-
Yasutomo UETSUJI, Fishim HWANG, Kazuyoshi TSUCHIYA, Eiji NAKAMACHI
Article type: Article
Session ID: 2816
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We proposed crystal growth prediction to fabricate new biocompatible piezoelectric material. At first, the energy of piezoelectric crystals, which are under epitaxit ial strain caused by mismatch between thin film and substrate, was evaluated by ab initio calculations. As a result, the energy shows differences between tensile and compressive strains, and among crystal growth orientations even if the same epitaxitial strain is applied. Then, we applied the energy by ab initio calculation to evaluate crystal growth on a substrate, and could predict preferred orientations.
View full abstract
-
Taku WATANABE, Tatsuya Hukuhara, Hiroshi Izui, Mitiharu Okano, Yasumas ...
Article type: Article
Session ID: 2817
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Recently, a novel sintering technology known as spark plasma sintering (SPS) has used for fabricating ceramics, functionally graded materials (FGM) and composites. SPS can consolidate samples at lower sintering temperature and for shorter sintering duration compared with conventional sintering methods, such a hot-pressing or HIP. Mechanical properties (three-point bending strength, Young's modulus and compressive strength) and biocompatibility of HAp/β-TCP FGM sintered by SPS were investigated. The FGM were sintered at a temperature of 1073K and at a pressure of 44.6 or 66.9MPa. The FGM compacts had higher three-point bending strength, Young's modulus and compressive strength than β-TCP. Natural bone formed on the surface of the FGM in the HAp-rich area and replacement for bone in the β-TCP-rich area. These results show that the HAp/β-TCP FGM sintered by SPS had high strength, excellent biocompatibility and controllability for graded bio-reaction.
View full abstract
-
Hiromi SUZUKI, Ryota TAKATORI, Daisaku TOKUNAGA, Hitoshi HASE, Takashi ...
Article type: Article
Session ID: 2818
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The purpose of this study was to establish a finite element stress analysis method of intervertebral discs in a rheumatoid arthritis (RA) patient with cervical involvement using a three dimensional (3D) computer model reconstructed from computer tomography (CT) and magnetic resonance (MR) images. Intervertebral disc 3D finite element models were created using point cloud data of endplates of cervical spine (C2-C7) vertebral bodies in three different positions; neutral, flexion, and extension positions. Transformations of each endplate in flexion and extension positions were determined using a volume merge method. Changes in stress/strain distribution during flexion and extension were analyzed using displacement data of the endplate as input data. Stress concentration was noted at both lateral regions in C2/3 and C3/4 intervertebral discs. However, no significant changes in stress distribution during motion were observed at C4/5, C5/6, and C6/7 intervertebral discs.
View full abstract
-
Satoshi GOHGI, Nozomu INOUE, Ryota TAKATORI, Hiromi SUZUKI, Takashi MA ...
Article type: Article
Session ID: 2819
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Despite the significant impairment associated with degenerative disc disease, a clear understanding of pathogenesis of disc degeneration is still lacking. In order to clarify the relationship between degenerative disc disease and morphological and biomechanical properties, an accurate measurement method is needed. Recent advancement of medical imaging has allowed us to create an in vivo three dimensional (3D) computer model with high accuracy. The purpose of the current study was to evaluate the disc height distribution and changes in stress distribution under compression loading of the rabbit lumbar intervertebral disc using a 3D computer model created from micro computer tomography images. The results of the study showed the contribution of 3D geometry of the endplate to stress concentration which may cause disc degeneration.
View full abstract
-
Tomohiro KAWASAKI, Kazuto TANAKA, Tsutao KATAYAMA, Suong-Hyu HYON
Article type: Article
Session ID: 2820
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Stereocomplex-type polylactic acid (SCPLA) is gaining attention in the various field due to its melting point of 220℃, which is higher than that of pure poly-L-lactic acid (PLLA) and poly-D-lactic acid (PDLA). However, exposure of polylactic acid (PLA) to environmental agents such as sunlight, water, heat, degrades its mechanical properties. This study reports the effect of water and high temperature environment on properties of PLA fiber. When SCPLA fiber was immersed in water at high temperature, tensile strength drastically decreased with the hydrolysis of SCPLA. Compared to the PLLA fiber, however, SCPLA fiber had a greater resistance to hydrolysis. When SCPLA fiber and PLLA fiber were immersed in water at high temperature, sem examination of these fibers revealed regular patterns of cracks running in the vertical direction to the fiber axis.
