Details of a Researcher - Takano, Naoki

Papers - Takano, Naoki

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Structural strength prediction for porous titanium based on micro-stress concentration by micro-CT image-based multiscale simulation

Naoki Takano, Ken Fukasawa, Kazuaki Nishiyabu

International Jouranal of Mechanical Sciences (International Journal of Mechanical Sciences) 52 ( 52 ) 229-235 - 235 2010.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 00207403

For the design of porous titanium component, differently from its use as functional materials, structural strength prediction algorithm is proposed based on the micro-stress concentration analyzed by the multiscale simulation. The modeling of real microstructure is carried out by the image-based technique with X-ray micro-CT. The multiscale computational method consists of asymptotic homogenization and finite element mesh superposition (FEMS) techniques. A criterion is proposed to predict the nonlinearity initiation point in the load and displacement curve by means of micro-stress distribution expressed by histogram. Only the constituent's yield strength is referred regardless of the microscopic morphology. The originality of this paper lies in the validation of the homogenization process, the modeling guideline of micro-mesh superposition onto macro-mesh in FEMS, and the strength prediction algorithm. L-shaped components with different pore diameter were discussed in both experiment and simulation. © 2009 Elsevier Ltd. All rights reserved.

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Biomechanical role of peri-implant trabecular structures during vertical loading

Takashi Ohashi, Satoru Matsunaga ,Ken Nakahara, Shinichi Abe, Yoshinobu Ida, Yuichi Yamatsu, Naoki Takano

Clinical Oral Investigation (Clinical Oral Investigations) 14 ( 5 ) 507-513 - 513 2009.08

Research paper (scientific journal), Joint Work, Accepted, ISSN 14326981

The aim of this study was to identify the load transfer paths in cortical bone and trabecular structure of cancellous bone in the jawbones for loads from endosseous implants. Maxillae were resected from beagle dogs 6 months after implant surgery and imaged using micro-computed tomography (micro-CT). A three-dimensional structure was produced based on the CT data and peri-implant trabecular structure was observed. Load transfer paths were analyzed from the results of three-dimensional finite element analysis. Furthermore, buffer actions in bone trabeculae when strain increased during stress analysis and when loads were applied were observed. Peri-implant bone trabeculae were seen extending into the upper and lower cortical bone from the fixture. The direction of bone trabecular alignment corresponded with the load transfer paths. In addition, analysis with increased strain confirmed that trabecular structures could serve as load buffers. These results suggest that bone trabeculae supporting load transfer from implants undergo remodeling. © 2009 Springer-Verlag.

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Creative design with multi-objective topology optimization

Chen Jian Ken Lee, Naoki Takano

Transactions of Japan Society for Computational Engineering and Science, Vol.2009 2009 Paper No.20090011 2009.07

Research paper (scientific journal), Joint Work, Last author, Accepted

Reduction of finite element mesh and model order for fast dynamic analysis of global/Local problem

Atsushi Sando, Naoki Takano, Mitsuteru Asai, Toshiyuki Toriyama, Shoji Kido, Jan.G.Korvonk

Jurnal of Solid Mechanics and Materials Engineering (JSME) 3 ( 3 ) 572 - 583 2009.03

Research paper (scientific journal), Joint Work, Accepted

Insertion testing of polyethylene glycol microneedle array into cultured human skin with biaxial tension

Naoki Takano, Hiroto Tachiawa, Takaya Miyano, Kazuaki Nishiyabu

Journal of Solid Mechanics and Materials Engineering (JSME) 3 ( 3 ) 604-612 2009.03

