Bayesian Optimization (BO). The optimized models were rigorously evaluated using four statistical metrics: Coefficient of Determination (R2), Mean Squared Error (MSE), Mean Absolute Error (MAE), and Root Mean Squared Error (RMSE). The evaluation results show that the BO–SVR model demonstrated superior prediction accuracy for both output responses and exhibited exceptional nonlinear fitting capability. This work establishes an effective modeling approach for simultaneous quality and efficiency optimization in wheel manufacturing.
Fuhao, Fan, Zhan, Yunlang, Zhan, Zhenfei, Yang, Yutong, Xiao, Yong, Huang, Shiyao
In-Situ Alloyed Strong and Ductile Titanium Alloy from Blended Metal Powders2026-99-02427/31/2026
Blended metal powders offer a compelling alternative to pre-alloyed powders in metal additive manufacturing by providing access to a wider range of alloy compositions and avoiding the high costs in producing pre-alloyed powders. In this work, a new and crack-free Ti-5AlMnScZrMgSiFe alloy (in wt.%) was manufactured by laser powder bed fusion (L-PBF) from mixed powders to investigate the microstructures, mechanical performance of printed parts. Ti-5 AlMnScZrMgSiFe alloy contains both alpha (α) and alpha prime (α′) phases. Further microstructural characterizations show that the L-PBF Ti-5 AlMnScZrMgSiFe contain dense dislocations and twins formed in additive manufacturing process. The as-printed Ti-5 AlMnScZrMgSiFe alloy exhibits a tensile fracture strength of ~950 MPa with a fracture elongation of ~12.5%. The eye-catching properties are attributed to the dense dislocations, nano-twins and solid-solution strengthening.
Feng, Shuai, Guan, Shuai, Kong, Haohao, Sun, Yingxiang, Song, Youpeng, Hou, Yaqing, Bi, Zhongnan, Zhang, Shaoming
A Stress Relief Method Based on a Hybrid Process of Shot Peening and Laser Directed Energy Deposition with the Same Materials2026-99-02327/31/2026
Laser directed energy deposition (LDED) is widely used in various fields due to its fine forming structure and superior performance. However, the characteristics of the hot forming process result in significant residual tensile stress in the formed materials, which affects the capability and useful life of the mechanism accessory. The hybrid manufacturing technology of shot peening (SP) and LDED has a significant influence on the elimination of defects and the improvement in microstructure of formed materials and reducing residual stress, but it also has limitations. To solve the problems, such as the introduction of powders and the difficulty in recycling and classification when using heterogeneous materials for shot peening in hybrid processes, this paper proposes a method of strengthening with the same material, establishes a thermal shot peening simulation model for the hybrid process, and conducts experimental verification. The research finds that the average generated stress of SP in hybrid manufacturing technology is -215.6 MPa, and the thickness of the strengthening layer is about 40 μm. The subsequent hot forming process will eliminate part of the induced stress by SP on the previous deposition, but the deposited stress on the surface is reduced compared with that in the single process. The hybrid manufacturing technology of SP and LDED, based on the same material, effectively utilizes the residual heat from the forming process, providing feasibility for engineering applications.
Zhang, Xiaoyu, Zhang, Min, Li, Dichen, Jiang, Yunfeng, Chen, Xinjin, Fei, Ya, Hu, Ying, Liu, Yuyang
Characterization and Fatigue Life Validation of a Mass-Reduced Drum Brake Spider Made from a Modified and Nanostructured Cast Iron2026-36-03037/30/2026
This study aimed at the characterization and validation of a drum-brake spider with mass reduction, using a new concept of a nanostructured ductile cast iron alloy. There is a well-known effort in developing lighter, more competitive products with higher safety and longer service life for brake systems. One of the approaches that enables this type of development is the use of new materials capable of delivering superior performance. Conventional ductile cast iron alloys used in brake spiders exhibit limited mechanical properties, which restricts mass reduction while still ensuring high durability in service. One way to obtain high-performance ductile cast iron alloys is through heat treatments such as austempering (ADI), which provides significant gains in mechanical strength but involves high cost and environmental liabilities due to the use of salt baths. The modified and nanostructured ductile cast iron alloy proposed in this work exhibited mechanical properties in the as-cast condition that meet the standards for ADI-treated ductile irons, showing an increase of 102% in tensile strength and 78% in yield strength compared to the baseline spider. Based on this new material, a topology optimization was performed on the baseline spider model, resulting in an optimized design with a 40% mass reduction. The model was validated using casting simulation software, and tooling was manufactured for producing the new optimized spider samples in the nanostructured ductile cast iron alloy. Static mechanical properties and microstructure were determined and approved, allowing the fatigue testing phase to proceed. Initially, the spider samples were instrumented with electrical strain gauges and subjected to the standard structural bench test known as the Chuker test, which can simulate real operating conditions of the brake system. Considering that this test requires extended bench time, an accelerated durability test was developed for the new spider model using three servo-controlled hydraulic cylinders, based on the stress levels obtained. The results from the accelerated durability bench test demonstrated superior fatigue life for the optimized spider compared to the baseline model, also validating the new testing procedure.
Titton, Angelo Pradella, Tuzzin, Matheus, Lopes, Carlos H. R., Marcon, Lucas, Pereira, Leonardo, Tedesco, Jaime Luiz, Boaretto, Joel, Vieceli, Alexandre, Klein, Aloísio N.