View full abstract
-
Takafumi MIZUNO, Noriyuki HISAMORI, Yukito HAGIHARA
Article type: Article
Session ID: 2821
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Cobalt-Chromium alloys possess outstanding corrosion resistance and wear resistance because of passive film of a few nanometers' thickness on their surfaces. In this study, we have clarified the damage accumulation mechanism of Co-Cr alloys under the simultaneous reaction of corrosion and wear in sodium chloride solution. We developed a new tribocorrosion system. A corrosion wear characteristic of these alloys was evaluated by the anodic polarization test, static polarization test, and natural potential test under simultaneous wear damage. Large corrosion pits and changes in wear form were observed on their surfaces.
View full abstract
-
Kouji FUJIMAKI, Noriyuki HISAMORI, Yukito HAGIHARA
Article type: Article
Session ID: 2822
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A material for medical application is required to have extended sustainability of mechanical strength together with fast bone replacement ability in human body. Composite material is preferred in the application because monolithic material does not meet the requirement. In this study, we have developed HAp/TCP composite. The mechanical property of the material is evaluated by the bending strength test. The bone replacement ability is evaluated by soaking the material in simulated body fluid (SBF). Measured result of concentration of Ca^<2+> ion in SBF indicated that the developed material has excellent bone replacement ability. The bending strength is maintained after I week of soaking in SBF due to precipitation of HAp on the surface proceeding to degrease of the strength at early stage of soaking due to dissolution of TCP.
View full abstract
-
Souichi SAEKI, [in Japanese], Youhei HASHIMOTO, Takashi SAITO, Takafum ...
Article type: Article
Session ID: 2823
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Acute coronary syndromes, e.g. myocardial infarctions, are caused by the rupture of unstable plaques on coronary arteries. The stability of plaque, which depends on bio-mechanical properties of fibrous cap, should be diagnosed crucially. Recently, Optical Coherence Tomography (OCT) has been developed as a cross-sectional imaging method of biological tissue with high resolution, i.e. 1〜10μm. It is, however, difficult to estimate biomechanical characteristics, e.g. instability of plaque, because OCT images have just speckle patterns by back-scattering from tissue. We proposed Optical Coherence Straingraphy (OCS), e.g. an estimator of micro bio-strain distribution, has been being improved on the basis of Optical Coherence Tomography. This is composed of the recursive cross-correlation technique, Adjacent Cross-correlation Multiplication (ACM) as a speckle noise reduction method and displacement vector correction which can take account of tissue uncompressibility. Thus this can provide an accurate strain map with high resolution. In this study, this was applied to simulated OCT images of compressed tissue samples to carry out the accuracy verifications. Consequently, it was quantitatively confirmed that the proposed method can obtain the accurate strain map with high resolution.
View full abstract
-
Jun OHHAMA, Satoshi KITAYAMA, Koetsu YAMAZAKI
Article type: Article
Session ID: 3124
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Sequential Approximate Optimization (SAO) is one of the most attractive research areas in the design optimization. The Radial Basis Function Network (RBFN) is used to construct the response surface. One of the important aspects in the SAO is the sampling strategy. This paper proposes the new method for the sampling strategy. The sampling function to add a new sample point is proposed. The local or global minima of the sampling function correspond to the sparse region of the sample points. To minimize the sampling function, a new sample point is found. The Particle Swarm Optimization (PSO) is used to minimize the sampling function. Through the numerical examples, the validity of proposed method is examined.
View full abstract
-
Koji SHIMOYAMA, Jin Ne LIM, Shinkyu JEONG, Shigeru OBAYASHI
Article type: Article
Session ID: 3125
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A new approach for multi-objective robust design optimization has been proposed and applied to a real-world design problem with a large number of objective functions. The present approach is assisted by response surface approximation and visual data-mining, which results in two major gains regarding computational time and data interpretation. The Kriging model for response surface approximation can realize accurate predictions of robustness measures, and dramatically reduces the computational time for objective function evaluation. In addition, the use of self-organizing maps as a data-mining technique allows visualization of complicated design information between optimality and robustness of design in a comprehensible two-dimensional form. Therefore, the extraction and interpretation of trade-off relations between optimality and robustness of design, and also the location of sweet-spots in the design space, can be performed in a comprehensive manner.
View full abstract
-
Eiji KATAMINE, Kenichi Shimizu, Hideyuki AZEGAMI
Article type: Article
Session ID: 3126
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A shape optimization method for volume minimization of thermoelastic fields is presented. The shape gradient of the shape optimization problems was derived theoretically using the adjoint variable method, the Lagrange multiplier method and the formulae of the material derivative. Reshaping was accomplished using a traction method that was proposed as a solution to the shape optimization problems. The validity of the proposed method was confirmed by the results of 2D numerical analysis.
