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Viscous Micropump Simulation by Particle/Continuum Methods

Journal of Shanghai Jiaotong university(Science) 2011年第3期16卷 364-367页

作者：王盛罗昔联雷康斌顾兆林 KASE Kiwamu Integrated Volume CAD System Research Program RIKEN Institute School of Human Settlement and Civil Engineering Xi'an Jiaotong University

A novel viscous micropump consisting of a cylindrical rotor eccentrically placed inside a microchannel is simulated by the two volume-cad(V-cad)framework-based flow solvers,i.e.,the direct simulation Monte Carlo(DSMC)package(named as V-DSMC)and the Navier-Stoke solver(named as V-Flow).V-DSMC is used in the case of the pump applied to gas,while V-Flow is applied to model the pump in the case of liquid working *** pumping performance curves under different liquid media with the variation of Reynolds number,as well as under different eccentricity factors are *** performance and the flow filed characteristics are very sensitive to the tangential momentum accommodation coefficient in the case of gas *** recirculations exist in the flow field,and the sizes of recirculation are different at the different operating points in a performance curve.

关键词： viscous micropump pumping performance flow field characteristics

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Ray-tracing simulation procedure for general GRIN media

Ray-tracing simulation procedure for general GRIN media

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Frontiers in Optics, FiO 2010

作者： Nishidate, Y. Nagata, T. Morita, S. Yamagata, Y. Teodosiu, C. Volume-CAD system research program RIKEN Saitama 351-0198 Japan

A ray-tracing procedure has been developed for general gradient refraction index (GRIN) media where the distribution and the media surface position are given as discrete point sets of arbitrary distributions. Ray trajectories in the GRIN media are calculated from the numerical solution of the ray equation with automatic step size monitoring. The moving least squares method is employed for local reconstructions of refraction index fields. The developed ray-tracing procedure is applied to simulation of the Luneburg lens. The spot radius of the Luneburg lens is less than 10 nanometers for 1 millimeter radius of the lens, and hence the ratio of the error to the problem dimension is less than 10-5. © 2010 OSA/FiO/LS 2010.

关键词： Ray tracing

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Effect of tool modeling accuracy on sheet metal forming simulation

Effect of tool modeling accuracy on sheet metal forming simu...

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作者： Hama, Takayuki Takamura, Masato Teodosiu, Cristian Makinouchi, Akitake Takuda, Hirohiko Department of Energy Science and Technology Kyoto University Yoshida-Honmachi Sakyo-ku Kyoto 606-8501 Japan Advanced Vehicle Manufacturing and Prototype Technology Department Nissan Motor Co. Ltd. 560-2 Okatsukoku Atsugi-shi Kanagawa 243-0192 Japan Integrated Volume-CAD System Program Institute of Physical and Chemical Research 2-1 Hirosawa Wako-shi Saitama 351-0198 Japan

This paper describes the effect of tool modeling accuracy on the accuracy of springback simulation in sheet metal forming. Simulations of a two-dimensional draw-bending process are carried out by using the polyhedral tool model and the model whose surface is smoothed by quadratic parametric surfaces proposed by Nagata [1]. It is found that the tool modeling, especially the normal vector accuracy in the present model, plays an important role in the prediction not only of deformation but also of stress distribution. The simulated results show that the tool model based on the so-called Nagata patch enables a more accurate and efficient simulation.

关键词： Sheet metal

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Springback Simulation of High Strength Steel Sheet using Local Interpolation for Tool Surfaces

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AIP Conference Proceedings 2007年第1期908卷 805-810页

作者： Takayuki Hama Cristian Teodosiu Akitake Makinouchi Hitoshi Fujimoto Hirohiko Takuda *Department of Energy Science and Technology Kyoto University Yoshida‐Honmachi Sakyo‐ku Kyoto 606‐8501 Japan ¶Volume‐CAD System Research Program The Institute of Physical and Chemical Research 2‐1 Hirosawa Wako‐shi Saitama 351‐0198 Japan †LPMTM‐CNRS University Paris 13 93430 Villetaneuse France

