研究者詳細 - 加藤　準治

論文 - 加藤　準治

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割線剛性を用いた簡便なマルチスケール解析による膨張性地山のトンネル安定性評価査読有り

劉暁東, 鵜之沢均, 加藤準治, 京谷孝史

日本計算工学会論文集 2018年10月

Current and future trends in topology optimization for additive manufacturing 査読有り

Jikai Liu, Andrew T. Gaynor, Shikui Chen, Zhan Kang, Krishnan Suresh, Akihiro Takezawa, Lei Li, Junji Kato, Jinyuan Tang, Charlie C. L. Wang, Lin Cheng, Xuan Liang, Albert. C. To

Structural and Multidisciplinary Optimization 57 巻 ( 6 ) 頁： 2457 - 2483 2018年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Verlag

Manufacturing-oriented topology optimization has been extensively studied the past two decades, in particular for the conventional manufacturing methods, for example, machining and injection molding or casting. Both design and manufacturing engineers have benefited from these efforts because of the close-to-optimal and friendly-to-manufacture design solutions. Recently, additive manufacturing (AM) has received significant attention from both academia and industry. AM is characterized by producing geometrically complex components layer-by-layer, and greatly reduces the geometric complexity restrictions imposed on topology optimization by conventional manufacturing. In other words, AM can make near-full use of the freeform structural evolution of topology optimization. Even so, new rules and restrictions emerge due to the diverse and intricate AM processes, which should be carefully addressed when developing the AM-specific topology optimization algorithms. Therefore, the motivation of this perspective paper is to summarize the state-of-art topology optimization methods for a variety of AM topics. At the same time, this paper also expresses the authors’ perspectives on the challenges and opportunities in these topics. The hope is to inspire both researchers and engineers to meet these challenges with innovative solutions.

DOI： 10.1007/s00158-018-1994-3

Scopus

Multi-phase field topology optimization of polycrystalline microstructure for maximizing heat conductivity 査読有り

Junji Kato, Shun Ogawa, Toshiki Ichibangase, Tomohiro Takaki

Structural and Multidisciplinary Optimization 57 巻 ( 5 ) 頁： 1937 - 1954 2018年5月

掲載種別：研究論文（学術雑誌）

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. The present study proposes multi-scale topology optimization for polycrystalline microstructures applying a multi-phase field method. The objective function is to maximize the heat compliance of macrostructure and the equality constraint is the material volume of constituents in an alloy consisting of two components with different heat conductivity. Two-scale steady-state heat conduction problem based on a homogenization method is conducted. The Allen-Cahn non-conserved time evolution equation with the additional volume constraint scheme is employed as the optimization strategy for updating the crystal configuration. In the time evolution equation, sensitivities of objective function with respect to phase-field variables are considered to relate topology optimization to the multi-phase field method. It is verified from a series of numerical examples that the proposed method has great potential for the development of material design underlying polycrystalline structure.

DOI： 10.1007/s00158-018-1965-8

Scopus

Two-scale topology optimization for composite plates with in-plane periodicity 査読有り

Shinnosuke Nishi, Kenjiro Terada, Junji Kato, Shinji Nishiwaki, Kazuhiro Izui

International Journal for Numerical Methods in Engineering 113 巻 ( 8 ) 頁： 1164 - 1188 2018年2月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：John Wiley and Sons Ltd

This study proposes a two-scale topology optimization method for a microstructure (an in-plane unit cell) that maximizes the macroscopic mechanical performance of composite plates. The proposed method is based on the in-plane homogenization method for a composite plate model in which the macrostructure is modeled using thick plate theory and the microstructures are three-dimensional solids. Macroscopic plate characteristics such as homogenized plate stiffnesses and generalized thermal strains are evaluated through the application of numerical plate tests applied to an in-plane unit cell. To handle large rotations of the composite plates, we employ a co-rotational formulation that facilitates working with the two-scale plate model formulated within a small strain framework. Two types of objective functions are tested in the presented optimization problems: one minimizes the macroscopic end compliance to maximize the macroscopic plate stiffness, whereas the other maximizes components of a macroscopic nodal displacement vector. Analytical sensitivities are derived based on in-plane homogenization formulae so that a gradient-based method can be employed to update the topology of in-plane unit cells. Several numerical examples are presented to demonstrate the proposed method's capability related to the design of optimal in-plane unit cells of composite plates. Copyright © 2017 John Wiley &amp
Sons, Ltd.

DOI： 10.1002/nme.5545

Scopus

Micro-macro concurrent topology optimization for nonlinear solids with a decoupling multiscale analysis 査読有り

Junji Kato, Daishun Yachi, Takashi Kyoya, Kenjiro Terada

International Journal for Numerical Methods in Engineering 113 巻 ( 8 ) 頁： 1189 - 1213 2018年2月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：John Wiley and Sons Ltd

The present study proposes a method of micro-macro concurrent topology optimization for a two-phase nonlinear solid to minimize the end compliance of its macrostructure undergoing large deformation. To reduce the computational costs to solve a 2-scale boundary value problem under geometrically nonlinear setting, we use the so-called method of decoupling multiscale structural analysis, in which the microscopic and macroscopic boundary value problems are decoupled in the homogenization process. An isotropic hyperelasticity model is used for the constitutive model for microstructures, while an orthotropic one is assumed to represent the macroscopic material behavior. Owing to this decoupling framework, the micro-macro concurrent optimization problem can be split into 2 individual problems at the microscale and macroscale for the sake of algorithmic simplicity. Also, a 2-scale adjoint sensitivity analysis can be performed within the framework of computational homogenization. It is verified from a series numerical examples that the proposed method is capable of computing the optimal structures at both microscale and macroscale, according to the level of applied load.

