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An interval finite element method for electromagnetic problems with spatially uncertain parameters

Science China(Technological Sciences) 2020年第1期63卷 25-43页

作者： WANG ZhongHua JIANG Chao NI BingYu WANG CongSi ZHONG JianFeng FANG Teng State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China Key Laboratory of Electronic Equipment Structure Design of Ministry of Education School of Electro-Mechanical EngineeringXidian UniversityXi'an 710071China Nanjing Research Institute of Electronics Technology Nanjing 210039China

During the manufacturing process of dielectric materials used in electromagnetic engineering, the electromagnetic parameters are often spatially uncertain due to the processing technology, environmental temperature, personal operations, etc. Traditionally,the random field model can be used to measure the spatial uncertainties, but its construction requires a large number of *** the contrary, the interval field model only needs the upper and lower bounds of the spatially uncertain parameters, which requires much less samples and furthermore is easy to understand and use for engineers. Therefore, in this paper, the interval field model is introduced to describe the spatial uncertainties of dielectric materials, and then an interval finite element method(IFEM) is proposed to calculate the upper and lower bounds of electromagnetic responses. Firstly, the interval field of the dielectric material is represented by the interval K-L expansion and inserted into the scalar Helmholtz wave equations, and thus the interval equilibrium equations are constructed according to the node-based finite element method. Secondly, a perturbation interval finite element method is developed for calculating the upper and lower bounds of electromagnetic responses such as the electric strength and magnetic strength. Finally, the effectiveness of the proposed method is verified by three numerical examples.

关键词： electromagnetic problems spatial uncertainty interval field model interval finite element method

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A Novel Two-Dimensional Non-Contact Platform Based on Near-Field Acoustic Levitation: Numerical and Experimental Investigations

SSRN

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SSRN 2023年

作者： Li, Wenjun Zhang, Pengfei Yang, Siyong Cai, Shenlin Feng, Kai State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan University Changsha410082 China Changsha Engineering and Research Institute Ltd. of Nonferrous Metallurgy Changsha410082 China

Near-field Acoustic Levitation (NFAL) is an advanced non-contact handling method with promising applications in the field of manufacturing semiconductors and Micro-Electro-Mechanical Systems. This study presents a novel two-dimensional non-contact platform based on NFAL, constructed by bumped and holed rails. The bumped rail is cross-placed under the holed rail, and the bumps are passed through the holes to ensure two rails being nested and combined. The effective region of the platform is consisted of bumped and non-holed regions simultaneously. The governing equation of squeeze film between the levitation plate and the platform is established, and the amplitude distribution of the rails is also introduced in the air film thickness. The performances, including air pressure and transportation capability, are obtained by the Reynolds equation, which is solved by the Newton iteration method. An experimental setup is constructed to test the levitation and transportation performance to verify the numerical research. Both numerical and experimental results prove that the platform based on NFAL is a feasible and easy method to realize non-contact two-dimensional transportation. © 2023, The Authors. All rights reserved.

关键词： Iterative methods

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Effect of Early CO2 Curing and Subsequent Water Curing on the Interfacial Transition Zone between Cement Paste and Aggregates

SSRN

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SSRN 2024年

作者： Huang, Yan Zhang, Jian Hu, Xiang Wang, Yue Drissi, Sarra Shi, Caijun College of Civil Engineering Hunan University Changsha410082 China Key Laboratory for Green & Advanced Civil Engineering Materials and Application Technology of Hunan Province Changsha410082 China Key Laboratory of Building Safety and Energy Efficiency Ministry of Education Hunan University Changsha410082 China Department of Civil Engineering and Energy Technology Faculty of Technology Art and Design Oslo Metropolitan University PO box 4 St Olavs Plass OsloNO-0130 Norway