Research paper (scientific journal), Joint Work, Accepted

Removing void elements for structural level set topology optimizaiton

Chen Jian Ken Lee, Zhiqian Zhang, Naoki Takano

Journal of Computational Science and Technology (JSME) 3 ( 1 ) 385 - 395 2009.01

Research paper (scientific journal), Joint Work, Accepted

Adjoint variable method for multi-objective sizing and shape optimization

Chen Jian Ken Lee, Wataru Furuya, Masato Tanaka, Naoki Takano

Journal of Computational Science and Technology (JSME) 3 ( 1 ) 275 - 286 2009.01

Research paper (scientific journal), Joint Work, Last author, Accepted

ナノ粒子分散材の3次元モルフォロジー分析と有限要素モデリング

高野直樹, 浅井光輝, 黄田尚宏, 橋本和信

材料 57 ( 5 ) 423 - 429 2008

Research paper (scientific journal), Joint Work, Lead author, Accepted

骨質を考慮した椎体海綿骨の高分解能ミクロ応力解析

田原大輔, 安達泰治, 高野直樹, 中野貴由

日本臨床バイオメカニクス学会誌 20 7 - 14 2008

Research paper (scientific journal), Joint Work, Accepted

透過型光学系を有する微小領域X線回折法によるヒト海綿骨内生体アパタイト結晶配向性の2次元定量解析

宮部さやか, 中野貴由, 石本卓也, 高野直樹, 安達泰治, 岩城啓好, 高岡邦夫, 馬越佑吉

日本金属学会誌 72 ( 1 ) 57 - 62 2008

Research paper (scientific journal), Joint Work, Accepted

HMS採血ポンプ用新型バイモルフ圧電アクチュエータの提案

上辻靖智, 長倉秀幸, 川原慎太郎, 黄輝心, 槌谷和義, 山本英毅, 高野直樹, 仲町英治

材料 56 ( 5 ) 477 - 482 2007.05

Research paper (scientific journal), Joint Work, Accepted

Two-dimensional quantitative analysis of preferential alignment of BAp c-axis for isolated human trabecular bone using microbeam X-ray diffractometer with a transmission optical system

Sayaka Miyabe, Takayoshi Nakano, Takuya Ishimoto, Naoki Takano, Taiji Adachi, Hiroyoshi Iwaki, Akio Kobayashi, Kuio Takaoka, Yukichi Umakoshi

Materials Transactions (Materials Transactions) 48 ( 3 ) 343 - 347 2007.03

Research paper (scientific journal), Accepted, ISSN 13459678

Two-dimensional quantitative analysis of microbeam X-ray diffraction (XRD) was performed using a transmission optical system to examine biological apatite (BAp) orientation in an isolated trabecula of a human fourth lumber vertebral body. The incident X-ray beam is 20 μm in diameter, which is small enough for the isolated trabecula despite a slight beam divergence of 0.2°. Integrated intensities of (002) and (310) are obtained separately by different incident angles and detector positions. Distribution of the preferential orientation of the BAp c-axis is finally calculated quantitatively as an integrated intensity ratio of (002)/(310) in a plane containing the trabecular direction. Preferential alignment of the BAp c-axis was finally determined to be perfectly parallel to the fiber direction in a rod-shaped trabecula, since accurate one-dimensional alignment is different from the alignment in the femoral cortical bone as a long bone that shows the local maximum of preferential alignment perpendicular to the longitudinal bone axis. For example, the integrated intensity ratio of (002)/(310) has a maximum value of 16 along the trabecular fiber and a minimum value of 0.09 in the perpendicular direction. Using this method, the anisotropy of BAp orientation in the trabecular bone can be quantitatively evaluated in the plane including the trabecular fiber. Thus, we successfully obtained a methodology that two-dimensionally analyzes the distribution of the BAp c-axis along all axes within a plane in a bone specimen. © 2007 The Japan Institute of Metals.

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An iterative solver applied to strongly coupled piezoelectric problems of porous Pb(Zr,Ti)O3 with nondestructive modelling of microstructure

Mitsuteru Asai, Naoki Takano, Yasutomo Uetsuji, Kunihiko Taki

Modelling and Simulation in Materials Science and Engineering 15 ( 6 ) 597 - 617 2007

Research paper (scientific journal), Joint Work, Accepted

均質化法による多孔質圧電材料のイメージベース・マルチスケール解析

浅井光輝, 高野直樹, 滝邦彦, 足森崇志, 日下貴之, 上辻靖智

材料 55 ( 12 ) 1111 - 1116 2006.12

Research paper (scientific journal), Joint Work, Accepted

海綿骨の骨梁モルフォロジーと生体アパタイト結晶配向性を考慮したマルチスケール応力解析

河貝光寛, 高野直樹, 中野貴由, 浅井光輝

材料 55 ( 9 ) 874 - 880 2006.08

Research paper (scientific journal), Joint Work, Accepted

生体硬組織の高分解能イメージベース・マルチスケールモデリング

山東篤, 櫛田慶幸, 高野直樹, 安達泰治, 中野貴由, 馬越佑吉, 石本卓也, 榎元孝俊, 河井まりこ, 山本敏男

日本計算工学会論文集 Paper No.20060017 2006

Research paper (scientific journal), Joint Work, Accepted

Image-based multi-scale modelling strategy for complex and heterogeneous porous microstructures by mesh superposition method