DOI： 10.1002/nme.5571

Scopus

弾塑性挙動を考慮したインフィル構造最適化に関する検証

鎌田浩基, 干場大也, 加藤準治, 京谷孝史

最適化シンポジウム講演論文集 2018.13 巻 ( 0 ) 頁： 113 2018年

多孔質充填構造のトポロジー最適化に関する研究

鎌田浩基, 干場大也, 加藤準治, 京谷孝史

計算力学講演会講演論文集 2018.31 巻 ( 0 ) 頁： 312 2018年

荷重条件の不確かさと幾何学的非線形性を考慮したトポロジー最適化

西野崇行, 干場大也, 加藤準治, 京谷孝史

計算力学講演会講演論文集 2018.31 巻 ( 0 ) 頁： 277 2018年

積層造形下での制約を考慮したラティス構造の最適化設計

小池雄介, 牛島邦晴, 加藤準治

計算力学講演会講演論文集 2018.31 巻 ( 0 ) 頁： 134 2018年

振動抑制を目的としたトポロジー最適化

遠藤拓真, 干場大也, 加藤準治, 京谷孝史

計算力学講演会講演論文集 2018.31 巻 ( 0 ) 頁： 291 2018年

Micro-texture design and optimization in hydrodynamic lubrication via two-scale analysis 査読有り

A. Waseem, I. Temizer, J. Kato, K. Terada

STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION 56 巻 ( 2 ) 頁： 227 - 248 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

A novel computational surface engineering framework is developed to design micro-textures which can optimize the macroscopic response of hydrodynamically lubricated interfaces. All macroscopic objectives are formulated and analyzed within a homogenization-based two-scale setting and the micro-texture design is achieved through topology optimization schemes. Two non-standard aspects of this multiscale optimization problem, namely the temporal and spatial variations in the homogenized response of the micro-texture, are individually addressed. Extensive numerical investigations demonstrate the ability of the framework to deliver optimal micro-texture designs as well as the influence of major problem parameters.

DOI： 10.1007/s00158-017-1713-5

Web of Science

Phase-field topology optimization model that removes the curvature effects 査読有り

Tomohiro Takaki, Junji Kato

Mechanical Engineering Journal 2017年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

<p>The conventional phase-field topology optimization (PFTO) models minimize not only the objective function but also the interface energy. In the present study, a new PFTO model, which minimizes only the objective function, is developed by removing the curvature effect from the conventional PFTO model. Simulations of elastic strain energy minimization under a constant-volume constraint condition of a cantilever are performed using the developed and conventional PFTO models. From the simulation results, we confirm that the developed PFTO model that removes the curvature effects can efficiently optimize only the objective function.</p>

DOI： 10.1299/mej.16-00462

Multiscale stability analysis of a tunnel in swelling rockmass applying secant stiffness

Xiaodong Liu, Junji Kato, Takashi Kyoya

4th ISRM Young Scholars Symposium on Rock Mechanics, YSS 2017 2017-May 巻頁： 284 - 287 2017年

掲載種別：研究論文（国際会議プロシーディングス）

Damage of tunnels often occurs in Japan caused by swelling smectite rockmass. For an effective countermeasure against the damage, mechanical interaction between tunnel lining and swelling rock mass are analyzed by a two-scale analysis based on a homogenization theory in this study. In the microscopic scale, swelling of smectite minerals and damage process of surrounding intact rocks induced by the swelling of smectite minerals are analyzed by a 3D continuous damage model. This microscopic analysis provides the averaged volumetric change and the damaged macroscopic stiffness of the representative volumetric element (RVE) of rock mass. In the macroscopic scale, therefore, stress distribution within/around the tunnel lining can be reasonably analyzed by using the averaged secant stiffness and its volumetric strain of the RVE. The mechanical interaction between the tunnel lining and swelling rock mass is discussed and examined as some case studies are carried out.

Scopus

熱変形制御を目的とする複合板のマルチスケールトポロジー最適化査読有り

西紳之介，寺田賢二郎，加藤準治，西脇眞二，泉井一浩

日本計算工学会論文集 2016年11月

2D-3D hybrid stabilized finite element method for tsunami runup simulations 査読有り

S. Takase, S. Moriguchi, K. Terada, J. Kato, T. Kyoya, K. Kashiyama, T. Kotani

Computational Mechanics 58 巻 ( 3 ) 頁： 411-422 2016年9月

An isotropic damage model based on fracture mechanics for concrete 査読有り

Mao, Kurumatani, Kenjiro Terada, Junji Kato, Takashi Kyoya , Kashiyama

2016年4月

Homogenization-Based Design of Surface Textures in Hydrodynamic Lubrication 査読有り

A. Waseem, I. Temizer, J. Kato, K. Terada

International Journal for Numerical Methods in Engineering, 2016年3月

逆均質化法を用いた微細亀裂分布の同定査読有り

加藤準治，河西亮輔，京谷孝史，寺田賢二郎

土木学会論文集A2 72 巻 ( 1 ) 頁： 27-37 2016年3月

構造物の破壊を考慮した有限被覆法に基づく構造流体連成解析査読有り

13. 高瀬慎介，森口周二，寺田賢二郎，小山直輝，金子賢治，車谷麻緒，加藤準治，京谷孝史

土木学会論文集A2 71 巻 ( 2 ) 頁： 203-212 2016年2月

超弾性複合材料の分離型マルチスケールトポロジー最適化査読有り

加藤準治，谷地大舜，西澤峻祐, 高瀬慎介，寺田賢二郎，京谷孝史

日本計算工学会論文 2,016 巻 2016年1月

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