2021/05/11 更新

写真a

アラキ ヨシカズ
荒木 慶一
ARAKI Yoshikazu
所属
大学院環境学研究科 都市環境学専攻 建築構造システム 教授
大学院担当
大学院環境学研究科
学部担当
工学部 環境土木・建築学科
職名
教授
連絡先
メールアドレス

学位 1

  1. 博士(工学) ( 1998年3月   京都大学 ) 

研究分野 1

  1. 社会基盤(土木・建築・防災) / 建築構造、材料

現在の研究課題とSDGs 1

  1. 南海トラフ地震に対する超高層建物の耐震安全性確保

経歴 1

  1. 京都大学   工学研究科

    2000年4月 - 2018年3月

      詳細を見る

    国名:日本国

学歴 1

  1. 京都大学   工学研究科

    - 1998年3月

      詳細を見る

    国名: 日本国

受賞 2

  1. 先端技術大賞「産経新聞社賞」

    2018年7月   フジサンケイビジネスアイ   大型単結晶超弾性合金の開発と制震構造への応用展開

    大森俊洋, 貝沼亮介, 喜瀬純男, 古河テクノマテリアル

     詳細を見る

    受賞区分:学会誌・学術雑誌による顕彰  受賞国:日本国

  2. 科研費審査員表彰

    2016年8月   日本学術振興会  

     詳細を見る

    受賞国:日本国

 

論文 17

  1. Rubble stone masonry buildings with cement mortar: base shear seismic demand comparison for selected countries worldwide 招待有り 査読有り 国際共著

    Frontiers in Built Environment   7 巻 ( 647815 ) 頁: 1 - 27   2021年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.3389/fbuil.2021.647815

  2. Orientation dependence of plasticity and fracture in single crystal superelastic Cu-Al-Mn SMA bars 招待有り 査読有り

    Kise, S., Araki, Y., Omori, T., Kainuma, R.

    Journal of Materials in Civil Engineering   33 巻 ( 04021027 ) 頁: 1 - 12   2021年1月

     詳細を見る

    担当区分:責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1061/(ASCE)MT.1943-5533.0003568

  3. Rubble Stone Masonry Buildings With Cement Mortar: Design Specifications in Seismic and Masonry Codes Worldwide 査読有り

    Schildkamp Martijn, Silvestri Stefano, Araki Yoshikazu

    FRONTIERS IN BUILT ENVIRONMENT   6 巻   2020年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Frontiers in Built Environment  

    DOI: 10.3389/fbuil.2020.590520

    Web of Science

    Scopus

  4. Chemical resistance of Cu-Al-Mn superelastic alloy bars in acidic and alkaline environment 査読有り

    Pareek, S, Kise, S, Yamashita, F, Gencturk B, Hosseini F, Brown S.A, Araki, Y

    ASCE Journal of Materials in Civil Engineering   33 巻   2020年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1061/(ASCE)MT.1943-5533.0003478

  5. Experimental characterization and performance improvement evaluation of an electromagnetic transducer utilizing a tuned inerter 査読有り

    Sugiura Keita, Watanabe Yuta, Asai Takehiko, Araki Yoshikazu, Ikago Kohju

    JOURNAL OF VIBRATION AND CONTROL   26 巻 ( 1-2 ) 頁: 56 - 72   2020年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JVC/Journal of Vibration and Control  

    DOI: 10.1177/1077546319876396

    Web of Science

    Scopus

  6. Cost analysis of mountain schools in nepal: Comparison of earthquake resistant features in rubble stone masonry vs. Concrete block masonry 査読有り

    Schildkamp M

    Frontiers in Built Environment   5 巻   2019年4月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Frontiers in Built Environment  

