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51st AIAA Aerospace sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013

作者： Zheng, Borui Wang, Zhongyi Gao, Chao Fang, Hong Xiong, Juntao Liu, Feng Luo, Shijun Northwestern Polytechnical University Department of Fluid Mechanics Xi'an 710072 China Beijing University of Aeronautics and Astronautics Department of Fluid Mechanics Beijing 100191 China Northwestern Polytechnical University National Key Laboratory of Science and Technology Aerodynamic Design and Research Xi'an 710072 China Beijing Institute of Nearspace Vehicle's System Engineering Department of Fluid Mechanics Beijing 100076 China University of California Department of Mechanical and Aerospace Engineering Irvine CA 92697-3975 United States

ISBN: (纸本)9781624101816

High angle of attack flows over a 20° conical forebody are computed by the commercial CFD code ANSYS CFX in this paper. The free-stream velocities are 10 to 70 m/s, the Reynolds number based on the forebody base diameter varies from 0.1×106 to 0.7×106, and the angle of attack ranges from 10° to 35°, the boundary layer is under free transition. The C-O structured meshes are used to compute the entire flow field. The axial and radial grid numbers are 81 and 121, respectively, while the circumferential grid points uniformly distributed with different grid number of 120, 180, 240 and 360, respectively. The pressure distributions over the forebody surface have been computed by three computational models, and the results computed by the transitional model agree well with the experimental data, which were measured over 40 roll angles with equal intervals for each test condition. The computed total pressure coefficient and axial vorticity distributions over the cross-flow section are studied. The three vortex pairs, i.e., the primary, secondary and tertiary vortex, separated from the forebody boundary layer at angle of attack of 15°-35° and wind speed of 10-70m/s are captured. The approximate conical flow features of pressure distribution and primary vortex location are identified. © 2013 by The Authors.

关键词： Angle of attack

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Stiffness performance estimation for biped locomotor WL-15

Stiffness performance estimation for biped locomotor WL-15

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2003 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM 2003

作者： Carbone, G. Sugahara, Y. Lim, H.O. Takanishi, A. Ceccarelli, M. Laboratory of Robotics and Mechatronics DiMSAT University of Cassino Via Di Biasio 43 CassinoFr03043 Italy Graduate School of Science and Engineering Waseda University 3-4-1 Ookubo Shinjuku-kuTokyo169-8555 Japan Kanagawa Institute of Technology Department of System Design Engineering 1030 Shimoogino AtsugiKanagawa243-0292 Japan Humanoid Robotics Institute Waseda University 3-4-1 Ookubo Shinjuku-kuTokyo169-8555 Japan

ISBN: (纸本)0780377591

In this paper a biped locomotor, named as WL-15 (Waseda Leg 15), is analyzed in terms of stiffness characteristics. Basic models and a formulation are proposed in order to deduce the stiffness matrix as a function of the most important design parameters of the WL-15 architecture. First numerical simulations and experimental tests are also carried out for stiffness performance estimation. © 2003 IEEE.

关键词： Anthropomorphic robots

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Development And Optimization of Airborne Display Scene Based on SCADE

Development And Optimization of Airborne Display Scene Based...

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science and technology Innovation (IAECST), International Academic Exchange Conference on

作者： Qian Song Li Zhang Ze Tian School of Electronic Information Xi'an Polytechnic University Xi' an Shaanxi China School of Electronic Information Xi' an Polytechnic University Xi' an Shaanxi China Key Laboratory of Aviation Science and Technology on Integrated Circuit and Micro-System Design Xi' an Shaanxi China

With the rapid development of avionics display field, the traditional graphics software development method can no longer meet the needs of high security and efficiency. This paper studies a development method based on SCADE Display, a high security graphics application development tool, analyses the principle and characteristics of SCADE Display, applies SCADE Display to design airborne display scene models, and tests, analyses and optimizes the process on a home-made test platform. Finally, the experimental results show that the optimized solution can effectively improve the development efficiency and graphics frame rate, and also verify the adaptability and functionality of the home-made platform.