View full abstract
-
Takanori CHIHARA, Koetsu YAMAZAKI, Ryoichi ITOH
Article type: Article
Session ID: 3127
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper has investigated effects of the bottle opening size (28, 33, 38mm) and the beverage type (green tea, carbonated drink) on drinking feelings in order to improve the comfort level of consumers when drinking directly from the opening of aluminum bottle. A survey over 120 Japanese subjects has been performed, and they have evaluated that the 33mm opening is the best no matter beverage type. Moreover, there is appropriate flow rate for subjects, and it has become clear from the results of three dimensional fluid-dynamics analysis that the flow rate of carbonated drink is less than that of green tea.
View full abstract
-
Yuki KAWAKAMI, Akira TODOROKI, Ryosuke MATSUZAKI
Article type: Article
Session ID: 3128
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Large wind tuebine blade is prospected to be CF/GF hybrid blade made with Carbon Fiber Reinforsced Plastic and Glass Fiber Reinforced Plastic, and structural optimization of the blade is multi-objective optimization problem (MOOP) about weight and material cost of blades. The optimum solutions for MOOP are Pareto optimum solutions. In this paper, the MOOP is solved using Multi-Objectibe Genetic Algorithm (MOGA). Meanwhile, blade structure is necessary to satisfy some constraints not to fracture under various load conditions. To evaluate the constraints, FEM analysis is used. This causes enormous calculation cost. In the present paper, to reduce this, some response surfaces approximating the degree of constraint satisfaction are created. Pareto solutions obtained using response surfaces don't necessarily satisfy the constraints because of approximation error. It is necessary to confirm whether they actually satisfy the constraints or not using FEM analysis. If some of the solutions don't satisfy the constraints, whose response data is added in, and the response surfaces are restructured to improve their accuracy. Repeating restructuring, obtained Pareto solutions will converge to exact Pareto Optima. As a result, the the number of FEM analysis is reduced to about 1300 times.
View full abstract
-
Ryo FURUKAWA, Kei MASUNISHI, Akihiro KOGA, Hiroyuki KAWASHIMA, Akio KO ...
Article type: Article
Session ID: 3129
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
For high-resolution retinal camera, we have developed an adaptive optics system using a membrane deformable mirror (DM) with electrostatic actuators. An aberration compensation algorithm is adopted in the system, which can generate appropriate control input by a linear combination of voltage templates prepared in advance, each of that forms a specific Zernike shape approximately. The nonlinear effect and strong coupling of control channels in continuous-surface DM make it difficult to form the desired mirror surface shapes. In this paper, we propose a computational method to obtain the voltage templates using genetic algorithm and grouping electrodes for reducing the number of independent voltage sources. The results show that the method can be used to obtain appropriate applied voltages for high-order Zernike shapes.
View full abstract
-
Naotaka Uchida, Shinji NISHIWAKI, Kazuhiro IZUI, Masataka YOSHIMURA, T ...
Article type: Article
Session ID: 3130
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper proposes a topology optimization using COMSOL which can conduct multiphysics analysis. First, a concept of topology optimization and the relaxation scheme for the design domain using the density method are briefly discussed. Next, the optimization problem for the stiffness maximization problem is formulated. An optimization algorithm is constructed based on this formulation. The details in numerical implementations using COMSOL are discussed. Finally, a numerical example is provided in order to confirm the usefulness of the proposed method.
View full abstract
-
Misuk YAMAZAKI, Masato KOBAYASHI, Syuichi KIKUKAWA
Article type: Article
Session ID: 3131
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A coupling analysis method has been developed for analyzing temperature distribution on electric devices by combining the structural stress analysis with electric-thermal conductivity analysis. Estimating the temperature distribution on electric devices is difficult because it is affected by the resistance on the interface, which depends on the magnitude of the contact pressure between structures. In previous approaches to solving this problem, the resistance was considered uniform, whereas the approach used in this method considers it distributed. The method comprises two calculations: the first uses only structural analysis to estimate the contact pressure, which determines the interface resistance and the second uses the electric-thermal conductivity to estimate the temperature distribution. The test results showed that the method works well in designing the shape of an electrode for a vacuum interrupter, which cuts off an electric current.
View full abstract
-
Eiji NIKURA, Atsushi MICHIMORI, Hiroaki SUGIURA
Article type: Article
Session ID: 3132
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes high rigidity technology of the cabinet for large-sized Projection TV (PTV). I have executed the structure analysis by using the design model of 73" PTV. In the result of the analysis, the molding cabinet did not obtain enough rigidity. Then we have examined the best reinforcement structures for the PTV. As the result, we have decreased deformation of cabinet to one-eighth by the self-weight and to one-fifth by twist force.