Evaluation of Structural Service Performance of Low-temperature Modified Asphalt Pavement based on Peavy-Duty traffic Engineering2026-99-16457/24/2026
Relying on the reconstruction project, the low-temperature modified asphalt pavement significantly reduces the construction temperature of the asphalt mixture by 40 °C compared with the traditional asphalt pavement, and improves the road performance of the material. By comparing the two mixture rolling schemes, the compaction effect of scheme 2 is better. For AC-13 mixture, the flexural tensile strength of USP-SBS composite modified asphalt mixture is 0.67 MPa higher than that of SBS modified asphalt mixture, and compared with SBS modified asphalt mixture, the final rut depth of USP-SBS composite modified asphalt mixture is 2.68 mm shallower than that of SBS modified asphalt mixture, and the total deformation rate is 43.8% lower than that of the latter. The post-construction quality evaluation shows that the stability of the low-temperature modified asphalt pavement test section under the bearing capacity and high-temperature-water coupling is better than that of the conventional road section, and the low-temperature stability is comparable to that of the two. This innovative application not only achieves energy saving and emission reduction but also provides a new solution for road construction under heavy traffic conditions.
Liu, Chuanfeng, Xu, Ke, Shi, Zheng, Hao, Jidong, Zhao, Liandi, Xianwei, Wang
Heat Treatment, Precipitation-Hardening Corrosion-Resistant, Maraging, and Secondary Hardening Steel PartsAMS2759/3K (Current)7/21/2026
This specification, in conjunction with the general requirements for steel heat treatment covered in AMS2759, establishes the requirements for heat treatment of precipitation-hardening corrosion-resistant, maraging, and secondary hardening steel parts. Parts are defined in AMS2759. Parts made from steels other than those specified in this specification may be heat treated in accordance with the applicable requirements herein using processing temperatures, times, and other parameters recommended by the material producer unless otherwise specified by the cognizant engineering organization. General ordering instructions are specified in AMS2759.
AMS F Corrosion and Heat Resistant Alloys Committee
Enhancement of Tractive Trafficability for a Four-Track Unmanned Amphibious Tracked Vehicle2026-99-05787/10/2026
This study addresses the insufficient tractive trafficability of four-track unmanned amphibious tracked vehicles (UATV) in beach terrain by proposing an optimization strategy based on coordinated suspension height and hitch point adjustment. A mathematical model of vehicle drawbar pull was established to systematically analyze the influence mechanisms of vertical load distribution, suspension adjustment, and hitch point elevation on tractive trafficability. DEM-MBD coupling simulations revealed differentiated traction laws under sandy loam and clay conditions, particularly regarding track overlap effects. Results demonstrate that in sandy loam, rear-axle traversal over front-axle tracks reduces drawbar pull due to soil loosening, whereas track overlap enhances drawbar pull in clay through soil compaction. Nine suspension-hitch configurations were tested, validating optimization strategies: increased front-axle loading (Configuration a) in sandy loam and reduced front-axle loading (Configuration f) in clay. These configurations significantly improved tractive trafficability.
Chen, Yaoyao, Gao, Xue, Wang, Wenhao, Xu, Xiaojun
Low-Temperature Internal Heating of Lithium-Ion Cells by Zero-Mean Square-Wave Current Excitation: Thermal Response and Aging Effects2026-01-07537/1/2026
Current lithium-ion batteries should generally only be charged above 0 °C, as charging below this temperature can promote lithium plating and irreversible degradation. However, conventional pack-level heating elements increase system mass and design complexity. In addition, heat is transferred from outside into the cell, causing the temperature inside the cell to rise slowly. This study evaluates internal Joule heating of cylindrical Li-ion cells using a zero-mean square-wave current excitation and quantifies the associated aging impact. LG INR21700-M50L cells were tested at 0 °C, −10 °C, and −20 °C with three excitation frequencies (50 Hz, 1 Hz, 10 mHz) at 5 A amplitude. Each cycle consisted of 30 min heating followed by 60 min cooling; reference capacity-based state of health (SOH) was assessed every 50 cycles up to 400 cycles. A maximum surface temperature rise of 14.3 K was achieved, with larger temperature rise at lower ambient temperature and lower excitation frequency. Capacity fade remained below approximately 1% for most conditions; however, at −20 °C and 10 mHz a pronounced SOH decrease to 87% was observed, indicating a critical operating regime. The results provide practical guidance for pulse-heating parameter selection and highlight the need for safeguards and further diagnostics in extreme low-frequency excitation at very low temperatures. This heating approach is particularly suitable for simpler battery-electric applications without thermal management, such as e-bikes or power tools. However, it may also be relevant for applications with existing thermal management systems, as it simplifies battery pack design.
Raiber, Stefan, Allmendinger, Frank, Degler, David, Parschau, Anke
Metal Injection Molded Nickel Based Alloy 718 Parts Hot Isostatically Pressed, Solutioned and AgedAMS5917 (Current)6/19/2026
This specification covers a corrosion and heat-resistant nickel alloy in the form of metal injection molded (MIM) parts.
