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3-d modeling of unsteady free-surface flow in open channel

JOURNAL OF HYdRAULIC RESEARCH 2004年第3期42卷 263-272页

作者： Faure, JB Buil, N Gay, B Cemagref Unite Rech Hydrol Hydraul Lyon France Univ Lyon 1 Lyon France Univ Lyon 1 UMR CNRS 5509 Lab Mecan Fluides & Acoust Lyon France

We present the hydrodynamic part of a three-dimensional model for pollutant dispersion in turbulent free-surface flow in open channels. It does not require any strong assumption such as hydrostatic pressure and is able to simulate an unsteady free-surface flow as flood waves or discharge over a weir. Our main objective was to model the moving free-surface and the boundary conditions under two constraints. The first constraint was to keep a point of view as close as possible to that of the 1-d modeling generally used in river engineering, especially relative to the upstream and downstream boundary conditions. The second one was that our model had to be sufficiently flexible to be implemented in a general computational fluid dynamics package. After describing our model, we present some numerical tests and comparisons with 1-d simulations from a hydrodynamic point of view.

关键词： free-surface flow Navier-Stokes equations shallow-water equations river flow 3-d modeling

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3-d modeling of automatic pressure gelation process for manufacturing gas insulated switchgear spacer using bio-based epoxy composite

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AdVANCEd COMPOSITE MATERIALS 2024年第5期33卷 689-705页

作者： Lee, Sangmook Dankook Univ Dept Chem Engn 126Jukjeon Dong Yongin 448701 Gyeonggi Do South Korea

In existing power devices, various insulating parts are manufactured with petroleum-based epoxy resin. However, as petroleum-based resources are gradually depleted and environmental problems have emerged, research on replacing petroleum-based products with eco-friendly materials as insulators has been actively conducted. Therefore, in this study, a molding simulation study of the Auto Pressure Gelation (APG) process, one of the leading technologies, was conducted to manufacture a gas insulated switchgear (GIS) spacer using an environmentally friendly bio-based epoxy composite. Using the heat dissipation and degree of cure obtained through the dynamic differential scanning calorimetry (dSC) test, it was applied to the Kamal-Sourour model which is a representative curing dynamics empirical formula. In addition, the viscosity change during the curing process was measured using a rheometer and applied to the cross Castro-Macoskco model. The results obtained were in good agreement with the experimental values. The parameters calculated above and other physical property values were input into Moldflow software, and simulation was performed targeting the three-phase spacer. While changing the temperature setting of the mold, the change and distribution of flow, temperature, and curing degree inside the product were observed during the reactive molding process. As a result, it was found that there was a possibility of clogging of the mold entrance at some set temperatures, and it was possible to suggest improvement directions to solve this problem. Through this series of research process, it is considered that it will be of great help in improving the quality problems of molded products and the process accordingly.

关键词： APG GIS spacer 3-d modeling cure kinetics chemorheology

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3-d modeling of proton exchange fuel cell cathode with a novel random generation of gas diffusion porous layer

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KOREAN JOURNAL OF CHEMICAL ENGINEERING 2021年第8期38卷 1703-1714页

作者： Bahoosh, Reza Jafari, Moosa Bahrainian, Seyed Saied Shahid Chamran Univ Ahvaz Mech Dept Ahvaz Iran Shahid Chamran Univ Ahvaz Mech Dept Ahvaz Iran

A 3d model for a section of cathode fuel cell comprised of a bipolar plate, a gas diffusion layer (GdL) and a catalyst layer was simulated. The diameter of the carbon fiber GdL is assumed to be the same;moreover, a new and simple method is introduced for the reconstruction of this layer numerically. This method gives the ability to model the heterogeneous and anisotropic structure of the GdL;furthermore, it allows easy implementation and provides realistic results with consideration of the lack of overlap between carbon fibers. The lattice Boltzmann method (LBM) was employed to simulate the flow and the electrochemical reaction. The impacts of changes in the activation potential and the GdL carbon fiber diameter on oxygen species and water vapor, as well as the electric current density distribution over the catalyst layer, were studied. The results showed that at higher values of the activation potential, the concentration of oxygen near the catalyst layer was lower. The current density over the catalyst layer also increased by increasing the activation potential;on the other hand, the mole fraction of water vapor in the cathode increased with the increase in the flow of gas products. Consequently, results indicated that the variation in the GdL carbon fiber diameter affects the distribution of reactants.

