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Volume 77, Issue 4
Displaying 1-8 of 8 articles from this issue
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[in Japanese]2004 Volume 77 Issue 4 Pages 117
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSDownload PDF (189K) -
Ryo OKUIZUMI, Gen AOKI2004 Volume 77 Issue 4 Pages 118-123
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSSeveral topics on applications and future problems of injection molding CAE (Computer Aided Engineering), and structural analysis using CAE for plastics parts are discussed from the view point of experience in our technical service.
By using injection molding CAE analyses, we can solve many kinds of injection molding problems. But, we think that we still need validations of analyses. Future problems for the injection molding CAE seem to be the estimation of higher-order structure of polymer, measurement of plastics properties and reliance of analyses.
For the example of structural analysis application, we introduce one of the non-liner structural analysis results of POM (polyoxymethylene) parts and the creep phenomenon of plastics cup holder. For more sophisticated application, future problems seem to be taking into account of the characteristic properties of plastics such as non-linearity, viscoelastic property, orientation of the material and so on.View full abstractDownload PDF (1218K) -
Takeshi ISHIKAWA2004 Volume 77 Issue 4 Pages 124-129
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSSince the melting theory in a single screw extruder was established by Tadmor in 1966, a large number of kinematic models has been proposed based on his model. According to his theory, the melting takes place at the interface between the hot barrel and the unmolten polymer called the solid bed. The heat conducted from the barrel and generated by viscous dissipation at the interface reduces the width of the solid bed along the screw down channel.
On the other hand, the melting theory in a twin screw extruder was recently proposed by Potente in the mid-90s and it is still developing. According to several observations, the melting processes are classified into the Tadmor type and the suspension type. The latter type of melting is that the solid particles which are dispersed in the melt reduce their size by heat conduction from the melt. Besides these models, Gogos referred to the importance of the energy dissipation caused by plastic deformations of solid materials in the kneading block region.
In this article, the author reviews the melting models of both the single and the twin screw extruders, focusing on the recent development in this field.View full abstractDownload PDF (943K) -
Satoru YAMAMOTO2004 Volume 77 Issue 4 Pages 130-135
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSIn this paper, we present a particle simulation method (PSM) for particle dispersed materials and a dissipative particle dynamics (DPD) simulation for a polyelectrolyte membrane for a fuel cell. In the PSM, a particle is modeled by using arrays of spheres and each pair of adjacent spheres is connected with three types of springs; stretch, bend, and twist for the deformability of the particle. The motion of the particles in flow is followed by solving the translational and rotational equations of motion for each constituent sphere considering the hydrodynamic interaction. The method was applied to predicting the microstructure of fiber and platelike particle dispersed systems, their rheological properties, and the motion of fillers in an injection molding flow. In the DPD simulation, we studied the mesoscopic structure of a Nafion membrane. Nafion and water are modeled by a coarse-grained method and the Flory-Huggins χ-parameters for these models are then estimated from the mixing energy calculation using an atomistic simulation. As a DPD result, water particles and hydrophilic particles of Nafion side chains spontaneously form aggregates and are embedded in the hydrophobic phase of the Nafion backbone. The cluster size and its dependence on the water content are in good agreement with experimental reports. The atomistic structure of the water channel is then generated based on the obtained mesoscopic structure, and a molecular dynamics simulation is performed.View full abstractDownload PDF (1399K) -
Naoki KOBAYASHI2004 Volume 77 Issue 4 Pages 136-139
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSOCTA is an integrated multi scale computer simulation platform for polymeric materials design. OCTA consists of four simulation programs and a common graphical user interface. Applicability of the OCTA was investigated to linear homo polymer blend systems such as heterophasic polyolefin-based elastomer blend systems. A morphology simulator SUSHI which utilized a mean field simulation system based on the self consistent field theory, was employed to predict the morphology of bulk materials which have multiphase structure, binary Polypropylene (PP)/Ethylene-Propylene-Rubber (EPR) and ternary PP/EPR/Polyethylene (PE) polymer blend systems. And the elastic modulus was predicted by MUFFIN/Elastica which is a part of multi phase dynamics simulator based on the finite element method, using the morphology of elastomer blend systems calculated by SUSHI. Predicted moduli show very good agreement to literature data of elastomer blend systems. Zooming-simulation scheme, combination of any simulation models with different scale, is a successful method for designing soft materials.View full abstractDownload PDF (725K) -
Toshiki TAKEI2004 Volume 77 Issue 4 Pages 140-146
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSRecently we are facing a lot of pressures from Auto suppliers for their design and manufacturing process in order to increase the productivity and keep the credibility of their products. When we look at vehicle there are so many components and assembly parts made of rubber and resin, for instance, tires, bushes, intake/exhaust parts, tubes and hoses.
Especially low frequency vibration characteristics are sometimes depends on Engine or driveline or suspension mount stiffness. Also in driving conditions, tire is quite important for performance of drivability, ride-comfort and noise/vibration.
Dynamic analysis for those components is also important to know their characteristics in operating conditions, however there are many unknown/unclear non-liner characteristics. This paper will explain how to identify the mechanism of vibration & noise by using tools and technologies developed by LMS and in order to understand easily, we will show the practical examples for tire case and how influence on total vehicle performance from rubber or resin components.View full abstractDownload PDF (2149K) -
Eisuke SETA2004 Volume 77 Issue 4 Pages 147-151
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThis paper focused on application of fluid/structure interaction to tire analysis, such as hydroplaning and prediction of tire traction on snow. A three-dimensional prediction model has been developed. An explicit finite element method (FEM) and a finite volume method (FVM) were used to model tire and fluid, respectively. Fluid deformation was calculated by the Eulerian formulation to solve the complex interaction between fluid and tire tread pattern.
Numerical modeling of snow was also studied in order to establish the prediction model. Snow was assumed to be an elasto-plastic material whose yield law was considered to be a single function of pressure.
Predicted hydroplaning performance and tire traction on snow were compared with those of the experimental data. Results were shown to be in good qualitative agreement.View full abstractDownload PDF (1604K) -
[in Japanese]2004 Volume 77 Issue 4 Pages 152-153
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSDownload PDF (420K)
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