著者

佐藤 勇気 山田 崇恭 泉井 一浩 西脇 眞二

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.851, pp.17-00081-17-00081, 2017 (Released:2017-07-25)

参考文献数

29

被引用文献数

2

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This paper proposes a scheme for imposing geometrical constraints in topology optimization for molding and milling so that optimal configurations that guarantee manufacturability can be obtained, based on the fictitious physical model. First, a level set-based topology optimization method is briefly described, and geometrical requirements for molding and milling are clarified. In molding, molded products must embody certain geometrical features so that mold parts can be separated, and milling cannot proceed unless the desired shape allows tool cutting faces to reach the workpiece. A fictitious physical model described by a steady-state advection-diffusion equation is then constructed based on the requirements. In the fictitious physical model, material domains are represented as virtual heat sources and an advection direction is aligned with a prescribed direction, along which mold parts are moved, or attitude in the case of a milling tool. Void regions, where the value of the fictitious physical field is high, represent either undercut geometries which would prevent the mold from being parted, interior voids that cannot be manufactured, or regions that a milling tool cannot reach. Next, a geometrical constraint is formulated based on the fictitious physical model. An optimization algorithm is then constructed. Finally, in the numerical examples, the proposed method yields manufacturable optimal configurations, confirming the validity and the utility of the proposed method.

著者

岸本 直樹 野口 悠暉 佐藤 勇気 泉井 一浩 山田 崇恭 西脇 眞二

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.17-00069-17-00069, 2017 (Released:2017-05-25)

参考文献数

24

被引用文献数

8

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Topology optimization is the most flexible type of structural optimization method. This method has been applied in a variety of physics problems dealing with a multitude of design problems. In a given design problem, however, the optimization problem often has conflicting evaluative functions, such as the need for high rigidity in combination with minimal weight. The difficulty of simultaneously achieving high performance for two or more functions may be further compounded because current topology optimization methods typically only deal with a single material. On the other hand, when multiple kinds of materials having various properties can be selected for use, the range of a designer's choices is increased and an appropriate solution that greatly improves product functions may be achieved. Thus, this paper presents a new topology optimization method for multi-materials that obtains high-performance configurations. We apply the Multi-Material Level Set (MM-LS) topology description model in the topology optimization method, which uses a total of n level set functions to represent n materials, plus the void phase. The advantage of the MM-LS model is that clear optimal configurations are obtained and the design sensitivity for multi-material structures can be easily calculated. The level set functions that are design variables are updated using the topological derivatives, which also function as design sensitivities, and we derive the topological derivatives for multiple materials. Through several numerical examples, we demonstrate the validity of the proposed method.

著者

三島 賢二 角野 浩史 山田 崇人 家城 斉 長倉 直樹 音野 瑛俊

出版者

日本地球惑星科学連合

雑誌

日本地球惑星科学連合2016年大会

巻号頁・発行日

2016-03-10

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3He/4He ratios in terrestrial samples vary more than three orders of magnitude, because primordial helium with 3He/4He of (1.4–4.6) x 10–4 has been diluted by addition of radiogenic 4He produced by decay of U- and Th-series elements in different degrees depending on 3He/(U+Th) ratio of each reservoir. This feature makes 3He/4He ratio a powerful tracer in geochemistry and cosmochemistry. Though atmospheric helium with 3He/4He ratio of 1.4 x 10–6 is used to calibrate 3He/4He measurement with a noble gas mass spectrometer, relatively low concentration and 3He/4He ratio of the atmospheric helium cause many difficulties to use it as a working standard for daily measurements. Thus noble gas laboratories often use their own working standards prepared from a natural gas sample with high 3He/4He ratio or by mixing of isotopically pure 3He and 4He. "He Standard of Japan" (HESJ) is one of the latter originally prepared by four noble gas laboratories in Japan [1] and now distributed worldwide as an interlaboratory standard [1,2]. However, 3He/4He ratio of HESJ was determined by comparison with that of atmospheric helium, i.e., absolute 3He/4He ratio has not been determined yet and the accuracy of the value still rely on the early determinations of absolute 3He/4He ratio of atmospheric helium [3].As long as 3He/4He ratio is used to compare relative contributions of primordial and radiogenic in each geochemical reservoir, absolute 3He/4He value of atmospheric helium or HESJ is less important. However, it is a critical issue in some applications of helium isotopes, such as tritium-3He dating and an experimental project to measure the neutron lifetime with total uncertainty of 1 sec (0.1%) using pulsed neutron source at J-PARC [4].A neutron decays into a proton, an electron, and an anti-neutrino with a lifetime of 880.3 ± 1.1 sec [5]. The lifetime is an important constant in the Big Bang nucleosynthesis (BBN) that controls amounts of primordial elements in our universe. In this experiment, the incident neutron flux is measured by counting 3He(n,p)3H reaction in a time projection chamber detector filled with 3He, 4He and CO2. To determine neutron lifetime with uncertainty less than 0.1%, 3He number density in the detector must be accurately known with even smaller uncertainty. As a part of this experiment, we are developing a gas handling system to control 3He number density with uncertainty of 0.1%. The 3He gas is mixed with research grade He in a vessel with measuring pressures of these gases precisely using a calibrated piezoresistive transducer.We fabricated control samples of known 3He/4He ratio using the gas handling system and measured the ratio using a sector type single focusing noble gas mass spectrometer with double collector system [6] at Dept. of Basic Sci., the Univ. of Tokyo by referring to HESJ. The results will contribute to determine the absolute 3He/4He value of HESJ, and that of atmospheric helium also [6].[1] J. Matsuda et al., Geochem. J. 36, 191 (2002).[2] Y. Sano, T. Tokutake, and N. Takahata, Anal. Sci. 24, 521 (2008).[3] Y. Sano, B. Marty and P. Burnard, “The Noble Gases as Geochemical Tracers”, Chapter 2. “Noble gases in the atmosphere”, Springer (2013).[4] Y. Arimoto, et al, Nucl. Inst. Meth. Phys. Res. A 799, 187–196, (2015).[5] K.A. Olive et al. (Particle Data Group), Chin. Phys. C, 38, 090001 (2014) and 2015 update.[6] H. Sumino et al., J. Mass Spectrom. Soc. Jpn. 49, 61 (2001).