This paper presents the effect of tool modelling accuracy on the simulation accuracy of springback in high strength steels. Simulations of a two‐dimensional draw‐bending process are carried out by using a polyhedral tool model whose surface is approximated by a polyhedron, and a model whose surface is smoothed by quadratic parametric surfaces proposed by Nagata [Nagata, Comput. Aided Geom. D, 22(2005), 55–59] (Nagata patch model). It is found that not only the shape accuracy but also the normal vector accuracy of tool models are of importance for accurate springback predictions. The use of the Nagata patch model is an efficient approach not only to improve the simulation accuracy but also to make the simulation be hardly influenced by the tool mesh, even for simulations of a high strength steel in which large amount of springback is involved.

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Approximation of Unorganized Point Set with Composite Implicit Surface

Approximation of Unorganized Point Set with Composite Implic...

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IEEE International Conference on Image Processing

作者： Arnaud Gelas Yutaka Ohtake Takashi Kanai Remy Prost CREATIS INSA UCBL CNRS UMR Lyon France Integrated Volume-CAD System Research Program RIKEN Saitama Japan Graduate School of Arts and Sciences University of Tokyo Japan

We propose a new approach for surface reconstruction from any unorganized point set, with a fixed amount of parameters. First, we consider some local approximations by compactly supported radial basis functions (CSRBFs), then blend them by a partition of unity method (PU). In our scheme, we start by selecting CSRBFs centers, then construct partitions, finally parameters are calculated in order to minimize, on each sub-domain, the mean square error with a regularization constraint. We demonstrate the effectiveness of our approach on several models with different points distributions.

关键词： Surface reconstruction Image reconstruction Partitioning algorithms Surface fitting Interpolation Art Mean square error methods Humans Approximation methods Image processing

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Directable animation of elastic objects 05

Directable animation of elastic objects

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Proceedings of the 2005 ACM SIGGRAPH/Eurographics symposium on Computer animation

作者： Kondo, Ryo Kanai, Takashi Anjyo, Ken-Ichi Keio University Japan RIKEN Integrated Volume-CAD System Research Program Japan OLM Digital Inc. Japan

ISBN: (纸本)9781595931986

There is a crucial demand in the computer animation industry to make animations that blend animator-specified expressive motion with physics-based realism. We propose a novel framework to create directable animation of elastically deformable objects. The directable animation is created with animator-specified keyframes and the motion trajectory of the deformable object, while maintaining a plausible realism. Our framework mainly consists of two complementary approaches. The first is a method to control the time-varying geometry of an elastic object, using a loose key-framing technique. In our keyframing, we introduce an FEM-based elastic deformation algorithm that allows us to rearrange the elastic object motion, guided by the shape or pose specified at each keyframe. The second is a motion compensation technique, which allows us to rearrange the physical behavior of elastically deformable objects under a user-specified trajectory. The animation examples demonstrate that our framework provides plausibly realistic deformation animations with greater controllability and usability than existing approaches. © 2010 ACM.

关键词： Animation

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Advanced desktop manufacturing system for micro-mechanical fabrication 7

Advanced desktop manufacturing system for micro-mechanical f...

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7th International Conference and Exhibition on Laser Metrology, CMM and Machine Tool Performance, LAMDAMAP 2005

作者： Ohmori, H. Uehara, Y. Katahira, K. Watanabe, Y. Suzuki, T. Lin, W. Mitsuishi, N. Asami, M. Ohmori Materials Fabrication Lab. ADSC DRI RIKEN Japan V-CAD Fabrication Team Integrated Volume-CAD System Research Program CIPS RIKEN Japan NEXSYS Corporation Japan

ISBN: (纸本)1861941188

A desktop manufacturing system has been developed for the advanced production shops. This is an advanced micro-mechanical fabrication tool for manufacturing advanced micro-components. This paper describes the concept and the features of the developed fabrication system, and also results achieved by the system. Good performances for micro-manufacturing on the desktop machines with ELID (ELectrolytic In-process Dressing), are demonstrated.