    DOI: 10.3389/fbuil.2019.00055

    Scopus

  7. Reaction, Phases, and Microstructure of Fly Ash-Based Alkali-Activated Materials 査読有り

    Matsuda Akira, Maruyama Ippei, Meawad Amr, Pareek Sanjay, Araki Yoshikazu

    JOURNAL OF ADVANCED CONCRETE TECHNOLOGY   17 巻 ( 3 ) 頁: 93 - 101   2019年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Advanced Concrete Technology  

    <p>The alkaline activator has a significant effect on the microstructure and mechanical properties of fly ash-based alkali activated products. This paper aims to identify the reaction products of fly ash (FA) activated with alkaline activators of different concentrations of Na<sub>2</sub>O and different SiO<sub>2</sub>/Na<sub>2</sub>O ratios. NaOH solution (NA), a mixture of NaOH and sodium silicate solution (MIX) and sodium silicate solution (LG) were used to activate fly ash.</p><p>Different techniques were used to characterize the reaction products of activated fly ash including X-ray diffraction (XRD) with Rietveld refinements, attenuated total reflectance Fourier transformer infrared (ATR-FTIR), <sup>29</sup>Si dipolar-decoupling (DD) magnetic angel spinning/nuclear magnetic resonance (<sup>29</sup>Si MAS/NMR) and <sup>27</sup>Al MAS NMR, field emission scanning electron microscopy (FE-SEM) attached with energy-dispersive X-ray (EDX) analyzer. Also, the fly ash-based alkali activated products were indentation tested using a Vickers indenter.</p><p>The results revealed that the main reaction product of alkali activation of fly ash is a sodium aluminosilicate gel (geopolymer) with high Si/Al ratio when sodium silicate was used as alkaline activator, while zeolite appeared as minority phase when fly ash was activated with NaOH solution or a mixture of NaOH and sodium silicate solution. Moreover, Na<sub>2</sub>O content and SiO<sub>2</sub>/Na<sub>2</sub>O ratio in the activator solution influence on the amount of amorphous phase and Q<sup>4</sup>(mAl) units formed in the alkali activated materials and that reflect on the mechanical properties.</p>

    DOI: 10.3151/jact.17.93

    Web of Science

    Scopus

    CiNii Article

  8. School Buildings in Rubble Stone Masonry With Cement Mortar in Seismic Areas: Literature Review of Seismic Codes, Technical Norms and Practical Manuals 査読有り

    Schildkamp Martijn, Araki Yoshikazu

    FRONTIERS IN BUILT ENVIRONMENT   5 巻   2019年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Frontiers in Built Environment  

    DOI: 10.3389/fbuil.2019.00013

    Web of Science

    Scopus

  9. Adhesion characteristics of geopolymer mortar to concrete and rebars 査読有り

    Pareek Sanjay, Kashima Hiroo, Maruyama Ippei, Araki Yoshikazu

    INTERNATIONAL CONFERENCE ON SUSTAINABLE CIVIL ENGINEERING STRUCTURES AND CONSTRUCTION MATERIALS (SCESCM 2018)   258 巻   2019年

     詳細を見る

    掲載種別:研究論文(学術雑誌)  

    DOI: 10.1051/matecconf/201925801012

    Web of Science

  10. Plastic hinge relocation in reinforced concrete beams using Cu-Al-Mn SMA bars 査読有り

    Pareek S., Suzuki Y., Araki Y., Youssef M. A., Meshaly M.

    ENGINEERING STRUCTURES   175 巻   頁: 765 - 775   2018年11月

     詳細を見る

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

    DOI: 10.1016/j.engstruct.2018.08.072

    Web of Science

    Scopus

  11. Enhancing the seismic performance of historic timber buildings in Asia by applying super-elastic alloy to a Chinese complex bracket system 査読有り

    Wenjun Xie, Yoshikazu Araki, Wen-Shao Chang

    International Journal of Architectural Heritage   12 巻 ( 4 ) 頁: 734 - 748   2018年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Taylor and Francis Inc.  

