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Fracture process analysis of notched brittle Metal based on mesoscopic plastic information Oriented to propose mechanism-based strength evaluation Methods;Example of Gray-Cast iron FC200

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engineering Failure Analysis 2025年

作者： Toyomitsu Harada Hiroshi noguchi Daisuke Sasaki Yuta Minami Takashi Yoshida Nobuya Sasaguri Department of Mechanical Engineering National Institute of Technology Kurume College 1-1-1 Komorino Kurume Fukuoka 830-8555 Japan Department of Mechanical Engineering Faculty of Engineering Kyushu University 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan Department of Materials System Engineering National Institute of Technology Kurume College 1-1-1 Komorino Kurume Fukuoka 830-8555 Japan Mechanical and Electrical Systems Engineering Advanced Course National Institute of Technology Kurume College1-1-1 Komorino Kurume Fukuoka 830-8555 Japan

A more rational characterization method for the strength of notched materials of heterogeneous brittle metals is desired than the present method without considering the real material behavior. This study aims to analyze the role of local plastic strain in the fracture process in notched brittle metals. In this study, we therefore conducted a four-point bending fracture test on gray cast iron with a semi-circular notch and performed fractography analysis of the fractured surfaces using an electron microscope and plastic strain analysis near the fractured surfaces using Electron BackScatter Diffraction. Based on the results, a model was proposed for the crack initiation and stable crack propagation mechanisms those clarified the role of the material structure and plastic strain on the crack behavior. This model divided the crack behavior into three stages. The first and second stages corresponded to the normal fracture process zone, wherein strain from the structure was the main cause of the crack propagation; however, in the third stage, the main cause was the elastic energy, which expressed the material as a continuum.

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Reversible Data Hiding Based on Pixel-Value-Ordering and Pixel Block Merging Strategy

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computers, Materials & Continua 2019年第6期59卷 925-941页

作者： Wengui Su Xiang Wang Yulong Shen College of Computer Science and Technology Xidian UniversityXi’an710071China Guangxi Key Laboratory of Manufacturing System&Advanced Manufacturing Technology College of Mechanical EngineeringGuangxi UniversityNanning530004China College of Telecommunications Engineering Xidian UniversityXi’an710071China

With the reversible data hiding method based on pixel-value-ordering,data are embedded through the modification of the maximum and minimum values of a block.A significant relationship exists between the embedding performance and the block *** pixel-value-ordering methods utilize pixel blocks with a fixed size to embed data;the smaller the pixel blocks,greater is the embedding ***,it tends to result in the deterioration of the quality of the marked ***,a novel reversible data hiding method is proposed by incorporating a block merging strategy into Li et al.’s pixel-value-ordering method,which realizes the dynamic control of block size by considering the image ***,the cover image is divided into non-overlapping 2×2 pixel ***,according to their complexity,similarity and thresholds,these blocks are employed for data embedding through the pixel-value-ordering method directly or after being emerged into 2×4,4×2,or 4×4 sized ***,smaller blocks can be used in the smooth region to create a high embedding capacity and larger blocks in the texture region to maintain a high peak signal-to-noise *** results prove that the proposed method is superior to the other three advanced *** achieves a high embedding capacity while maintaining low distortion and improves the embedding performance of the pixel-value-ordering algorithm.

关键词： Reversible data hiding pixel-value-ordering prediction error expansion dynamic block partition

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Deformation in axial compression of aluminum tubular structures with ribs

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Keikinzoku/Journal of Japan Institute of Light Metals 2019年第8期69卷 379-386页

作者： Yokoya, Keisuke Miyazaki, Makoto Tojo, Yusuke Yamashita, Minoru Institute of Technology Nagano College Advanced Course of Production and Environment System National 716 Tokuma Nagano-shi Nagano381-8550 Japan Department of Mechanical Engineering Tokyo Institute of Technology [2-12-1 Ookayama School of Engineering Meguro-ku Tokyo152-8552 Japan Department of Mechanical Engineering National Institute of Technology Nagano Japan DENSO Aircool Corporation Japan Department of Mechanical Engineering Gifu University Japan

Dynamic compression behavior of various kinds of polygonal tubular structures with ribs are investigated. Square hollow structures and that with rib reinforcement of aluminum extrusions are in dynamic axial compression, using a drop hammer. Numerical simulation was also conducted for the wider variety of cross-sectional shapes and reinforcements. The effect of the axial length, cross-sectional shape and reinforcing rib arrangement on the deformation behavior were investigated. Comparable compressive force was obtained when the cross-sectional area of the structure is similar, even if the number of edges in cross-section increases from four (square) to eight. Rib reinforcement is very effective for the improvement of the crush or energy absorbing performance. Deformation behavior was successfully predicted by the numerical simulation. Numerical simulation of the compression of the various polygonal tubular structures with radial ribs was also carried out. The number of radial ribs in cross-section of the polygonal hollow structure has a positive relationship to the deformation constraint at corners and the torsional rigidity, consequently, the crush resistance increased. © 2019 The Japan Institute of Light Metals.

