Browse Topic: Supply chain management

Items (16,337)
This specification establishes the requirements for the following types of self-locking nuts in thread diameter sizes 0.1380 through 0.6250 inch: a Wrenching Nuts: i.e., hexagon, double hexagon, and spline nuts. b Anchor Nuts: i.e., plate nuts, gang channel nuts, and shank nuts. The wrenching nuts, shank nuts, and nut elements of plate and gang channel nuts are made of a corrosion- and heat-resistant nickel-base alloy of the type identified under the Unified Numbering System as UNS N07001 and of 180000 psi axial tensile strength at room temperature, with maximum conditioning of parts at 1400 °F prior to room temperature testing.
E-25 General Standards for Aerospace and Propulsion Systems
In a complex and ever-changing environment, achieving stable and precise SLAM (Simultaneous Localization and Mapping) presents a significant challenge. The existing SLAM algorithms often exhibit limitations in design that restrict their performance to specific scenarios; they are prone to failure under conditions of perceptual degradation. SLAM systems should maintain high robustness and accurate state estimation across various environments while minimizing the impact of noise, measurement errors, and external disturbances. This paper proposes a three-stage method for registering LiDAR point cloud. First, the multi-sensor factor graph is combined with historical pose and IMU pre-integration to provide a priori pose estimation; then a new method for extracting planar features is used to describe and filter the local features of the point cloud. Second, the normal distribution transform (NDT) algorithm is used as coarse registration. Third, the feature to feature registration is used for
Li, ZhichaoTong, PanpanShi, WeigangBi, Xin
Temperature segregation significantly affects the compaction of asphalt mixtures and the durability of the asphalt pavement layer. Uneven cooling of the mixture during transportation is a key factor contributing to temperature segregation. This study uses finite element simulations to analyze the temporal and spatial temperature evolution during the transportation of asphalt mixtures. A temperature segregation evaluation index (TSIv) is proposed to assess the significance of various factors affecting segregation. Support vector regression (SVR), random forest regression (RFR), and extreme gradient boosting (XGBoost) models are employed to predict temperature changes during transportation and optimize the predictive models. The results indicate that the proportion of areas with a temperature difference of less than 10°C is consistently the highest, followed by areas with a temperature difference greater than 25°C, and then those with temperature differences in the ranges of 10-16°C and
Cheng, HaoMa, TaoTang, FanlongFan, Jianwei
The introduction of autonomous truck platoons is expected to result in drastic changes in operational characteristics of freight shipments, which may in turn have significant impacts on efficiency, energy consumption, and infrastructure durability. Since the lateral positions of autonomous trucks traveling consecutively within a lane are fixed and similar (channelized traffic), such platooning operations are likely to accelerate damage accumulation within pavement structures. To further advance the application of truck platooning technology in various pavement environments, this study develops a flexible evaluation method to evaluate the impact of lateral arrangement within autonomous truck platoons on asphalt pavement performance. This method simplifies the impact of intermittent axle load applications along the driving direction within a platoon, supporting platoon controllers in directly evaluating pavement damage for different platoon configurations. Specifically, a truck platoon
Wenlu, YuYe, QinChen, DaoxieMin, YitongChen, Leilei
Highway construction zones present substantial safety challenges due to their dynamic and unpredictable traffic conditions. With the rising number of highway projects, limited accident data during brief construction phases underscores the need for alternative safety evaluation methods, such as traffic conflict analysis. This study addresses vehicular safety issues within the Kunshan section of the Shanghai-Nanjing Expressway, focusing on conflict risk assessment through a spatio-temporal analysis of a construction zone. Using drone-captured video, vehicle trajectories were extracted to derive key operational indicators, including speed and acceleration, providing a spatio-temporal foundation for analyzing traffic flow and conflict dynamics. A novel **Comprehensive Collision Risk Index (CCRI)** was introduced, integrating Time-to-Distance-to-Collision (TDTC) and Enhanced Time-to-Collision (ETTC) metrics to enable a multidimensional assessment of conflict risk. The CCRI captures both
Zhang, YuwenGuo, XiuchengMa, Yuheng
The swift and relentless progression of drone technology has ushered in novel opportunities within the realm of urban logistics, especially for the potential of drones to modify last-mile delivery and improve customer fulfillment through mobile application integration, offering the potential for delivery systems that are both efficient and environmentally sustainable. This development is not just a technological leap but a transformative shift in how goods are moved within urban spaces, potentially reducing traffic congestion and emissions from traditional vehicles. Nevertheless, the safety issues of drone flights in cities are becoming increasingly serious, and the accountability related to drone accidents is not clear, raising concerns in society regarding the use and safety of drones. Therefore, to fully utilize the potential of drones in urban logistics, the incorporation of drones into the urban airspace environment necessitates the establishment of a strong regulatory and policy