    Historic timber structures widely distributed in East Asia are suffering from the earthquakes. This article aims to develop a technique to enhance the seismic performance of historic timber buildings with the Dou-Gon system. High-strength steel bars and super-elastic alloy bars are used in this study to benchmark conventional Dou-Gon system that uses wood pegs to connect the base Dou and the column. Pushover tests were carried out under different loading conditions. The factors discussed in this study include vertical load imposed on the Dou-Gon system and the pre-strained levels of super-elastic bars. The results from this study has shown that the simple technique enhances the energy dissipation capacity and the ultimate strength of the base Dou-Gon system. Base Dou-Gon system with super-elastic alloy bar connections also show a better aseismic performance due to its constant damping behavior and longer fatigue life. Moreover, pre-strain of the super-elastic alloy bar provides a better damping behavior to the base Dou system.

    DOI: 10.1080/15583058.2018.1442528

    Scopus

  12. Mechanical splicing of superelastic Cu-Al-Mn alloy bars with headed ends

    Kise S.

    Smart Materials and Structures   27 巻 ( 6 )   2018年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Smart Materials and Structures  

    DOI: 10.1088/1361-665X/aabf0d

    Web of Science

    Scopus

  13. Structural control with tuned inertial mass electromagnetic transducers 査読有り

    Takehiko Asai, Yoshikazu Araki, Kohju Ikago

    Structural Control and Health Monitoring   25 巻 ( 2 )   2018年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:John Wiley and Sons Ltd  

    This paper investigates the validity of the tuned inertial mass electromagnetic transducer (TIMET) applied to building structures subjected to seismic motions. The TIMET is a device inspired by two innovative structural control devices proposed recently, that is, tuned viscous mass damper and electromagnetic transducer. The TIMET consists of a spring, an inertial mass produced by a ball screw mechanism, and an electromagnetic transducer part composed of a motor and an electrical circuit. The stiffness of the spring is tuned such that the inertial mass resonates with the vibrating building. This makes the motor installed in parallel with the inertial mass run up in an efficient way, and the vibration energy is converted to electrical energy effectively. As a result, vibration of the building decays fast and electrical energy is stored. This generated energy that is reusable for the self-powered control systems, structural health monitoring, emergency power source, and so on. In this paper, through numerical simulation studies employing the scaled three-story building model proposed for benchmark studies, the vibration reduction and energy harvesting capabilities of the TIMET is explored and the application potentiality to civil structures is discussed.

    DOI: 10.1002/stc.2059

    Scopus

  14. Consistent DOF reduction of tall steel frames 査読有り

    Yoshikazu Araki, Masahito Ohno, Isoshi Mukai, Naoki Hashimoto

    Earthquake Engineering and Structural Dynamics   46 巻 ( 10 ) 頁: 1581 - 1597   2017年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:John Wiley and Sons Ltd  

    This paper presents an energy-consistent approach for reducing the number of degrees-of-freedom (DOFs) in tall steel frames. In the present approach, the moment resistance of beams and columns in each story is represented by the moment resistance of a rotational spring and a beam-column element, respectively. The shear resistance provided by braces in each story is represented by the shear resistance of a shear spring. Furthermore, the resistance to the overturning moment provided by axial resistance of columns in each story is represented by the moment resistance of a rotational spring. These representations are carried out by achieving the equivalence between the strain energy stored and dissipated in the elements in the full (unreduced) DOF models and the strain energy stored and dissipated in the corresponding elements in the reduced DOF models. The accuracy of the present approach is demonstrated through numerical examples, which compare the results of nonlinear time history analyses obtained using the full and reduced DOF models. In the numerical examples, the response is estimated for 20-story and 40-story steel frames with and without buckling-restraint braces subjected to a suite of near-fault and far-fault ground motions. The present approach is useful in estimating the response of tall steel frames having non-regular member arrangements to a suite of intense ground motions including near-fault ones, where it is crucial to capture the influence of higher mode effects on collapse mechanisms. Copyright © 2017 John Wiley &amp
    Sons, Ltd.