关键词： Reinforcement

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Comprehensive insights into electrical properties enhancement of boron‑sulfur co-doped diamond via ion implantation: First principles calculation and experimental validation

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Diamond and Related Materials 2025年 157卷

作者： Wang Zhao Bing Wang Zhanqiang Liu Honglu Li Zhaoliang Yu Pengyang Wang School of Mechanical Engineering Shandong University Jinan 250061 PR China Shandong Key Laboratory of High Performance Tools and System Jinan 250061 PR China Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education Jinan 250061 PR China State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan 250061 PR China Department of Computer and Information Science University of Macau PR China

Diamond presents great potential for applications as high‑temperature and high-power electronic devices as a new generation of semiconductor material. However, the inherent low electrical conductivity limits diamond applications. This study aims to reveal the conductive mechanism of boron (B)‑sulfur (S) co-doped diamond for conductivity enhancement with density-functional theory (DFT) calculations and ion implantation experiments. Firstly, the effects of B-S co-doping on diamond's electrical properties are investigated by analyzing the band structure and electron transport at different doping ratios using DFT. Secondly, Precision doping into single-crystal diamond is achieved via ion implantation, followed by annealing to remove lattice defects. Thirdly, the lattice integrity after doping is assessed by Raman spectroscopy, the chemical compositions and bonding states are analyzed by X-ray photoelectron spectroscopy, and the electrical properties of the co-doped diamonds are evaluated by Hall effect measurements. First-principles calculations show that B-S co-doping also generates additional acceptor and donor energy levels that couple, leading to more uniformly distributed impurity levels, a narrower band gap, altered electron transitions, and coupling in specific orbitals. These modifications imply that a B:S co-doping ratio of 1:2 may be favorable for enhanced carrier activation and improved electrical transport behavior. Based on first-principles calculations and Hall effect experiments the optimal conductivity occurs at a B:S ratio of 1:2, which gives better conductivity compared to single doping or other ratios. These findings Preliminary provide complementary theoretical and experimental evidence supporting the modulation of electrical conductivity through B-S co-doping.

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Fatigue strength simulation of natural porous structure

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International Journal of the Society of Material engineering for Resources 2018年第2期23卷 167-172页

作者： Tanaka, Yohei Masuyama, Tomoya Takahashi, Takeshi Iizuka, Hiroshi Course of Mechanical and Control Engineering Department of Advanced Engineering Course National Institute of Technology Tsuruoka College 104 Ino-oka sawada TsuruokaYamagata997-8511 Japan Course of Mechanical Engineering Department of Creative Engineering National Institute of Technology Tsuruoka College Higashine Yamagata999-3716 Japan Sanwa Yushi Co.Ltd. Higashine Yamagata999-3716 Japan Department of Mechanical System Engineering Faculty of Engineering Yamagata University 4-3-16 Jonan Yonezawa Yamagata992-8510 Japan

Rice hull which is one of the agricultural wastes in Japan has been demanded to reuse as the industrial materials. Rice hull silica carbon (RHSC) material, made from rice hull is produced by mixing rice hull powder with a phenol resin, and then carbonizing and the mixture in the nitrogen gas atmosphere at high temperatures. The RHSC is a porous carbon material utilizing natural porous structure originated from the rice hull. Therefore, reduction in environmental pollution is expected by the RHSC which is inexpensive and unique. In addition, a core competence of low friction coefficient, lubrication free, and high water resistance was reported for the RHSC in previous research. However, the RHSC has low reliability of strength originated potentially from the porous structure. Since the reliability of the RHSC is evaluated by a fatigue test which is required several weeks, calculating the fatigue strength by simulation analysis is useful. In this study, fatigue strength simulation analysis in natural porous structure was figured out and the size effect which influences the strength of the material was investigated. ©2018 Soc. Mater. Eng. Resour. Japan