关键词： Graphics Adaptation models Technological innovation Analytical models Codes Atmospheric modeling Optimization methods

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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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Distribution of Dislocation-Twin Interaction in Twip Steel Under Different Loading Modes

SSRN

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SSRN 2022年

作者： Guo, Xiangru Mao, Ningdong Sun, Chaoyang Wang, Chunhui Cui, Yinan Xiong, Zhiping Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China School of Mechanical Engineering University of Science and Technology Beijing Beijing100083 China Applied Mechanics Lab School of Aerospace Engineering Tsinghua University Beijing100084 China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing Institute of Technology Beijing100081 China

The tension-compression asymmetry and orientation effect of dislocation-twin boundary (TB) interactions in twinned TWIP steels were investigated using the discrete dislocation dynamics simulations and Schmid's law. The different types of dislocations dominate the TB migration in the twinned TWIP steel during tension and compression with the same loading orientation, and the asymmetric dislocation reactions at TB were attributed to the different leading partials produced after the dissociation of dislocation under different loading modes (tension or compression). Moreover, the complex dislocation-TB interactions, such as dislocations traversing TB, cross slip, dissociation, pile up and so on, were determined by considering the orientation effect of dislocation activation and the asymmetry of dislocation dissociation. The research advances the understanding of asymmetric behavior of twin and its influence on the macro hardening in plastic deformation of TWIP steels. © 2022, The Authors. All rights reserved.

关键词： Dissociation

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Small-Target Infrastructure Detection with Spatial Tracking and Multi-Level Feature Extraction of Railway Track Scenes

Small-Target Infrastructure Detection with Spatial Tracking ...

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Intelligent Communication, Sensing and Electromagnetics (ICSE), International Conference on

作者： Heng Du Huaiming Cang Yiwen Bai Xinyi Wang Beijing Elephant Technology Co. Ltd Beijing China School of Transportation Science and Engineering Beihang University Beijing China The State Key Lab of Intelligent Transportation System Beijing China Tianjin Key Laboratory for Advanced Mechanical System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) Tianjin China

ISBN: (数字)9798350354935

ISBN: (纸本)9798350354942

In the field of railway transportation, with the continuous improvement of train running speed and the continuous increase of operating mileage, it becomes particularly important to ensure the safety and integrity of small-target infrastructure along the railway train. Although many small-target detection methods have been proposed, the research on small-target infrastructure detection along rail trains is very rare. To solve this problem, this paper proposes a small-target infrastructure detection network with spatial tracking and multi-level feature extraction based on Yolov8n. The experimental results show that ST-YOLO has a 3.6% mAP improvement on the OSDaR23 dataset compared to the baseline Yolov8n, and shows significant advantages over other state-of-the-art methods.

关键词： Rails Transportation Railway safety Switches Feature extraction Rail transportation Real-time systems Sensors Safety Monitoring

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A Fluid-Filled Tubular Dielectric Elastomer Variable Stiffness Structure Inspired by the Hydrostatic Skeleton Principle

A Fluid-Filled Tubular Dielectric Elastomer Variable Stiffne...

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IEEE International Conference on Robotics and Automation

作者： Tao Wang Yue Li Yuanjie Li Jinhua Zhang Jun Hong Michael Yu Wang Key Laboratory of Education Ministry for Modern Design & Rotor-Bearing System Xi'an Jiaotong University Xi'an Shaanxi China Department of Mechanical and Aerospace Engineering & Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Kowloon Hong Kong

This work presents a novel variable stiffness structure consisting of a fiber-constrained dielectric elastomer tube filled with insulating oil. The tensile stiffness of the structure can be adjusted by voltages and its initial value can be customized according to the initial pre-stretch of the material. The structure has a dimension of ～30 mm diameter ×50 mm length. A mathematical analysis is established to predict the initial tensile stiffness of the structure. The changes of the tensile stiffness of the structure under voltages are verified experimentally. The results show a decrease of the tensile stiffness of the device by 25% at 4 kV and the decrement is also related to the elongation of the structure. With different pre-stretches and dimensions of the dielectric elastomer, one can obtain devices with different variation ranges of tensile stiffness.

关键词： Electron tubes Strain Oils Muscles Hydraulic systems Force Soft robotics

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Recrystallization Mechanism and Texture Evolution of Pre-Twinned Zr702 During Annealing

SSRN

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SSRN 2022年

作者： Zeng, Qinghui Qiu, Risheng Bi, Fengxian Wang, Lixia Song, Shiyong Zeng, Qihang College of Intelligent Manufacturing Engineering Chongqing University of Arts and Sciences Chongqing402160 China College of Materials Science and Engineering Chongqing University Chongqing400044 China Chongqing Jianshe Vehicle System Co. LTD. Chongqing400054 China Science and Technology on Reactor Fuel and Materials Laboratory Sichuan Chengdu610041 China