Ma, JieYang, JunjieDiao, WeileDu, YilingChen, Weiqi
Most autonomous vehicles employ a relatively conservative lane-changing strategy in freeway system. In the diversion areas, autonomous vehicles typically initiate lane-changing to curb lanes at lower speeds at a considerable distance from the diversion point, resulting in a decrease in the overall traffic efficiency within the diversion areas. However, lane-changing decision points excessively close to exit ramps can exacerbate the urgency of the lane-changing process, prompting irrationally forced lane-changing and increasing the collision risk. To provide decision-making references for the safe and rapid diverging of autonomous vehicles in freeway diversion areas, this study proposes a minimum diversion decision distance (MDDD) model for autonomous vehicles through microscopic lane-changing trajectory data. Specifically, the lane-changing process was divided into waiting for the acceptable gap stage and executing the lane-changing stage in this model. Subsequently, UAV aerial
Li, ZhenFaLuo, BaoGuoYang, QiChen, XuPan, BingHong
Technology for lane line semantic segmentation is crucial for ensuring the safe operation of intelligent cars. Intelligent cars can now comprehend the distribution and meaning of scenes in an image more precisely thanks to semantic segmentation, which calls for a certain degree of accuracy and real-time network performance. A lightweight module is selected, and two previous models are improved and fused to create the lane line detection model. Finally, experiments are conducted to confirm the model's efficacy. This paper proposes a lightweight replacement program with the aim of addressing the issue of large parameterization in the generative adversarial network (GAN) model and difficult training convergence. The overall network structure is selected from the Pix2Pix network in the conditional generative adversarial network, and the U-net network of the generator is cut and replaced by the Ghost Module, which consists of a modified downsampling module that enhances the global fusion
Yang, KunWang, Jian
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
Li, KangjiaoCao, YichiZhou, BojianWang, ShuaiqiYu, Yaofeng
To accurately predict the fuel consumption of vehicles, this study proposes a vehicle fuel consumption prediction model based on the VMD-CNN-BiGRU algorithm by considering six road spatial features such as road grades, one-way road attributes and intersection attributes. First, the VMD algorithm is employed to reduce the nonlinearity and nonsmoothness of the raw data by determining the optimal number of VMD decomposition modes. Then, the CNN-BiGRU algorithm is used to predict each modal component after decomposition, and the obtained prediction results are compared and analyzed with the prediction results of existing CNN-BiGRU, EMD-CNN-BiGRU and EEMD-CNN-BiGRU models. The results show that the VMD-CNN-BiGRU model significantly outperforms other models in terms of prediction performance and can accurately capture the trend of vehicle fuel consumption, thus effectively verifying the superiority and feasibility of the model. In addition, this study provides an in-depth analysis of the
Gao, YatingYan, LixinDeng, GuangyangChen, Siyuan
This specification provides dimensional standards for crimp type contact wire barrel design and is a replacement for MS3190. Some wire barrel designs may exist in AS39029 but are not considered approved for future use, therefore, will not appear in this specification. The crimp barrel sizes listed in this document have been standardized in AS39029 and AS22520 specifications, tools and contacts are available to support these listed sizes. These crimp barrel requirements shall be used for any contact, regardless of whether it is a standard or non-standard contact configuration. The specification lists details for three types of wire barrels: A, B, and C. Wire barrel type A is not recommended for new design. Table 4 lists each AS39029 detail sheet wire barrel type.
AE-8C1 Connectors Committee
The present study aims to assess the tensile properties of Caryota urens fibre reinforced polyester composites. Composites were fabricated with different fiber weight fractions starting from 5% to 35% with 5% increment. The mechanical testing of composite material was conducted using ASTM standards. The results indicated that the tensile, impact, and flexural properties of composite material were increased up to 25% fiber weight fraction; after that, they have been reduced due to some factors, like fiber distribution, which may not be uniform, and adhesion between fiber and matrix may be reduced. The optimal weight fraction of caryota urens fiber found from this study is 25%. The maximum tensile, impact, and flexural strength obtained for the composites were 36.22 MPa, 62.21 MPa, and 0.224 N/m, respectively. Water absorption characteristics show the increase of water intake behavior of composites due to their hydrophobic nature.
