Browse Topic: Fabrication

Items (2,838)
This research demonstrates a facile method for fabricating an anti-icing coating through spray deposition on a metallic substrate. A dual-layer structure was designed to enhance icephobic properties: a primer layer incorporating fluorocarbon resin, butyl acetate, and rod-shaped micrometer-sized metal oxides to establish a secondary roughness morphology, followed by a topcoat composed of butyl acetate and nano-scaled superhydrophobic particles. Evaluation of the coating performance revealed a maximum water contact angle of 171.9°, indicating exceptional hydrophobicity. Furthermore, the coating exhibited notable abrasion resistance and anti-icing capabilities against overlaying ice.
Li, DongyangXu, ZelongWu, JiangTong, WeiWang, WeiqingCong, RimeiQian, JiaweiQu, Shaohui
This study investigates the interaction mechanism between ultraviolet nanosecond pulsed lasers and polyetheretherketone (PEEK). By integrating finite element simulations with experimental validation, the work explores the laser microtexturing characteristics of PEEK surfaces and evaluates the influence of microtextures on the material’s surface biocompatibility. First, the interaction between the laser and the PEEK polymer was analyzed, and a laser ablation model was established using the COMSOL Multiphysics simulation platform. Using finite element simulation, the effects of spot overlap ratio were investigated by adjusting the average laser power, while the influence of single-pulse energy on the ablation characteristics of the PEEK surface was examined by varying the scanning speed. Subsequently, ultraviolet nanosecond laser processing experiments were conducted on planar PEEK microtextures based on the simulation results. Taking surface microgrooves on PEEK as representative structures, the variations in groove depth and width under different combinations of laser parameters were analyzed. The parameters, including average laser power, scanning speed, and repetition frequency, were optimized to identify processing conditions that yield stable depth and width, along with good surface flatness. Finally, experiments have initially verified that the microtextured PEEK surface may improve biocompatibility and regulate surface wettability to a certain extent.
Wu, YifanWang, XiaohuiHan, YujieJin, Shuo
Metal fins with complex structural surfaces play a crucial role in cooling highly heat-intensive electronic products, and a facile method for fabricating such metal fins is urgently needed. Herein, a simple machining method was proposed for fabricating metal fins with novel waveform structures. The new machining method combined plowing extrusion and cutting (PE-C) processes, enabling one-step fabrication of wavy fins, exhibiting excellent flexibility and efficiency. The combined PE-C tool was first designed and manufactured. Subsequently, experiments for fabricating wavy fins were developed and conducted. Based on this, an in-depth analysis of forming procedures was performed using in-situ experimental insights. Moreover, forming characteristics of wavy fins under key parameters (e.g., the tool rake angle γ^c and the cutting velocity V^c) were discussed. Results show that the novel wavy fins were successfully manufactured by the proposed PE-C method. Wavy fins exhibited excellent, well-developed surfaces with a complete corrugation structure, and their geometric dimensions could be adjusted through processing parameters. The new PE-C method utilized two consecutive stages (i.e., the PE and cutting stages) to achieve the fabrication of wavy fins. The PE stage shaped the uncut metal surface into grooved structures, while the cutting stage transformed the groove structure into a waveform structure. Multiple folding principles, rather than conventional shear deformation, were utilized to achieve wavy fins. Reducing the γ^c and V^c would contribute to obtaining fins with the larger waveform structures. PE-C exhibited excellent potential in the field of heat exchange metal fin manufacturing.
Zhang, BaoyuLiu, ShudengYe, Zhitong
The present review evaluates recent advances in the development of Welding-Based Additive Manufacturing (WBAM) technologies using arc, high-energy density, solid-state, and hybrid welding systems by providing an interdisciplinary assessment of technological aspects, sensing, process optimization, and multi-process strategies. It is concluded that, in spite of considerable progress in process optimization and control, there exist numerous paradoxes associated with relationships among process conditions, structure, and properties, especially those related to heat input effects on material microstructure and performance. An important finding is the fragmentation of predictive modeling approaches, where physics-based and data-driven methods remain inadequately integrated, limiting generalizability and accuracy. Another important conclusion is related to the dominance of the effect of thermal history and multi-physical phenomena on the mechanical performance of the material produced by WBAM technologies. Besides, the complexity and contradiction in defect generation mechanisms, monitoring, and evaluation methodologies restrict the development of process standardization and certification. New directions in intelligent fabrication based on artificial intelligence and digital twins are identified.
Santhana Babu, A.V.John Rajan, A.Mishra, AishwaryChakravarthy, P.Jayabalakrishnan, D.
It is a general practice to test aero engines to evaluate their performance in specially designed indoor test facilities after assembly, repaired or overhaul. Acoustic features are provided in the test facility to attenuate the noise level to a comfortable and acceptable level. Design of these features specially air intake and exhaust silencers are a challenging task in a flow field like aero-engine test facility considering the very high sound pressure level generated by them during test containing a very wide frequency band. Moreover, growing population and location of these facilities in the vicinity of residential areas has added this challenge in multifold. Also, the capital investment in building these facilities is huge due to their large size and longer construction time. Hence, the correct execution at first shot including design, fabrication and commissioning is very important. An attempt has been made to reduce design errors or improve the accuracy in the design stage by using commercially available acoustics analysis tools followed by laboratory measurement of sample features, which will reduce the lead time and cost of the project in design and implementation of the acoustic features for aero engine test facilities used for military application. This paper outlines the design of acoustics features such as air intake silencers, air cooled exhaust silencer, acoustic panels, sound proof doors and bullet resistant view window, which has produced significant improvement of noise level in and around the test facility.