关键词： Carbon

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A novel method to increase energy density of permanent magnet machine based on multi-physical field analysis

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UPB Scientific Bulletin, Series D: mechanical engineering 2020年第4期82卷 79-92页

作者： Zheng, Qingchun Zhao, Yangyang Zhu, Peihao Wang, Sen Liu, Jingna Ma, Wenpeng Li, Xiang Xiao, Yinhong Wang, Naixin Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China School of Computer Science Tianjin University of Technology Tianjin300384 China School of Automation Shenyang Institute of Engineering Shenyang110136 China Baoding Power Supply Company Hebei Electric Power Company State Grid Corporation of China Baoding071000 China

As an important component of all-electric aircraft, the main propulsion machine is developing towards high energy density, high efficiency and high fault tolerance. In order to improve the energy density of main propulsion machine for all-electric aircraft, a novel approach, which can be used for excellent performance improvement of electric machine of all-electric aircraft, is reported in this paper. The analytical formula of energy density is put forward and the design method of high energy density permanent magnet machine is presented. A high energy density machine with rated power of 30kW is designed, and the electromagnetic field simulation analysis, strength and stress structure verification, temperature field simulation analysis and multi-physical field coupling analysis are obtained. A prototype is developed, the experiment platform is established, and experiments are performed. The energy density of main propulsion machine designed is up to 21kW·N·m/kg2, and the index is increased by 3.2 times. The optimal method based on the multi-physical field analysis can be also applied to other high energy density machines. © 2020, Politechnica University of Bucharest. All rights reserved.

关键词： Electromagnetic fields

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A registration-aided domain adaptation network for 3D Point cloud based place recognition

arXiv

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arXiv 2020年

作者： Qiao, Zhijian Hu, Hanjiang Shi, Weiang Chen, Siyuan Liu, Zhe Wang, Hesheng Department of Automation Insititue of Medical Robotics Key Laboratory of System Control and Information Processing of Ministry of Education Key Laboratory of Marine Intelligent Equipment and System of Ministry of Education Shanghai Jiao Tong University Shanghai200240 China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology China Department of Mechanical Engineering Carnegie Mellon University United States Department of Computer Science and Technology University of Cambridge United Kingdom

In the field of large-scale SLAM for autonomous driving and mobile robotics, 3D point cloud based place recognition has aroused significant research interest due to its robustness to changing environments with drastic daytime and weather variance. However, it is time-consuming and effort-costly to obtain high-quality point cloud data for place recognition model training and ground truth for registration in the real world. To this end, a novel registration-aided 3D domain adaptation network for point cloud based place recognition is proposed. A structure-aware registration network is introduced to help to learn features with geometric information and a 6-DoFs pose between two point clouds with partial overlap can be estimated. The model is trained through a synthetic virtual LiDAR dataset through GTA-V with diverse weather and daytime conditions and domain adaptation is implemented to the real-world domain by aligning the global features. Our results outperform state-of-the-art 3D place recognition baselines or achieve comparable on the real-world Oxford RobotCar dataset with the visualization of registration on the virtual dataset. Copyright © 2020, The Authors. All rights reserved.

关键词： Three dimensional computer graphics

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Range Verification using Prompt Gamma-rays with Energy Spectral Analysis in Geant4 Based Proton Therapy Simulation

Range Verification using Prompt Gamma-rays with Energy Spect...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Tsukasa Aso Hiroki Oke Teiji Nishio Department of Electronics and Computer Engineering National Institute of Technology Toyama College Japan Control Information System Engineering Program Advanced Course National Institute of Technology Toyama College Japan Department of Medical Physics Tokyo Women’s Medical University Japan

ISBN: (数字)9781728141640

ISBN: (纸本)9781728141657

Range verification of therapeutic proton beam is crucial in proton therapy to confirm the irradiation field for ensuring effects and safety of the treatment. The irradiation field reconstruction using prompt gamma-rays generated from excited nuclides by proton beam has being studied for the purpose of precision medicine. A simulation tool based on fundamental physics processes employs an important role to understand intermediate relationship between physics interactions and detected observables, and to optimize a detector system with its analysis method. Previously, we reported on the simulation study about an irradiation field reconstruction by using prompt gamma-rays of whole energy range. In this study, we analyzed the energy spectrum and reconstructed the image of irradiation field by using prompt gamma-rays corresponding to a particular energy peak. The simulation was performed for proton beam with a target placed at the isocenter by using Geant4 based particle therapy system simulation framework. A simple tubular detector was placed around the target, in which the kinetic energy and the detected position of each gamma-ray were recorded. The irradiation field was then reconstructed in the ordered subset expectation maximization method. The reconstructed irradiation fields were compared with the dose distribution in the target. The peak positions of these depth distributions were compared each other and discussed about the range verification of therapeutic proton beam.