AMS F Corrosion and Heat Resistant Alloys Committee
Carburizing and Heat Treatment of Carburizing Grade Steel PartsAMS2759/7F (Current)6/15/2026
This specification, in conjunction with the general requirements for steel heat treatment covered in AMS2759, establishes the requirements and procedures for three classes of gas, vacuum, liquid, and low-pressure carburizing (LPC) and related heat treatment of parts fabricated from carburizing-grade steels. Parts made from steels other than those specified in the detail specifications may be heat treated in accordance with the applicable requirements using processing temperatures, times, and other parameters recommended by the material producer. This specification does not cover pack carburizing.
AMS B Finishes Processes and Fluids Committee
Plating, GoldAMS2422G (Current)6/8/2026
This specification covers the requirements for electrodeposited gold plate.
AMS B Finishes Processes and Fluids Committee
Quantifying Life Cycle Environmental Impact of Emerging Aluminum High-Pressure Die Cast (HPDC) Mega-Castings Replacing Stamped Steel Solutions13-07-01-00046/4/2026
Over the last few years, there has been an uptick in the exploration and implementation of aluminum high-pressure die casting (HPDC) mega-castings as replacements for conventional stamped steel parts in vehicles. This trend is expected to increase with common justifications, including claims of reduced costs and lower environmental impacts associated with the replacement of dozens of individual parts with a single casted piece, along with reduced demands on associated tooling and machinery. However, the data and literature to support these claims are limited and at times contradictory, with some studies showing increased costs and energy demands for mega-casting technologies. This study presents the results of a literature review and a gate-to-gate life cycle inventory (LCI) adapted from conventional HPDC aluminum casting unit processes that may be used to quantify potential life cycle global warming potential (GWP), cumulative energy demand (CED), and other environmental impacts of aluminum mega-castings. A set of cradle-to-gate example calculations is also provided to demonstrate the application of the inventory and significance of the findings, which point to significantly higher GWP and CED for aluminum mega-castings versus stamped steel parts and warrant further study to inform vehicle design decision makers.
Sebastian, Brandie, Balzer, Russ
Mitigating Cracking in COP Optics through Annealing and Step-Torquing2026-26-07646/1/2026
Polymeric optical materials such as Cyclo Olefin Polymer (COP) are adopted in aerospace lighting systems due to their excellent optical clarity, dimensional stability, moldability and weight saving advantages over glass. However, their relatively low toughness and the presence of residual molding stress make them prone to crack initiation during mechanical fastening. During its installation, crack formation was consistently observed around self-tapping screw interfaces, raising concerns over reliability, maintainability, and compliance with durability requirements. A structured Design of Experiments (DOE) was performed to identify root causes and evaluate potential mitigation methods. The investigation revealed that residual stresses in the COP material, combined with localized stress concentrations during screw tightening, were the primary drivers of crack initiation. Two complementary process improvements were identified and validated as part of mitigation plan: (i) annealing of the optics prior to assembly to relieve internal stress, and (ii) using step-torquing method to fasten the screws, to gradually distribute applied loads and reduce localized stress peaks. Post-assembly observation over three days confirmed a significant reduction in crack initiation. The combined annealing and step-torquing approach demonstrated a substantial reduction in crack generation probability, providing a practical and repeatable process for enhancing the robustness of polymeric optic assemblies. This work contributes a generalizable methodology for mitigating assembly-induced failures in advanced polymer materials and supports broader adoption of lightweight, high-performance optics in aerospace applications.
S, Nikhil, Singh, Abhimanyu Kumar, Katageri, Praveen, SP, Pradeep, Chandra, Praveen
Investigation of Aluminium Alloy Composites Reinforced with Zirconium oxide and Solid Lubricant Attributes for Brake and Clutch Components of Aircrafts2026-26-07526/1/2026
For brake and clutch components of aircraft vehicles which require higher mechanical strength and wear resilient, light-weight aluminium composites were developed infusing solid lubricant. In this study, hybrid composites were developed using powder metallurgy route with aluminum alloy AA356 and various amounts of zirconium oxide (ZrO2) (0, 5, 10, 15, and 20 wt.%) as reinforcements. A solid lubricant hexagonal boron nitride (hBN) at a fixed 5 wt.% is considered. Following the appropriate ASTM guidelines, the specimens were mechanically characterized by measuring their density, porosity, micro-hardness, compression strength, impact strength, and flexural strength, among other properties. The findings showed that the composites' mechanical and physical behaviour were greatly affected by the inclusion of ZrO2. Porosity increased as a result of particle clustering and interfacial voids, while density increased gradually as ceramic content increased. Consistently increasing ZrO2 addition led to micro-hardness improvements; at 20 wt.% reinforcement, values reached their maximum, indicating that the hard ceramic phase contributed to better surface resistance. The best balance between particle reinforcement and matrix continuity was suggested by the compression and flexural strengths peaking at 15 wt.% ZrO2. However, when the addition was raised to 20 wt.%, brittleness and porosity began to marginally deteriorate. Unreinforced and lower ZrO2 composites had superior toughness in impact, whereas materials with a higher content had a poorer energy absorption capacity. The 5 wt.% hBN improved fracture arresting capabilities and helped load transmission over the interface. Inclusion of hBN provides solid-lubricating tribofilm formation that enhances the tribological performance. This study reveals that AA356/ZrO2-hBN hybrid composites have good hardness and compressive strength improvements, with 15 wt.% ZrO2 being the best composition with good strength, toughness, and wear resistance.