Mitsuhiro Kawagai, Atsushi Sando, Naoki Takano

Modelling and Simulation in Materials Science and Engineering (Modelling and Simulation in Materials Science and Engineering) 14 ( 1 ) 53 - 69 2006

Research paper (scientific journal), Joint Work, Accepted, ISSN 09650393

This study is focused on the multi-scale modelling strategy for complex and heterogeneous microstructures of real materials by automatic image-based modelling and finite element mesh superposition method. The synergetic application of the conventional asymptotic homogenization method and the authors' mesh superposition method has been proposed to obtain the microscopic responses under high gradient of macroscopic fields at the macroscopic crack tip and/or interface, for instance. For complex and random microstructures, automatic image-based voxel meshing by means of x-ray CT is commonly required; however, it cannot always adapt to the mathematical theory of microscopic modelling in the mesh superposition method. Therefore, a modelling technique for mesh refinement is proposed in this paper using additional elements for insulation in consideration of the theoretical background of the mesh superposition method. In this paper, we provide the modelling procedure and its theoretical consideration of mesh refinement for flexible modelling of real materials. To demonstrate the technique, a numerical example of a porous ceramic component with random microstructure and macroscopic crack is illustrated. © 2006 IOP Publishing Ltd.

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Finite element analysis of fiber-reinforced fixed partial dentures

Takashi Nakamura, Tatsuo Ohyama, Tomonori Waki, Soichiro Kinuta, Kazumichi Wakabayashi, Naoki Takano, Hirofumi Yatani

Dental Materials Journal (Dental Materials Journal) 24 ( 2 ) 275 - 279 2005

Research paper (scientific journal), Joint Work, Accepted, ISSN 02874547

Two-dimensional finite element models were created for a three-unit posterior fixed partial denture. An experimental resin-impregnated glass fiber was used as the fiber-reinforced composite (FRC) for the framework. The FRC was evaluated using varying combinations of position and thickness, alongside with two types of veneering composite. A load of 50 N simulating bite force was applied at the pontic in a vertical direction. Tensile stress was examined using a finite element analysis program. Model without FRC showed tensile stress concentrations within the veneering composite on the cervical side of the pontic - from the connector area to the bottom of the pontic. Model with FRC at the top of the pontic had almost the same stress distribution as the model without FRC. Models with 0.4-0.8 mm thick FRC positioned at the bottom of the pontic showed maximum tensile stresses reduced by 4-19% within the veneering composite.

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Stress analysis of endodontically treated anterior teeth restored with different types of post material

Takashi Nakamura, Tatsuo Ohyama, Tomonori Waki, Soichiro Kinuta, Kazumichi Wakabayashik Yoshihiko Mutobe, Naoki Takano, Hirofumi Yatani

Dental Materials Journal (Dental Materials Journal) 25 ( 1 ) 145 - 150 2005

Research paper (scientific journal), Joint Work, Accepted, ISSN 02874547

Finite element analysis was performed to evaluate stress distribution in maxillary central incisors treated endodontically and restored with a post and an all-ceramic crown. Tensile stress at tooth root was analyzed using two-dimensional finite element models with different post diameters and lengths. One post length was 1/3 of the root (short), while the other was 2/3 of the root (long); one post diameter was 1/3 of the root (narrow), while the other was 2/3 of the root (wide). The following combinations were used for posts and cores: gold alloy cast post and core, commercial stainless steel post and resin core, and fiber post and resin core. Results showed that the fiber post produced less stress on the root dentin around the post tip than did the metal posts. This finding thus suggested that to reduce the stresses that cause root fracture, a long, thin fiber post should be used.

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多孔体モルフォロジーのディジタルイメージベース・アナリシス

高野直樹, 辻村幸治

日本機械学会論文集(A編) 70 ( 694 ) 787 - 793 2004.06

Research paper (scientific journal), Joint Work, Lead author, Accepted

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