Gouda, Bansidhar
This research investigates the fabrication and evaluation of Delrin (polyoxymethylene, POM) composites reinforcing 5-20 wt.% chopped ramie fiber (RF). The polymer composites were fabricated via the injection moulding technique. Glass transition temperature (Tg), thermal conductivity, Vicat softening temperature (VST), heat deflection temperature (HDT), melt flow index (MFI), and coefficient of linear thermal expansion (CLTE) were the various thermal characteristics of the sustainable composites that were systematically evaluated as per the ASTM standards. The addition of RF drastically altered the Delrin matrix's performance. Among the formulations, the composite with 15 wt.% RF had the best combination of properties: higher VST and HDT values, which provide greater dimensional stability at high temperatures; lower CLTE, resulting in less thermal expansion; comparatively better thermal conductivity; and improved heat dissipation. Eventually, there was a moderate drop in the MFI, indicating more rigid polymer chains that restrict the flowability of the composite, thereby increasing its heat-withstanding capabilities. DSC analysis revealed a slight upward shift in Tg and increased crystallinity, suggesting restricted polymer chain mobility and enhanced load transfer at 20 wt.% RF loadings, agglomeration effects, and weaker interfacial bonding with the matrix led to deterioration in properties. Aircraft cabin components like interior panels, ducting supports, and lightweight non-structural fittings requires dimensional stability, thermal resistance, and mechanical reliability under fluctuating flight conditions.
S, ThirumalvalavanSenthilkumar, N.Selvarasu, S
Polyimides are a class of polymers with imide rings in their main chains. They are renowned for their exceptional mechanical properties, high-temperature resistance, low-temperature endurance, and resistance to chemical solvents, which allow for long-term use under harsh medical operating conditions. Consequently, research on polyimide films has garnered widespread attention. In this study, a two-step method was employed to simplify and optimize the preparation process of polyimide. Initially, a polyamic acid (PAA) solution was prepared, and PAA films were fabricated using a spin coater. Subsequently, the films were imidized to obtain polyimide (PI) films. The impact of various parameters, such as spinning speed, layer number, and temperature, on the film-forming properties of polyimide was investigated using the method of controlling variables. The findings indicate that by setting the spin coater parameters to 700 revolutions per minute (r/min) for 90 seconds, followed by a transition to a high speed of 2200 r/min for 210 seconds for spinning the PAA solution, and then subjecting the film to a temperature gradient of 100°C for 1 hour, 150°C for 1 hour, 200°C for 2 hours, and 300°C for 2 hours for imidization, a complete and mechanically robust polyimide film can be produced. The average light transmittance of the film across a wavelength range of 400-2500 nm is 90.46%.
Huang, JiehaoXu, ZihuiZhao, KaihongLin, QitingHu, WenzhongWang, Liying
This organizational process survey provides insight into the technical aspects of approved airworthy aircraft modifications applied in government organization vertical lift flight test. The publication reviews processes applied by the National Research Council of Canada's Flight Research Laboratory (NRC-FRL) and its Airworthiness Control System to enable research flight testing. Dominated by the need for integrating experimental payloads, the NRC-FRL embeds a Design and Fabrication Service organization for modification of internal and external client projects and flight test aircraft. In context of experimental flight testing, this work reviews technical information on process, facilities, and methodology for airworthy integration of flight test payloads. Information is used to synthesize recommendations in experimental vertical lift flight testing that satisfy both formal (regulated compliance) and informal (compliance intent) airworthiness requirements.
Alexander, MarcLong, TerryLebrun, CamileDay, JamesMelnik, HarleyThomas, Jeffrey
Fiber Reinforced Additive Manufacturing (FRAM) combines the geometric freedom of additive manufacturing with the high stiffness-to-weight advantages of composite materials, making it a promising approach for lightweight automotive components. The mechanical performance of fiber-reinforced composites is strongly influenced by fiber orientation, which highlights the importance of optimization methods that can effectively exploit anisotropic behavior. Existing FRAM optimization research has focused primarily on structural performance and has given limited attention to manufacturability challenges. This gap is significant, as overhangs and the resulting need for support structures can substantially increase print time, material consumption, and production cost, restricting broader industrial uptake. This research introduces a multi-objective topology optimization framework that incorporates Design for Additive Manufacturing (DfAM) principles by minimizing both structural compliance and support material requirements. The key contribution is a differentiable formulation of support generation that enables support-related penalties to be embedded within a gradient-based optimization process. The results demonstrate that substantial reductions in support usage and overall production effort can be achieved with only minimal impact on structural performance. The integrated framework advances FRAM design practice by uniting performance and manufacturing efficiency, strengthening its potential for next-generation automotive applications where weight, stiffness, and production cost must all be optimized simultaneously.
Wotten, ErikKim, Il Yong
This research investigates the alterations in microstructure, microhardness, and joint strength resulting from the dissimilar friction stir welding (FSW) of WE43 magnesium alloy to AA7075 aluminium alloy. The study specifically analyses the role of FSW process parameters in the formation of intermetallic compounds (IMCs), the evolution of grain structure, the resultant microhardness distribution across the weld zone, and the joint tensile strength. A comprehensive microstructural characterization was performed utilizing optical microscopy (OM), field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDS), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). These analyses confirmed significant grain refinement in the stir zone and the identification of various IMCs at the weld interface. Microhardness mapping indicated a gradient profile, with the weld nugget exhibiting superior hardness attributed to its dynamically recrystallized, fine-grained microstructure. Crucially, the low-heat-input FSW (LFSW) variant yielded a substantial increase in average microhardness, reaching 126 HV in the stir zone (SZ), due to grain refinement induced by severe plastic deformation. This configuration achieved a joint efficiency of approximately 68.7% relative to the WE43 base material. The enhancement in mechanical performance is directly linked to a modified joint preparation strategy that successfully suppressed the formation of brittle AlMg IMCs, instead fostering the formation of harder MgZn, Al2CuMg, and AlMgZn compounds. These findings underscore the efficacy of the LFSW technique in fabricating dissimilar WE43-AA7075 joints with favourable mechanical properties and a consistent microhardness profile. The process parameters are strategically selected to achieve better joint properties and form defect-free joints.