Senthilkumar, N.
Wear Resilience Characteristics of Silicon Nitride Strengthened AZ31 Magnesium Composite2026-26-07406/1/2026
To develop magnesium matrix composites, ceramic silicon nitride (Si3N4) particles are added to the magnesium (AZ31) matrix at 2 wt.%. The composite is produced via disintegrated melt deposition vacuum-stir-casting procedure. Microstructural studies reveal the presence of Si3N4 particles and their uniform spreading. An L9 orthogonal array, planned using Taguchi’s experimental design, is selected for three wear parameters; axial load (AL), rotational speed (RS), and time duration (TD) with trials as per the G99 standard in the pin-on-disc apparatus to assess the wear resilient of the composite. Experimental results show an increase in axial stress, and wear loss (WL) increases dramatically. Because the area of contact shrinks as RS increases, WL diminishes dramatically. When the AL is low, the friction coefficient (CoF) increases, and when the AL is large, CoF drops. When the RS is increased, CoF decreases. To optimize multiple responses effectively, the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) approach was adopted. According to the analysis, the ideal combination turned out to be a 10 N A, an RS of 275 rpm, and a TD of 1000 seconds. ANOVA results show that AL (56.99%) and RS (27.2%) contribute more, with a regression coefficient of 92.99%. Abrasive and adhesive wear mechanisms are observed from the worn-out surface micrographs.
Senthilkumar, N., Dhinakar Raj, C K
A New Electrolyte Points to Stronger, Safer BatteriesTBMG-552556/1/2026
Researchers at Columbia Engineering have developed a new gel electrolyte that both improves the lifetime and safety of anode-free lithium batteries, an emerging battery architecture that could dramatically boost energy density while simplifying manufacturing. Although such design promises higher energy density and lower cost, the approach has long been plagued by short battery life and safety concerns caused by unstable lithium plating and parasitic reactions at the electrode-electrolyte interface.
Evaluation of Mechanical Tensile Properties on TIG-Welded AISI 304L Austenitic Stainless Steel Using Principal Component Analysis05-19-04-00275/14/2026
The reliability of welded joints is a vital factor in modern manufacturing, directly affecting product performance and durability. This study investigates methods to enhance the mechanical and metallurgical quality of butt joints in AISI 304L stainless steel welded by the gas tungsten arc (GTA) process. A systematic experimental design was implemented using the Taguchi method with an L9 orthogonal array, considering welding current, gas flow rate, and travel speed as the main parameters. To determine overall weld performance, the joints were characterized by measuring ultimate tensile strength (UTS), yield strength, percentage elongation, and examining their microstructural morphology. An experimental strategy based on the Taguchi approach has been implemented. The welding performance of the material was investigated, and the process parameters were optimized using multiresponse optimization through principal component analysis (PCA), incorporating an orthogonal array design, signal-to-noise (S/N) ratio, and analysis of variance (ANOVA). C1G1S3—the predicted optimal parameter combination—is the ideal factor configuration as determined by PCA (welding current = 100 A, gas flow rate = 10 L/min, travel speed = 2 mm/sec). Results demonstrate that precise control of process parameters significantly enhances weld quality. The methodology also provides a systematic framework that engineers and practitioners can apply to produce reliable stainless steel welds with improved accuracy and predictability.
Ghosh, Nabendu, Roy, Angshuman
Optimizing Coil Structural Parameters to Enhance the Sensitivity of Wear Particle Sensor2026-01-50335/14/2026
If wear particles generated during the operation of automobile engines are not monitored in time, they will contaminate the lubricating oil, leading to system failures or even accidents. Therefore, real-time wear particle monitoring is crucial for the stable operation of engines. Among mainstream wear particle monitoring sensors, the three-coil inductive sensor demonstrates significant application potential due to its ability to distinguish wear particle materials and strong resistance to environmental interference. However, its insufficient sensitivity to small-diameter wear particles limits further performance improvement. This paper takes the three-coil inductive wear particle monitoring sensor as the research object. First, a mathematical model of the sensor’s operation is established based on the law of electromagnetic induction, clarifying the relationship between structural parameters (such as channel radius, turns, coil spacing, and length) and the peak induced voltage. Subsequently, Multiphysics simulation software is employed to quantitatively analyze the influence of each structural parameter on the induced voltage, identifying directions for parameter optimization. Furthermore, orthogonal experiments are conducted to optimize discrete parameters, determining optimal levels for key parameters such as channel radius and coil spacing. Then, the simulated annealing algorithm is applied to achieve precise optimization of continuous parameters, ultimately obtaining the optimal combination of coil structural parameters. Experimental validation based on the optimized parameters shows that the peak-to-peak induced voltage for 1000 μm wear particles measured by the sensor optimized with the simulated annealing algorithm reaches 2.43 V, which is approximately 41 times higher than the 0.06 V observed before optimization. Additionally, the optimization effect of the simulated annealing algorithm further improves by 38.86% compared to the orthogonal experiment. In addition, experimental tests were also carried out on small-diameter abrasive particles of 100 μm, with the peak-to-peak value of the induced voltage reaching 0.38 V. The results confirm that this coil structural parameter optimization method effectively enhances the sensor’s sensitivity to small-diameter wear particles, providing a theoretical basis and technical support for the structural design and performance improvement of three-coil inductive wear particle monitoring sensors.