    DOI: 10.1002/eqe.2870

    Scopus

  15. Ultra-large single crystals by abnormal grain growth 査読有り

    Tomoe Kusama, Toshihiro Omori, Takashi Saito, Sumio Kise, Toyonobu Tanaka, Yoshikazu Araki, Ryosuke Kainuma

    NATURE COMMUNICATIONS   8 巻 ( 354 )   2017年8月

     詳細を見る

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

    Producing a single crystal is expensive because of low mass productivity. Therefore, many metallic materials are being used in polycrystalline form, even though material properties are superior in a single crystal. Here we show that an extraordinarily large Cu-Al-Mn single crystal can be obtained by abnormal grain growth (AGG) induced by simple heat treatment with high mass productivity. In AGG, the sub-boundary energy introduced by cyclic heat treatment (CHT) is dominant in the driving pressure, and the grain boundary migration rate is accelerated by repeating the low-temperature CHT due to the increase of the sub-boundary energy. With such treatment, fabrication of single crystal bars 70 cm in length is achieved. This result ensures that the range of applications of shape memory alloys will spread beyond small-sized devices to large-scale components and may enable new applications of single crystals in other metallic and ceramics materials having similar microstructural features.

    DOI: 10.1038/s41467-017-00383-0

    Web of Science

  16. Adjustable vertical vibration isolator with a variable ellipse curve mechanism 査読有り

    Takehiko Asai, Yoshikazu Araki, Kosuke Kimura, Takeshi Masui

    Earthquake Engineering and Structural Dynamics   46 巻 ( 8 ) 頁: 1345 - 1366   2017年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:John Wiley and Sons Ltd  

    This paper presents a passive vertical quasi-zero-stiffness vibration isolator intended for relatively small objects. The present isolator has features of compactness, long stroke, and adjustability to various load capabilities. To realize these features, we use constant-force springs, which sustain constant load regardless of their elongation, and propose a variable ellipse curve mechanism that is inspired by the principle of ellipsographs. The variable ellipse curve mechanism can convert the restoring force of the horizontally placed constant-force springs to the vertical restoring force of the vibration isolator. At the same time as converting the direction, the vertical restoring force can be adjusted by changing the ratio of the semi-minor axis to the semi-major one of the ellipse. In this study, a prototype of a class of quasi-zero-stiffness vibration isolator with the proposed variable ellipse curve mechanism is created. Shaking table tests are performed to demonstrate the efficacy of the present mechanism, where the prototype is subjected to various sinusoidal and earthquake ground motions. It is demonstrated through the shaking table tests that the prototype can reduce the response acceleration within the same specified tolerance even when the mass of the vibration isolated object is changed. Copyright © 2017 John Wiley &amp
    Sons, Ltd.

    DOI: 10.1002/eqe.2859

    Scopus

  17. Energy harvesting potential of tuned inertial mass electromagnetic transducers 査読有り

    Takehiko Asai, Yoshikazu Araki, Kohju Ikago

    MECHANICAL SYSTEMS AND SIGNAL PROCESSING   84 巻   頁: 659 - 672   2017年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

    The demand for developing renewable energy technologies has been growing in today's society. As one of promising renewable energy sources, large-scale energy harvesting from structural vibrations employing electromagnetic transducers has recently been proposed and considerable effort has been devoted to increase the power generation capability. In this paper, we introduce the mechanism of a tuned inertial mass electromagnetic transducer (TIMET), which can absorb vibratory energy more efficiently by tuning the parameters to adjust the system. Then we propose a new vibratory energy harvester with the TIMET and determine the parameter values for the device with a simple static admittance (SA) control law to maximize the energy harvested from a stationary stochastic disturbance. To investigate the energy harvesting potential of the TIMET further, the performance -guaranteed (PG) control and the LQG control proposed in the literature are applied as well. Then the numerical simulation studies are carried out and the effectiveness of the proposed energy harvester is examined by comparing the traditional electromagnetic transducers. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ymssp.2016.07.048