This study investigated the effect of early CO2 curing and subsequent saturated lime water curing on the interfacial transition zone (ITZ) between cement paste and aggregate, focusing on bond strength, pore structure, and phase compositions. The CO2 curing followed by water curing is an effective and sustainable method to enhance the ITZ's performance. The CO2 curing eliminated portlandite oriented within the ITZ and promoted the formation of calcite and silica-rich gels, resulting in a 10% reduction in porosity, a 20 µm decrease in thickness and a 50% enhancement in bond strength of the ITZ. The continuous hydration of the uncarbonated clinker during subsequent water curing further reduces the porosity and enhances the bond strength of the ITZ. Furthermore, the utilization of CO2 curing has demonstrated remarkable efficiency in enhancing the performance of the ITZ adjacent to limestone compared to granite. This can be attributed to the lower energy barrier for nucleation and faster rate of calcite nucleation on the surface of limestone. © 2024, The Authors. All rights reserved.

关键词： Carbon dioxide

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Revealing the roles of martensitic transformation in affecting the fatigue resistance of austenitic stainless steel with heterogeneous grain size distribution

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Scripta Materialia 2024年 246卷

作者： Li, W.P. He, B.B. Sun, Y.H. Yen, H.W. Huang, M.X. Jiang, C. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China China Academy of Safety Science and Technology Beijing100012 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Department of Materials Science and Engineering National Taiwan University Taipei10617 Taiwan High Entropy Materials Center National Tsing Hua University Hsinchu30013 Taiwan Department of Mechanical Engineering The University of Hong Kong Hong Kong Hong Kong

The present work investigates the roles of martensitic transformation on the small fatigue crack growth behavior and fatigue resistance of a 316 L austenitic stainless steel. Martensitic transformation with varied block size takes place along crack path and at the crack tip. The large martensite blocks are vulnerable to crack propagation as the cracks can easily penetrate the block interior, leaving flat facets on the fracture surface. In contrast, the ultrafine martensite blocks can provide an enduring resistance on fatigue crack extension and deflect the crack propagation by cracking along their irregular and dense block boundaries. Considering the correlation between martensite block size, mechanical stability and prior austenite grain size, the present work suggests that austenite grain refinement is beneficial for improving fatigue properties of steels containing metastable austenite grains. © 2024

关键词： Martensitic transformations

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An Experimental and Theoretical Investigation on Residual Stress of 7075-T651 Aluminum Alloy Hole Under Electromagnetic Cold Expansion

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SSRN 2024年

作者： Tang, Kangjie Zhang, Xu Wu, Dingfeng Dong, Dongying Deng, Huakuan Cui, Junjia College of Automotive and Mechanical Engineering Changsha University of Science and Technology Changsha410114 China College of Energy and Power Engineering Changsha University of Science & Technology Changsha410114 China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha410082 China

Electromagnetic cold expansion (ECE) process was proposed in this work. Based on thick cylinder theory and ECE experiments, the theoretical plastic radius, hole wall stress, radial stress, circumferential stress and release stress under different expansion rates (ERs) were studied. The released strain, RS and tensile strength were measured. The fracture micromorphology after tensile tests was characterized. The results showed that the maximum theoretical plastic zone radius, internal stress, radial stress and circumferential stress reached 15.8716mm, 982.866MPa, -820.87MPa and -271.36MPa, respectively, and it also increased with ER increasing. The large ER led to a large theoretical plastic region radius and stress level. The maximum release strain, radial and circumferential RS under different ERs reached -3032.82μΕ, 600.93MPa and 601.13MPa respectively, and the larger ER would lead to the increase of release strain and RS. In addition, the maximum radial and circumferential release stress and the average tensile strength of ECE samples were 1402.63MPa, 747.54MPa and 49.607kN, respectively, and the increase of residual tensile stress level (ER increased) reduced the average tensile strength of samples. With the decreased ER and stress level, the initial crack position tended to transition from the entrance and exit surfaces to the middle position, and the crack propagation angle and axial crack size gradually decreased. The ECE process at large ER led to a larger plastic zone radius, and the residual tensile stress led to the change of initial crack position and crack propagation angle. © 2024, The Authors. All rights reserved.