Yin, Hao, Zhao, Lijun, Shen, Yitao
Chrome-Free Surface Pretreatment Prior to PaintingAMS3175B (Current)5/7/2026
This specification establishes requirements for chrome-free surface pretreatment materials used for surface preparation of metallic surfaces prior to applying organic coatings.
AMS G8 Aerospace Organic Coatings Committee
Hardness and Conductivity Inspection of Wrought Aluminum Alloy PartsAMS2658E (Current)5/6/2026
This specification establishes hardness and electrical conductivity acceptance criteria for finished or semifinished parts made from wrought aluminum alloys after heat treatment (see 8.6).
AMS D Nonferrous Alloys Committee
How Machina Labs is Reshaping Defense Manufacturing with AI-Driven 7-Axis Robotics26AERP05_015/1/2026
Machina Labs recently closed its latest round of financing with $124 million, enough to develop a facility featuring up to 50 of its RoboCraftsman cells capable of producing thousands of complex structural assemblies for aerospace and defense customers - a list that already includes Lockheed Martin and the U.S. Air Force, among others. Founded in 2019, Machina Labs is a California-based company that seeks to reinvent metal manufacturing with a robot that uses artificial intelligence (AI) to rapidly form and assemble complex military grade structures directly from digital design files. RoboCraftsman is the company's manufacturing robot that leverages its proprietary “RoboForming” process to integrate multiple manufacturing processes - including metal forming, trimming, scanning, and heat treating - into a single containerized machine.
Plating, Nickel-Thallium-Boron or Nickel-Boron, Electroless DepositionAMS2433E (Current)4/25/2026
This specification covers the requirements for an electroless nickel-thallium-boron or nickel-boron deposit on various substrates.
AMS B Finishes Processes and Fluids Committee
Investigation of Metallurgical and Mechanical Behaviors of AA6061-AA2017 Joints Produced by Single- and Double-Pass Friction Stir Welding: Influence of Base Material Position and Post-Weld Shot Peening Technique05-19-04-00264/13/2026
The growing demand for lightweight, high-strength materials in marine and aerospace structures has promoted the use of friction stir welding (FSW) for welding dissimilar aluminum alloys. However, tensile residual stresses and microstructural heterogeneities often degrade weld integrity. This study investigates the combined impact of base material positioning, single- and double-pass FSW, and post-weld shot peening (SP) on the metallurgical and mechanical properties of AA6061–AA2017 joints. Five welding configurations were examined to evaluate how varying base material positions on the advancing and retreating sides affect material flow and mechanical behavior. Post-weld SP effectively presented compressive residual stresses, reduced surface defects, and refined surface grains. The average grain size in the stir zone was reduced from 5.2 μm (single-pass) to 2.0 μm (double-pass U-turn) after SP, confirming significant grain refinement through dynamic recrystallization. Mechanical testing revealed that double-pass FSW with opposite weld direction (U-turn) followed by SP achieved the highest performance, with ultimate tensile strength (UTS) improving from 246 MPa to 289 MPa (≈17% increase) and tensile elongation rising from 8.78% to 9.41%. Microhardness in the heat-affected zone improved up to 127 VHN, countering thermal softening effects. The synergistic effect of double-pass welding and SP enhanced homogeneity, fatigue resistance, and surface integrity. The results establish SP as an efficient post-FSW treatment for dissimilar aluminum joints, offering quantifiable improvements in strength and ductility, making the process highly suitable for demanding marine and aerospace structural applications.
Nukathoti, Raja Sekhar, Battina, N. Malleswara Rao, Vanthala, Varaha Siva Prasad, Chirala, Hari Krishna, Maloth, Balu
Steel, Corrosion-Resistant, Investment Castings, 16Cr - 1.9Ni - 0.08N (431), As CastAMS5353G (Current)4/12/2026
This specification covers a corrosion-resistant steel in the form of investment castings.
AMS F Corrosion and Heat Resistant Alloys Committee
Aluminum Alloy, Sheet and Plate, Alclad 4.4Cu - 1.5Mg - 0.60Mn (2024 -T361 Sheet/Plate with 1½% Alclad) Solution Heat Treated, 6% Cold Worked and Naturally AgedAMS4194F (Current)4/8/2026
This specification covers an aluminum alloy in the form of sheet and plate, alclad both sides, supplied in the -T361 temper.
AMS D Nonferrous Alloys Committee
Machine Learning-Based Prediction of Tensile Properties in Cast Stainless Steel Influenced by Chemical Composition Variation2026-01-02374/7/2026
In the category of cast stainless steels, there are several variants per different level of addition of chromium, vanadium along with some minor elements, such as molybdenum, niobium, tungsten to meet the requirement of corrosion and oxidation resistance. However, the influence of chemical composition variations on the mechanical properties of cast SS continues to lack a clear understanding. In the present study, via machine learning, the effects of each element on the tensile properties of the selected cast stainless steel are studied. The machine learning model is then used to predict how variations in elements affect tensile behavior, with the predictions validated through physical testing.