    Web of Science

▼全件表示

MISC 8

  1. Plastic hinge relocation in reinforced concrete beams using Cu-Al-Mn SMA bars 査読有り

    S.Pareeka, Y.Suzuki, Y.Araki, M.A.Youssef, M.Meshalyd  

    Engineering Structures175 巻   頁: 765-775   2018年11月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)  

    DOI: 10.1016/j.engstruct.2018.08.072

  2. Enhancing the seismic performance of historic timber buildings in Asia by applying super-elastic alloy to a Chinese complex bracket system 査読有り

    Wenjun Xie, Yoshikazu Araki, Wen-Shao Chang  

    International Journal of Architectural Heritage12 巻 ( 4 ) 頁: 734 - 748   2018年5月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)   出版者・発行元:Taylor and Francis Inc.  

    Historic timber structures widely distributed in East Asia are suffering from the earthquakes. This article aims to develop a technique to enhance the seismic performance of historic timber buildings with the Dou-Gon system. High-strength steel bars and super-elastic alloy bars are used in this study to benchmark conventional Dou-Gon system that uses wood pegs to connect the base Dou and the column. Pushover tests were carried out under different loading conditions. The factors discussed in this study include vertical load imposed on the Dou-Gon system and the pre-strained levels of super-elastic bars. The results from this study has shown that the simple technique enhances the energy dissipation capacity and the ultimate strength of the base Dou-Gon system. Base Dou-Gon system with super-elastic alloy bar connections also show a better aseismic performance due to its constant damping behavior and longer fatigue life. Moreover, pre-strain of the super-elastic alloy bar provides a better damping behavior to the base Dou system.

    DOI: 10.1080/15583058.2018.1442528

    Scopus

  3. Mechanical splicing of superelastic Cu-Al-Mn alloy bars with headed ends

    S. Kise, A. Mohebbi, M. S. Saiidi, T. Omori, R. Kainuma, K. C. Shrestha, Y. Araki  

    Smart Materials and Structures27 巻 ( 6 )   2018年5月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)  

    © 2018 IOP Publishing Ltd. This paper examines the feasibility of mechanical splicing using a steel coupler to connect headed ends of superelastic Cu-Al-Mn alloy (Camalloy) bars and steel reinforcing bars to be used in concrete structures. Although threading of Camalloy is as easy as that of steel, mechanical splicing using threaded ends requires machining of Camalloy bars into dog-bone shape to avoid brittle fracture at the threaded ends. The machining process requires significant time and cost and wastes substantial amount of the material. This paper attempts to resolve this issue by applying mechanical splicing using steel couplers to connect headed ends of Camalloy and steel reinforcing bars. To study its feasibility, we prepare 3 specimens wherein both ends of each Camalloy bar (13 mm diameter and 300 mm length) are connected to steel reinforcing bars. The specimens are tested under monotonic, single-cycle, and full-cycle tension loading conditions. From these tests, we observed (1) excellent superelasticity with recoverable strain of around 6% and (2) large ductility with fracture strain of over 19%. It should be emphasized here that, in all the specimens, ductile fracture occurred at the locations apart from the headed ends. This is in sharp contrast with brittle fracture of headed superelastic Ni-Ti SMA bars, most of which took place around the headed ends. From the results of the microstructural analysis, we identified the following reasons for avoiding brittle fracture at the headed ends: (1) Precipitation hardening increases the strength around the boundary between the straight and headed (tapered) portions, where stress concentration takes place. (2) The strength of the straight portion does not increase significantly up to the ductile fracture if its grain orientation is close to 0 0 1.