Santhanam, KRaja, K.Naveen, MSaranbala, MM, Naveenkumar
The scope of this document is to provide an overview, process, and implementation guidance on use of blockchain technology for a secure, immutable, and traceable digital authorized release certificate. This document does not standardize the process nor is it meant for authorities to recognize the standard as an acceptable means of recording data collected through the required authorized release certificate (ARC) tags.
G-31 Digital Transactions for Aerospace
The automotive industry is facing unprecedented pressure to reduce costs without compromising on quality and performance, particularly in the design and manufacturing. This paper provides a technical review of the multifaceted challenges involved in achieving cost efficiency while maintaining financial viability, functional integrity, and market competitiveness. Financial viability stands as a primary obstacle in cost reduction projects. The demand for innovative products needs to be balanced with the need for affordable materials while maintaining structural integrity. Suppliers’ cost structures, raw material fluctuations, and production volumes must be considered on the way to obtain optimal costs. Functional aspects lead to another layer of complexity, once changes in design or materials should not compromise safety, durability, or performance. Rigorous testing and simulation tools are indispensable to validate changes in the manufacturing process. Marketing considerations are also
Oliveira Neto, Raimundo ArraisSouza, Camila Gomes PeçanhaBrito, Luis Roberto BonfimGuimarães, Georges Louis Nogueira
The cost of electric vehicles (EVs) is significantly influenced by lithium-ion batteries, which typically account for about 40% of the total price, primarily due to the critical minerals content. Notably, minerals for cathode production are prone to scarcity and market price fluctuations. Moreover, the extraction of these minerals through mining activities poses substantial environmental challenges, including carbon emissions and resource depletion. In response to these concerns, recycling emerges as strategic to ensure the sustainability of electrification and secure the mineral supply chain. This paper presents findings from a study on recycling EV batteries using hydrometallurgical processes, encompassing the resynthesis of cathode materials utilizing recycled resources. The hydrometallurgical method exhibited an extraction efficiency surpassing 90%, with no direct CO2 emissions. Validation of the resynthesis phase involved the fabrication of cells with resynthesized cathodes
Obara, Rafael BrisollaErthal, LeopoldoSouza, Cleiton OliveiraRoggerio, LeonardoFreitas, Heverson RenanLima, Ana Luiza LorenzenBassani, Jean Carlos
Organizations need to maintain their processes at high levels of efficiency to be competitive, asset management and industrial maintenance are extremely important to obtain positive results in optimizing operating costs, saving energy resources, reduction of environmental impacts among other characteristics that are considered differential for organizations. In this scenario, methods are increasingly being sought to assist managers in decision-making processes that contain several alternatives and selection criteria involved. The AHP and TOPSIS methods have been widely associated with prioritization studies, cost evaluation, resource selection, suppliers, among others. Thus, the selection of equipment and industrial elements can be evaluated by means of multicriteria decision methods where the criteria considered important by specialists in the area are inserted into the model. The objective of this article was to present a selection process for spur gears based on stress analysis and
de Oliveira, Geraldo Cesar Rosariode Oliveira, Vania Aparecida RosarioSilva, Carlos Alexis AlvaradoGuidi, Erick SiqueiraSalomon, Valério Antonio PamplonaRosado, Victor Orlando Gamarrade Azevedo Silva, Fernando
Competitive companies constantly seek continuous increases in productivity, quality and services level. Lean Thinking (LT) is an efficient management model recognized in organizations and academia, with an effective management approach, well consolidated theoretically and empirically proven Within Industry 4.0 (I4.0) development concept, manufacturers are confident in the advantages of new technologies and system integration. The combination of Lean and I4.0 practices emerges from the existence of a positive interaction for the evolutionary step to achieve a higher operational performance level (exploitation of finances, workload, materials, machines/devices). In this scenario where Lean Thinking is an excellent starting point to implement such changes with a method and focus on results; that I4.0 offers powerful technologies to increase productivity and flexibility in production processes; but people need to be more considered in processes, in a context aligned with the Industry 5.0
Braggio, LuisMarinho, OsmarSoares, LuisLino, AlanRabelo, FábioMuniz, Jorge