Mishra, Neelam, Biswas, Surjayan, V S, Rajamanickam, Aluru, Phani, Liu, Yi, Akbari, Meysam, Coryell, Jason
Tensile and Fatigue Behavior of High Pressure Die Cast AE44 Magnesium Alloy at Elevated Temperatures2026-01-02344/7/2026
Tensile and cyclic behavior of high pressure die cast AE44 magnesium alloy have been studied at room temperature and elevated temperatures up to 350°C. Anelastic behavior has been found in both tensile and cyclic loading at the temperature below 200°C. With increasing temperature, the anelasticity disappears, and tensile and cyclic behaviors become like other engineering materials, such as steels and aluminum alloys, i.e. the total strain contains only elastic strain and plastic strain. A method to determine the yield strength at 0.2% plastic strain (σ0.2) is proposed. By using the proposed method, the yield strength σ0.2 is found to be higher than that determined using the traditional method, which is more suitable to the materials that do not exhibit anelasticity. It is believed that the anelasticity is closely related to twinning in Mg alloy, which disappears at elevated temperatures.
Liu, Yi, Yang, Wenying, Coryell, Jason
Strain-Based Fracture Assessment of Tailor Welded Blanks under Complex Loading Conditions2026-01-02314/7/2026
Tailor Welded Blanks are critical for automotive lightweighting yet prone to premature failure due to differential thickness and strength across the weld. This study utilized digital image correlation (DIC) to analyze the maximum in-plane principal Hencky strain (E₁max) and axial strain (εₐₓₐₗ) of TWBs under complex loading conditions, including biaxial and plane-strain states. Twelve distinct material stack-ups were tested to evaluate the impact of material difference on formability. Results indicated that differential properties significantly altered strain distribution, often forcing localization onto the thinner or softer sheet. While UHSS welds provided high load capacity with limited ductility, combinations using HSLA or IF substrates were susceptible to early localization and unstable fracture. Comparative heatmaps illustrate strain evolution across all samples, providing spatial insights beyond conventional force–displacement analysis. Metallurgical characterization confirmed a strong correlation between failure behavior and microstructural features, specifically heat-affected zone softening and martensitic transformation. Notably, once the strength ratio exceeds 2.0, biaxial stretchability drops sharply and failure transitions from base-metal necking to weld-initiated cracking, indicating a severe mechanical mismatch effect. The observed hierarchy of critical strains (E₁ biaxial > E₁ plane-strain > E₁ uniaxial) confirms that biaxial testing represents the upper-bound deformability condition for these welded blanks. Collectively, these findings provide actionable guidance for optimizing TWB design in battery electric vehicle structures, where material heterogeneity and complex loadings are prevalent challenges.
Aminzadeh, Ahmad, Sheng, ZiQiang, Huang, Lu, McCarty, Eric, Biro, Elliot
Breakthrough in Carbon-Based Battery Materials Improves Safety, Durability, and PowerTBMG-548554/1/2026
This research demonstrates a new way to make carbon-based battery materials much safer, longer lasting, and more powerful by fundamentally redesigning how fullerene molecules are connected. Today’s lithium-ion batteries rely mainly on graphite, which limits fastcharging speed and poses safety risks due to lithium plating. These research findings mean progress toward safer electric vehicles, longer-lasting consumer electronics, and more reliable renewable-energy storage.
Simulation-Based Evaluation of Lithium-Ion Batteries Manufacturing Performance2026-01-70052/27/2026
Lithium-ion batteries (LIBs) have become indispensable components in diverse energy applications driven by their high energy density, long cycle life, and low self-discharge. These excellent characteristics are directly influenced by their manufacturing processes, where variations in battery design and processing parameters will lead to significant differences in performance. Therefore, reliable and efficient evaluation of battery performance across manufacturing processes is essential for quality assurance and process improvement. Traditional methods rely on formation cycling and associated electrochemical tests, which are time and cost intensive. Different from them, a simulation-based approach for manufacturing performance evaluation is proposed in this study. The method employs the pseudo two dimensions (P2D) electrochemical model within the PyBaMM framework, where model parameters such as electrode type, electrode size, and particle size are derived from manufacturing data and built-in parameter data. The model predicts key performance indicators including capacity, resistance, and loss of lithium inventory (LLI) under specified tests conditions. A LGM50T cell was tested under varying operational scenarios, demonstrating the feasibility of the approach. Results indicate that low temperature condition significantly accelerates degradation and Lithium plating, with the capacity degradation at 5 °C reaching about three times that at 25 °C, while moderate variations in charge current rate induce only minor differences of about 0.5%. Simultaneously, depth of discharge (DOD) and average state of charge (SOC) have similar effects on capacity degradation and LLI. By replacing extensive reality tests with physics-based simulations, this method enables rapid evaluation of manufactured or unprocessed battery process formulas, substantially reducing time and material costs while providing mechanistic insights into process performance interactions.