    DOI: 10.1088/1361-665X/aabf0d

    Scopus

  4. Structural control with tuned inertial mass electromagnetic transducers 査読有り

    Takehiko Asai, Yoshikazu Araki, Kohju Ikago  

    Structural Control and Health Monitoring25 巻 ( 2 )   2018年2月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)   出版者・発行元:John Wiley and Sons Ltd  

    This paper investigates the validity of the tuned inertial mass electromagnetic transducer (TIMET) applied to building structures subjected to seismic motions. The TIMET is a device inspired by two innovative structural control devices proposed recently, that is, tuned viscous mass damper and electromagnetic transducer. The TIMET consists of a spring, an inertial mass produced by a ball screw mechanism, and an electromagnetic transducer part composed of a motor and an electrical circuit. The stiffness of the spring is tuned such that the inertial mass resonates with the vibrating building. This makes the motor installed in parallel with the inertial mass run up in an efficient way, and the vibration energy is converted to electrical energy effectively. As a result, vibration of the building decays fast and electrical energy is stored. This generated energy that is reusable for the self-powered control systems, structural health monitoring, emergency power source, and so on. In this paper, through numerical simulation studies employing the scaled three-story building model proposed for benchmark studies, the vibration reduction and energy harvesting capabilities of the TIMET is explored and the application potentiality to civil structures is discussed.

    DOI: 10.1002/stc.2059

    Scopus

  5. Consistent DOF reduction of tall steel frames 査読有り

    Yoshikazu Araki, Masahito Ohno, Isoshi Mukai, Naoki Hashimoto  

    Earthquake Engineering and Structural Dynamics46 巻 ( 10 ) 頁: 1581 - 1597   2017年8月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)   出版者・発行元:John Wiley and Sons Ltd  

    This paper presents an energy-consistent approach for reducing the number of degrees-of-freedom (DOFs) in tall steel frames. In the present approach, the moment resistance of beams and columns in each story is represented by the moment resistance of a rotational spring and a beam-column element, respectively. The shear resistance provided by braces in each story is represented by the shear resistance of a shear spring. Furthermore, the resistance to the overturning moment provided by axial resistance of columns in each story is represented by the moment resistance of a rotational spring. These representations are carried out by achieving the equivalence between the strain energy stored and dissipated in the elements in the full (unreduced) DOF models and the strain energy stored and dissipated in the corresponding elements in the reduced DOF models. The accuracy of the present approach is demonstrated through numerical examples, which compare the results of nonlinear time history analyses obtained using the full and reduced DOF models. In the numerical examples, the response is estimated for 20-story and 40-story steel frames with and without buckling-restraint braces subjected to a suite of near-fault and far-fault ground motions. The present approach is useful in estimating the response of tall steel frames having non-regular member arrangements to a suite of intense ground motions including near-fault ones, where it is crucial to capture the influence of higher mode effects on collapse mechanisms. Copyright © 2017 John Wiley &amp
    Sons, Ltd.

    DOI: 10.1002/eqe.2870

    Scopus

  6. Ultra-large single crystals by abnormal grain growth 査読有り

    Tomoe Kusama, Toshihiro Omori, Takashi Saito, Sumio Kise, Toyonobu Tanaka, Yoshikazu Araki, Ryosuke Kainuma  

    NATURE COMMUNICATIONS8 巻 ( 354 )   2017年8月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Producing a single crystal is expensive because of low mass productivity. Therefore, many metallic materials are being used in polycrystalline form, even though material properties are superior in a single crystal. Here we show that an extraordinarily large Cu-Al-Mn single crystal can be obtained by abnormal grain growth (AGG) induced by simple heat treatment with high mass productivity. In AGG, the sub-boundary energy introduced by cyclic heat treatment (CHT) is dominant in the driving pressure, and the grain boundary migration rate is accelerated by repeating the low-temperature CHT due to the increase of the sub-boundary energy. With such treatment, fabrication of single crystal bars 70 cm in length is achieved. This result ensures that the range of applications of shape memory alloys will spread beyond small-sized devices to large-scale components and may enable new applications of single crystals in other metallic and ceramics materials having similar microstructural features.