Design validation plays a crucial role in the overall cost and time allocation for product development. This is especially evident in high-value manufacturing sectors like commercial vehicle electric drive systems or e-axles, where the expenses related to sample procurement, testing complexity, and diverse requirements are significant. Validation methodologies are continuously evolving to encompass new technologies, yet they must be rigorously evaluated to identify potential efficiencies and enhance the overall value of validation tests. Simulation tools have made substantial advancements and are now widely utilized in the development phase. The integration of simulation-based or simulation-supported validation processes can streamline testing timelines and sample quantities, all the while upholding quality standards and minimizing risks when compared to traditional methods. This study examines various scenarios where the implementation of advanced techniques has led to a reduction in
Leighton, MichaelTuschkan, AlwinPlayfoot , Ben
The computational efficiency of dynamic programming (DP) energy management strategies is enhanced through the discretization of state variables in this study. The upper and lower bounds of SOC (State of Charge) and the SOC variation at each moment are calculated using the maximum and minimum power of the range extender, which eliminates invalid state combinations and significantly reduces the size of the feasible state set. To investigate the impact of different sampling intervals on SOC during various phases, intervals at 1s, 2s, 4s, 5s, and 10s are set for both charge retention and consumption phases. It is revealed that in the consumption phase, different sampling intervals minimally affect SOC, with trajectories closely matching. However, in the charge retention phase, the impact of different sampling intervals on SOC is significant, resulting in considerable differences in SOC trajectories. Additionally, in the charging-discharging (CD) phase, fuel consumption significantly varies
Wei, ChangyinWei, YiyuYang, DinghaoWang, YichenLiu, Dezheng
Modern vehicles are increasingly integrating electronic control units (ECUs), enhancing their intelligence but also amplifying potential security threats. Vehicle network security testing is crucial for ensuring the safety of passengers and vehicles. ECUs communicate via the in-vehicle network, adhering to the Controller Area Network (CAN) bus protocol. Due to its exposed interfaces, lack of data encryption, and absence of identity authentication, the CAN network is susceptible to exploitation by attackers. Fuzz testing is a critical technique for uncovering vulnerabilities in CAN network. However, existing fuzz testing methods primarily generate message randomly, lacking learning from the data, which results in numerous ineffective test cases, affecting the efficiency of fuzz testing. To improve the effectiveness and specificity of testing, understanding of the CAN message format is essential. However, the communication matrix of CAN messages is proprietary to the Original Equipment
Shen, LinXiu, JiapengZhang, ZhuopengYang, Zhengqiu
In today's world, the electric vehicle (EV) industry is experiencing a remarkable boom with increasing global demand. With it, comes the surging and unprecedented need for EV batteries. Recycling these batteries has become of crucial importance, as it not only plays a vital role in ensuring the security of the battery supply chain but also serves as a key measure for reducing greenhouse gas emissions. However, there are still several issues that remain unresolved in this domain. Unsettled Issues Regarding Electric Vehicle Battery Recycling delves deep into these issues, thoroughly exploring the current state of the industry and potential solutions to drive sustainable EV battery recycling. By addressing these challenges, we can strive towards a more sustainable future in the EV sector. Click here to access the full SAE EDGETM Research Report portfolio.
Lin, XiaoSaputra Lase, Irdanto
LIDAR-based autonomous mobile robots (AMRs) are gradually being used for gas detection in industries. They detect tiny changes in the composition of the environment in indoor areas that is too risky for humans, making it ideal for the detection of gases. This current work focusses on the basic aspect of gas detection and avoiding unwanted accidents in industrial sectors by using an AMR with LIDAR sensor capable of autonomous navigation and MQ2 a gas detection sensor for identifying the leakages including toxic and explosive gases, and can alert the necessary personnel in real-time by using simultaneous localization and mapping (SLAM) algorithm and gas distribution mapping (GDM). GDM in accordance with SLAM algorithm directs the robot towards the leakage point immediately thereby avoiding accidents. Raspberry Pi 4 is used for efficient data processing and hardware part accomplished with PGM45775 DC motor for movements with 2D LIDAR allowing 360° mapping. The adoption of LIDAR-based AMRs
Feroz Ali, L.Madhankumar, S.Hariush, V.C.Jahath Pranav, R.Jayadeep, J.Jeffrey, S.
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