Ahmad, TariqKhan, Noor ZamanAhmad, BabarSiddiquee, Arshad Noor
Expeditionary environments (such as remote exploration missions, forward military operations, and disaster response zones) demand adaptive manufacturing solutions to support vehicle sustainment in the absence of traditional supply chains. This work introduces a conceptual mathematical framework for modeling the constraints and tradeoffs inherent to expeditionary manufacturing, with a focus on vehicle repair and spare parts fabrication using low-energy and simple automated systems including desktop-scale 3D printers and CNC machines. The model integrates key variables such as energy availability, material transport cost, fabrication time, and environmental limitations to support rapid decision-making on part manufacturability and in-field feasibility. A case study involving the on-demand production of some common wear and failure parts on a vehicle, including suspension components and the water pump, is used to demonstrate how this framework can guide the selection of suitable manufacturing technologies, part redesign or repair for field printing. This modeling approach highlights how predictive modeling can optimize both component geometry and process parameters to meet requirements while minimizing energy expenditure and logistics overhead. This work informs future efforts in resilient vehicle system design by embedding manufacturability considerations into the early stages of development, particularly for platforms intended for deployment in expeditionary environments. It offers practical guidance to designers, logisticians, and mission planners seeking to integrate field-capable manufacturing into vehicle lifecycle support.
Mollan, CalahanPandey, VijitashwaPatterson, Albert E.
Master Bond EP40 is a two-part, room temperature curing epoxy for bonding, sealing, coating, and encapsulating. EP40 bonds well to a variety of substrates, including naval steel, the primary structural metal used in the shipbuilding industry. Master Bond Inc., Hackensack, NJ To reduce its environmental impact and pollution, the shipping industry is investigating methods to construct more lightweight ships. One potential method is using adhesive bonding techniques to replace traditional welding and riveted joints on ships to fabricate lighter ships with smaller carbon footprints. However, adhesives age and deteriorate when exposed to moisture, high temperatures, and ultraviolet light. This makes it necessary to understand how they age in maritime environments to determine whether they can truly replace traditional welding techniques. To this end, researchers at Centro de Investigación en Tecnologías Navales e Industriales (CITENI) and Centro de Investigación TIC (CITIC) developed a new method for studying adhesive aging on naval steel substrates. Master Bond EP40 was selected as the test adhesive for this method due to its strong performance and suitability for marine conditions. By using EP40, the team ensured that the observed adhesive bonding behavior would reflect a high-quality epoxy's potential in ship structures. The goal was to evaluate how EP40 bonds to naval steel and how the bulk epoxy material would behave in seawater to provide insights into the construction of lighter ships using this approach.
Multimodal sensors, capable of simultaneously acquiring multiple physical or chemical signals, have shown broad application potential in fields such as health monitoring, soft robotics, and energy systems. However, current multimodal sensors often suffer from complex fabrication processes and signal decoupling challenges, which limit their practical deployment. To address these issues, this work presents a thin-film temperature–strain multimodal sensor (FTSMS) fabricated via laser processing. The temperature-sensing unit, based on the Seebeck effect, achieves a sensitivity of 9.08 μV/°C, while the strain-sensing unit, utilizing BaTiO₃/AlN@PDMS as the sensitive layer, exhibits a gauge factor (GF) of 43.2. By integrating distinct sensing mechanisms (thermovoltage for temperature and capacitance change for strain), the FTSMS enables self-decoupled measurements over 20–90 °C. Applied in LIB monitoring, it successfully captures real-time temperature and strain variations during charge-discharge cycles and provides multidimensional information throughout thermal runaway (TR) processes, enabling early TR warning and supporting safety-oriented battery design.
Wang, ZiweiLi, ZhenglinGao, YangXuan, Fuzhen
With plenty of references to national security and international competition, the University of Arkansas held the grand opening of MUSiC, the first multiuser silicon carbide (SiC) fabrication facility in the U.S. in mid-November. Helmed by Dr. H. Alan Mantooth, the founding director of the UA Power Group (UAPG), the new MUSiC facility will expand the UAPG's capabilities thanks in part to $20 million in funding from the National Science Foundation's Mid-scale Research Infrastructure-1 Program (Mid-scale RI-1), with additional support from the ARL's Army Research Office and X-FAB. Congressman Steve Womack (R) made it clear that, even when the federal government is pulling back funding for research efforts across the country, he still supports the work at MUSiC. “This facility is vital,” Womack said during MUSiC's opening ceremony. “Vital to our nation, vital to our national security, vital to our economic development, and we're in a fast-paced cavalry battle right now with near peers around the globe for research on these issues. It is essential we win that race.”
Blanco, Sebastian
With the increasing complexity of traffic conditions, the computational burden of multi-object tracking algorithms has grown, making it difficult to meet the requirements for tracking accuracy and real-time performance. In this paper, we proposed a road vehicle multi-object tracking method by improving and optimizing the YOLOv5 detection algorithm and the DeepSORT tracking algorithm. A Channel Attention(CA) mechanism is introduced into the existing YOLOv5 algorithm to construct the fusion algorithm CA-YOLOv5, and the feature extraction network structure of YOLOv5 is reconstructed by adding a prediction layer to improve the accuracy of vehicle detection. The ReID (Re-identification) network in DeepSORT algorithm is adopted as ResNet neural network to construct the fusion algorithm ResNet-DeepSORT. And it combined with data and feature enhancement, as well as high accuracy detection results of road vehicles. Thus, it improves the tracking accuracy and reduces the number of ID jumps to realize the multi-target tracking of road vehicles. Experimental results show that the proposed method increases mAP by 1.7%, MOTA by 0.9%, MOTP by 12.6%, and decreases ID switch by 27.7%, Average FPS by 1.69, meeting the tracking requirements for vehicles in practical autonomous driving scenarios, compared with that of the original tracking algorithm.
