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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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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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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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Simulation of Fluid-Structure Interaction Using Cartesian Grid with Cut Cells

Simulation of Fluid-Structure Interaction Using Cartesian Gr...

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

作者： Kangbin Lei Masako Iwata Ryutaro Himeno Product Performance Simulation Team Integrated Volume-CAD System Research Program RIKEN 2-1 Hirosawa Wako-shi Saitama 351-0198 Japan Product Performance Simulation Team Integrated Volume-CAD System Research Program RIKEN 2-1 Hirosawa Wako-shi Saitama 351-0198 Japan Product Performance Simulation Team Integrated Volume-CAD System Research Program RIKEN 2-1 Hirosawa Wako-shi Saitama 351-0198 Japan

A voxel grid method combined with cut cells has been developed for simulating two-dimensional unsteady, viscous, and incompressible flows with arbitrary boundaries. The volume of fluid (VOF) approach based on finite volume method (FVM) is employed to accurately discretize the governing equation in voxel cells that are cut by irregular boundaries. The precision of solution in the cut cells is ensured by special discretizations near the embedded boundaries. The accuracy and robustness of the proposed method are validated by simulating viscous flow around a stationary cylinder. Moreover, in order to verify the ability of this method to simulate the flow fields with arbitrarily moving boundaries, the fluid-structure interaction of bluff body in forced oscillation and vortex-induced vibration are also investigated by employing voxel method developed in this paper. Calculation results show that lock-in phenomenon in wind engineering, in which the vortex-shedding is synchronized with the vibration of cylinder, is consistent with experimental data, the cylinder resonance state caused by vortex-induced vibration is also in reasonable agreement with results calculated by Arbitrary Lagrangian Eulerian (ALE) finite element method (FEM).

关键词： Simulation of Fluid-Structure Interaction Using Cartesian Grid with Cut Cells

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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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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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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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Sheet Forming Simulation Using a Static FEM program and Considering the Elastic Deformation of Tools

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AIP Conference Proceedings 2004年第1期712卷

作者： Masato Takamura Kenichi Ohura Hideyuki Sunaga Toshihiko Kuwabara Akitake Makinouchi Cristian Teodosiu Integrated Volume‐CAD System Program RIKEN 2‐1 Hirosawa Wako‐shi Saitama 351‐0198 Japan Department of Mechanical Systems Engineering Tokyo University of Agriculture and Technology 2‐24‐16 Nakacho Koganei‐shi Tokyo 184‐8588 Japan LPMTM‐CNRS University Paris 13 93430 Villetaneuse France

In sheet forming simulations using the finite‐element method (FEM), the elastic deformation of tools during the forming process can play an important role, particularly when accurate analysis is required to predict complex defects such as springback phenomena. However, in simulations of stamping parts with complex geometries, such as automotive body parts, it would be necessary to use hundreds of thousands or even more elements for a tool model to take into account its elastic deformation within a coupled FEM analysis. Therefore, in most simulations based on incremental FEM, tools are regarded as non‐deformable bodies to avoid excessive computation times. In this study, the authors propose an efficient algorithm to deal with the contact between the sheet and the deformable tools, which is specialized for the coupling of the effects between nonlinear‐elastoplastic and linear‐elastic bodies in the framework of a static explicit time integration scheme. Stamping experiments of square cup deep drawing with a flexible blank holder were also conducted and the results compared with numerical ones. These results confirmed the ability of the coupled simulations to predict the influence of the tool elasticity on the behavior of the sheet.

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