关键词： Fabrication

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Finite Element Simulation of Sheet Metal Forming Process Using Local Interpolation for Tool Surfaces

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AIP Conference Proceedings 2005年第1期778卷 185-190页

作者： Takayuki Hama Masato Takamura Cristian Teodosiu Akitake Makinouchi Hirohiko Takuda *Department of Energy and Science Technology Kyoto University Yoshida‐Honmachi Sakyo‐ku Kyoto 606‐8501 Japan ¶Integrated Volume‐CAD System Program The Institute of Physical and Chemical Research2‐1 Hirosawa Wako‐shi Saitama 351‐0198 Japan †LPMTM‐CNRS University Paris 13 93430 Villetaneuse France

Treatment of contact between a sheet and tools is one of the most difficult problems to deal with in finite‐element simulations of sheet forming processes. In order to obtain more accurate tool models without increasing the number of elements, this paper describes a new formulation for contact problems using interpolation proposed by Nagata for tool surfaces. A contact search algorithm between sheet nodes and the interpolated tool surfaces was developed and was introduced into the static‐explicit elastoplastic finite‐element method code STAMP3D. Simulations of a square cup deep drawing process with a very coarsely discretized punch model were carried out. The simulated results showed that the proposed algorithm gave the proper drawn shape, demonstrating the validity of the proposed algorithm.

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Numerical Investigation on Formability of Ellipse Deep Drawing by Sheet Hydroforming

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AIP Conference Proceedings 2005年第1期778卷 549-554页

作者： Hiroshi Utsugi Takayuki Hama Motoo Asakawa Tomohiro Hatakeyama Akitake Makinouchi Hiroyuki Amino Yang Lu *Graduate School of Science and Engineering Waseda University 3‐4‐1 Ohkubo Shinjuku‐ku Tokyo 169‐8555 Japan ¶Department of Energy and Science Technology Kyoto University Yoshida‐Honmachi Sakyo‐ku Kyoto 606‐8501 Japan †Department of Mechanical Engineering Waseda University 3‐4‐1 Ohkubo Shinjuku‐ku Tokyo 169‐8555 Japan ‡Integrated Volume‐CAD System Program The Institute of Physical and Chemical Research 2‐1 Hirosawa Wako Saitama 351‐0198 Japan oundAmino Corporation 555 Misonodaira Fujinomiya Shizuoka 418‐0004 Japan

This paper presents the numerical investigation on the formability of the sheet hydroforming by a finite element method. The finite element method code for sheet hydroforming simulation was developed based on the static‐explicit finite‐element method code STAMP3D. Experiments and Simulations of ellipse deep drawings were performed. The simulated thickness strain distribution which has two local thinnings at the punch shoulder and at the upper part of the side wall well agreed with the experimental one, thus demonstrating the validity of the developed code. Moreover, the effects of the friction increasing effect which is one of the main features in the sheet hydroforming on the formability were examined by comparing the results between the simulations with the friction coefficient μ=0 and those with μ=0.15. When μ=0 was employed, the local thinning at the upper part of the side wall disappeared. This showed that the occurring the two local thinnings in the sheet hydroforming was originated in the friction increasing effect.

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Large Scale Coupling Analysis of Fluid Flow and Heat Transfer in Solid with Complex Geometry

Large Scale Coupling Analysis of Fluid Flow and Heat Transfe...

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The Sixth World Congress on Computational Mechanics in Conjunction with the Second Asian-Pacific Congress on Computational MechanicsⅠ

作者： Minoru Shirazaki Ryutaro Himeno Integrated Volume-CAD System Research Program RIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan Integrated Volume-CAD System Research Program RIKEN 2-1 Hirosawa Wako Saitama 351-0198 Japan

Heat transfer between fluid and solid, which occurs in heat exchangers, steam generators and so forth, is one of the most important phenomena in the field of engineering. The phenomenon has been studied by many researchers with numerical approaches. In many numerical simulations, however, it is assumed that the temperature or the heat flux on solid surface is constant as thermal boundary conditions.

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