Bo, LiuJing, WuYanping, ZhouJing, Li
Objective:Methods:Conclusion:
Dai, HongzhouLi, JianZhao, DiLiu, Haoran
The rapid development of civil aviation industry makes it difficult for traditional flight scheduling methods to cope with the increasingly complex air transport demand. In this study, an AI-based civil aviation transportation scheduling optimisation system is designed, integrating a novel deep reinforcement learning framework with a validated multimodal fusion algorithm (MMFA) to address spatiotemporal dependencies in aviation data to construct the core architecture of the system. Measurement results show that the system effectively reduces the average flight delay time by 58.1%, improves the slot utilisation rate by 21.3%, increases the flight punctuality rate to 93.7%, and shortens the response time to emergencies by 62.5%. The high performance and significant economic benefits demonstrated by the system in the real environment provide a feasible solution for the intelligent upgrading of civil aviation transport.
Li, Mohan
The market-oriented reform of railway coal transport price is a key initiative to optimize the transport structure and enhance the railway’s market share in coal transport. Based on the competitive relationship between road and railway, this paper explores the impact of the floating pricing mechanism of railway coal transport on the allocation of capacity and enterprise benefits. Firstly, we construct a model to consider the selection behaviour of highway and railway freight transport modes to reveal shippers’ choice of coal transport modes, and analyse shippers’ preference for highway and railway based on transport cost, timeliness and price elasticity; secondly, we combine railway coal transport clearing rules with market-oriented floating pricing policy, establish a pricing decision model with the goal of optimizing transport volume and carrier revenue, and quantify the full railway tariff, transport time and volume, surplus and so on. Secondly, we establish a pricing decision model with the objective of optimizing transport volume and carrier revenue, quantify the correlation between railway full-time tariff, transport time and indicators such as transport volume and surplus, and simulate the competitive equilibrium between railway and highway under different floating zones. The case study shows that, coal freight price floating coefficient in the 0-30% range, the railway in the coal transport market share with the increase in price concessions was first rapidly rising after the growth rate of slowing down the trend, the owner of the price sensitivity of the marginal utility of the diminishing; through the adjustment of the price of coal and carbon transport, the railway freight sector not only to increase the market share of the coal industry, but also conducive to the achievement of their own business objectives, for the railway transport enterprise The formulation of coal transport price provides a scientific and reasonable reference basis.
Liu, LiYang, LeiCai, Zhenghong
In order to better understand the development level and the degree of development of the transportation network in different areas of the Hexi Corridor, the accessibility of the transportation network in the Hexi Corridor is studied. Firstly, calculate the road density of each county and district in the Hexi Corridor. Then, in view of the topographic characteristics of the Hexi Corridor, introduce the shortest travel time and travel cost into the gravity model, consider the accessibility of both road and railway transportation modes between nodes, construct a comprehensive accessibility model, and analyze the spatial characteristics of the comprehensive accessibility of each county and district in the Hexi Corridor. Secondly, the gravitational model is used to analyze the economic connection intensity among the counties and districts in the Hexi Corridor. Finally, calculate the Gini coefficient, draw the Lorenz curve, and analyze the fairness of the comprehensive accessibility of the Hexi Corridor. Research shows that the comprehensive accessibility and economic connection centrality of each county and district in the Hexi Corridor present a spatial structure of “one belt and one core”, and both the comprehensive accessibility and economic connection centrality show a attenuation from the core area to the strip-shaped area. Liangzhou District of Wuwei City is the main core area of the Hexi Corridor. The Gini coefficient of comprehensive accessibility based on the cumulative proportion of population and GDP is all within the unfair range, and the overall development of the Hexi Corridor and the distribution of the transportation network are unfair. The research results can provide decision support for the optimization of the transportation network, economic development and tourism development in the Hexi Corridor.
Jiang, PingMu, HaiboPeng, Zhiwei
With the rapid development of metro network operation, metro passenger flow congestion propagation occurs frequently. Accurately modeling passenger flow congestion propagation is crucial for alleviating metro passenger flow congestion and formulating corresponding control strategies. Traditional modeling methods struggle to effectively capture the complex spatiotemporal dependency relationships in metro networks. To improve the accuracy of congestion propagation modeling, this paper proposes a Dynamic Spatiotemporal Graph Convolutional Network (DSTGCN). The model integrates node attributes and temporal encoding through a dynamic adjacency matrix generation module, uses multi-head attention mechanisms to adaptively learn the time-varying propagation intensity between nodes, and combines static topology to construct dynamic adjacency matrices. A multi-scale spatiotemporal feature extraction module is designed, employing temporal convolution and spatial attention mechanisms to mine periodic and local correlation features, and aggregating historical states with different time lags through stacked graph convolutions. Experimental results on real metro datasets verify the effectiveness of each module of the model and reveal the inherent laws of passenger flow congestion propagation in metro networks. The research provides theoretical support for congestion early warning and dynamic regulation in metro network operation.
Chen, BeijiaWang, JunhangShao, Jiayu
In order to determine the ranking of factors affecting passengers’ evaluation of the aircraft cabin, a cabin evaluation system for aircraft was constructed by studying domestic and foreign literature. Taking the aircraft cabin as the research object, the Analytic Hierarchy Process (AHP) is used to construct an aircraft cabin evaluation system consisting of 3 primary indicators and 15 secondary indicators. The comprehensive weights of each indicator are determined through a combination of qualitative and quantitative research methods, providing important references for aircraft cabin design.
Cai, Ruihong
Railway is a key component driving innovation and sustainability in transportation systems. Aiming at solving the problems of metal reflection, oil contamination and complex background interference in railway wheel tread defect detection, this paper will focus on the railway wheel tread defect detection method, SEN-YOLO, based on the YOLOv5s and the comparison between different generations of YOLO detection. To better adapt the model to actual detection scenarios, multi-stage dynamic data augmentation strategy combining illumination robustness optimization and motion blur simulation is designed to construct a railway wheel dataset that closely mirrors real-world conditions. In terms of model architecture, the YOLOv5s-based approach integrates the Squeeze-and-Excitation Networks (SENets) module to enhance the capture of minor defect features and employs an adaptive feature fusion strategy to mitigate background noise. To further improve detection accuracy and generalization, the YOLOv5s network structure is optimized. A multi-scale feature fusion algorithm in the backbone network improves processing of different scale defect features; Additionally, the feature enhancement module is depoyed in the neck network boosts feature expression and the ability to distinguish; Furthermore, an adaptive loss function in the head network balances detection effects. Trained on the open-source railway wheel tread defect dataset from Roboflow and tested, SEN-YOLO achieves 84.1% mAP on the custom dataset and a detection speed of 35 FPS on an RTX3070 GPU, a 12% improvement over the baseline YOLOv5s model. Comparative experiments with other mainstream object detection algorithms show that SEN-YOLO performs well with high detection accuracy and stability, meeting the practical needs of railway wheel tread defect detection.