关键词： 3-d modeling Random Generation Gas diffusion Layer Proton Exchange Fuel Cell GdL

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3-d modeling of Induced Seismicity Along Multiple Faults: Magnitude, Rate, and Location in a Poroelasticity System

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JOURNAL OF GEOPHYSICAL RESEARCH-SOLId EARTH 2018年第11期123卷 9866-9883页

作者： Chang, K. W. Yoon, H. Sandia Natl Labs Geotechnol & Engn Dept POB 5800 Albuquerque NM 87185 USA Sandia Natl Labs Geomech Dept POB 5800 Albuquerque NM 87185 USA

Understanding of the potential to injection-induced seismicity along faults requires the response of fault zone system to spatiotemporal perturbations in pore pressure and stress. In this study, three-dimensional (3-d) model system consisting of the caprock, reservoir, and basement is intersected by vertical strike-slip faults. We examine the full poroelastic behavior of the formation and perform the mechanical analysis along each fault zone using the Coulomb stress change. The magnitude, rate, and location of potential earthquakes are predicted using the spatial distribution of stresses and pore pressure over time. Rapid diffusion of pore pressure into conductive faults initiates failure, but the majority of induced seismicity occurs at deep fault zones due to poroelastic stabilization near the injection interval. Less permeable faults can be destabilized by either delayed pore pressure diffusion or poroelastic stressing. A two-dimensional (2-d) horizontal model, representing the interface between the reservoir and the basement, limits diffusion of pore pressure and deformation of the formation in the vertical direction that may overestimate or underestimate the potential of earthquakes along the fault. Our numerical results suggest that the 3-d modeling of faulting system including poroelastic coupling can reduce the uncertainty in the seismic hazard prediction by considering the hydraulic and mechanical interaction between faults and bounding formations.

关键词： induced seismicity basement fault 3-d modeling poroelasticity fluid injection

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3-d modeling and hexahedral mesh generation method based on failure characteristics of remanufactured centrifugal compressor impeller

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JOURNAL OF INdUSTRIAL ANd PROdUCTION ENGINEERING 2016年第5期33卷 339-347页

作者： Xu, Lei Cao, Huajun Shu, Linsen Chongqing Univ State Key Lab Mech Transmiss Chongqing 630044 Peoples R China Shaanxi Univ Technol Coll Mech Engn Hanzhong Shaanxi Peoples R China

The precision of the 3-d model and the mesh quality of the remanufactured impeller are directly related to the accuracy of the results of numerical simulation analysis. In order to acquire high accuracy results, 3-d modeling/hexahedral mesh technologies for remanufactured centrifugal compressor impellers are investigated. A method to reconstruct the structural characteristics of the remanufactured centrifugal compressor impellers, which was based on the measurement points of the structural characteristics and NURBS curve and surface theory, was proposed on the basis of the failure characteristics. Besides, the 3-d model construction process of the remanufactured centrifugal compressor impeller was introduced in detail. Furthermore, based on the 3-d model, a hexahedral meshing method was proposed. The quality of the remanufactured impeller mesh was analyzed with Jacobian matrix. The results showed that the 3-d model and the hexahedral mesh in this study met the accuracy requirement of the FEM analysis.

关键词： 3-d modeling hexahedral mesh failure characteristics remanufactured impeller

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3-d modeling and monitoring system on intelligent film-lifting shovel based on BECKHOFF

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JOURNAL OF COMPUTATIONAL METHOdS IN SCIENCES ANd ENGINEERING 2021年第4期21卷 1031-1040页

作者： Wu, Xiaoyan Wang, Shu Wang, Xinnan He, Guogeng Hubei Polytech Univ Sch Mech & Elect Engn Huangshi 435003 Hubei Peoples R China Huangshi Dongbei Elect Appliance Co Ltd Postdoctoral Res Workstn Huangshi 435000 Hubei Peoples R China Huazhong Univ Sci & Technol Sch Energy & Power Engn Wuhan 430074 Hubei Peoples R China Hubei Key Lab Intelligent Conveying Technol & Dev Huangshi 435003 Hubei Peoples R China

Film shovel is the key device for mechanized operation of residual film recovery, in which the depth of soil breakage of the shovel is related to the degree of damage to the plastic film and the recovery efficiency of the residual film. However, the current mode of operation requires experience and visual inspection, which often leads to low level of mechanization and inefficient operation. The topic is to improve the existing residual film recovery device, focusing on the three-dimensional modeling and monitoring system of intelligent film lifting shovel. By optimizing the three-dimensional structure of the intelligent film-lifting shovel and kinematics simulation analysis based on Adams software, the design inclination angle of the loosening shovel is 60 degrees, and the breaking depth of the safe operation is 20-50 mm. Then through the use of Ethernet interface based on EtherCAT bus and the real-time bidirectional communication between BECKHOFF CX2030 controller and module and HMI, the on-line data transmission in the process of intelligent film shovel operation is realized. Field test results verify that the intelligent film-lifting shovel is feasible in the intelligent operation and recovery efficiency of the residual film recovery operation, which can greatly improve the efficiency of the whole machine operation.

