Details of a Researcher - Takano, Naoki

Probabilistic prediction of mechanical behavior of additively manufactured product considering geometrical imperfections associated with building direction

Mizuki Maruno, Naoki Takano

Mechanical Engineering Journal (JSME) 8 ( 6 ) 1 - 13 2021.12

Research paper (scientific journal), Joint Work, Accepted

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Experimental study on deformability of polymeric dental aligner by digital image correlation method

Naoki Yamaguchi, Kohta Ito, Pietro Oldani, Motoya Shiogama, Moeka Sawamura, Haruhisa Nakano, Koutaro Maki and Naoki Takano

Journal of the Society of Materials Science, Japan (日本材料学会) 70 ( 1 ) 57 - 63 2021.01

Research paper (scientific journal), Joint Work, Accepted

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Influence of higher orders of Neumann expansion on accuracy of stochastic linear elastic finite element method with random physical parameters

Lucas Degeneve and Naoki Takano

Mechanical Engineering Letters (JSME) 6 20-00228 2020.10

Research paper (scientific journal), Joint Work, Accepted

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鋼材成分のばらつきを考慮した焼入れプロセスの相変態－熱伝導連成解析と温度に対する感度解析

古川達也, 高野直樹, 杉本剛, 木島秀弥, 田村茂之

日本機械学会論文集 86 ( 887 ) 2020.06

Research paper (scientific journal), Accepted

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Stochastic nonlinear multiscale computational scheme for short fiber reinforced composites to study the influence of microstructural variability on Damage Propagation

Tien-Dat Hoang, Yutaro Abe, Shinya Nakamura, Akio Miyoshi, Naoki Takano

(SN Applied Sciences) 2 ( 182 ) 1 - 16 2020.01

Research paper (scientific journal), Joint Work, Accepted

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Study on Compressive Property of Aluminum Alloy Lattice Structure Additively Manufactured by 3D Printing Technology

Naoki Takano, Hideo Takizawa, Kohta Ito, Kento Odaka, Satoru Matsunaga, Shinichi Abe

Journal of the Society of Materials Science, Japan (Society of Materials Science, Japan) 68 ( 4 ) 351 - 357 2019.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 0514-5163

<p>In order to discuss the quality assurance of additively manufactured lattice structure made by aluminum alloy (AlSi10Mg) using 3D printing technology or selective laser sintering technique, compression test, micro-CT imaging and finite element analysis were carried out. The specimens were manufactured by 2 printing service companies with different expertise, which led to the choice of different process parameters such as the building direction, support structure, powder bed temperature and laser scanning speed. The largely scattered compressive peak loads were in good linear positive correlation with the weight, which is the easiest and convenient index for the quality assurance. On the other hand, the apparent density was almost the same. The reason why the weight of the products was largely scattered was investigated by micro-CT image analysis and finite element analysis. Also by comparison with the CAD data, the influence of manufacturer-dependent process parameters on the strength was discussed.</p>

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First-order Perturbation-based Stochastic Homogenization Method Applied to Damage Prediction for Composite Materials

Tien-Dat Hoang and Naoki Takano

Acta Mechanica (Acta Mechanica) 230 ( 3 ) 1061 - 1076 2018.12

Research paper (scientific journal), Joint Work, Accepted, ISSN 00015970

© 2018, Springer-Verlag GmbH Austria, part of Springer Nature. In this paper, a first-order perturbation-based stochastic homogenization method was developed to predict the probabilities of not only macroscopic properties but also microscopic strain damage in multiphase composite materials, considering many random physical parameters. From the stochastic solution of microscopic strains, damage propagation was analyzed to predict where progressive damage would occur in the microstructures of composites subject to a given macroscopic strain. As an example, a short fiber-reinforced plastic, consisting of short fibers, matrix, and interphase, was used to show the influence of random physical parameters for each constituent material on the variability of the homogenized properties and microscopic strain. In another example, a coated particle-embedded composite material was stochastically analyzed to consider even slight influences of uncertainty in the mechanical properties of the coating material and show damage propagation in this coating layer. Characteristic displacements representing material heterogeneity were thoroughly investigated and extensively used with the aim of reducing