Yan, Yifei, Meng, Jinhao, Song, Zhengxiang, Zhang, Shirui, Pan, Yuhao, Yang, Peihao, Peng, Jichang
Investigation of Failure Mechanisms in Lithium Metal Solid-State Batteries Based on In Situ Electrochemical Impedance Spectroscopy2026-01-70362/27/2026
With the growing global demand for sustainable energy and high-performance mobile devices, lithium metal solid-state batteries (LMBs) have emerged as a research hotspot in the field of energy storage due to their exceptional high energy density and significant safety advantages. However, the growth of lithium dendrites and their penetration through the solid electrolyte remain key issues leading to battery short-circuiting and failure. To date, there has been a lack of effective in situ research methods to reveal the failure mechanisms, which has severely restricted the commercialization of LMBs. This study innovatively employs in situ electrochemical impedance spectroscopy (EIS) to investigate lithium plating behavior in symmetric cells during critical current density (CCD) tests under room temperature and elevated temperature conditions. By analyzing characteristic signals at 1 MHz, this study presents the in situ impedance changes at the grain boundaries and interfaces of the battery, revealing that lithium plating is a dynamic reduction-oxidation process. We summarize two modes of lithium plating: one involves lithium metal deposition at the interface due to local current density inhomogeneity; the other involves lithium metal deposition at grain boundaries far from the electrode due to concentration gradient differences. The study further reveals that lithium plating at grain boundaries is the primary cause of battery failure. This research highlights the unique advantages of in situ EIS in the field of solid-state battery research and its applicability to various material systems. Moreover, the proposed lithium plating mechanism provides a theoretical basis for optimizing battery design and enhancing battery safety, thereby facilitating the realization of high-energy-density solid-state batteries.
Liu, Zexuan, Wu, Senming, Chen, Ying, Luan, Weiling, Chen, Haofeng
Electrochemical–Thermal Coupled Modeling and Optimization of Fast Charging for Lithium-Ion Batteries2026-01-70112/27/2026
This study systematically investigates methods to enhance the fast-charging capability of lithium-ion batteries through advanced simulation. The electrochemical reaction mechanism, heat generation mechanism, and lithium plating mechanism are analyzed in detail, and an electrochemical–thermal coupled model incorporating a lithium plating sub-model is established. A hybrid parameter identification strategy, combining random search, grid search, and manual adjustment, is employed to calibrate the model across different operating conditions, thereby improving its accuracy in reproducing real battery behavior. Lithium plating is selected as the primary indicator to evaluate fast-charging performance. Based on simulation results, the effects of both operational parameters and structural parameters on lithium plating are thoroughly analyzed. The results indicate that lower charging rates, elevated charging temperatures, higher electrode porosity, and reduced tortuosity are favorable for suppressing lithium plating. These conditions improve the uniformity of lithium deposition while alleviating concentration gradients of lithium ions, thus offering valuable insights for battery material design and practical applications. Furthermore, optimized charging protocols are developed on the basis of conventional strategies and their associated impacts on battery behavior. Two novel approaches—the group-based optimized charging protocol and the adaptive optimization-based charging protocol—are proposed by dynamically adjusting the charging rate according to real-time electrochemical states. Validation on the developed electrochemical–thermal model confirms that the proposed protocols can achieve high-rate charging without inducing lithium plating. As a result, charging time is significantly reduced while ensuring safety and reliability. Overall, this research not only provides a comprehensive methodology for modeling and parameter identification but also offers practical strategies for protocol optimization. With solid-state batteries regarded as a promising future technology, the present work provides a potential basis for their advancement.
Zhao, Peiqiang, Zhan, Wenwei, Qi, Ji, Yi, Yong
Lithium Plating-Induced Surface Pressure Evolution in Lithium-Ion Pouch Cells under Rigid Constraints2026-01-70132/27/2026
In practical applications, power cells face a mix of external influences such as temperature variations and structural limits (rigid constraints) that trigger intricate electrochemical and mechanical reactions. This study systematically explores the temporal evolution of surface pressure in lithium-ion pouch cells subjected to rigid mechanical constraints under varying thermal conditions, with a specific focus on the interplay among mechanical stress, lithium intercalation, and lithium plating. To investigate the battery’s electrochemical and mechanical responses, this work integrates experimental measurements with an electrochemical–mechanical coupling model. The analysis is performed under initial loads of 0.3, 0.5, and 1.0 MPa at 25 °C (ambient temperature) and 0 °C (representative low-temperature condition). At 25 °C, surface pressure followed a two-stage pattern: first, stress relaxation occurred, followed by a shift into quasi-steady cycling (cycle-to-cycle variations are minimal). This pattern is largely driven by the reversible volume changes in the electrodes as lithium ions are alternately inserted (intercalation) and removed (deintercalation) during electrochemical cycling of the cells. At 0 °C, slower ion transport and reaction kinetics promoted lithium plating, causing irreversible anode expansion and a continuous rise in surface pressure. Concurrently, the depletion of active lithium diminished the electrode’s maximum achievable state of charge (SOC). This limitation curtailed the degree of electrode expansion and contraction throughout charge–discharge cycles, resulting in a decrease in the amplitude of pressure fluctuations on the battery surface during cycling. Numerical simulations confirmed that lithium plating and SOC degradation collectively shaped the mechanical response at low temperatures. The proposed model accurately replicates experimental pressure evolution and distinguishes between reversible and irreversible contributions to volume changes. This work reveals how temperature and mechanical loading jointly regulate surface pressure and capacity retention, offering insights relevant to battery pack design and the optimization of low-temperature performance.