With the aim of tailoring the texture of Zr alloys by twin recrystallization, the recrystallization mechanism and texture evolution of a tensile-twin-containing Zr702 were investigated in this work. Two types of rolling modes, simple rolling along former normal direction (ND) and cross rolling along former ND and rolling direction (RD) at cryogenic temperature, were conducted in a Zr702 sheet with a basal texture to activate high density tensile twins, and subsequent annealing was applied to induce twin recrystallization. During cryogenic rolling, [[EQUATION]] and [[EQUATION]] tensile twins were activated, which resulted in a texture change of c-axis keeping away from ND and tilting close to transverse direction (TD) along the ND-TD plane. And a [[EQUATION]] twin band- [[EQUATION]] twin band- [[EQUATION]] twin band lamellar structure formed inside the twinned grains at high thickness reductions due to the growth of [[EQUATION]] twins between parallel [[EQUATION]] twins. When rolling direction is RD for cross rolling, the grain orientations were more beneficial to the activation of prismatic slip than tensile twinning, leading to lower area fractions of tensile twins and sluggish texture change in cross-rolled samples. However, the final textures of the two types of rolled samples at 30% thickness reduction were similar. During annealing, twin recrystallization in tensile twins featured by bulging of twin boundaries and conventional discontinuous recrystallization at original grain boundaries occurred in twinned grains. Recrystallized grains formed in tensile twins had orientations closed to the un-recrystallized twins and contributed to the generation of a uniform texture of c-axis tilted close to TD along ND-TD plane in rolled and annealed samples, regardless of the different area fractions of twins and the various rolled textures at different thickness reductions. Few recrystallized grains nucleating in [[EQUATION]] twins gave rise to the disappearance of c-axis p

关键词： Textures

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One-dimensional non-linear consolidation of soft foundation with upper crust with depth-dependent additional stress

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Materials Research Innovations 2015年 19卷 S9198-S9204页

作者： Zhang, J.H. Wang, Y.L. Cen, G.M. Jiang, W.W. Zheng, J.L. Wu, H.X. National Engineering Laboratory of Highway Maintenance Technology Changsha University of Science and Technology Changsha410114 China Texas Transportation Institute Texas A and M University System College StationTX77843 United States Guangdong Highway Design Institute Co. Ltd. Guangzhou510030 China Jiangxi Ganyue Expressway Co. Ltd. Nanchang330029 China

A model for one-dimensional non-linear consolidation of a soft foundation with an upper crust with depth-dependent additional stress was presented in this paper. The semi-analytical solution of this model with the boundary condition of the pervious top was derived, which was proved by comparing with the classical solution of a one-layered foundation under an instantaneous loading. Then, the effects of the depth-dependent additional stress on the consolidation of the double-layered foundation were revealed. The results show that the depth-dependent additional stress inside foundation has a great influence on the consolidation rate at the former stage and final settlement of the double-layered foundation. If the change of the additional stress along the depth is neglected, an underestimated consolidation rate and overestimated final settlement will be obtained. © W. S. Maney & Son Ltd 2015.

关键词： Foundations

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Emergent grain boundary phases in stressed polycrystalline thin films

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Physical Review Materials 2023年第8期7卷 083602-083602页

作者： Mengyuan Wang Ruilin Yan Xiao Han Hailong Wang Moneesh Upmanyu CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Hefei Anhui 230027 China Group for Simulation and Theory of Atomic-Scale Material Phenomena (stAMP) Department of Mechanical and Industrial Engineering Northeastern University Boston Massachusetts 02115 USA

The grain boundary (GB) microstructure influences and is influenced by the development of residual stresses during synthesis of polycrystalline thin films. Recent studies have shown that the frustration between the preferred growth direction and rotations of abutting crystals to local cusps in GB energies leads to internal stresses localized within nanoscopic surface layers around the valleys and ridges that form at emergent boundaries (eGBs). Using a combination of continuum frameworks, numerical analyses, and all-atom simulations of bicrystal 〈111〉 copper films, we show that eGBs tune their surface morphology and rotation extent in response to external strains. Compression favors rotation to and growth of low-energy GB phases (complexions) at eGB valleys while tension favors the transitions at eGB ridges, a reflection of the stress-induced mass efflux/influx that changes the energetic balance between interfacial and deformation energies. Molecular dynamics simulations of strained and growing bicrystal films reveal that the eGB phase transition is coupled to island formation at the surface triple junctions, providing a direct link between eGB phases and surface step flow. The interplay between eGB structure, morphology, and mechanics emerges as a crucial ingredient for predictive understanding of stress and morphological evolution during film growth, with broad implications for multifunctional response of polycrystalline surfaces in a diverse range of surface phenomena such as surface-mediated deformation, interfacial embrittlement, thermal grooving, stress corrosion, surface catalysis, and topological conduction.

关键词： Grain boundaries Interface & surface thermodynamics Surface & interfacial phenomena Surface reconstruction Solid-solid interfaces Thin films Molecular dynamics

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