关键词： Residual stresses

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Learnable Operational design Condition Monitor for Failure Prediction in Autonomous Driving

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SSRN 2025年

作者： Xu, Haowei Bian, Yougang Li, Yang Qin, Hongmao Zhou, Hanchu Chang, Fangrong Wang, Shaofei Ye, Qing State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Research and Development Center of Transport Industry of Self-driving Technology China Merchants Chongqing Communications Technology Research and Design Institute Co. Ltd. Chongqing China School of Traffic and Transportation Engineering Central South University Changsha China Department of Data and System Engineering The University of Hong Kong Hong Kong School of Resources and Safety Engineering Central South University Changsha China School of Data Science China

Ensuring the safety of Autonomous Driving Systems (ADS) across diverse and unpredictable operational scenarios remains a significant challenge for accident prevention. Central to this effort is the continuous monitoring of Operational design Conditions (ODC), which encompass both in-vehicle factors and external Operational design Domain (ODD). However, the absence of robust methodologies to precisely identify ODC boundaries hinders the deployment and adoption of high-level ADS. This paper introduces a learnable ODC monitor designed to identify implicit operational design condition boundaries to prevent ADS failures. By integrating a state-space duality encoder and a Bayesian neural network decoder, we propose an efficient learnable ODC monitor, termed ODCNet. Furthermore, to further enhance prediction reliability, residual error analysis with linear discrimination is applied for calibrating prediction. Experimental results demonstrate ODCNet's superiority in failure prediction compared to baseline models, achieving a balance between safety and coverage. These findings contribute to advancing data-driven accident prediction and prevention strategies, ensuring safer deployments of ADS in complex environments. © 2025, The Authors. All rights reserved.

关键词： Autonomous vehicles

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Foveated glasses-free 3D display with ultrawide field of view via a large-scale 2D-metagrating complex

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Light(Science & Applications) 2021年第11期10卷 2217-2225页

作者： Jianyu Hua Erkai Hua Fengbin Zhou Jiacheng Shi Chinhua Wang Huigao Duan Yueqiang Hu Wen Qiao Linsen Chen School of Optoelectronic Science and Engineering&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University215006SuzhouChina Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province&Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University215006SuzhouChina State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan University410082ChangshaChina SVG Optronics Co.Ltd215026SuzhouChina

Glasses-free three-dimensional(3D)displays are one of the game-changing technologies that will redefine the display industry in portable electronic ***,because of the limited resolution in state-of-the-art display panels,current 3D displays suffer from a critical trade-off among the spatial resolution,angular resolution,and viewing *** by the so-called spatially variant resolution imaging found in vertebrate eyes,we propose 3D display with spatially variant information *** experiences with smooth motion parallax are maintained at the central view,while the viewing angle is enlarged at the periphery *** is enabled by a large-scale 2D-metagrating complex to manipulate dot/linear/rectangular hybrid shaped ***,a video rate full-color 3D display with an unprecedented 160°horizontal viewing angle is *** thin and light form factors,the proposed 3D system can be integrated with off-the-shelf purchased flat panels,making it promising for applications in portable electronics.

关键词： portable spatially glasses

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Data-Driven Adaptive Predictive Cooperative Control for Multi-Robot Aircraft Skin Measurement

Data-Driven Adaptive Predictive Cooperative Control for Mult...