关键词： Image reconstruction Radiation effects Gamma-rays Particle beams Medical treatment Detectors

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High-density implantable neural electrodes and chips for massive neural recordings

Brain‐X

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Brain‐X 2024年第2期2卷

作者： Longchun Wang Yanxing Suo Jiahao Wang Xuanqi Wang Kai Xue Jingjing An Xun Sun Qinyu Chen Xiaochen Tang Yang Zhao Bowen Ji Jingquan Liu Department of Micro/Nano Electronics Shanghai Jiao Tong University Shanghai China National Key Laboratory of Advanced Micro and Nano Manufacture Technology Shanghai Jiao Tong University Shanghai China DCI Joint Team Collaborative Innovation Center of IFSA Shanghai Jiao Tong University Shanghai China Unmanned System Research Institute Northwestern Polytechnical University Xi'an Shaanxi China National Key Laboratory of Unmanned Aerial Vehicle Technology Xi'an Shaanxi China Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace School of Mechanical Engineering Northwestern Polytechnical University Xi'an Shaanxi China Institute of Guizhou Aerospace Measuring and Testing Technology Guiyang Guizhou China Leiden Institute of Advanced Computer Science (LIACS) Leiden University Leiden The Netherlands Klipsch School of Electrical and Computer Engineering New Mexico State University Las Cruces New Mexico USA Yang Zhao Bowen Ji and Jingquan Liu.

High-density neural recordings with superior spatiotemporal resolution powerfully unveil cellular-scale neural communication, showing great promise in neural science, translational medicine, and clinical applications. To achieve such, many design and fabrication innovations enhanced the electrode, chip, or both for biocompatibility improvement, electrical performance upgrade, and size miniaturization, offering several thousands of recording sites. However, an enormous gap exists along the trajectory toward billions of recording sites for brain scale resolution, posing many more design challenges. This review tries to find possible insight into mitigating the gap by discussing the latest progress in high-density electrodes and chips for neural recordings. It emphasizes the design, fabrication, bonding techniques, and in vivo performance optimization of high-density electrodes. It discusses the promising opportunities for circuit-level and architecture-level multi-channel chip design innovations. We expect that joint effort and close collaboration between high-density electrodes and chips will pave the way to high-resolution neural recording tools supporting cutting-edge neuroscience discoveries and applications.

关键词： brain-computer interface massive neural recording high density implantable electrodes implantable chips

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Study on fluttering characteristics of articulated flat plate flag

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IOP Conference Series: Materials Science and engineering 2020年第1期920卷

作者： Masaki Yamagishi Hiroki Shida Department of Mechanical Engineering Toyohashi University of Technology 1-1 Hibarigaoka Tempaku Toyohashi 441-8580 JAPAN Electric & Mechanical System Engineering Advanced Course National Institute of Technology Nagaoka College 888 Nishikatakai Nagaoka Niigata 940-8532 JAPAN

For wind/water power generation, we have been trying to harness flow-induced vibration, and we used a flag as the oscillating body. The flag was made of flat plates joined by articulations. To achieve a suitable design in engineering, it is important to clarify the fluttering characteristics of this articulated flat plate. The fluttering characteristics were therefore investigated experimentally in a wind tunnel. In the experiment, several rectangular plates were tested in several conditions of stream-wise length, span-wise length, thickness, and density. To investigate the fluttering characteristics, the fluttering frequency in a uniform flow velocity was focused on. The fluttering mode was observed simultaneously. It was found that an articulated flat plate flutters in a uniform flow and has a steady fluttering mode. The fluttering frequency increases with increasing uniform flow velocity for all conditions. The frequency was higher when the streamwise-length was short, thickness was thin, and density was small. It was found that there were two modes of fluttering: node-less mode and one-node mode. Furthermore, the dimensional analysis was performed, and the results show that the non-dimensional number consisting of the Strouhal number, Reynolds number, and mass ratio became constant.

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