Du, Yingyue, Chen, Ying, Luan, Weiling, Chen, Haofeng
Tools for Peening Intensity Determination and VerificationJ442_202602 (Current)2/17/2026
This SAE Recommended Practice defines requirements for equipment and supplies to be used in measuring shot peening intensity and other surface enhancement processes. It is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances. Guidelines for use of these items can be found in SAE J443 and SAE J2597.
Surface Enhancement Committee
Blackening Solution for Steel Touch-Up MethodAMS2484D (Current)2/16/2026
This specification covers the requirements for an inorganic blackening solution for steel, applied at room temperature.
AMS B Finishes Processes and Fluids Committee
Aluminum Alloy, Sheet and Plate, Alclad 4.4Cu - 1.5Mg - 0.60Mn (Alclad 2024, -T361 Sheet and Plate) Solution Heat Treated, 6% Cold Worked, and Naturally AgedAMS4466C (Current)2/13/2026
This specification covers an aluminum alloy in the form of alclad sheet and plate 0.020 to 0.500 inch (0.508 to 12.70 mm), inclusive, in thickness, supplied in the -T361 temper (see 8.5).
AMS D Nonferrous Alloys Committee
Genetic Algorithm Based Optimization of Chaboche Kinematic Hardening Parameters along with the Validation of FE Model through Characterized Crack Initiation2026-28-00862/12/2026
In the context of electro-mobility for commercial vehicles, the failure analysis of a connector panel in a DCDC converter is crucial, particularly regarding crack initiation at the interface of busbar and plastic component. This analysis requires a thorough understanding of thermo-mechanical behavior under thermal cyclic loads, necessitating kinematic hardening material modeling to account for the Bauschinger effect. As low cycle fatigue (LCF) test data is not available for glass fiber reinforced polyamide based thermoplastic composite (PA66GF), we have adopted a novel approach of determining non-linear Chaboche Non-Linear Kinematic Hardening (NLK) model parameters from monotonic uniaxial temperature dependent tensile test data of PA66GF. In this proposed work a detailed discussion has been presented on manual calibration and Genetic Algorithm (GA) based optimization of Chaboche parameters. Due to lack of fiber orientation dependent test data for PA66GF, here von Mises yield criteria based Chaboche NLK model is implemented as a macro-mechanical phenomenological model based on test data with random fiber orientation. After material modelling as described above the thermo-mechanical finite element (FE) simulation has been conducted on Connector panel assembly with temperature cycling from -40°C to 80°C. The assembly under consideration is composed of busbars, insert mold and outer connector body of plastic PA66GF. It is observed from the simulation result that though the equivalent plastic strain is much higher at 80°C in comparison to the same at -40°C, the equivalent von Mises stress is comparatively lower at 80°C than at -40°C because of Bauschinger effect while reversing load, which in turn validates the implementation of proper kinematic hardening material model to address the physical phenomenon. Finally, the FE model is validated through characterized crack initiation site in the plastic component comparing with equivalent plastic strain, von Mises stress and stress triaxiality evaluated from simulated result.
Basu, Parichay, Srinivasappa, Naveen
Aluminum Alloy Hand Forgings and Rolled Rings, 1.0Mg - 0.60Si - 0.28Cu - 0.20Cr (6061-T652), Solution Heat Treated, Stress Relief Compressed, and Precipitation Heat TreatedAMS4248E (Current)2/6/2026
This specification covers an aluminum alloy in the form of hand forgings up to 8 inches (203 mm), inclusive, in nominal thickness and a cross-sectional area not over 256 square inches (1652 cm2) and rolled rings up to 3.5 inches (89 mm), inclusive, in nominal thickness and with an OD to wall thickness ratio of 10:1 or greater (see 8.6).
AMS D Nonferrous Alloys Committee
Direct Deposition of Nickel Abrasion Guards on to Carbon Filled Composite Rotor Blade StructuresSM-2026-VLADA-51991/27/2026
Composite materials have become widely adopted in commercial aviation, as aerospace manufacturers look to use them to drive weight reduction and improved fuel efficiency in new aircraft designs. In the case of aircraft rotary blades, the poor wear properties of these materials have necessitated the development of metal leading edge guards that can provide critical protection against erosion and impact damage during flight. Electroforming has been a leading process for the manufacture of these protective guards, with nickel parts providing excellent wear resistance that significantly extends the service life of the rotary blade assembly. Currently there has not been a focus on utilizing direct electrodeposition of metal on to carbon filled epoxy composite structures, as traditional plating-on-plastics approaches require considerable effort in surface preparation and normally do not provide adequate adhesion to the underlying structure. Alpha Metalcraft Group has been working in cooperation with aerospace suppliers in the design of an electroplating ready composite structure that would allow for direct nickel deposition, provide excellent adhesion, and significantly reduce both the time and cost for the manufacture of ready-to-assembly rotary blade structures. Test panels were constructed of commercially available prepreg materials or by resin infusion of dry fabrics that incorporated different metal containing conductive layers to allow for the direct deposition through a nickel sulfamate electrodeposition process. Different surface modification strategies were investigated to expose the metal conducting layer and thereby provide the metal-to-metal bonding surfaces required for successful electrodeposition.
Cazzaniga, Luigi
Plating, Silver, Copper Strike, Low BakeAMS2412M (Current)1/26/2026
This specification covers the requirements for silver deposited on metal parts with a copper strike between the basis metal and the silver deposit.
AMS B Finishes Processes and Fluids Committee
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