关键词： Residual film recovery filmlifting shovel 3-d modeling iintelligence monitoring

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Portable 3-d modeling using visual pose tracking

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COMPUTERS IN INdUSTRY 2018年 99卷 53-68页

作者： Strobl, Klaus H. Mair, Elmar Bodenmueller, Tim Kielhoefer, Simon Wuesthoff, Tilo Suppa, Michael German Aerosp Ctr DLR Robot & Mech Ctr D-82230 Wessling Germany X Dev LLC 1600 Ampitheatre Pkwy Mountain View CA 94043 USA Ringstr 38 D-86911 Diessen Germany Robocept GmbH Kaflerstr 2 D-81241 Munich Germany

This work deals with the passive tracking of the pose of a close-range 3-d modeling device using its own high-rate images in realtime, concurrently with customary 3-d modeling of the scene. This novel development makes it possible to abandon using inconvenient, expensive external trackers, achieving a portable and inexpensive solution. The approach comprises efficient tracking of natural features following the Active Matching paradigm, a frugal use of interleaved feature-based stereo triangulation, visual odometry using the robustified V-GPS algorithm, graph optimization by local bundle adjustment, appearance-based relocalization using a bank of parallel three-point-perspective pose solvers on SURF features, and online reconstruction of the scene in the form of textured triangle meshes to provide visual feedback to the user. Ideally, objects are completely digitized by browsing around the scene;in the event of closing the motion loop, a hybrid graph optimization takes place, which delivers highly accurate motion history to refine the whole 3-d model within a second. The method has been implemented on the dLR 3d-Modeler;demonstrations and abundant video material validate the approach. These types of low-cost systems have the potential to enhance traditional 3-d modeling and conquer new markets owing to their mobility, passivity, and accuracy. (C) 2018 Elsevier B.V. All rights reserved.

关键词： 3-d modeling Pose tracking SLAM Visual odometry

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3d modeling system using rotary vision sensor

3D modeling system using rotary vision sensor

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Conference on Machine Vision and Its Optomechatronic Applications

作者： Hayashi, J Shima, d Hata, S Higashi, N Kaida, K Kagawa Univ Takamatsu Kagawa 7610396 Japan

ISBN: (纸本)0819455563

We have developed an experimental system for 3-d sensing using rotary vision sensor. Visual inspection systems are widely used for assembled PCB inspection. In many cases, these systems employ sophisticated optical systems, and to calibrate or adjust the system requires much effort of specialists. Also, the systems are very much specialized to the specified task and cannot be used for wide variety of applications. Recently, CCd cameras can be easily used for many applications and we proposed a experimental system for 3-d sensing using relative stereo method, last year. Using the idea, this time, we developed a new 3-d sensing system using the rotary vision sensor and motion picture analysis method. It can extract 3-d shape of objects with high reliability. In this paper, we introduce the idea of this system with experimental results.

关键词： 3-d modeling visual inspection system relative stereo method rotary vision sensor

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A survey of sketch-based 3-d modeling techniques

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INTERACTING WITH COMPUTERS 2009年第3期21卷 201-211页

作者： Cook, Matthew T. Agah, Arvin Univ Kansas Dept Elect Engn & Comp Sci Lawrence KS 66045 USA

As 3-d modeling applications transition from engineering environments into the hands of artists, designers, and the consumer market, there is an increasing demand for more intuitive interfaces. In response, 3d modeling and interface design communities have begun to develop systems based on traditional artistic techniques, particularly sketching. Collectively this growing field of research has come to be known as sketch-based modeling, however the name belies a diversity of promising techniques and unique approaches. This paper presents a survey of current research in sketch-based modeling, including a basic introduction to the topic, the challenges of sketch-based input, and an examination of a number of popular approaches, including representative examples and a general analysis of the benefits and challenges inherent to each. (C) 2009 Elsevier B.V. All rights reserved.

关键词： Human computer interaction User interface 3-d modeling Interaction styles Sketch-based modeling

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An Integrated Framework for 3-d modeling, Object detection, and Pose Estimation From Point-Clouds

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IEEE TRANSACTIONS ON INSTRUMENTATION ANd MEASUREMENT 2015年第3期64卷 683-693页

作者： Guo, Yulan Bennamoun, Mohammed Sohel, Ferdous Lu, Min Wan, Jianwei Natl Univ Def Technol Coll Elect Sci & Engn Changsha 410073 Hunan Peoples R China Univ Western Australia Sch Comp Sci & Software Engn Crawley WA 6009 Australia

3-d modeling, object detection, and pose estimation are three of the most challenging tasks in the area of 3-d computer vision. This paper presents a novel algorithm to perform these tasks simultaneously from unordered point-clouds. Given a set of input point-clouds in the presence of clutter and occlusion, an initial model is first constructed by performing pair-wise registration between any two point-clouds. The resulting model is then updated from the remaining point-clouds using a novel model growing technique. Once the final model is reconstructed, the instances of the object are detected and the poses of its instances in the scenes are estimated. This algorithm is automatic, model free, and does not rely on any prior information about the objects in the scene. The algorithm was comprehensively tested on the University of Western Australia data set. Experimental results show that our algorithm achieved accurate modeling, detection, and pose estimation performance.

关键词： 3-d modeling 3-d object detection 3-d object recognition point-cloud pose estimation range image

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