著者

牛根 靖裕 白須 裕之 山田 崇仁

出版者

一般社団法人情報処理学会

雑誌

情報処理学会研究報告人文科学とコンピュータ(CH) (ISSN:09196072)

巻号頁・発行日

vol.2007, no.9, pp.57-64, 2007-01-27

被引用文献数

2

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「唐代行政地理の概念モデル」に基づき、実際の史料から概念モデルに即したデータモデルを提示する事を目的とする。内容は、以下の三つに分かれる。(')「唐代行政地理情報」についての問題を整理。(Ⅱ)関連史料の紹介とデータモデルの基本方針の提示。(、)『新唐脅 $地理志・『元和郡縣圃志』の二つの史料を対象としたデータモデルの提示。このモデルにより、単なるテキスト全文検索では実現不可能な「時間によって変化する行政鷺の状態遷移情報」「史料の内容に則した情報(異説を含めた)」の検索が可能となる。The purpose of this report is a thing to present the data model from actual historical materials according to "Conceptual model of the Tang Administrative Geography". The content, divides into three kinds of the following. (0 The problem of "Tang Administrative Geography" is arranged, (n) A basic policy of the data model is presented as the introduction of related historical materials. (m)The data model is presented intended for two historical materials of "XinTangShu DiLiZhi (『新唐書』地理志) " and "YuanHeJun-XianTuZhi (元和郡縣園志) ". Retrieving information on "Life cycle of an administrative district" that cannot be achieved in the model presented by this text by a mere text full-text search becomes possible.

著者

佐藤 泰 山田 崇裕 松本 幹雄 脇谷 雄一郎 海野 泰裕 柚木 彰

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会 年会・大会予稿集 2010年秋の大会

巻号頁・発行日

pp.109, 2010 (Released:2010-10-18)

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Triple to Double Coincidence Ratio (TDCR)法は液体シンチレーション計測法の一種であり、3本の光電子増倍管を用いて、液体シンチレータと混合した線源の放射能を絶対測定する方法である。今回、炭素14の測定に関して、理論計算により計数率をTDCR値の数値関数として求め、繰り返し計算により、実験値にフィッティングすることで、放射能絶対値を求めた。

著者

松本 敏郎 高橋 徹 山田 崇恭 山田 崇恭

出版者

名古屋大学

雑誌

挑戦的萌芽研究

巻号頁・発行日

2011

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固体中に動吸振構造を有する別の材料定数を持つ固体を埋め込んだ周期構造により有効な振動遮断特性を有する構造を,数値計算の支援により創成するための方法論の開発を目的として,境界要素法による動弾性体の無限周期構造と有限周期構造に対して固有振動数を解析する方法,および動弾性体に対して形状の制御にレベルセット関数を用い,得られた境界を実際に要素分割して境界要素法により最適なトポロジーを得る方法を開発した。

著者

牛根 靖裕 白須 裕之 山田 崇仁

出版者

一般社団法人情報処理学会

雑誌

情報処理学会研究報告人文科学とコンピュータ(CH) (ISSN:09196072)

巻号頁・発行日

vol.2007, no.95, pp.17-24, 2007-09-27

被引用文献数

1

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本報告では、唐代資料に記述される情報を引用する際に必要となる概念モデルと語彙の設計作業の一貫である。ここでは、情報を明示する際に使用される表現の中で最低限必要な情報である、「書籍」と「版本」を対象とする。まず、現代の出版技術を前提とした「書籍」の概念として、個々の実体を有する本としての「Copy」と、書名等によって抽象化された「Book」の二つを提示する。これらの二つの「書籍」の概念を元に設計した概念モデルを踏まえて、古典文献特有の書誌情報である「版本」とその相互関係について着目した概念モデルの設計と語彙の提示を行う。付録として、本論で提示した概念モデルを利用した『元和郡縣圖志』の書誌情報の OWL 語彙とその例を記述したものを本稿末尾に掲載した。When a history scholar presents conflicting views or differences between texts, he must indicate the source where he has his grounds for showing them. Our aim of research is to present a method of representing location information of references and quotations in the research on the Tang dynasty. This paper presents a conceptual model and a vocabulary of only references to documents. In the first, we discuss concepts of books that depend on the modern publication technologies. "Book" is an abstract concept of books which have only bibliographical information, and "Copy" is a concrete one of book entities. In the second, we revise these concepts to the case of manuscripts, woodblock printing, and photo offset copies. Our conceptual model is based on "matters of printing", in order to make up losses on bibliographical information on documents in ancient China.