    DOI: 10.1038/s41467-017-00383-0

    Web of Science

  7. Adjustable vertical vibration isolator with a variable ellipse curve mechanism 査読有り

    Takehiko Asai, Yoshikazu Araki, Kosuke Kimura, Takeshi Masui  

    Earthquake Engineering and Structural Dynamics46 巻 ( 8 ) 頁: 1345 - 1366   2017年7月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)   出版者・発行元:John Wiley and Sons Ltd  

    This paper presents a passive vertical quasi-zero-stiffness vibration isolator intended for relatively small objects. The present isolator has features of compactness, long stroke, and adjustability to various load capabilities. To realize these features, we use constant-force springs, which sustain constant load regardless of their elongation, and propose a variable ellipse curve mechanism that is inspired by the principle of ellipsographs. The variable ellipse curve mechanism can convert the restoring force of the horizontally placed constant-force springs to the vertical restoring force of the vibration isolator. At the same time as converting the direction, the vertical restoring force can be adjusted by changing the ratio of the semi-minor axis to the semi-major one of the ellipse. In this study, a prototype of a class of quasi-zero-stiffness vibration isolator with the proposed variable ellipse curve mechanism is created. Shaking table tests are performed to demonstrate the efficacy of the present mechanism, where the prototype is subjected to various sinusoidal and earthquake ground motions. It is demonstrated through the shaking table tests that the prototype can reduce the response acceleration within the same specified tolerance even when the mass of the vibration isolated object is changed. Copyright © 2017 John Wiley &amp
    Sons, Ltd.

    DOI: 10.1002/eqe.2859

    Scopus

  8. Energy harvesting potential of tuned inertial mass electromagnetic transducers 査読有り

    Asai, T, Araki, Y, Ikago, K  

    Mechanical Systems and Signal Processing84 巻   頁: 659-672   2017年2月

     詳細を見る

    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)  

    DOI: 10.1016/j.ymssp.2016.07.048

▼全件表示

科研費 6

  1. 超高層の耐震設計に死角はないか?―漸増ねじれ倒壊とそのカラクリ―

    2020年4月 - 2023年3月

    科学研究費補助金  基盤研究(A)

      詳細を見る

    担当区分:研究代表者 

  2. 単結晶形状記憶合金大型部材の力学

    2017年6月 - 2019年3月

    科学研究費補助金  研究成果公開促進費 (研究成果公開発表)

      詳細を見る

    担当区分:研究代表者 

  3. 2015年ネパール・ゴルカ地震で被災した学校建物の復旧技術に関する調査研究

    2017年4月 - 2021年3月

    科学研究費補助金  基盤研究(B)

      詳細を見る

    担当区分:研究代表者 

  4. 無機新材料の利用を核とするコンクリート系複合材料・部材・補修補強技術の開拓と展開

    2016年4月 - 2019年3月

    科学研究費補助金  基盤研究(A)

      詳細を見る

    担当区分:研究代表者 

  5. 無機新材料を用いたコンクリート系複合材料・部材のマルチスケール力学モデル構築

    2016年 - 2020年3月

    科学研究費補助金 

      詳細を見る

    担当区分:研究代表者 

  6. 大質量比TMDを用いた大規模構造振動エネルギーハーベスティング技術の開拓

    研究課題/研究課題番号:26630256  2014年4月 - 2018年3月

    荒木 慶一

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:4030000円 ( 直接経費:3100000円 、 間接経費:930000円 )

    本研究では、近年新たな制振装置として大きな注目を集める同調回転慣性質量機構を用いた大質量比TMDをモーターと接続することで、構造物の振動エネルギーを電気エネルギーへと効率的に変換し大規模エネルギーハーベスティングが可能となる同調回転慣性質量トランスデューサーを提案した。数値シミュレーションと実験を通して、提案装置の有効性を発電装置、制振装置の両方の側面から示した。

▼全件表示