引用

Data Driven Control and Learning Systems (DDCLS)

作者： Xueming Zhang Haoran Tan Xing Jiang Yaonan Wang Gang Wang College of Electrical and Information Engineering Hunan University Yuelu District Changsha Hunan P. R. China State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan University Changsha P. R. China School of Automation Beijing Institute of Technology Beijing P. R. China

ISBN: (数字)9798350361674

ISBN: (纸本)9798350361681

This paper presents a novel approach to addressing the relative position problem in aircraft skin measurement based on data-driven predictive cooperative control (DDPCC) for multi-robot systems. Specifically, the study focuses on the interaction between two compound mobile robots, namely the tracker and scanner, and transforms the relative position problem into a formation control problem involving two robot chassis and a virtual leader. Leveraging the principles of predictive control, we introduce a control input criterion function, by incorporating the cross-tracking error between each robot and its neighbors, as well as its anticipated control input increment in the future. It turns out that the controller design and stability analysis of this DDPCC approach do not require explicit mathematical models. Through extensive simulations, we demonstrate the effectiveness and practicality of the proposed strategy.

关键词： Transforms Position measurement Control systems Skin Mathematical models Stability analysis Multi-robot systems

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Numerical Trajectory Planning of Panel Installation with Optimal Energy Consumption for Redundant Articulating Crane

SSRN

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SSRN 2024年

作者： Li, Penghao Zhang, Bangji Zhang, Zheshuo Hu, Wen Zhang, Jie Dai, Di State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle Hunan University Changsha China Intelligent Transportation System Research Center Hangzhou City University Hangzhou China School of Vehicle and Mobility Tsinghua University Beijing China College of Automotive and Mechanical Engineering Changsha University of Science and Technology Changsha China

The automatic installation of panels has become crucial in numerous industries scenarios. This paper proposed a trajectory planning method to addresses the position and posture adjustment of panel installation using redundant articulating cranes. Configuration space of the crane and rotation matrix are combined to investigate the strong coupling of the panel's position and posture. Moreover, the study combines the motion modes of the crane with the sequential analysis of redundant motion to assess energy consumption, incorporating energy efficiency as one of the planning objectives. Simultaneously, an intrinsic connection between the motion sequences within the C-space and safety considerations is analyzed. The installation experiment is performed with a real crane. The experimental results indicate that the proposed method achieves the function of installation of panels, which can make both the panel’s position and posture safely reach the predetermined state with less energy consume. © 2024, The Authors. All rights reserved.

关键词： Cranes

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Enhancing Cross-Dataset Performance of Distracted Driving Detection With Score Softmax Classifier And Dynamic Gaussian Smoothing Supervision

arXiv

引用

arXiv 2023年

作者： Duan, Cong Liu, Zixuan Xia, Jiahao Zhang, Minghai Liao, Jiacai Cao, Libo State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Faculty of Engineering and IT University of Technology Sydney UltimoNSW2007 Australia College of Automotive and Mechanical Engineering ChangSha University of Science Technology Changsha410114 China

Deep neural networks enable real-time monitoring of in-vehicle drivers, facilitating the timely prediction of distractions, fatigue, and potential hazards. This technology is now integral to intelligent transportation systems. Recent research has exposed unreliable cross-dataset driver behavior recognition due to a limited number of data samples and background noise. In this paper, we propose a Score-Softmax classifier, which reduces the model overconfidence by enhancing category independence. Imitating the human scoring process, we designed a two-dimensional dynamic supervisory matrix consisting of one-dimensional Gaussian-smoothed labels. The dynamic loss descent direction and Gaussian smoothing increase the uncertainty of training to prevent the model from falling into noise traps. Furthermore, we introduce a simple and convenient multichannel information fusion method;it addresses the fusion issue among arbitrary Score-Softmax classification heads. We conducted cross-dataset experiments using the SFDDD, AUCDD, and the 100-Driver datasets, demonstrating that Score-Softmax improves cross-dataset performance without modifying the model architecture. The experiments indicate that the Score-Softmax classifier reduces the interference of background noise, enhancing the robustness of the model. It increases the cross-dataset accuracy by 21.34%, 11.89%, and 18.77% on the three datasets, respectively. The code is publicly available at https://***/congduan-HNU/SSoftmax. Copyright © 2023, The Authors. All rights reserved.

关键词： Deep neural networks

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