You, LijieMo, YayelinTu, JingjieZhou, Hang
This paper integrates the theoretical models of Transformer and BiGRU to construct the Transformer BiGRU Global Attention model, with the aim of enhancing the model’s ability to extract key information. Through the implementation of a cross-attention mechanism to amalgamate features and enhance feature representation, the model attains exact prediction of main engine fuel consumption for vessels. Compared to the Transformer and BiGRU models, our model achieves 86% higher prediction accuracy, enabling more accurate prediction of ship main engine fuel consumption. This furnishes data support for the purpose of comparison with original factory data, thereby facilitating the assessment of engine fault conditions.
Liu, ZicongZhang, DefuLv, HongbinZhu, Wei
Missions to the moon and other planets will require large-scale infrastructure that would benefit from autonomous assembly by robots without on-site human intervention. Modular and reconfigurable structures, such as those built from lattice-based building blocks, are reusable and easy to manufacture. Furthermore, reconfigurable systems have the potential to outperform traditional, fixed infrastructure in applications that require high levels of flexibility in addition to structural strength and rigidity. NASA Ames Research Center has developed a novel and efficient mobile bipedal robot system to construct low-mass, high precision, and largescale infrastructure.
NASA has developed a novel approach for macroscale biomaterial production by combining synthetic biology with 3D printing. Cells are biologically engineered to deposit desired materials, such as proteins or metals, derived from locally available resources. The bioengineered cells build different materials in a specified 3D pattern to produce novel microstructures with precise molecular composition, thickness, print pattern, and shape. Scaffolds and reagents can be used for further control over material product. This innovation provides modern design and fabrication techniques for custom-designed organic or organic-inorganic composite biomaterials produced from limited resources.
In the electrical machines, detrimental effects resulted often due to the overheating, such as insulation material degradation, demagnetization of the magnet and increased Joule losses which result in decreased lifetime, and reduced efficiency of the motor. Hence, by effective cooling methods, it is vital to optimize the reliability and performance of the electric motors and to reduce the maintenance and operating costs. This study brings the analysis capability of CFD for the air-cooling of an Electric-Motor (E-Motor) powering on Deere Equipment's. With the aggressive focus on electrification in agriculture domain and based on industry needs of tackling rising global warming, there is an increasing need of CFD modeling to perform virtual simulations of the E-Motors to determine the viability of the designs and their performance capabilities. The thermal predictions are extremely vital as they have tremendous impact on the design, spacing and sizes of these motors.
Singh, BhuvaneshwarTirumala, BhaskarBadgujar, SwapnilHK, Shashikiran
With the global increase in demand for construction equipment, companies face immense pressure to produce more products in a competitive and sustainable way by utilizing advanced manufacturing technologies. Additionally, the need for data analytics and Industry 4.0 is increasing to take better decisions early in the development cycles and during the production phase. Advanced manufacturing processes & adopting Industry 4.0 is the only viable solution to address these challenges. However, the implementation of advanced manufacturing processes in heavy fabrication and construction equipment factories has been slow. A significant challenge is that the products being produced were originally designed for conventional manufacturing processes. When factories are becoming smart and connected through Industry 4.0 solutions, companies must reconsider many established assumptions about advanced manufacturing processes and their benefits. To maximize efficiency gains, improve safety standards, and enhance the reliability of automated manufacturing systems, engineers must adopt machine connectivity, advanced welding processes, sustainable welding, etc. This paper aims to investigate the requirements of the latest technologies in manufacturing and highlight the applications in construction equipment manufacturing. Key Projects 1. Weld Machine Connectivity (WMC) 2. High Deposition Welding (HDW) 3. High Frequency Mechanical Impact (HFMI)
Bhorge, PankajSaseendran, UnnikrishnanRodge, Someshwar
Innovators at NASA Johnson Space Center have developed additively manufactured thermal protection system (AMTPS) comprised of two printable heat shield material formulations. These formulations are directly applied by 3D printer or other robotic extrusion system and bonded to a spacecraft to devise a heat shield suitable for atmospheric entry. This technology could significantly decrease heat shield or thermal protection system (TPS) fabrication cost and time.
The assessment of collision risks is crucial for effective risk control and scientific management of maritime safety. To prevent maritime transportation accidents, an accident causation model has been proposed to analyze risks in maritime transportation systems. The 24-model further analyzes the impact pathways of accident factors in the accident chain and calculates the fit of HOF-related factors. Using Bayesian Networks as a foundation and the 24-model as a tool, a Bayesian Network model for collision risk is constructed by identifying risk factors and determining their correlations, utilizing accident data from Chinese maritime authorities. Utilizing a Bayesian Network to construct a ship collision risk model that couples HOF and calculates conditional probabilities of relevant node occurrences. To explore the coupled relationships between nodes in a network, this study employs the N-K model to construct a safety risk coupling model for ship collision accidents, calculating risk values for different coupling types within the model. Case analysis shows that accidents result from dynamic interaction and linear combination of risk factors. The analysis of experimental results indicates that various accident factors contribute differently to overall maritime risk. Human factors are the direct cause of maritime ship collision accidents. From the perspective of coupled risk, organizational factors, as root influences, are crucial aspects that bridge resource management needs to focus on. The application of this model provides maritime personnel with a novel approach to mitigate the risk of maritime collisions.