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Biomechanical Analysis of Likelihood of Optic Canal Damage in Peri-orbital Fracture

Tomohisa nagasao, Tadaaki Morotomi, Motone Kuriyama, Motoki Tamai, Yoshiaki Sakamoto and Naoki Takano

Computer Assisted Surgery (Computer Assisted Surgery) 23 ( 1 ) 1 - 7 2018.04

Research paper (scientific journal), Joint Work, Accepted

© 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Purpose: Detection of optic canal fractures is often difficult because of the subtleness of the fracture. If we could clarify impact on which region around the orbit is likely to accompany the fracture of the optic canal, the knowledge should be useful to make early diagnosis of optic canal fractures. The present study was conducted to elucidate this issue. Methods: Ten finite element models were produced simulating the skulls of ten humans (8 males and 2 females; 43.8 ± 10.2 y/o). The peri-orbital area of each of the ten models was divided into eight regions in a clockwise fashion per 45 degrees. These regions were defined as Superior-Medial (0–45 degrees), Medial-Superior (45–90 degrees), Medial-Inferior (90 to 135 degrees), Inferior-Medial (135 to 180 degrees), Inferior-Lateral (180–225 degrees), Lateral-Inferior (225 to 270 degrees), Lateral-Superior (270–315 degrees), and Superior-Lateral regions (315–360 degrees), respectively. Dynamic simulation of applying traumatic energy on each of these regions was conducted. Resultant fracture patterns were evaluated using finite elem

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General Formulation of the First-order Perturbation Based Stochastic Homogenization Method Using Many Random Physical Parameters for Multi-phase Composite Materials

Pin Wen, Naoki Takano and Shusuke Akimoto

Acta Mechanica (Acta Mechanica) 229 ( 5 ) 2133 - 2147 2018.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 00015970

© 2018, Springer-Verlag GmbH Austria, part of Springer Nature. In the numerical prediction of the homogenized macroscopic properties of an arbitrary heterogeneous material with periodic microstructure, a general formulation of the first-order perturbation-based stochastic homogenization method is presented in a discretized form based on the finite element method in order to consider the variability or uncertainty of the mechanical properties of the material models. Many random parameters are defined for each material model and for each component of the stress–strain matrix of the constituent’s material model. The first-order terms of the characteristic displacement are thoroughly studied both theoretically and numerically, and are also used in the verification of the developed computer code. The comparison with the Monte Carlo simulation also supports the proposed formulation.

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Stochastic Prediction of Apparent Compressive Stiffness of Selective Laser Sintered Lattice Structure with Geometrical Imperfection and Uncertainty in Material Property

Naoki Takano, Hideo Takizawa, Pin Wen, Kento Odaka, Satoru Matsunaga and Shinichi Abe

International Journal of Mechanical Sciences (International Journal of Mechanical Sciences) 134 347 - 356 2017.11

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

© 2017 Elsevier Ltd Aiming at the future applications of a lattice structure manufactured by selective laser sintering for bone scaffold in the biomedical field, by putting highlight on the possible imperfections influenced by different manufacturing strategies, a numerical prediction method was studied and compared with compressive test results. To consider the geometrical imperfections as well as the uncertainty in sintered material property, the first-order perturbation based stochastic homogenization (FPSH) method was employed. To be able to compare products made by three different printing service companies, maraging steel was used in this study, which was commonly available. Several geometrical imperfections were categorized into kink, notch and hole, and representative dimensions were parameterized and measured statistically using micro-CT images. They were also correlated to the building direction and support types. The numerical prediction revealed the reduction of stiffness in a stochastic way qualitatively. The constructed database of the geometrical imperfections and the FPSH method will be useful in the next occasion of manufacturing unexperienced product.

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