View full abstract
-
Eiji MURAKAMI, Koutarou KAWAMURA, Noriyuki ICHINOSE
Article type: Article
Session ID: 3133
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
An advanced design system for steel frame structure has been developed. The system can automatically generate beams and using coordinates data of equipment loading points, and determine optimal layout of vertical bracings, and then create 3D-CAD model data. To develop the automatic beam layout program, new beam generation algorithms have been originally developed. The algorithms are based on the rules derived from knowledge of design engineers and member layouts of actual plants in the past. The capability of the algorithms has been verified to confirm practicality of the system. The whole steel structure model was employed in the verification test. The test showed that approximately 90% of beams successfully generated and period of the design could be reduced by approximately one third.
View full abstract
-
Takashi YAMAMOTO, Shinichi MARUYAMA, Shinji NISHIWAKI, Masataka YOSHIM ...
Article type: Article
Session ID: 3134
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes a new design method for optimizing the thickness distribution of a multilayered structure located on the coupling surface between a structure and an acoustic cavity. The design method incorporates a transfer matrix for the multilayered structure including a poroelastic media layer. The one-dimensional transfer matrix adopted here is an approximate representation addressing vibro-acoustic effects inherent in a multilayered structure and balances calculation times and desired accuracy. In this study, the problem of minimizing the acoustic pressure is formulated under the volume constraint. Numerical results show that acoustic response is significantly reduced by an optimal thickness distribution having a total volume equal to or less than that of the initial thickness.
View full abstract
-
Kohta HARIYA, Sergey DMITRIEV, Nobuhiro YOSHIKAWA
Article type: Article
Session ID: 3135
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
An optimum design methodology is investigated for FRP pressure vessel of hydrogen gas with plastic liner. The isotensoid design of uniform tensile strain along fiber is a major candidate for the minimum weight optimum design, since the fiber bears internal pressure most efficiently. The isotensoid design is theoretically derived from membrane modeling of FRP layers, neglecting three-dimensional effect. We derived a minimum weight design method taking account of three-dimensional effect exactly. The baseline design is given by the isotensoid design of membrane theory, then the minimum weight design is searched for through iterative calculations of maximum strain analyses along fiber and layer thickness determinations. The random searched technique is included in the solution search to avoid local minimum. The validity of the proposed method is demonstrated in problem of burst proof test.
View full abstract
-
Masatoshi SHIMODA, Shingo OOSHITA
Article type: Article
Session ID: 3136
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, we present a shape optimization method by using pyramid shape basis vectors for a natural frequency problem of plate and shell structures. The local embossed shape besides the global shape can be optimized by this method. The pyramid shape basis vectors are created using the small lattice domains so as to express the local shape variation in the normal direction on the surface, which is based on the concept of the shape function of the finite element method. The morphing technique is employed to vary the domain consisting of the several finite elements. A natural frequency set as the objective function is maximized tracking the mode under a volume constraint condition. The results for two examples show the validity of this method to optimize both the global shape and the local embossed shape of plate and shell structures for the natural frequency problem. In addition, the results of a stiffness problem of the same models are presented for comparison.
View full abstract
-
Tadayoshi MATSUMORI, Koetsu YAMAZAKI
Article type: Article
Session ID: 3137
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We have proposed a new design method to optimize a cooling pipe shape in the three-dimensional space for plastic injection molding die by applying the response surface approach and shape optimization technique. To evaluate the optimality of cooling pipe arrangement and shape, cooling rate and temperature distribution in the die, which are primal factors to cause residual stresses producing some defects in the molded plastic, are used as objective functions. Then the cooling pipe shape and position to minimize the two objective functions simultaneously by using optimization techniques has been obtained. The proposed method has been applied to some cooling pipe shape design of 3-dimensional problem to discuss the availability off the method.
View full abstract
-
Kenzen TAKEUCHI, Makoto TSUKINO
Article type: Article
Session ID: 3138
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In structural optimization, the shape of structure must be satisfied with some constraint conditions considering manufacturing process, mechanical symmetry and outward appearance. This paper describes a shape optimization technique for symmetrical structures using multipoint constraints based on traction method. Shape variation of traction method is obtained as a solution of a boundary value problem of linear elastic continuum loaded with traction in proportion to the shape gradient. In the shape variation analysis, multipoint constraints are introduced to keep the symmetry of the structure. This technique is applied to a simple optimization problem of circular cross section cantilever. The validity of this technique is confirmed by comparison between theoretical result and the numerical result. Furthermore, a numerical result of a shape optimization problem of a road wheel is shown as a practical application.
View full abstract
-
Article type: Appendix
Pages
App4-
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