Li, JianminZhang, XiaochuanJia, DaweiZang, RuLyu, Hongguang
Target tracking is an important component of intelligent vehicle perception systems, which has outstanding significance for the safety and efficiency of intelligent vehicle driving. With the continuous improvement of technologies such as computer vision and deep learning, detection based tracking has gradually become the mainstream target tracking framework in the field of intelligent vehicles, and target detection performance is the key factor determining its tracking performance. Although remarkable progress has been made in current 3D object detection networks, a single network still struggles to provide stable detection for distant and occluded targets. Besides, traditional tracking methods are based on single-stage association matching, which can easily lead to identity jumps and target loss in case of missed detections, resulting in poor overall stability of the tracking algorithm. To solve the above problem, a hierarchical association matching method using a dual object detection network is proposed, which compensates for the poor performance of multi-modal 3D detection on distant targets due to the sparsity of point clouds through a lightweight 2D detection network. In addition, to alleviate the problem of missing detection caused by inadequate confidence of occluded targets, a strategy of implementing hierarchical correlation based on the confidence level of detection boxes is also proposed. The above proposed methods are deployed in an unscented Kalman filter based on the constant turn rate and velocity model, and the sort method is used for trajectory lifecycle management to construct a complete target tracking system. The experiments of the nuScenes dataset and real vehicle data shows that our method can achieve more robust multi-target tracking performance.
Wu, ShaobinChu, YunfengLi, YixuanSu, ShengjieLiu, ZhaofengLi, XiaoanSi, Lingrui
Composite Materials Handbook Volume 3 - Revision HR-64010/16/2025
The third volume of this six-volume compendium provides methodologies and lessons learned for the design, analysis, manufacture, and field support of fiber-reinforced, polymeric-matrix composite structures. It also provides guidance on material and process specifications and procedures for using the data that is presented in Volume 2. The information provided is consistent with the guidance provided in Volume 1, and is an extensive compilation of the current knowledge and experiences of engineers and scientists from industry, government, and academia who are active in composites. The Composite Materials Handbook, referred to by industry groups as CMH-17, is a six-volume engineering reference tool that contains over 1,000 records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites. CMH-17 provides information and guidance necessary to design and fabricate end items from composite materials. It includes properties of composite materials that meet specific data requirements as well as guidelines for design, analysis, material selection, manufacturing, quality control, and repair. The primary purpose of the handbook is to standardize engineering methodologies related to testing, data reduction, and reporting of property data for current and emerging composite materials. It is used by engineers worldwide in designing and fabricating products made from composite materials.
CMH-17
Researchers blend theoretical insight and precision experiments to entangle photons on an ultra-thin chip. Harvard University, Allston, MA In the race toward practical quantum computers and networks, photons - fundamental particles of light - hold intriguing possibilities as fast carriers of information at room temperature. Photons are typically controlled and coaxed into quantum states via waveguides on extended microchips, or through bulky devices built from lenses, mirrors, and beam splitters. The photons become entangled - enabling them to encode and process quantum information in parallel - through complex networks of these optical components. But such systems are notoriously difficult to scale up due to the large numbers and imperfections of parts required to do any meaningful computation or networking. Could all those optical components could be collapsed into a single, flat, ultra-thin array of subwavelength elements that control light in the exact same way, but with far fewer fabricated parts?
A research team led by scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) has developed a new fabrication technique that could improve noise robustness in superconducting qubits, a key technology for enabling large-scale quantum computers.
Through the Artemis campaign, NASA will send astronauts on missions to and around the Moon. The agency and its international partners report progress continues on Gateway, the first space station that will permanently orbit the Moon, after visiting the Thales Alenia Space facility in Turin, Italy, where initial fabrication for one of two Gateway habitation modules is nearing completion.
The scope of this SAE Aerospace Recommended Practice (ARP) is to establish the procedure for creating titles of aerospace tubing and clamp installation documents generated by SAE Subcommittee G-3E.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Aqueous zinc-ion batteries (ZIBs) have attracted extensive attention due to their high safety, abundant reserves, and environmental friendliness. Iodine with high abundance in seawater (55 μg L-1) is highly promising for fabricating zinc-iodine batteries due to its high theoretical capacity (211 mAh g-1) and appropriate redox potential (0.54V). However, the low electrical conductivity of iodine hinders the redox conversion for an efficient energy storage process with zinc. Additionally, the formed soluble polyiodides are prone to migrate to the Zn anode, leading to capacity degradation and Zn corrosion.
In this work, Genetic Algorithm (GA) optimized Proportional Integral Derivative (PID) controller is employed in the active suspension. The PID gain values are optimally tuned based on the objective function by the Integral Time Absolute Error (ITAE) criteria of various suspension measures like vehicle body displacement, suspension and tire deflections. The proposed GAPID controller is experimentally validated through the 3-DOF quarter-car (QC) test rig model. The fabricated model with passive suspension system (PASS) and active suspension system (ACSS) with an electrical actuator is presented. The schematic representation of the fabricated test set-up with and without ACSS is also illustrated. Further, simulation and experimental response of the fabricated model with and without ACSS are compared. It is identified that the proposed GAPID controller attenuates the sprung mass acceleration by about 41.64 % and 29.13 % compared with PASS for the theoretical as well as experimental cases respectively.
A, ArivazhaganKandavel, Arunachalam
MEMS is a more complex technology than traditional semiconductors. They are 3D structures with moving parts, making them much more difficult to fabricate. If you’re designing a semiconductor, you may be able to take advantage of an existing process development kit (PDK), which your foundry can provide to you. There is no equivalent approach in MEMS. It’s a “one process, one product” paradigm that requires a high level of customization. That takes time, money, and resources.
The mass production of conventional silicon chips relies on a successful business model with large “semiconductor fabrication plants” or “foundries.” New research by KU Leuven and imec shows that this “foundry” model can also be applied to the field of flexible, thin-film electronics. Adopting this approach would give innovation in the field a huge boost.
The metal inert-gas (MIG) welding technique employed for aluminum alloy automotive bumpers involve a complex thermo-mechanical coupling process at elevated temperatures. Attaining a globally optimal set of model parameters continues to represent a pivotal objective in the pursuit of reliable constitutive models that can facilitate precise simulation of the welding process. In this study, a novel piecewise modified Johnson-Cook (MJ-C) constitutive model that incorporates the strain-temperature coupling has been proposed and developed. A quasi-static uniaxial tensile model of the specimen is constructed based on ABAQUS and its secondary development, with model parameters calibrated via the second-generation non-dominated sorting genetic algorithm (NSGA-II) method. A finite element simulation model for T-joint welding is subsequently established, upon which numerical simulation analyses of both the welding temperature field and post-welding deformation can be conducted. The results indicate that the implementation of the MJ-C constitutive model improves the precision of the simulation by 78.8% and provides an accurate representation of the mechanical behavior of the T-joint of aluminum alloy sheet metal during the welding process. Ultimately, the calibrated heat source model and constitutive model are employed to construct the welding model of the automotive bumper, accurately predicting the deformation and residual stress that arise during the welding process of the bumper while identifying the optimal welding sequence. This optimal sequence achieves a 41.3% reduction in welding deformation of the bumper, benefiting the bumper bolted to the body. Through the simulation and optimization method, lowering costs and expediting the design cycle.
Yi, XiaolongMeng, DejianGao, Yunkai
3D-printed microscopic particles, so small that to the naked eye they look like dust, have applications in drug and vaccine delivery, microelectronics, microfluidics, and abrasives for intricate manufacturing. However, the need for precise coordination between light delivery, stage movement, and resin properties makes scalable fabrication of such custom microscale particles challenging. Now, researchers at Stanford University have introduced a more efficient processing technique that can print up to 1 million highly detailed and customizable microscale particles a day.
Purdue University material engineers have created a patent-pending process to develop ultrahigh-strength aluminum alloys that are suitable for additive manufacturing because of their plastic deformability.
Since the rapid development of the shipping and port industries in the second half of the twentieth century, the introduction of container technology has transformed cargo management systems, while simultaneously increasing the vulnerability of global shipping networks to natural disasters and international conflicts. To address this challenge, the study leverages AIS data sourced from the Vessel Traffic Data website to extract ship stop trajectories and construct a shipping network. The constructed network exhibits small-world characteristics, with most port nodes having low degree values, while a few ports possess extremely high degree values. Furthermore, the study improved the PageRank algorithm to assess the importance of port nodes and introduced reliability theory and risk assessment theory to analyze the failure risks of port nodes, providing new methods and perspectives for analyzing the reliability of the shipping network.
Li, DingCheng, ChengZhao, XingxiLi, Zengshuang
Shared autonomous vehicles systems (SAVS) are regarded as a promising mode of carsharing service with the potential for realization in the near future. However, the uncertainty in user demand complicates the system optimization decisions for SAVS, potentially interfering with the achievement of desired performance or objectives, and may even render decisions derived from deterministic solutions infeasible. Therefore, considering the uncertainty in demand, this study proposes a two-stage robust optimization approach to jointly optimize the fleet sizing and relocation strategies in a one-way SAVS. We use the budget polyhedral uncertainty set to describe the volatility, uncertainty, and correlation characteristics of user demand, and construct a two-stage robust optimization model to identify a compromise between the level of robustness and the economic viability of the solution. In the first stage, tactical decisions are made to determine autonomous vehicle (AV) fleet sizing and the initial vehicle distribution. In the second stage, operational decisions are made under scenarios of fluctuating user demand to optimize vehicle relocation strategies. To enhance the efficiency of model resolution, the original two-stage robust optimization model is decomposed into separable subproblems, which are transformed using duality theory and linearization. An effective solution is achieved through a precise algorithm utilizing column-and-constraint generation (C&CG). Numerical experiments are conducted on a small-scale network to validate the effectiveness of the model and algorithm. Furthermore, adjustments to the demand fluctuation scenarios are made to assess the impact of uncertain budget levels Γ on the total revenue of SAVS. This research provides AV sharing service operators with an optimal relocation scheduling strategy that balances robustness and economic efficiency.
Li, KangjiaoCao, YichiZhou, BojianWang, ShuaiqiYu, Yaofeng
Additive Manufacturing (AM), particularly Fused Deposition Modeling (FDM), has emerged as a revolutionary method for fabricating complex geometries using a variety of materials. Polyethylene terephthalate glycol (PETG) is a thermoplastic material that is biodegradable and environmentally friendly, making it a preferred choice in additive manufacturing (AM) due to its affordability and ease of use. This study aims to optimize the FDM settings for PETG material and investigate the impact of key process parameters on printing performance. An experimental study was conducted to evaluate the influence of crucial factors in FDM, including layer thickness, infill density, printing speed, and nozzle temperature, on significant outcomes such as dimensional accuracy, surface quality, and mechanical properties. The use of the Grey Relational Analysis (GRA) approach enabled a systematic assessment of multi-performance characteristics, facilitating the optimization of the FDM process. The findings demonstrated that the GRA approach is an effective tool for determining optimal parameter settings to enhance printing productivity and ensure the production of high-quality components. This study provides deeper insights into the Fused Deposition Modeling (FDM) process for Polyethylene terephthalate glycol (PETG) material, offering valuable strategies for improving manufacturing processes. By leveraging the GRA approach, this work highlights a reliable method for enhancing printing efficiency and quality, thereby promoting the wider adoption of FDM technology across various industries such as prototyping, manufacturing, and healthcare.
Pasupuleti, ThejasreeNatarajan, ManikandanKumar, VKiruthika, JothiKatta, Lakshmi NarasimhamuSilambarasan, R
This study investigates the fabrication and characterization of overhanging structures using the Cold Metal Transfer (CMT) pulse based Wire Arc Additive Manufacturing (WAAM) technique, specifically targeting automotive applications on commercial aluminum components. Focusing on optimal welding strategies for overhanging structures, components are fabricated by providing offsets during consecutive deposition of layers, thus producing parts with angles of 45°, 60° and 90° inclinations from the substrate. Three specimens undergo around twenty-five layers of deposition, resulting in structurally sound joints within this specified angle range. AA 4043 electrode is utilized, and welding parameters are optimized through trials by verifying with bead on plate deposition. Successful outcomes are achieved within the specified angle range, though challenges arise beyond 60°, complicating the maintenance of desired weld quality. The study further evaluates the microstructure, microhardness, and tensile properties of aluminum alloy (AA 4043) samples fabricated at different build orientations (90°, 45°, and 60°). Microhardness measurements indicate that the 60° orientation exhibits the highest hardness values across all positions, suggesting superior material strength and consistency. Tensile tests reveal that specimens fabricated at a 60° build orientation demonstrate the highest Ultimate Tensile Strength (UTS) of 217 MPa and a total elongation of 23.6%, indicating optimal mechanical performance. Microstructural analysis supports these findings, showing refined grain structures and uniform phase distribution in the 60° orientation compared to the rest. Conversely, samples at a 90° build orientation display inferior mechanical properties, with the lowest UTS (122 MPa) and total elongation (17.0%). This study also provides a foundational understanding of the importance of optimal welding strategies and orientations in the CMT pulse based WAAM process for overhanging structures, emphasizing its relevance for automotive applications for its potential in producing complex, high-performance aluminum structures suitable for automotive components.
A, AravindS, JeromeA, Rahavendran
Soft-bending actuators are gaining considerable attention in robotics for handling delicate objects and adapting to complex shapes, making them ideal for biomimetic robots. Soft pneumatic actuators (SPAs) are preferred in soft robotics because to their safety and compliance characteristics. Using negative pressure for actuation, it enhances stability by reducing the risk of sudden or unintended movements, crucial for delicate handling and consistent performance. Negative pressure actuation is more energy-efficient, safe and are less prone to leakage, increasing reliability and durability. This paper involves development of a new soft pneumatic actuator design by comparing various designs and to determine its performance parameters. This paper depicts on designing, and fabricating flexible soft pneumatic actuators working under negative pressure for soft robotic applications. The material used for fabrication was liquid silicone rubber and uniaxial tensile tests were conducted to characterise the properties of materials used to fabricate the soft actuator. The design process begins with conceptualizing the gripper's geometry and layout, considering factors such as material properties, actuation mechanisms etc. Finite element analysis is then employed to evaluate the performance and behavior of the gripper under different loading conditions in negative pressure. Moulds were manufactured using rapid prototyping machine for manufacturing soft pneumatic actuators. Experimental studies were conducted and compared with simulation results.
Warriar J S, SreejithSadique, AnwarGeorge, Boby
A novel sintering method of bridging the two mechanically polished and oriented single-crystals together face-to-face in a non- environmental controlled atmosphere to fabricate the bicrystal substrate of NaCl of macroscopic thickness, with a common zone axis and having planarity over large areas, has been developed. Epitaxial [001] bicrystalline thin face-centered cubic (fcc) metal film of surface-reactive metal-containing tilt grain boundary across the interface is first grown in high vacuum directly by flash deposition on initially fabricated [001] oriented bicrystalline substrate of NaCl. The [001] tilt boundary, thus produced, and is examined by electron microscopy to characterize grain boundary morphology and structure. The findings of some preliminary investigations are then presented. A distinct atomic structure is observed for 310 and 210 inclination. Both HAADF-STEM and Diffraction images reveal that such fabricated high-angle grain boundary accommodates minor deviations from the exact high coincidence density ∑=5 misorientation. The potential use of the present technique is extended to produce a wide variety of homophase bicrystals, containing grain boundaries at the midplane, normal to any crystallographic surface without the necessity of a separate bonding operation.
Dish, NilabhGautam, AbhayBehera, RakeshBanka, HemasunderChavan, Pradeep
Aluminum Matrix Composites (AMCs) are gaining traction in aerospace, automotive, and marine industries due to their superior mechanical properties. By integrating hard ceramic particles such as silicon carbide (SiC) and aluminum oxide (Al₂O₃) into aluminum matrices, these composites exhibit enhanced wear resistance and strength-to-weight ratios. This study explores the fabrication and characterization of 6061-T6 aluminum alloy matrix composites, reinforced individually with SiC and Al₂O₃ particles through the squeeze casting technique. The research includes a comprehensive analysis of microstructures and mechanical properties, focusing on compressive strength, Brinell hardness, and tribological behavior. Findings reveal that SiC and Al₂O₃ reinforcements boost compressive strength by up to 27% and 47%, respectively, and increase hardness by up to 29% and 20%, respectively, compared to unreinforced aluminum.
Thirumavalavan, R.Santhosh, V.Sugunarani, S.Regupathi, S.Sundaravignesh, S.
Nowadays, there are many technologies emerging like firefighting robots, quadcopters, and drones which are capable of operating in hazardous disaster scenarios. In recent years, fire emergencies have become an increasingly serious problem, leading to hundreds of deaths, thousands of injuries, and the destruction of property worth millions of dollars. According to the National Crime Records Bureau (NCRB), India recorded approximately 1,218 fire incidents resulting in 1,694 deaths in 2020 alone. Globally, the World Health Organization (WHO) estimates that fires account for around 265,000 deaths each year, with the majority occurring in low- and middle-income countries. The existing fire-extinguishing systems are often inefficient and lack proper testing, causing significant delays in firefighting efforts. These delays become even more critical in situations involving high-rise buildings or bushfires, where reaching the affected areas is particularly challenging. The leading causes of fires include electrical faults, open flames, and negligence, with a notable percentage stemming from cooking-related incidents. This research introduces a prototype of a quadcopter designed to extinguish fires, which is equipped with a mechanism for releasing balls. The prototype utilizes experimental items to mimic fire-suppressing balls, establishing a basis for potential applications in firefighting technology.
Karthikeyan, S.Nithish, U.Sanjay, S.Sibiraj, T.Vishnu, J.
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